Microbes

Front 1

Staphylococcus aureus (S. aureus)

Back 1

Dis: skin and soft tissue infections, abscesses, endocarditis, gastroenteritis (food poisoning), pneumonia (rarely in healthy ppl, except w H1N1), toxic shock syndrome

Chxs: Gram positive cocci in clusters. Coagulase positive (If report reads coagulase negative Staphylococci - think S. epidermidis which is less likely to be pathogenic than S. aureus.) Most isolates produce Beta-lactamase.

H&Ts: found on human skin and in nose. Transmission is usually via the hands.

Lab dx: Gram stain and routine C&S

E. Be aware of (HA-MRSA) as well as (CA-MRSA).

Front 2

Streptococcus pyogenes (Group A strep)

Back 2

Dis: pharyngitis, cellulitis and other skin infections, rheumatic fever, glomerulonephritis. Toxic shock syndrome.

Chrx: gram positive cocci in chains, Beta-hemolytic.

H&T: human throat and skin. Transmitted via respiratory droplets. There can be a carrier w/o s/s

Lab dx: Gram stain and culture. When suspect as cause of pharyngitis may order "strep screen" (plate has abx to kill off nf) or rapid antigen test (~20 min very sensitive).

Front 3

Streptococcus agalactiae (Group B strep)

Back 3

Dis: neonatal meningitis and sepsis

Chxs: gram positive cocci in chains. Beta hemolytic.

Habitat is the vagina, transmission occurs during birth. Mother should be screened (vaginal swab) prior to birth to prevent trans.

Lab Dx: Gram stain and culture.

Front 4

Enterococcus

Back 4

Dis: UTI and biliary tract are most common.

Chxs: Gram positive cocci in chains. Vancomycin-resistant enterococci (VRE) are important cause of nosocomial infections.

Habitat is the colon, urethra and female genital tract can be colonized. May enter bloodstream during GI or GU (gastrourinary) manipulations.

Lab Dx: Gram stain and culture (will diff entero from other strep).

Front 5

Streptococcus pneumoniae

Back 5

Dis: Most common are otitis media, sinusitis, pneumonia (og infx in lungs) and meningitis (hematogenous spread). Most virulent strain will have capsules.

Chxs: Gram positive "lancet-shaped" cocci in pairs (diplococci) or short chains. Alpha-hemolytic.

Habitat is the human upper respiratory tract. Transmission is via respiratory droplets.

Lab Dx.: Gram stain and culture

Front 6

Viridans Group Streptococci

Back 6

Dis: Endocarditis is the most important

Chxs: Gram positive cocci in chains. Alpha-hemolytic.

Habitat is the human oropharynx (part of nf). Transmission commonly occurs at dentist in pts w faulty heart valve - bacteria will settle on valve causing endocarditis.

Lab Dx: Gram stain and culture

*MOST COMMON BACTERIA CAUSING ENDOCARDITIS IN NON-IV DRUG USERS

Front 7

Peptostreptococcus

Back 7

Dis: Can be involved in dental and other abscesses. Usually found as mixed anaerobic infection.

Chxs: Gram positive anaerobic streptococci that are part of nf of mouth and colon.

Front 8

Clostridium tetani

Back 8

Dis: Tetanus (not as common is US bc of vaccine)

Chxs: anaerobic, gram-positive, spore-forming rod.

Habitat is the soil. Spores can survive a long time in soil.

Lab Dx: organism seldom isolated (clinical dx)

Front 9

Clostridium botulinum

Back 9

Disease: Botulism- paralysis in muscles, prevents contraction, very dangerous if in the lungs.

Chxs: anaerobic, gram positive, spore forming rod

Habitiat is the soil. Organism and toxin transmitted in improperly preserved food.

Lab dx: presence of toxin in patient's stool or serum.

Front 10

Clostridium difficile

Back 10

Disease: causes antibiotic associated pseudomembranous colitis. Can acquire up to 3mo after taking ANY abx- most common w clindamycin

Habitat in human colon; transmission is fecal-oral.

Chxs: Anaerobic, Gram-positive, spore forming rod.

Lab dx: Stool toxin assay - exotoxin is detected in stool samples.

