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640 Cards in this Set
- Front
- Back
What is the screening test for HIV?
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ELISA which detects antibodies to HIV proteins.
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A positive HIV ELISA test is confirmed by what test?
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Western Blot which detects antibodies to HIV proteins.
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What are the limitations to the HIV ELISA and Western Blot tests?
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False negatives in the first 1-2 months following infection, and false positives in neonates born to HIV positive mothers)
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What test is currently used to monitor HIV therapy effects on viral load? It can also be used to detect infection within the first 2 months of infection.
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PCR/Viral load test
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A CD4+ count less than what is diagnostic for AIDS?
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<200
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What are the 4 stages of HIV infection?
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Flulike (acute), Feeling fine (latent), Falling CD4+ count, Final crisis (= the four F's)
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Where does HIV replicate during the latent phase infection?
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Lymph nodes
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What opportunistic infections affect the brain in AIDS?
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Cryptococcal (meningitis), toxoplasmosis, CMV (encephalopathy), PML (JC virus)
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What opportunistic infections affect the eyes in AIDS?
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CMV (retinitis)
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What opportunistic infections affect the mouth and throat in AIDS?
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Thrush (Candida albicans), HSV, CMV, EBV (hairly leukoplakia)
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What opportunistic infections affect the lungs in AIDS?
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P. jiroveci (carnii)pneumonia, TB, histoplasmosis
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What opportunistic infections affect the GI in AIDS?
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Cryptosporidium, Mycobacterium avium, CMV, EBV (non-Hodgkin's lymphoma)
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What opportunistic infections affect the skin in AIDS?
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Shingles (VZV), Kaposi's sarcoma (HHV-8)
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What opportunistic infections affect the genitals in AIDS?
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Herpes, warts, cervical cancer (HPV)
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What types of infections are AIDS patients at risk for with CD4+ counts less <400
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Thrush, tinea pedis, shingles, TB, and other bacterial infections
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What types of infections are AIDS patients at risk for with CD4+ counts less <200
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HSV, cryptosporidium, coccidiodomycosis, Pneumocystis pneumonia
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What types of infections are AIDS patients at risk for with CD4+ counts less <100
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Candidal esophagitis, toxoplasmosis, histoplasmosis
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What types of infections are AIDS patients at risk for with CD4+ counts less <50
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CMV retinitis, M. avium, cryptococcal meningitis
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How does HIV gain access to the brain causing HIV encephalitits? What are the histological characteristics of HIV encephalitis?
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Virus gains access via infected macrophges. Appears as microglial nodules with multinucleated giant cells
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What is a prion?
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A infectious particle containing only protein (NO genetic material) encoded my cellular genes
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What is the difference in protein structure between normal prions and pathological prions?
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Normal are alpha helices, pathological are beta-pleated sheets
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What are some of the diseases caused by prions?
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Creutzfeldt-Jakob disease, kuru, scrapie (sheep), and mad cow disease
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Spongiform encephalopathy is associated with what type of infection?
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Prion
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Normal flora of the skin?
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Staph. epidermidis
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Normal flora of the nose?
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Staph. epidermidis and colonized by S. aureus
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Normal flora of the oropharynx?
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Strep. viridans
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Normal flora of dental plaque?
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Strep. mutans
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Normal flora of the colon?
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Bacteroides fragilis > E. coli
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Normal flora of the vagina?
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Lactobacillus, and colonized by E. coli, and group B Strep
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Common causes of pneumonia in neonates (<4wks)
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Group B strep and E. coli
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Common causes of pneumonia in children (4wk-18yr)
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RSV, Mycoplasma, Chlamydia pneumonia, Strep. Pneumoniae (Runts My Cough Sputum)
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Common causes of pneumonia in adults (18yr-40yr)
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Mycoplasma, Chlamydia pneumonia, Strep. Pneumoniae
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Common causes of pneumonia in adults (40yr-65yr)
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Strep. Pneumoniae, H. influenzae, anaerobes, viruses, Mycoplasma
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Common causes of pneumonia in the elderly (65+)
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Strep. Pneumoniae, viruses, anaerobes, H. influenzae, gram- rods
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Nosocomial pneumonia is caused by what organisms?
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Staph, and enteric gram- rods
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Pneumonia in immunocompromised patients is caused by what organisms?
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Staph, enteric gram- rods, fungi, viruses, P. jiroveci (in HIV)
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What organism is typically associated with pneumonia in a patient with cystic fibrosis?
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Pseudomonas
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What are the organisms that cause atypical pneumonia?
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Mycoplasma, Legionella, Chlamydia
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What are the three most common bacterial causes of newborn meningtitis?
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Group B strep, E. coli, and Listeria
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What are some of the common bacterial causes of meningitis in children?
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Strep.pneumoniae, N. meningitidis, H. influenzae
|
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What are some of the common bacterial causes of meningitis in adults?
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N. meningitidis, enteroviruses, S. pneumoniae
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What are some of the common bacterial causes of meningitis in the elderly?
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S. pneumoniae and gram- rods
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What group of enteroviruses is a common cause of meningitis?
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coxsackievirus
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Compared to normal what would be the CSF findings in a patient with bacterial meningitis in regards to Pressure, Cell type present, Protein, and Sugar?
|
Pressure - increased
Cell type - PMNs Protein - increased Sugar - decreased |
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Compared to normal what would be the CSF findings in a patient with fungal/TB meningitis in regards to Pressure, Cell type present, Protein, and Sugar?
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Pressure - increased
Cell type - lymphociytes Protein - increased Sugar - decreased |
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Compared to normal what would be the CSF findings in a patient with viral meningitis in regards to Pressure, Cell type present, Protein, and Sugar?
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Pressure - normal/increased
Cell type - lymphocytes Protein - normal/increased Sugar - normal |
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Osteomyelitis is most commonly caused by which organism?
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S. aureus
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Osteomyelitis in a patient with sickel cell disease is usually caused by which organism?
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Salmonella
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Osteomyelitis in the vertabrae (i.e. Pott's disease) is most commonly caused by which organism?
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M. tuberculosis
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In osteomyelitis, which two inflammatory tests are classicly seen to be elevated, although they are not specific?
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CRP and ESR
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What are the symptoms of a UTI?
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Dysuria, polyuria, increased urgency, suprapubic pain
|
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What are the symptoms of pyelonephritis?
|
fever, chills, flank pain, and CVA tenderness
|
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The most common cause of UTIs are by ascending infections. What organism most frequently the cause?
|
E. coli
|
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What are some predisposing factors to developing a UTI?
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obstruction, kidney surgery, catheters, gynecologic abnormalities, diabetes, and pregnancy
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Fact Card on UTI diagnosis
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A positive leukocyte esterase test = bacterial UTI
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Fact Card on UTI diagnosis
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A positive nitrite test = gram negative bacterial UTI
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What organisms are part of ToRCHeS infections?
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Toxoplasma gondii, Rubella, CMV, HIV, HSV-2, Syphilis
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What is the classic triad in neonatal Toxoplasma gonii infection?
|
Chorioretinitis, intracranial calcifications, and hydrocephalus. May be asymptomatic at birth.
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A neonate presents with deafness, cataracts, and patent ductus arteriosis, microcephaly, mental retardation, and blueberry muffin rash. What are they infected with?
|
Rubella
|
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What are the symptoms of CMV infection in neonates?
|
petechial rash, intracranial calcifications, mental retardation, hepatosplenomegaly, microcephaly, and jaundice. 90% are asymptomatic at birth.
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How is HSV-2 transmitted to the fetus?
|
During birth
|
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What are some of the symptoms associated with HSV-2 infections in a newborn?
|
Encephalitis, conjuctivitis, and vesicular skin lesions
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|
Syphilis in a newborn presents as what?
|
skin lesions, jaundice, saddle nose, saber shins, CN VIII deafness, rhinits
|
|
Clinical features of gonorrhea are?
|
urethritis, cervicitis, PID, prostatitis, epididymitis, arthritis, and a purulent discharge
|
|
What stage of syphilis do you see painless chancre?
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Primary
|
|
Seconday syphilis has what clinical features?
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Fever, skin rashes, lymphadenopathy, condylomata lata
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Gummas, tabes dorsalis, and aortits of characteristic of which stage of syphilis?
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Tertiary
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|
What agent is responsible for genital herpes?
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HSV-2
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What are the symptoms of active genital herpes ?
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painful ulcers…Systemic symptoms MAY include fever, headache, myalgia
|
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Reiter's syndrome, urethritis, cervicitis, conjuctivitis are all symptoms of what STD?
|
Chlamydia
|
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Lymphogranuloma venereum is caused by what organism?
|
Chlamydia
|
|
A strawbery-colored cervix with corskscrew motility on wet prep indicates infection with what?
|
Trichomonas vaginalis
|
|
What diagnostic type of cells would you see in the epithelium of someone infected with HPV6 or HPV11?
|
koilocytes
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Chancroid is characterized by painful genital ulcers and inguinal adenopathy. What is the offending organism?
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Haemophilus ducreyi
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|
Bacterial vaginosis is caused by what organism? What are clinical features?
|
Gardnerella vaginalis -- malodorous discharge (fishy), positive whiff test
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Fact Card on Salpingitis and what it is a Risk Factor For
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Ectopic pregnancy, infertility, chronic pelvic pain, and adhesions
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What is the most common STD in the U.S.?
|
C. trachomatis
|
|
Nosocomial UTIs are caused by what organism most often?
|
E. coli
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|
Nosocomial wound infections are caused by what organism most often?
|
S. aureus
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Which bug causes a nosocomial infection by living in respiratory therapy equipment?
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Pseudomonas
|
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Bug Hints for the Boards (if all else fails) -- Pus, empyema, abscess
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S. aureus
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Bug Hints for the Boards (if all else fails) -- Pediatric infection
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H. influenzae
|
|
Bug Hints for the Boards (if all else fails) -- Branching rods in oral infection
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Actinomyces israelii
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Bug Hints for the Boards (if all else fails) -- Traumatic open wound
|
Clostridium perfringes
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Bug Hints for the Boards (if all else fails) -- Surgical wound
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S. aureus
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Bug Hints for the Boards (if all else fails) -- Dog or cat bite
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Pasturella multocida
|
|
Bug Hints for the Boards (if all else fails) -- Currant jelly sputum
|
Klebsiella
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Bug Hints for the Boards (if all else fails) --Sepsis/meningitis in newborn
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group B strep
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What nematodes infect orally (ingested)?
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Enterobius, Ascaris, Trichinella (mnemonic: EAT)
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What nematodes infect through the skin (cutaneous)?
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Stongyloides, Ancylostoma, Necator
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What parasite causes brain cysts and seizures?
|
Taenia solium (cysticercosis)
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|
What parasite causes liver cysts?
|
Echinococcus granulosus
|
|
What helminth causes vitamin B12 deficiency?
|
Diphyllobothrium latum
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What trematode causes biliary tract disease?
|
Clonorchis sinensis
|
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What clinical findings are associated with Schistosoma haematobium?
|
Hematuria and Bladder cancer
|
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What nematodes causes microcytic anemia?
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Ancylostoma and Necator
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What nematode causes perianal pruritus?
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Enterobius (pinworm)
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What organism causes Typhoid fever?
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Salmonella typhi
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What organism causes Typhus?
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Rickettsia rickettsii (endemic) and Rickettsia prowazekii
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What is the most common STD?
|
Chlamydia trachomatis
|
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What flagellated protozoan causes greenish vaginal discharge?
|
Trichomonas vaginalis
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What organism causes Chagas' disease?
|
Trypanosoma cruzi
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What nematode can be found in undercooked meat?
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Trichinella spiralis
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What is the only DNA virus that is single stranded?
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Parvovirus
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What are the 3 DNA viruses with circular DNA?
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Papilloma, Polyoma, Hepadnavirus
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What is the only virus with double stranded DNA?
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Reovirus
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What are the naked (non-enveloped) viruses?
|
RNA: Calcivirus, Picornavirus, Reovirus DNA: Parvovirus, Adenovirus, Papilloma, Polyoma
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What is the only virus that does not acquire its envelope from the host plasma membrane? Where does it acquire its membrane?
|
Herpesviruses acquired envelopes from nuclear membrane of host cell.
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What is the only class of virus that is diploid?
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Retroviruses (contain 2 identical ssRNA molecules)
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Where do DNA viruses replicate?
|
Nucleus
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Where do all but 2 RNA viruses replicate?
|
Cytoplasm
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What 2 RNA viruses replicate in the nucleus?
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Influenza and Retroviruses
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What is the name of the structure that contains the nucleic acid in an enveloped virus?
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Capsid
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What is the only DNA virus that is NOT icosahedral?
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Poxvirus
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What is the only DNA virus that does not replicate in the nucleus?
|
Poxvirus
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What causes zoster (shingles)?
|
Varicella Zoster Virus (VZV)
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What causes heterophile antibody positive mononucleosis?
|
Epstein Barr Virus (EBV)
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What infection is most common in transplant recipients?
|
CMV
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What virus is associated with Kaposi's sarcoma?
|
HHV-8
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What STD remains latent in sensory ganglia and causes genital vesicles?
|
HSV-2
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What virus can be visualized using a Tzanck preparation?
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HSV-2
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What causes pink eye (conjunctivitis)?
|
Adenovirus
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What virus is a common causes of febrile pharyngitis?
|
Adenovirus
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What virus causes aplastic crises in sickle cell disease?
|
Parvovirus B19
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What virus causes erythema infectiosum (fifth disease)? What is the physical finding associated with this disease?
|
Parvovirus B19; Slapped cheek appearance
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What virus is associated with condylomata acuminata (venereal warts)?
|
HPV types 6 and 11
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What virus is associated with cervical cancer?
|
HPV types 16 and 18
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What disease does JC virus cause?
|
Progressive Multifocal Leukoencephalopathy (PML) in HIV patients
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|
What virus causes molluscum contagiosum?
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Poxvirus
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What killed vaccine is used to prevent polio?
|
Salk
|
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Is the measles/mumps/rubella vaccine live attenuated or killed?
|
MMR vaccine is live attenuated
|
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What vaccines are killed?
|
Rabies, Influenza, Salk Polio, HAV (mnemonic: RIP Always)
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What vaccine is recombinant?
|
HBV (HBsAg)
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What causes worldwide influenza pandemics?
|
Reassortment (exchange of segments between genomes)
|
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What is recombination?
|
Exchange of genes between 2 chromosomes by crossing over
|
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How is Varicella Zoster Virus (VZV) transmitted?
|
Respiratory secretions
|
|
What causes negative heterophile antibody mononucleosis?
|
CMV
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What virus is often cultured from urine and whose cells have owl's eye appearance?
|
CMV
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What test is used to assay HSV-1, HSV-2 and VZV?
|
Tzanck test (intranuclear eosinophilic inclusions can be seen)
|
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What cells does EBV infect?
|
B cells
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What are the signs and symptoms of mononucleosis caused by EBV?
|
Fever, hepatosplenomegaly, pharyngitis, lymphadenopathy
|
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What virus is associated with Burkitt's Lymphoma (t8;14)?
|
EBV
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What three virus families do not have envelopes?
|
Picornavirus, Calcivirus, and Reovirus
|
|
What virus family has double stranded RNA?
|
Reovirus
|
|
What virus family does SARS belong to?
|
Coronavirus
|
|
What viruses are in the picornavirus class?
|
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, HAV (PERCH)
|
|
Mechanism of picornavirus replication?
|
RNA translated into large polypeptide that is cleaved by proteases
|
|
Cause of the common cold?
|
Rhinovirus, sometimes Coronavirus
|
|
Symptoms of yellow fever virus?
|
High fever, black vomitus, jaundice
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What virus family is Rubella virus in?
|
Togavirus
|
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Cause of German (3-day) measles?
|
Rubella virus
|
|
Major cause of acute diarrhea and gastroenteritis in infants?
|
Rotavirus
|
|
Genome of rotavirus?
|
dsRNA
|
|
What virus family are the influenza viruses in?
|
Orthomyxoviruses
|
|
Genome of influenza viruses?
|
ssRNA
|
|
Influenza vaccine type?
|
Killed viral vaccine
|
|
Major antigens on influenza viruses (2)?
|
Hemagglutinin and neuraminidase
|
|
What is reassortment of viral genomes called (e.g. human flu A + swine flu A)?
|
Genetic shift
|
|
What are minor changes in flu genomes called (based on random mutations)?
|
Genetic drift
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Treatment/prophylaxis of influenza A?
|
Amantadine & rimantadine
|
|
Treatment of both influenza A & B?
|
Oseltamivir & zanamivir
|
|
Viruses in the paramyxovirus class?
|
Parainfluenza (croup), mumps, measles, RSV
|
|
What are Koplik spots?
|
Diagnostic finding in measles (red spots with blue-white center on buccal mucosa)
|
|
What are the 3 C's of measles (clinical findings)?
|
Cough, Coryza, and Conjunctivitis
|
|
Symptoms of mumps virus?
|
Parotitis, Orchitis, and Meningitis (Parotid/testes as big as POMs)
|
|
What virus family does rabies virus belong to?
|
Rhabdovirus
|
|
Characteristic cytoplasmic inclusions found in rabies?
|
Negri bodies
|
|
What is the time course for rabies infection?
|
Long incubation period of weeks-months
|
|
What class of virus is typically transmitted by arthropods?
|
Arboviruses
|
|
What is the primary transmission route of HAV?
|
Fecal-oral
|
|
What virus class is HAV?
|
RNA picornavirus
|
|
What virus class is HBV?
|
DNA hepadnavirus
|
|
How is HBV typically spread?
|
Parenteral, sexual, or maternal-fetal
|
|
Mechanism of HBV replication?
|
DNA-->RNA via RNA polymerase; RNA-->DNA via reverse transcriptase
|
|
What virus class is HCV?
|
RNA flavivirus
|
|
Which hepatitis virus most likely causes chronic hepatitis and hepatic cancer?
|
HCV
|
|
What virus must be present for hepatitis D virus to infect?
|
HBV
|
|
Which hepatitis virus causes high mortality in pregnant women?
|
HEV
|
|
What serologic test indicates prior infection with hepatitis A?
|
IgG HAVAb
|
|
What serologic test indicates current infection/carrier state with hepatitis B?
|
HBsAg
|
|
What antibody provides immunity from hepatitis B?
|
HBsAb (antibody to surface antigen)
|
|
What does the antibody against hepatitis B core antigen show?
|
Window period: IgM HBcAb shows recent disease and IgG HBcAb shows chronic disease
|
|
What enzyme creates dsDNA from RNA in HIV?
|
Reverse transcriptase
|
|
What two envelope proteins does HIV use to gain entry into human cells?
|
gp41 and gp120
|
|
What proteins does HIV bind to on human cells?
|
CXCR4 and CCR5
|
|
Name the fluoroquinolones
|
Ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin, moxifloxacin, gatifloxacin, enoxacin. Nalidixic Acid is a quinolone
|
|
Mechanism of fluoroquinolones
|
Inhibit DNA Gyrase (topoisomerase II). Bactericidal. DON'T TAKE WITH ANTACIDS
|
|
Clinical Use of fluoroquinolones
|
gram neg. rods of urinary and GI tracts - Pseudomonas, Neisseria; some gm. Positives
|
|
Toxicity of fluoroquinolones
|
GI upset, superinfection, skin rash, headache, dizziness. Contraind. In pregnancy and children (damage to cartilage). Causes tendonitis in adults, leg cramps in children
|
|
Mechanism of Metronidazole
|
Forms toxic metabolites in the bacterial cell that damage DNA. Bactericidal.