Front 11

Clostridium perfringens

Back 11

Diseases: Gas gangrene (myonecrosis) and food poisoning

Chxs: Anaerobic, Gram-positive, spore forming rods.

Habitat: Soil and human colon.

Lab dx: Gram stain and anaerobic culture.

Front 12

Bacillus anthracis

Back 12

Dis: Anthrax (common in animals, rare in humans). Cutaneous, pulmonary and gastrointestinal forms of anthrax

Chxs: Large spore-forming gram-positive rod. Anthrax toxin.

Habitat: Organism persists in soil for years. Humans most often infected cutaneously at time of trauma to skin. Spores can be inhaled into the lungs.

Front 13

Listeria monocytogenes

Back 13

Dis: meningitis and sepsis in newborns and immunocompromised adults.

Chx: small gram positive rods

Habitat: widely distributed in nature.

Lab dx: Gram stain and culture

Front 14

Corynebacterium diptheriae

Back 14

Dis: Causes diphtheria via toxin. Starts as sore throat and is followed by systemic invasiveness.

Chxs: Gram positive rods with beaded appearance.

Habitat: Other Corynebacterium species (diphtheroids) are members of normal flora (skin, upper respiratory tract)

Lab dx: Culture (throat swab) on special medium (Loeffler’s/Tellurite). Demonstrate toxin production.

*Vaccine for diphtheria usually comes w tetanus vaccine- very ↓ prevalence in US bc of vaccine.

Front 15

Neisseria meningitidis
(Meningococcus)

Back 15

Dis: Meningitis and meningococcemia

Chxs: Gram negative "kidney-bean" shaped diplococci with large polysaccharide capsule.

Habitat is the upper respiratory tract. Transmission is via respiratory droplets.

Lab dx: Gram stain and culture. CSF culture = meningitidis (Cant tell the diff b/t meningitidis and gonorrhea in gram stain)

*Most common cause of meningitis in ADULTS is N. meningitidis and S. pneumoniae

Front 16

Neisseria gonorrhoeae
(Gonococcus)

Back 16

Dis: Gonorrhea. Also neonatal conjunctivitis and pelvic inflammatory disease

Chxs: Gram negative “kidney bean” shaped diplococci. Insignificant capsule. Habitat is the human genital tract. Transmission is by sexual contact.

Lab dx: Gram stain and culture. On gram stain organism is seen intracellularly w/in neutrophils.
Culture: grown on special warm media (abx that kill nf found in vagina) – Thayer Martin (culture done less often). Currently most facilities do “DNA probe" or nucleic acid amplification test.

Front 17

Escherichia coli

Back 17

Dis: UTI, sepsis (after surgery), neonatal mengitis and "traveler's diarrhea" are most common. Causes confusion in elderly. E. Coli 0157:H7 (from cows) causes hemorrhagic colitis.

Chxs: GNR, ferment lactose

Habitat is the colon. Colonizes vagina and urethra. Acquired during birth in neonatal meningitis and by the fecal-oral route in diarrhea.

Lab dx: Gram stain and culture. Typing of organism for O & H antigens.

Estimate ~75-85% UTIs caused by E. coli

Front 18

Salmonella species

Back 18

Dis: Enterocolitis. Sepsis with abscesses occasionally.

Chxs: GNR, non-lactose fermenting

Habitat is the enteric tract of humans and animals. Transmission is by the fecal oral route.

Lab dx: Culture

S. typhi: causes typhoid fever (thypoid mary carrier state), human only source, not typical to other salmonella diseases, rare in US bc of vaccine

S. Enterididis: all of salmonella species that cause GI infx (diarrhea/vomiting)

Front 19

Shigella species

Back 19

Disease: enterocolitis (dysentery: large amounts of water in diarrhea- can cause dehydration)

Chxs: GNR, non-lactose fermenting

Habitat is the human colon only; unlike Salmonella there are no animal carriers for Shigella. Transmission is by the fecal-oral route.

Lab dx: Culture

Front 20

Campylobacter jejuni

Back 20

Diseases: enterocolitis - one of the most common causes (more so than salmonella/shigella)

Chxs: curved (comma-shaped) GNR

Habitat is human and animal feces. Transmission is by the fecal oral route.