|
|
Clinical Use of metronidazole
|
Antiprotozoal. GET GAP - Giardia, Entamoeba, Trichomonas, Gardnerella, Anaerobes (Bacteriodes, Clostridium). Use with bismuth and amoxicillin for triple therapy vs. H Pylori
|
|
Toxicity of metronidazole
|
Disulfiram-like reaction with alcohol, headache, metallic taste
|
|
Mechanism of polymixins (E+B)
|
Binds to cell membranes of bacteria and disrupts their osmotic properties. Cationic, basic proteins = act like detergent
|
|
Clinical use of polymixins
|
reistant gm. Neg. infections
|
|
Toxicity of polymixins
|
Neurotoxicity, acute renal tubular necrosis
|
|
Mycobacterium Prophylaxis and Treatment
|
Proph - Isoniazid; Treat - Isoniazid, rifampin, ethambutol, pyrazinamide
|
|
M. avium-intracellulare Prophylaxis and Treatment
|
Proph - Azithromycin; Treat - Azithromycin, rifampin, ethambutol, streptomycin
|
|
M. leprae Prophylaxis and Treatment
|
Proph - N/A; Treat - Dapsone, rifampin, clofazimine
|
|
Anti TB Drugs
|
INH-SPIRE - Streptomycin, Pyrazinamide, Isoniazid, rifampin, ethambutol. Cycloserine 2nd line. Impt SE of ethambutol = optic neuropathy, SE of others = hepatotoxicity
|
|
Mechanism of Isoniazid
|
Decrease synth of mycolic acids
|
|
Clinical use of isoniazid
|
Mycobact. Tuberculosis. Only agent used solo as prophylaxis
|
|
Toxicity of isoniazid
|
Hemolysis if G6PD defic, neurotoxicity, hepatotoxicity, SLE-like symps. PYRIDOXINE (vit B6) can prevent neurotoxicity
|
|
Mechanism of rifampin
|
Inhibit DNA-dep. RNA polymerase
|
|
Clinical Use of rifampin
|
Myco. TB, delay resistance to dapsone when used for leprosy. Used for meningococcal prophylaxis and chemoprophylaxis in contact of children with H. Influenze B
|
|
Toxicity of rifampin
|
Minor hepatotoxicity and drug interactions (inc. P450s); orange body fluids
|
|
Resistance to penicillins/cephalosporins
|
beta-lactamase cleavage of beta-ring, or altered PBP (MRSA)
|
|
Resistance to Aminoglycosides
|
modification via acetylation, adenylation, or phosphorylation
|
|
resistance to vancomycin
|
terminal D-Ala of cell wall replaced with D-lac = decr. Affin
|
|
resistance to chloramphenicol
|
modification via acetylation
|
|
resistance to macrolides
|
methylation of rRNA near erythromycin's ribosome-binding site
|
|
resistance to tetracycline
|
decr. Uptake or incr. transport out of cell
|
|
resistance to sulfonamides
|
altered enzyme, decr. Uptake or incr. PABA synth
|
|
resistance to quinolones
|
altered gyrase of reduced uptake
|
|
Meningococcal prophylaxis
|
rifampin, minocycline
|
|
gonorrhea prophylaxis
|
ceftriaxone
|
|
syphilis prophylaxis
|
benzathine penicillin G
|
|
History of recurrent UTI prophylaxis
|
TMP-SMX
|
|
Pneumo. Jiroveci prophylaxis
|
TMP-SMX (drug of choice), aerosolized pentamidine
|
|
Endocarditis with surg/dental procedure prophylaxis
|
penicillins
|
|
treatment of resistant MRSA/VRE
|
MRSA - vancomycin; VRE - linezolid and streptogramins
|
|
mechanism of amphotericin B
|
binds ergosterol, forms membrane pores that allow leakage of electrolytes
|
|
clinical use of amphotericin B
|
wide spectrum of systemic mycoses (Cryptococcus, Blastomyces, Cocciodes, Aspergillus, Histoplasma, Candida, Mucor. Intrathecal for fungal meningitis. Does not cross BBB
|
|
toxicity of amphotericin B
|
fever/chills, hypotension, nephrotoxic (decr. With hydration), arrhythmias, anemia, IV phlebitis. Use LIPOSOMAL amphoB to decr. toxicity
|
|
mechanism of nystatin
|
binds ergosterol, disrupt fungal membranes. Too toxic for systemic use
|
|
clinical use of nystatin
|
swish and swallow for oral candidiasis, topical for diaper rash/vaginal candidiasis
|
|
Azoles
|
fluconazole, ketoconazole, clotrimazole, miconazole, itraconazole, voriconazole
|
|
mechanism of azoles
|
inhibit fungal steroid synthesis (ergosterol)
|
|
clinical use of azoles
|
systemic mycoses. Fluconazole - cryptococcal meningitis in AIDS and all candidal infections. Ketoconazole - blastomyces, cocciodes, histoplasma, candida albicans, hypercortisolism. Clotrimazole and miconazole - topical fungal infections
|
|
toxicity of azoles
|
hormone synthesis inhibition (gynecomastia), liver dysfunction (inhib CYP450), fever and chills
|
|
mechanism of flucytosine
|
inhibit DNA synth by conversion to fluorouracil - compete with uracil
|
|
clinical use of flucytosine
|
systemic fungal infections (candida, cryptococcus) and in combo with ampB
|
|
toxicity of flucytosine
|
naus/vomit, diarrhea, BM suppression
|
|
mechanism of caspofungin
|
inhibit cell wall synthesis
|
|
clinical use of caspofungin
|
invasive aspergillus
|
|
toxicity of caspofungin
|
GI upset, flushing
|
|
mechanism of terbinafine
|
inhibit fungal enzyme squalene epoxidase
|
|
clinical use of terbinafine
|
dermatophytoses (onchomycoses specifically)
|
|
mechanism of griseofulvin
|
interfere with microtubule function, disrupt mitosis. Deposits in keratin-containing tissues (nails)
|
|
clinical use of griseofulvin
|
oral treatment of superficial infections, inhib growth of dermatophytes (tinea, ringworm)
|
|
toxicity of griseofulvin
|
teratogenic, carcinogenic, confusion, headaches, inc. P450 and warfarin metabolism
|
|
mechanism of amantadine
|
block viral penetration/uncoating (M2 prot), may buffer pH of endosome. Also causes release of dopamine from intact nerve signals
|
|
clinical use of amantadine
|
prophylaxis and treatment for Influenza A, Parkinsons Dz
|
|
toxicity of amantadine
|
ataxia, dizziness, slurred speech - fewer SEs with Rimantidine
|
|
resistance to amantadine
|
mutated M2 protein. 90% of influenza strains resistant = NOT USED ANYMORE
|
|
mechanism of zanamivir/oseltamivir
|
inhibit influenza neuraminidase = decr. Release of progeny virus
|
|
clinical use of zanamivir/oseltamivir
|
Influenza A & B
|
|
mechanism of ribavirin
|
inhib synth of guanine nucleotides by competitively inhibiting IMP dehydrog.
|
|
clinical use of ribavirin
|
RSB, chronic HCV
|
|
toxicity of ribavirin
|
hemolytic anemia. SEVERE TERATOGEN
|
|
mechanism of acyclovir
|
monophosphorylation by HSV/VZV thymidine kinase. Triphosphate formed by cellular enzymes. Preferentially inhib viral DNA polymerase by chain termination
|
|
clinical use of acyclovir
|
HSV, VZV, EBV. HSV-induced mucocutaneous and genital lesions as well as encephalitis. Prophylaxis in immunocomp pts. VZV = use FAMCICLOVIR. No effect on latent HSV/VZV
|
|
toxicity of acyclovir
|
well tolerated
|
|
resistance to acyclovir
|
lack thymidine kinase
|
|
mechanism of ganciclovir
|
5'-monophosphate formed by a CMV viral kinase or HSV/VZV thymidine kinase. Triphosphate formed by cellular kinases. Preferentially inhib viral DNA polymerase
|
|
clinical use of ganciclovir
|
CMV, especially in immunocomp pts
|
|
toxicity of ganciclovir
|
leukopenia, thrombocytopenia, renal toxicity. More toxic to host enzymes than acyclovir.
|
|
resistance to ganciclovir
|
mutated CMV DNA polymerase or lack of viral kinase
|
|
mechanism of foscarnet
|
viral DNA polymerase inhibitor that binds to the pyrophosphate binding site of the enzyme. Does not require activation by viral kinase
|
|
clinical use of foscarnet
|
CMV retinitis in immunocomp pts when ganciclovir fails, acyclovir-resistant HSV.
|
|
toxicity of foscarnet
|
nephrotoxicity
|
|
resistance to foscarnet
|
mutated DNA polymerase
|
|
Which bacteria are gram positive cocci?
|
Staphyylococcus, Streptococcus, Enterococcus
|
|
How do you distinguish S. aureus from S. epidermis and S. saprophyticus?
|
Staph aureus is catalase positive, coagulase positive. The other 2 are catalase positive and coagulase negative.
|
|
Describe Streptococcus vs. Staphyloccocus characteristics microscopically.
|
Strep is gram positive (purple/blue) chains. Staph is gram positive clusters (like grapes)
|
|
Which Bacteria are gram positive rods (bacilli)?
|
Clostridium (anaerobe), Corynebacterium, Listeria, and Bacillus
|
|
Which bacteria are alpha hemolytic?
|
S. pneumoniae and Viridans streptococci--plate is green (partial hemolysis)
|
|
Which bacteria are beta hemolytic?
|
Group A strep: S. pyogenes--plate is clear (complete hemolysis)
|
|
Which gram positive cocci can cause no hemolysis, alpha or beta hemolysis?
|
Enterococci (E. faecalis)
|
|
What bacteria are quellung positive, optochin sensitive and bile soluble?
|
S. pneumoniae Note: OVRPS (overpass) = Optochin Viridans is resitant, pneumoniae is sensitive.
|
|
What is a defining microscopic characteristic of Strep pneumoniae?
|
Lancet diplococci
|
|
What bacteria are optochin resistant and not bile soluble?
|
Viridans streptococci
|
|
How do you distinguish Group A Strep from Group B strep?
|
Grp A is bacitracin sensitive, GpB is bacitracin resistant Note: B-BRAS = Bacitracin- grp B strep resistant; gp A strep sensitive
|
|
Which Streptococcus has a capsule?
|
Strep pneumoniae (quellung positive)
|
|
What bacteria are Novobiocin Resistant? Novobiocin senstive?
|
Staph saprophyticus is Resistant; Staph epidermis is Sensitive; NOTE: NO StRES
|
|
What does an alpha hemolytic plate look like? Beta-hemolytic?
|
Alpha forms a green ring around colonies on blood agar; Beta form a clear area of hemolysis on blood agar.
|
|
What are the qualities of Listeria monocytogenes microscopically?
|
Listeria monocytogenes are gram positive rods with tumbling motility.
|
|
What characteristic of Staph aureus allows it to evade the immune system?
|
Protein A (virulence factor) binds Fc-IgG, inhibiting fixation and phagocytosis
|
|
Which organisms cause Toxic shock syndrome?
|
Caused by either Staph aureus TSST-1 toxin or Strep pyogenes.
|
|
What toxins does Staph aureus produce and what diseases do they cause?
|
TSST-1 superantigen: Toxic shock syndrome; Exfoliative toxin: scalded skin syndrome; Enterotoxins (preformed): rapid-onset food poisoning.
|
|
Which inflammatory disease can Staph aureus produce?
|
Skin infections, organ abscesses and pneumonia. Also causes acute bacterial endocarditis and osteomyelitis.
|
|
How does TSST-1 produce it effects?
|
It is a superantigen that binds to MHC II and T-cell receptor, resulting in polyclonal T-cell activation
|
|
What is the mechanism of resistance of a MRSA infection?
|
Methicillin Resistant S. aureus is resistant to B-lactams due to altered penicillin-binding proteins. *Important cause of serious nosocomial and community-acquired infections
|
|
How does rheumatic fever present and who is the culprit?
|
No rheum for SPECCulations: Subcutaneous nodules, Polyarthritis, Erythema margination, Chorea, Carditis. **Strep pyogenes.
|
|
What test can be used to detect recent S. pyogenes infection?
|
ASO titer
|
|
Antibodies to what part of S. pyogenes can enhance host defenses but also give rise to a serious infection?
|
M protein. Antibodies can give rise to rheumatic fever.
|
|
What complications can occur due to a Strep pyogenes pharyngitis?
|
Rheumatic fever and glomerulnephritis. Note: Pharyngitis gives you rheumatic PHever and glomerulonePHritis.
|
|
What pyogenic, toxigenic and immunologic diseases can Strep pyogenes cause?
|
Pyogenic: Pharyngitis, cellulitis, impetio; Toxigenic: scarlet fever, toxic shock syndrome; Immunologic: rheumatic fever and acute glomerulonephritis.
|
|
What are the 4 main diseases does Strep pneumoiae causes?
|
MOPS: Meningitis, Otitis media, Pneumonia, Sinusitis. It is also associated with rusty sputum, sepsis in sickle cell anemia and splenectomy
|
|
What characteristics of Strep pneumoniae help it evade the immune system?
|
Encapsulated and IgA protease
|
|
What are 3 main diseases Gp B streptococci is associated with?
|
Pneumonia, meningitis, and sepsis; mainly in babies
|
|
What diseases does Enterococci cause?
|
UTIs and subacute meningitis. Vancomycin resistant enterococci (VRE) are an important cause of nosocomial infections.
|
|
What are enterococci resistant to?
|
Penicillin G and some are Vancomycin resistant
|
|
What is Lancefield grouping based on and what is included in Lancefield group D?
|
It is based on differences in the C carbohydrate on the bacterial wall. Group D includes enterococci and nonenteroccal gp D streptococci.
|
|
Where can Staphylococcus epidermidis be found?
|
Component of normal skin flora, infects prosthetic devices, catheters, and blood cultures.
|
|
How is Listeria monocytogenes spread?
|
Ingestion of unpasteurized milk/cheese or by vaginal transmission during birth.
|
|
How does Listeria monocytogenes move from cell to cell?
|
They form actin rockets
|
|
What diseases/complications can Listeria monocytogenes cause in pregnant women?
|
amnionitis, speticemia, and spontaneous abortion
|
|
What disease can Listeria monocytogenes cause in infants?
|
Granulomatosis infantseptica, neonatal meningitis
|
|
What disease can Listeria monocytogenes cause in the immunocompromised? How about healthy individuals?
|
Immunocompromised: meningitis; Healthy: mild gastroenteritis
|
|
What is unique about Actinomyces and Nocardia microscopically?
|
They are both gram positive rods that form long branching filaments resembling fungi
|
|
What does Actinomyces israelii cause?
|
It is a gram positive anaerobe that causes oral/facial abscesses that may drain through sinus tracts in skin. **Normal oral flora
|
|
Where is Nocardia asteroides found and what disease can it cause?
|
It is found in the soil. It is a weakly acid-fast gram-positive aerobe that causes pulmonary infections in immunocompromised.
|
|
What can Actinomyces and Nocardia be treated with?
|
SNAP: Sulfa for Nocardia Actinomyces use Penicillin.
|
|
What pathological findings distinguish Primary Tuberculosis from Secondary TB?
|
Primary TB: Ghon Complex=TB granulomas (Ghon Focus- usually lower lobes) with lobar and perihilar lymph node involvement. Secondary TB has fibrocaseous cavitary lesions.
|
|
Where is extrapulmonary tuberculosis found?
|
CNS (parenchymal tuberculoma or meningitis), vertebral body, lymphadenitis, renal or GI
|
|
What is Pott's disease?
|
Extrapulmonary TB in the vertebral bodies
|
|
What does PPD+ signify?
|
The patient either has a current Tuberculosis infection, past exposure or BCG vaccination
|
|
What is a distinguishing microscopic characteristic of Mycobacteria?
|
They are all acid-fast organisms
|
|
What are the symptoms of Tuberculosis?
|
Fever, night sweats, weight loss, and hemoptysis
|
|
What are the two types of Leprosy and which has a worse Prognosis?
|
Tuberculoid (self-limited) and Lepromatous (due to failed cell-mediated immunity--its worse). Note: LEpromatous = LEthal
|
|
What are the main treatments for Leprosy?
|
Long term Dapsone (#1), alternates: rifampin, clofazimine/dapsone combo.
|
|
What are the side effects/toxicity of dapsone?
|
Hemolysis and methemoglobinemia
|
|
Where does Mycobacterium leprae infect and what is the reservoir in the U.S?
|
Infects the skin and superficial nerves. Armadillos are the reservoir in the U.S.
|
|
How does Mycobacterium kansaii present?
|
pulmonary TB-like symptoms
|
|
How does Mycobacterium scrofulaceum present and what age group?
|
Cervical lympadenitis in kids
|
|
What population does Mycobacterium avium-intracellulare present in and how?
|
Disseminated disease in AIDS, often multi-drug resistant.
|
|
are fungal spores asexual or sexual?
|
most asexual
|
|
budding yeast with pseudohyphae at 20 ⁰C and germ tube formation at 37⁰C
|
candida albicans
|
|
treatment for fungus that causes esophagitis in immunocompromised, endocarditis in IV drug users, vaginitis
|
candida albicans. nystatin if superficial infection; amphotericin B for systemic
|
|
tiny yeast inside macrophages in bat droppings causes?
|
pnemumonia. Histoplasmosis
|
|
fungi with broad-based budding that causes lung disease that can disseminate
|
Blastomycosis
|
|
Fungus endemic to SW US and California. Causes pneumonia and meningitis
|
Coccidiodomycosis
|
|
fungus with spherule filled with endospores
|
Coccidiodomycosis
|
|
budding yeast with Captain's wheel formation
|
Paracoccidiodomycosis
|
|
treatment for systemic fungal infection with granulomas?
|
amphotericin B
|
|
treatment for histo, blasto, or coccidiodomycosis that has not disemminated
|
fluconazole, ketoconazole
|
|
Malassezia furfur causes? Treatment?
|
tinea versicolor. Topical miconazole
|
|
treatment for pruritic annular lesions caused by dermatophytes
|
topical azoles
|
|
diagnostic test for thrush, vulvovaginitis, disseminated candidiasis
|
germ tube test
|
|
mold with septate hyphae that branch at 45⁰ angles
|
apergillus fumigatus
|
|
what does aspergillus cause?
|
bronchopulmonary aspergillosis, fungus ball in lung, invasive aspergillosis in immunocompromised with Chronic granulomatous disease
|
|
opportunistic fungal infections
|
Candida albicans, Aspergillus, Cryptococcus neoformans, Mucor and Rhizopus
|
|
encapsulated yeast that causes meningitis
|
cryptococcus neoformans
|
|
yeast found in soil or pigeon droppings. Identified by India ink stain
|
cryptococcus neoformans
|
|
mold with nonseptate hypahe braching at wide angles
|
mucor and rhizopus
|
|
who gets mucormycosis?
|
ketoacidotic diabetic and leukemic patients
|
|
diabetic patient with black necrotic tissue in nasal cavity and frontal lobe abscesses. What fungus is the cause?
|
mucor and rhizopus
|
|
yeast that causes diffuse interstitial pneumonia, especially in AIDS patients
|
pneumocystis jiroveci
|
|
patient has diffuse bilateral infiltrates on CXR and you suspect a fungal cause. Treatment?
|
TMP-SMX, pentamidine, dapsone for P. jiroveci
|
|
thorn prick causes pustule with ascending lymphangitis. Cause?
|
sporothrix schenckii
|
|
treatment for sporotrichosis?
|
itraconazole or potassium iodide
|
|
person went camping and now has diarrhea. Organism and treatment?
|
giardia lamblia. Metronidazole
|
|
green vaginal discharge with itching and burning. Organism and treatment?
|
trichomonas vaginalis. Metronidazole
|
|
cause of Chagas' disease
|
trypanosoma cruzi
|
|
characteristics of Chagas' disease?
|
dilated cardiomyopathy, megacolon, megaesophagus
|
|
Reduviid bug transmits?
|
Trypansoma cruzi to cause Chagas disease
|
|
African sleeping sickness carrier
|
tsetse fly
|
|
organisms that cause African sleeping sickness
|
Trypansoma gambiense and rhodesiense
|
|
person has spiking fevers, hepatosplenomegaly, and pancytopenia. Disease and organism?
|
Visceral leishmaniasis (kal-azar) caused by Leishmania donovani
|
|
transmits leishmaniasis
|
sandfly
|
|
treatment for leishmaniasis
|
sodium stibogluconate
|
|
cyclic fever with headache, anemia and splenomegaly
|
malaria
|
|
diagnosis of malaria
|
blood smear
|
|
treatment of malaria
|
cholorquine (primaquine if have P. Vivax or P ovale), sulfadoxine + pyrimethamine, mefloquine, quinine
|
|
malaria organisms with dormant forms in liver
|
Plasmodium vivax and P. Ovale
|
|
organism in northeastern US that causes fever and hemolytic anemia
|
babesia, transmitted by Ixodes tick
|
|
blood smear shows Maltese crosses. Causative protozoa?
|
babesia, transmitted by Ixodes tick
|
|
treatment of babesiosis
|
quinine, clindamycin
|
|
causes severe diarrhea in AIDS patients
|
cryptosporidium
|
|
causes brain abscesses in AIDS patients. Also causes birth defects
|
toxoplasma gondii
|
|
treatment for toxoplasma gondii
|
sufadiazine + pyrimethamine
|
|
why should pregnant women avoid cats?
|
to avoid toxoplasma gondii, found in cat feces
|
|
bloody diarrhea/dysentery, liver abscess, RUQ pain
|
Entamoba histolytica
|
|
treatment for amebiasis?
|
metronidazole and iodoquinol
|
|
protozoan that causes rapidly fatal meningoencephalitis?
|
Naegleria fowleri
|
|
transmission of Naegleria fowleri?
|
swimming in freshwater lakes; enters through cribriform plate
|
|
worm that causes anal pruritis and treatment
|
enterobius vermicularis (pinworm). Mebendazole/pyrantel pamoate
|
|
treatment for intestinal infection caused by ascaris lumbricoides?
|
mebendazole/pyrantel pamoate
|
|
roundworm found in pork. Muscle inflammation and periorbital edema
|
trichinella spiralis
|
|
treatment for trichinella spiralis
|
thiabendazole
|
|
worm that penetrates skin. Treatment?
|
strongyloides. Ivermectin/thiabendazole
|
|
worm found in drinking water that causes skin ulcerations and inflammation
|
dracunculus medinensis. Treat with niridazole
|
|
cause of river blindness
|
onchocerca volvulus, transmitted by blackfly
|
|
treatment for river blindness?
|
ivermectin
|
|
transmits loa loa?
|
deer fly, horse fly, mango fly
|
|
worm that blocks lymphatics?
|
wuchereria bancrofti
|
|
treatment for wuchereria bancrofti and toxocara canis
|
diethylcarbamazine
|
|
undercooked pork worm
|
taenia solium
|
|
taenia solium causes what?
|
cysticercosis and neurocysticercosis
|
|
treatment for neurocysticercosis?
|
albendazole
|
|
helminth in dog feces that causes liver cysts
|
Echinococcus granulosus
|
|
Schistosoma presentation?
|
granulomas, fibrosis, and inflammation of spleen and liver
|
|
worm in undercooked fish that causes pigmented gallstones and cholangiocarcinoma
|
clonorchis sinensis
|
|
worm in undercooked crab meat that causes inflammation and bacterial infection of the lung
|
Paragonimus westermani
|
|
treatment of Schistosoma, clonorchis sinensis, and Paragonimus westermani
|
Praziquantel
|
|
General mechanism of action of penicllins and cephalosporins?
|
Block cell wall synthesis by inhibition of peptidoglycan cross-linking
|
|
Which drug class acts by disrupting bacterial cell membranes?
|
Polymyxins
|
|
What bacterial enzymes do quinolones block?
|
DNA topoisomerases
|
|
Which drugs block peptidoglycan synthesis?
|
Bacitracin, Vancomycin
|
|
Which bacterial process is blocked by sulfonamides and trimethoprim?
|
Nucleotide synthesis
|
|
Which drugs block protein synthesis at 50S ribosomal subunit?
|
Chlormaphenicol, acrolides, clindamycin, streptogramins (quinupristin, dalfopristin), linezolid
|
|
Where do aminoglycosides and tetracyclines act?
|
30S ribosomal subunit
|
|
Clinical use of penicillin?
|
Bactericidal for Gram-pos cocci, rods; Gram-neg cocci and spirochetes.
|
|
Toxicity of penicillin?
|
Hypersensitivity reactions, hemolytic anemia
|
|
Mechanism of penicillin?
|
Bind PBPs, block transpeptidase cross-linking of cell wall, activate autolytic enzymes
|
|
Which penicillins are penicillinase-resistant?
|
Methicillin, nafcillin, dicloxacillin
|
|
Clinical use of penicllinase-resistant penicillins?
|
Staph aureus (except MRSA)
|
|
Are ampicillin and amoxicillin penicillinase-resistant?
|
No (penicillinase-sensitive; use with clavulanic acid)
|
|
Clinical use of ampicillin and amoxicillin?
|
Haemophilus influenzae, E. coli, Listeria monocytogenes, Proteus mirabilis, Salmonella, enterococci
|
|
Toxicity of ampicillin and amoxicillin?
|
Hypersenstivity, ampicllin rash, pseudomembranous colitis
|
|
Clinical use of ticarcillin, carbenicillin, piperacillin?
|
Pseudomonas and Gram-neg rods (penicillinase sensitive; use with clavulanic acid)
|
|
Mechanism of cephalosporins?
|
beta-lactams, inhibit cell wall synthesis, less sensitive to penicillinase, bactericidal
|
|
Clinical use of 1st generation cephalosporins?
|
Gram-pos cocci (Proteus, E.coli, Klebsiella)
|
|
Names of 1st generation cephalosporins?
|
Cefazolin, cephalexin
|
|
Names of 2nd generation cephalosporins?
|
Cefoxitin, cefaclor, cefuroxime
|
|
Clinical use of 2nd generation cephalosporins?
|
Gram-pos cocci (Haemophilus, Enterobacter aerogenes, Neisseria, Proteus, E.coli, Klebsiella, Serratia)
|
|
Names of 3rd generation cephalosporins?
|
Ceftriaxone, cefotaxime, ceftazidime
|
|
Clinical use of 3rd generation cephalosporins?
|
Serious Gram-neg infections resistant to other beta-lactams- meningitis, Psuedomonas, gonorrhea
|
|
Name of 4th generation cephalosporin?
|
Cefepime
|
|
Clinical use of 4th generation cephalosporin?
|
Increased activity against Pseudomonas and Gram-pos organisms
|
|
Toxicity of cephalosporins?
|
Cross hypersenstivity with penicillins, increased nephrotoxicity of aminoglycosides, disulfiram-like reaction with EtOH
|
|
Mechanism of aztreonam?
|
Monobactam resistant to beta-lactamases; inhibits cell wall synthesis; synergistic with aminoglycosides
|
|
Clinical use of aztronam?
|
Gram-neg rods (Klebsiella, Pseudomonas, Serratia) For penicillin-allergic patients and those with renal insuff (can't use aminoglycosides)
|
|
Toxicity of aztreonam?
|
Occasional GI upset; well-tolerated
|
|
What drug is always co-administered with imipenem? Why?
|
Cilastatin- an inhibitor of renal dihydropeptidase I to reduce imipenem inactivation in renal tubules
|
|
Is imipenem beta-lactamase resistant?
|
Yes
|
|
Clinical use of imipenem and meropenem?
|
Gram-pos cocci, Gram-neg rods and anaerobes. Drug of choice for Enterobacter.
|
|
Toxicity of imipenem and meropenem?
|
GI distress, skin rash and CNS toxicity (seizures) at high plasma levels (less with meropenem)
|
|
Mechanism of vancomycin?
|
Inhibits cell wall mucopeptide formation by binding D-ala-D-ala portion of precursors. Bactericidal
|
|
Mechanism of resistance to vancomycin?
|
Amino acid change of D-ala-D-ala to D-ala-D-lac
|
|
Clinical use of vancomycin?
|
Serious Gram-pos multidrug-resistant organisms (S.aureus, C.diff)
|
|
Toxicity of vancomycin?
|
Nephrotoxicity, ototoxicity, thrombophlebitis, red man syndrome (pretreat with antihistamines)
|
|
Names of aminoglycosides?
|
Gentamicin, neomycin, amikacin, tobramycin, streptomycin
|
|
Mechanism of aminoglycosides?
|
Inhibit formation of initiation complex and cause misreading of mRNA. Bactericidal
|
|
Why are aminoglycosides ineffective against anaerobes?
|
Require oxygen for uptake
|
|
Clinical use of aminoglycosides?
|
Severe Gram-neg rod infections. Synergistic with beta-lactams
|
|
Toxicity of aminoglycosides?
|
Nephrotoxicity (esp if used with cephalosporins), ototoxicity (esp when used with loop diuretics), teratogenic
|
|
Names of tetracyclines?
|
Tetracycline, doxycycline, demclocycline, minocycline
|
|
Mechanism of tetracyclines?
|
Bind to 30S and prevent attachment of aminoacyl-tRNA
|
|
What inhibits tetracycline absorption in the gut?
|
Divalent cations (calcium, iron)
|
|
Use of demeclocylcine?
|
Diuretic in SIADH because ADH antagonist
|
|
Clnical use of tetracyclines?
|
Vibrio cholerae, acne, Chlamydia, Ureasplasma, Urealyticum, Mycoplasma, Tularemia, H.pylori, Borrelia, Rickettsia
|
|
Toxicity of tetracyclines?
|
GI distress, discoloration of teeth, inhibition of bone growth in kids, photosensitivity, teratogen
|
|
Names of macrolides?
|
Erythromycin, azithromycin, clarithromycin
|
|
Mechanism of macrolides?
|
Inhibit protein synthesis by blocking translocation; bind to the 23S rRNA of the 50S ribosomal subunit. Bacteriostatic
|
|
Clinical use of macrolides?
|
URIs, pneumonias, STDs--Gram-pos cocci (strep), Mycoplasma, Legionella, Chlamydia, Neisseria
|
|
Toxicity of macrolides?
|
GI discomfort, acute cholestatic heptatitis, eosinophilia, skin rashes. Drug interations (increased plasma conc) with theophyllines, oral anticoags
|
|
Mechanism of chloramphenicol?
|
Inhibits 50S peptidyltransferase activity. Bacteriostatic
|
|
Clinical use of chloramphenicol?
|
Meningitis (H.influenze, N.meningitidis, S.pneumoniae)
|
|
Toxicity of chlormphenicol?
|
Anemia, aplastic anemia, gray baby syndrome
|
|
Mechanism of clindamycin?
|
Blocks peptide bond formation at 50S ribosomal subunit. Bacteriostatic
|
|
Clinical use of clindamycin?
|
Treat anaerobic infections (Bacteroides fragilis, C.perfringens)
|
|
Toxicity of clindamycin?
|
Pseudomembranous colitis, fever, diarrhea
|
|
Names of sulfonamides?
|
Sulfamethoxazole (SMX), sulfisoxazole, triple sulfas, sulfadiazine
|
|
Mechanism of sulfonamides?
|
PABA antimetabolites inhibit dihydropteroate synthetase. Bacteriostatic
|
|
Clnical use of sulfonamides?
|
Gram-pos, Gram-neg, Nocardia, Chlamydia, UTI
|
|
Toxicity of sulfonamides?
|
Hypersensitivity reactions, hemolysis if G6PD deficient, nephrotoxicity, photosensitivity, kernicterus, displace other drugs from albumin
|
|
Mechanism of trimethoprim?
|
Inhibits bacterial dihydrofolate reductase. Bacteriostatic
|
|
Clinical use of trimethoprim?
|
Used in combo with SMX- causing sequential block of folate synthesis. Recurrent UTIs, Shigella, Salmonella, Penumocystis jiroveci
|
|
Toxicity of trimethoprim?
|
Megaloblastic anemia, leukopenia, granulocytopenia (supplement folic acid)
|
|
Which drugs should be avoided in pts with sulfa drug allergies?
|
Sulfonamides, sulfasalazine, sulfonylureas, thiazide diuretics, acetazolamide, furosemide
|
|
Which bugs do not gram stain well?
|
Treponema, Rickettsia, Mycobacteria, Mycoplasma, Legionella pneumophila, Chlamydia (pneumonic: These Rascals May Microscopically Lack Color)
|
|
Why doesn't Treponema gram stain well?
|
too thin to be visualized
|
|
Why doesn't Rickettsia gram stain well?
|
intracellular parasite
|
|
Why doesn't Mycobacteria gram stain well?
|
high-lipid-content cell wall requires acid-fast stain
|
|
Why doesn't Mycoplasma gram stain well?
|
no cell wall
|
|
Why doesn't Legionella pneumophila gram stain well?
|
primarily intracellular
|
|
Why doesn't Chlamydia gram stain well?
|
intracellular parasite; lacks muramic acid in cell wall
|
|
How can you visualize treponemes?
|
darkfield microscopy & fluorescent Ab staining
|
|
How can you visualize Mycobacteria?
|
acid fast
|
|
How can you visualize Legionella?
|
silver stain
|
|
Describe the phases of the bacterial growth curve?
|
lag phase, log phase, stationary phase, death phase (graph is shown on a log scale)
|
|
What is the lag phase?
|
period of little bacterial growth-- metabolic activity without division
|
|
What is the log phase?
|
linear bacterial growth on the log scale- rapid cell division
|
|
What is the stationary phase?
|
no growth- nutrient depletion slows growth, spore formation in some bacteria
|
|
What is the death phase?
|
linear decrease in number of bacterial cells on log scale- prolonged nutrient depletion and buildup of waste products lead to death
|
|
What is the source of exotoxins?
|
certain species of gram+ and gram- bacteria
|
|
What is the source of endotoxins?
|
outer cell membrane of most gram- bacteria and listeria
|
|
Are exotoxins secreted from the cell?
|
YES
|
|
Are endotoxins secreted from the cell?
|
NO
|
|
What is the chemistry of exotoxins?
|
polypeptide
|
|
What is the chemistry of endotoxins?
|
lipopolysaccharide
|
|
Where is the location of genes for an exotoxin?
|
plasmid or bacteriophage
|
|
Where is the location of genes for an endotoxin?
|
bacterial chromosome
|
|
What is the toxicity of an exotoxin?
|
high (fatal dose is about 1ug)
|
|
What is the toxicity of an endotoxin?
|
low (fatal dose is hundreds of micrograms)
|
|
What are the clinical effects from an exotoxin?
|
Various
|
|
What are the clinical effects from an endotoxin?
|
fever, Shock
|
|
What is the mode of action of an exotoxin?
|
various modes
|
|
What is the mode of action of an endotoxin?
|
includes TNF and IL-1
|
|
What is the antigenicity of an exotoxin?
|
induces high-titer antibodies called antitoxins
|
|
What is the antigenicity of an endotoxin?
|
poorly antigenic
|
|
What are vaccines to an exotoxin?
|
toxoids used as vaccines
|
|
What are vaccines to an endotoxin?
|
No toxoids formed and no vaccine available
|
|
What is the heat stability of an exotoxin?
|
destroyed rapidly at 60 deg Celsius (except Staphylococcal enterotoxin)
|
|
What is the heat stability of an endotoxin?
|
stable at 100 deg Celsius for 1 hr
|
|
What are typical diseases from an exotoxin?
|
Tetanus, botulism, diptheria
|
|
What are typical diseases from an endotoxin?
|
meningococcemia, sepsis by G- rods
|
|
What is the definition of bacterial virulence factors?
|
Promote evasion of host immune response
|
|
Describe the virulence of protein A? What bacteria is it part of?
|
Binds Fc region of Ig; S. aureus
|
|
Describe the virulence of IgA protease? What bacteria is it secreted by?
|
Enzyme that cleaves IgA; polysaccharide capsules also inhibit phagocytosis; secreted by S. pneumoniae, H. influenza, Neisseria
|
|
Describe the virulence of Group A streptococcal M protein?
|
helps prevent phagocytosis
|
|
Describe the action of superantigens?
|
bind directly to MHC II and T-cell receptor simultaneously, activating large numbers of T cells to stimulate release of IGN-gamma and IL-2
|
|
Describe the S. aureus superantigen. Is it an exotoxin or endotoxin?
|
TSST-1 superantigen causes toxic shock syndrome (fever, rash, shock). EXOTOXIN
|
|
What are the other S. aureus toxins?
|
enterotoxins that cause food poisoning, exfoliatin that causes staphylococcal scalded skin syndrome
|
|
Describe the S. pyogenes superantigen. Is it an exotoxin or endotoxin?
|
scarlet fever- erythrogenic toxin causes toxic shock-like syndrome. EXOTOXIN
|
|
What does an ADP ribosylating A-B toxin do?
|
interferes with host cell function. B (binding component) binds to receptor on surface of host cell, enabling endocytosis. A (active component) then attaches an ADP-ribosyl to a host cell protein (ADP-ribosylation), altering protein function.
|
|
Describe the cornebacterium diphtheriae ADP ribosylating A-B toxin. Is it an exotoxin or endotoxin?
|
inactivates elongation factor (EF-2)- similar to Psuedomonas exotoxin A; causes pharyngitis and pseudomembrane in throat; EXOTOXIN
|
|
Describe the Vibrio cholerae ADP ribosylating A-B toxin. Is it an exotoxin or endotoxin?
|
ADP ribosylation of G protein stimulates adenylyl cyclase; incresase pumping of Cl- into gut and decreased Na+ absorption. Water moves into gut lumen; causes voluminous rice-water diarrhea. EXOTOXIN
|
|
Describe the E. coli ADP ribosylating A-B toxin. Is it an exotoxin or endotoxin?
|
heat-labile toxin stimulates Adenylate cyclase. Heat-stable toxin stimulates Guanylate cyclase. Both cause watery diarrhea. Labile like the Air, stable like the Ground. EXOTOXIN
|
|
Describe the Bordetella pertussis ADP ribosylating A-B toxin. Is it an exotoxin or endotoxin?
|
Increases cAMP by inhibiting G-alpha-inhibitory; causes whooping cough; inhibits chemokine receptor causing lymphocytosis. EXOTOXIN
|
|
Describe the action of clostridium perfringens toxin? Is it an exotoxin or endotoxin?
|
alpha toxin causes gas gangrene; get double zone of hemolysis on blood agar. EXOTOXIN
|
|
Describe the action of C. tetani toxin? Is it an exotoxin or endotoxin?
|
blocks the release of inhibitory neurotransmitters GABA and glycine; causes lockjaw; SPASTIC paralysis; EXOTOXIN
|
|
Describe the action of C. botulinum toxin? Is it an exotoxin or endotoxin?
|
blocks the release of Ach; causes anticholinergic symptoms, CNS paralysis, especially cranial nerves; spores found in canned food, honey (causes floppy baby); FLACCID paralysis; EXOTOXIN
|
|
Describe the action of bacillus anthracis toxin? Is it an exotoxin or endotoxin?
|
1 toxin in the toxin complex is an adenylate cyclase; EXOTOXIN
|
|
Describe the action of Shigella toxin? Is it an exotoxin or endotoxin?
|
shiga toxin (also produced by E. Coli O157:H7) cleaves host cell rRNA; also enhances cytokine release, causing HUS. EXOTOXIN
|
|
Describe the action of S. pyogenes toxin? Is it an exotoxin or endotoxin?
|
Streptolysin O is a hemolysin; antigen for ASO Ab, which is used in the diagnosis of rheumatic fever. EXOTOXIN
|
|
What is the definition of an endotoxin?
|
A lipopolysaccharide found in the cell wall of G- bacteria (N-dotoxin is an integral part of gram-Negative cell wall.)
|
|
Endotoxin is heat___________ (labile/ stable?)
|
stable
|
|
What is an example of an endotoxin?
|
lipid A
|
|
What does an endotoxin do?
|
activates macrophages, activates complement (alternative pathway), activates Hageman factor
|
|
After an endotoxin activates macrophages, what important components are released?
|
IL-1, TNF, Nitric oxide
|
|
What does IF-1 cause?
|
fever
|
|
What does TNF cause?
|
Fever, hemorrhagic tissue necrosis
|
|
What does nitric oxide cause?
|
hypotension (shock)
|
|
After an endotoxin activates complement, what is released?
|
C3a, C5a
|
|
What does C3a cause?
|
hypotension, edema
|
|
What does C5a cause?
|
neutrophil chemotaxis
|
|
After an endotoxin activates Hageman factor, what occurs?
|
the coagulation cascade--> DIC
|
|
How do you differentiate Neisseria species?
|
on the basis of sugar fermentation
|
|
What do Neisseria meningococci ferment?
|
maltose and glucose (MeninGococci)
|
|
What do Neisseria gonococci ferment?
|
Glucose (Gonococci)
|
|
What color is the pigment produced by S. aureus?
|
yellow
|
|
What color is the pigment produced by Pseudomonas aeruginosa
|
blue-green
|
|
What color is the pigment produced by Serratia marcescens?
|
red
|
|
What gram (-) cocci is a Maltose and Glucose fermenter?
|
Neisseria meningitidis (MeninGococci)
|
|
What gram (-) cocci only ferments Glucose?
|
Neisseria gonorrhoeae (Gonococci)
|
|
What are 2 gram (-) coccoid rods?
|
Haemophilus influenzae and Bordetella pertussis
|
|
What 2 gram (-) rods are fast fermenters of lactose?
|
Klebsiella and Escherichia coli (Enterobacteriaceae)
|
|
What gram (-) rod is a lactose nonfermenter and oxidase (+)?
|
Pseudomonas
|
|
What 3 gram (-) rods are lactose nonfermenters and oxidase (-)?
|
Shigella, Salmonella, and Proteus (Enterobacteriaceae)
|
|
What Neisseria species has a polysaccharide capsule, ferments maltose, and has a vaccine?
|
N. meningitidis
|
|
What are 4 pathologies caused by N. gonorrhoeae (Gonococci)?
|
Gonorrhea, septic arthritis, neonatal conjunctivitis, and Pelvic Inflammatory Disease (PID)
|
|
What are 2 pathologies caused by N. meningitidis (Meningococci)?
|
Meningitis (meningococcemia) and Waterhouse-Friderichsen syndrome (hemorrhagic adrenalitis)
|
|
What gram (-) cocci ferment glucose and produce IgA proteases?
|
Neisseria (gonorrhoeae and meningitidis)
|
|
What 4 pathologies can HaEMOPhilus cause?
|
Epiglottitis, Meningitis, Otitis media, and Pneumonia
|
|
What factors do H. influenzae require when cultured on chocolate agar?
|
Factors V (NAD) and X (hematin)
|
|
What does the H. influenzae type B vaccine contain and is it given?
|
Type B capsular polysaccharide conjugated with diphtheria toxoid; between 2-18 months of age
|
|
Name 7 species of Enterobacteriaceae.
|
E. coli, Salmonella, Shigella, Klebsiella, Enterbacter, Serratia, and Proteus
|
|
What antigen is the endotoxin of Enterobacteriaceae?
|
Somatic (O) antigen
|
|
What antigen determines virulence of Enterobacteriaceae?
|
Capsular (K) antigen
|
|
What antigen is found in motile species of Enterobacteriaceae?
|
Flagellar (H) antigen
|
|
Name 4 characteristics of Enterobacteriaceae.
|
COFFEe: Capsular, O antigen, Flagellar antigen, Ferment glucose, Enterobacteriaceae
|
|
What causes pneumonia in alcoholics and diabetics with red currant jelly sputum?
|
Klebsiella
|
|
What are the 3 A's of Klebsiella?
|
Aspiration pneumonia, Abscess in lungs, Alcoholics
|
|
What agar is used to culture pink colonies of lactose-fermenting enteric bacteria?
|
MacConkey's agar (Lactose is KEE. MacConKEE's agar)
|
|
What non-lactose-fermenting Enterobacteriaceae invade intestinal mucosa and cause bloody diarrhea?
|
Salmonella and Shigella
|
|
How is Salmonella's motility different from Shigella's?
|
Salmonella: flagella; Shigella: actin polymerization
|
|
Which produces H2S, Salmonella or Shigella?
|
Salmonella
|
|
Which is more virulent, Salmonella or Shigella?
|
Shigella
|
|
What are 4 symptoms of Salmonella typhi (typhoid fever)?
|
Fever, diarrhea, headache, and rose spots on abdomen
|
|
How is Salmonella and Shigella transmitted?
|
Food, Fingers, Feces, Flies
|
|
Where are outbreaks of Yersinia enterocolitica common?
|
Day-care centers
|
|
How is Y. enterocolitica transmitted?
|
Pet feces, contaminated milk, and pork
|
|
What 2 pathologies can Y. enterocolitca mimic?
|
Crohn's disease or appendicitis
|
|
What gram (-) rod is urease (+) and creates an alkaline environment?
|
Helicobacter pylori (urease breath test)
|
|
What are 2 common pathologies caused by H. pylori?
|
Gastritis and 90% of duodenal ulcers
|
|
What 3 things is H. pylori a risk for?
|
Peptic ulcer, gastric adenocarcinoma, and lymphoma
|
|
Name a genus of obligate intracellular parasites that need CoA and NAD and have an arthropod vector.
|
Rickettsiae
|
|
What is the triad of symptoms for rickettsiae?
|
Headache, fever, and rash (vasculitis)
|
|
What rickettsia causes Q fever (pneumonia), is transmitted by aerosol, has no rash, and has no vector?
|
Coxiella burnetii
|
|
Compared to typhus, where do rickettsial rashes start?
|
Hands and feet (Rickettsia on the wRists, Typhus on the Trunk)
|
|
What pathology, caused by Rickettsia rickettsii, presents with rash on palms and soles, headache, and fever?
|
Rocky Mountain spotted fever (tick vector)
|
|
What 3 pathologies present with rash on palms and soles?
|
Rocky Mountain spotted fever, syphilis, and coxsackievirus A (hand, foot, and mouth disease)
|
|
What does R. typhi cause?
|
Endemic typhus (flea vector)
|
|
What does R. prowazekii cause?
|
Epidemic typhus (louse vector)
|
|
What is the vector for Ehrlichia?
|
Tick (Ehrlichiosis)
|
|
What does the Weil-Felix reaction assay for?
|
Antirickettsial antibodies (cross-react with Proteus antigen)
|
|
What rickettsial disease has a (-) Weil-Felix?
|
Q fever (Coxiella)
|
|
What can be seen on Giemsa or fluorescent antibody-stained smear for Chlamydiae?
|
Cytoplasmic inclusions
|
|
What 4 things can C. trachomatis cause?
|
Reactive arthritis, conjunctivitis, urethritis, and PID
|
|
What can C. pneumoniae and C. psittaci cause?
|
Atypical pneumonia
|
|
What is unusual about the Chlamydial cell wall?
|
Lacks muramic acid
|
|
What form of Chlamydia Enters cell via endocytosis?
|
Elementary body
|
|
What form of Chlamydia Replicates in cells?
|
Reticulate body
|
|
What does C. trachomatis serotypes A, B, and C cause?
|
ABC: Africa/Blindness/Chronic infection
|
|
What does C. trachomatis serotypes L1, 2, and 3 cause?
|
L1-3: Lymphogranuloma venereum
|
|
What does C. trachomatis serotypes D-K cause?
|
Urethritis/PID, ectopic pregnancy, neonatal pneumonia or conjunctivitis
|
|
What are 3 spirochetes?
|
BLT: Borrelia (B is Big), Leptospira, and Treponema
|
|
Which spirochete is the only one that can be visualized by dyes in light microscopy?
|
Borrelia
|
|
Which spirochete is visualized with dark-field microscopy?
|
Treponema
|
|
How are spirochetes mobile?
|
Axial filaments
|
|
What question mark-shaped spirochete can cause Weil's disease (icterohemorrhagic leptospirosis)?
|
Leptospira interrogans (Weil's: jaundice, azotemia, fever, hemorrhage, and anemia)
|
|
What can Borrelia burgdorferi cause and via what vector?
|
Lyme disease (Ixodes tick)
|
|
What 2 symptoms are found during Stage 1 of Lyme disease?
|
Erythema chronicum migrans (bull's eye rash) and flu-like symptoms
|
|
What 2 manifestations are found during Stage 2 of Lyme disease?
|
Neurologic and cardiac manifestations
|
|
What 2 symptoms are found during Stage 3 of Lyme disease?
|
Chronic monoarthritis and migratory polyarthritis
|
|
What does Treponema pallidum cause?
|
Syphilis
|
|
What does T. pertenue cause?
|
Yaws (tropical infection with + VDRL test)
|
|
What is characteristic of primary syphilis?
|
Painless chancre (localized)
|
|
What is characteristic of secondary syphilis?
|
Maculopapular rash on palms and soles and condylomata lata (Secondary=Systemic)
|
|
What is characteristic of tertiary syphilis?
|
Gummas, aortitis, neurosyhphilis (tabes dorsalis), and Argyll Robertson pupil
|
|
What 4 things are characteristic to congenital syphilis?
|
Saber shins, saddle nose, CN VIII deafness, and Hutchinson's teeth
|
|
What is characteristic of an Argyll Robertson pupil?
|
Prostitute's pupil: accomodates but does not react to light (tertiary syphilis)
|
|
What is the FTA-ABS test specific for?
|
Treponemes; FTA-ABS: Find the Ab-ABSolutely; most specific, earliest (+), long (+) duration
|
|
Interpret +VDRL and +FTA.
|
Active Treponema infection
|
|
Interpret +VDRL and -FTA.
|
Probably false positive Treponema infection
|
|
Interpret -VDRL and +FTA.
|
Successfully treated Treponema infection
|
|
What does VDRL detect?
|
Nonspecific Ab reacts with beef cardiolipin (Dx: syphilis, Viruses [mononucleosis and hepatitis), Drugs, Rheumatic fever, SLE, and Leprosy)
|
|
zidovudine (AZT)
|
thymidine nucleoside analog phosphorylated by cellular kinases to tri-P active form (host thymidine kineses are S-phase specific inhibiting RT; also acts as DNA chain terminator (b/c N3 group on 3'OH)
|
|
lamivudine (3TC) See above
|
nucleoside analog inhibitor of RT, phosphorylated by cell enzymes to active Rx
|
|
tenofovir
|
like AZT inhibits RT by competing w/dATP for incorporation into DNA, causing chain termination; unlike AZT it is a nucleotide prodrug (adenosine monophosphate analog that is hydrolyzed to tenofovir phosphonate, which is further phosphorylated by cellular enzymes be active at inhibiting RT
|
|
Emtricitabine
|
Fluorinated analog of 3TC that inhibits RT by competing for dCTP incorporation into DNA; chain termination
|
|
efavirenz
|
non-nucleoside/non-competitive inhibitor or RT that does not require phosphorylation for activity
|
|
lopinavir
|
prevents viral protease from cleaving gag-pol polypeptide into separate functional proteins; fits into protease active site and acts as a competitive inhibitor; results in non-infectious viral particles
|
|
ritonavir
|
Used to boost levels of ther Protease Inhibitors
|
|
enfuvirtide
|
inhibits the fusion of viral (HIV-1) and cellular (CD4+) membrances to block initial entry; binds gp41 subunit of HIV glycoprotein
|
|
Maraviroc
|
Chemokine co-receptor (CRR5) antagonist to block entry of HIV into cells
|
|
Raltegravir
|
Inhibitis HIV-1 integrase, prevents integration into the genome
|
|
Mechanism of Interferon
|
Block stages of viral RNA and DNA synthesis, induce ribonuclease
|
|
Alcoholic vomits gastric contents and has foul-smelling sputum. Organism? Etiology? Treatment?
|
Anaerobes (aspiration pneumonia). Rx: Ceftriaxone + azithromycin/moxifloxacin.
|
|
Middle-aged male presents with acute onset monoarticular joint pain and bilateral Bell's palsy. Disease? Transmission? Organism? Rx?
|
Lyme disease. Ixodes (tick)--> Borrelia burgdorferi (spirochete). Rx: doxycycline
|
|
Patient's UA shows WBC casts. Disease/problem? Organism? Rx?
|
Pyelonephritis. Org: E. coli (most common), Enterococcus, Staph, Proteus. Rx: TMP/SMX (Quinolone if Enterococcus).
|
|
Patient presents with 'rose gardener's' scenario (thorn prick with large ulcers along lymphatic drainage). Organism?
|
Sporothrix schenckii (rare fungus. House episode: guy gives his wife roses because he cheated and got critically ill.)
|
|
Med student has a burning feeling in his gut after meals. Gastric mucosa biopsy=G- rods. Diagnosis (test?)? Tx? Pathogenicity factors (of organism)?
|
H. pylori (peptic ulcer disease, stomach CA (risk)). Urea breath test. Pathogen: cagA (type 4 secr syst->makes IL-8), NAP (activates neutrophils), VacA (vacuolizing toxin). Pathogenicity=inflammation!
|
|
32-y/o M has 'cauliflower' skin lesions. Biopsy=broad-based budding yeast. Organism? Rx?
|
Blastomyces. Rx=Itraconazole
|
|
Breast-feeding F suddenly develops redness & swelling of right breast. PE=fluctuating mass. Diagnosis?
|
Mastitis caused by S. aureus.
|
|
20-y/o college student presents w/ lymphadenopathy, fever & hepatosplenomegaly. His serum agglutinates sheep RBCs. What cell is infected? Etiology?
|
B cells (infectious mononucleosis; EBV ('owl eye inclusions').
|
|
3 hrs after eating custard at a picnic, a whole family began vomiting (awesome)! 10 hrs later they were better. Organism? Pathophysiology?
|
S. aureus (preformed enterotoxin (superantigen) caused vomiting w/in hours…heat stable)
|
|
Infant becomes flaccid after eating honey. Organism? Mechanism? Compare to a related (same genus) spp.?
|
Clostridium botulinium (Clostridia=G+ anaerobes, 'drumstick-shaped' (spores)). Mech: inhibits vSNAREs->ACh release into post-synaptic cleft blocked). C. tetani-->inhib GABA release at inh interneurons in CNS (retroaxonal transport). Tetanus=immunization (Px) / TT IgG (acute, sx). Botox=anti-toxin.
|
|
Male presents with squamous cell carcinoma on his penis. Etiology? Tx?
|
HPV. No treatment (for HPV). Immunizaiton for women.
|
|
Patient develops endocarditis 3 wks after receiving a prosthetic heart valve. Organism (be specific down to species)? Tx?
|
S. epidermidis. Rx: Vancomycin (or resistance analysis d/t MDR).
|
|
55-y/o smoker & heavy drinker presents with a (new) cough and flu-like sx. Gram stain=no organisms. Silver stain=G- rods. Diagnosis? Tx?
|
Legionella pneumophila (pleomorph, b-lactamase(+), prevent vacuole<->lysosome fusion, sources: pools, water towers). Rx=Rifampin + erythromycin.
|
|
After taking clindamycin, patient develops toxic megacolon and diarrhea. Organism? Tx?
|
Clostridium difficile (Enterocolitis). Rx=metronidazole or vancomycin. 'Q: How do you get off the C. diff train? A: take the metro or a van.'
|
|
25-y/o presents with 3 days fever, chills & a painful, swollen knee. Diagnosis? Tx?
|
Septic arthritis (key: unilat/asymmetrical; many etiologies, common=N. gonorrheae). Rx=ceftriaxone (if etio uncertain), Pen G if certain N. gonorrheae.
|
|
19-y/o F college student presents with vaginal pruritis and a thick, curdy discharge. Etiology? Tx?
|
Candida albicans. Clotrimazole (topical or oral, but oral C/I with alcohol consumption (consideration)).
|
|
30-y/o F returns from a camping trip and complains of watery diarrhea and cramps. Organism? Tx?
|
Giardia lamblia (Traveler's diarrhea; 2nd most common (parasitic) cause of diarrhea (#1=cryprosporidium)). Rx: Metronidazole (adults), Nitazoxanide (peds), Paromomycin (pregnant F). Pathophys: d/t hosts own immune rxn. Immunity: IgA (in endemic areas-contam water).
|
|
Bacterial peptidoglycan: composition and function? What class of antibiotics targets this structure?
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Carb backbone (N-Ag~N-Am) + x-linked peptide side chains (thin in G-/thick in G+); support, resists osmotic pressure. Beta-Lactams target the x-link D-Ala-D-Ala (last 2 of pentapeptide).
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Bacterial cell wall: composition, function & clinical significance?
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Supported by peptidoglycan (inner), techoic acid induces IL-1/TNF-a (Fxn: surface antigen). Only G+.
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Bacterial outer membrane (& periplasm): composition, function & significance?
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Lipid A induces IL-1/TNF-a (Antigen=polysaccharide). Fxn: site of LPS/endotoxin (surface Ag)=only G-. Periplasm=only in G- (space btw. outer & inner membrane).
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Bacterial plasma membrane: composition & function?
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Lipoprotein bilayer. Site of oxidative & transport enzymes.
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Bacterial ribosomes: structure & function, clinical significance, examples?
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50S + 30S = 70S (protein synthesis from mRNA). Different from eukaryotic ribosomes=Rx target (Aminoglycosides, tetracyclines, tigecycline, chloramphenicol, macrolides, clindamycin & linezolid).
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Bacterial capsule: structure, function, clinical significance & examples?
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Polysaccharide (except: B. anthracis D-Glutamate=glycoprotein); protects against phagocytosis=immune evasion/chronic infections. Examples: S. pneumoniae, H. influenzae (b), Klebsiella pneumoniae, P. aeruginosa, N. meningitidis, Cryptococcus neoformans ('Some killers have pretty neat capsules'). Hib and Strep vaccines are directed at capsule.
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Bacterial pilus/fimbriae: structure/function?
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Glycoprotein (mostly CHO); adherence, sex pilus forms during conjugation.
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Bacterial flagellum: structure/function?
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Protein/motility (Notably: H. pylori).
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Bacterial spore: structure, function, clinical significance?
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Keratin-like coating--resistance to env't stressors. B. anthracis, Clostridium spp.
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Bacterial plasmids: structure, function, clinical significance?
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DNA (circular)-contains variety of genes for antibiotic resistance (beta-lactamase), enzymes and toxins (shigella toxin).
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Bacterial glycocalyx: structure, function, clinical significance?
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Polysaccharide-mediates adherence to surfaces (esp. foreign). Catheters, medical implants (P. aeruginosa, S. epidermidis).
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Bacteria with unusual structures: Mycoplasma vs. Mycobacteria
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Mycoplasma: sterols (no cell wall)-->'walking pneumonia'. Mycobacteria: mycolic acid (high lipid content)--> TB, leprosy, MAC complex (AIDS).
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Common structures to G+ and G- (name 5). 1 unique structure of each (G+, G-)?
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Common: flagellum, pilus, capsule, peptidoglycan (G+ >> G-), cytoplasmic membrane. G- only: LPS/endotoxin, outer membrane. G+: cell wall (techoic acid).
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