Lab dx: gram stain and culture on special agar.

Front 21

Klebsiella pneumoniae

Back 21

Diseases: Pneumonia (aspiration of vomitus is a risk factor, UTI and sepsis. Can cause liver abscesses in diabetics.

Chxs: GNR, polysacchardide capsule, ferments lactose.

Habitat is the upper respiratory and enteric tracts.

Lab dx: Gram stain and culture

Front 22

Enterobacter cloacae

Back 22

Diseases: UTI, nosocomial infections.

Characteristics: Ferments lactose.

EXTREMELY ABX RESISTANT

Front 23

Serratia marcescens

Back 23

Diseases: Nosocomial infections – pneumonia, UTIs sepsis.

Chxs: GNR, highly antibiotic resistant

Lab dx: Culture – red pigmented colonies

Front 24

Proteus species

Back 24

Diseases: UTI and sepsis

Chxs: GNR, non-lactose fermenting

Habitat: human colon and the environment (soil & water)

Lab dx: gram stain and culture. Spreads across agar plate, not just colonies like other bacteria.

Front 25

Helicobacter pylori

Back 25

Diseases: Gastritis (is a risk factor for stomach cancer) and peptic ulcer disease (PUD). Infection is risk factor for gastric carcinoma.

Chxs: Curved GNR

Habitat: Human stomach. Transmission is by ingestion.

Lab dx: Serologic tests (initial dx). “Urea breath test”- bacteria turns urea into ammonia and pt will exhale CO2- and fecal antigen test (both r test for a cure). Gram stain and culture.

*is starting to resist abx

Front 26

Pseudomonas aeruginosa

Back 26

Dis: Wound infection, UTI, pneumonia and sepsis. Important cause of nosocomial infections. Puncture wound- if pt is wearing athletic shoes, more at risk for psuedomonas. Fear for bone infx

Chxs: GNR, non-lactose fermenting. Produces blue-green pigment.

Habitat is mainly water sources.

Lab Dx: Gram stain & culture

Front 27

Bacteroides fragilis

Back 27

Dis: Most common cause of serious anaerobic infections: peritonitis and other intra-abdominal infections, septicemia.

Chxs: Anaerobic, non-spore-forming, gram negative rods.

Habitat: Bacteroides spp. are predominat organisms of colon.

Lab dx: Gram stain, anaerobic culture and sensitivities.

Front 28

Hemophilus influenzae

Back 28

Dis: Meningitis, otitis media, sinusitis, pneumonia, epiglottitis

Chxs: Small gram neg. coccobacilli. Pleomorphic- various forms or "cocco- baccilus". Type b capsule and non-typeable strains.

Habitat is the upper respiratory tract. Transmission is via respiratory droplets.

Lab dx: Gram stain and culture on chocolate agar

Front 29

Moraxella catarrhalis

Back 29

Dis: Respiratory pathogen. Otitis media, sinusitis, bronchitis, pneumonia.

Chxs: Gram negative cocco-baccilus. Transmitted by respiratory aerosol. Most produce beta-lactamase.

Lab dx: Routine culture and sensitivities

Front 30

Legionella pneumophilia

Back 30

Diseases: Legionnaires' disease (atypical pneumonia), pontiac fever (usually seen in older ppl).

Chxs: GNR but stains poorly. Difficult to grow.

Habitat is environmental water sources. Transmission is via aerosol. Person to person transmission does not occur.

Lab Dx: Usually diagnosed serologically or urine antigen test.

Front 31

Bordetella pertussis

Back 31

Disease: Whooping cough (pertussis)

Chxs: Small gram negative rods.

Habitat: Human respiratory tract. Transmission via respiratory droplets.

Lab Dx: Culture on Bordet-Gengou agar. PCR

Front 32

Pasturella multocida

Back 32

Disease: Wound infections usually from bites. Puncture wound infections- onset is usually rapid w/ in 24 hrs.

Chxs: Gram negative rods

Habitat: Mouth of cats and dogs and other animals

Front 33

Treponema pallidum

Back 33

Disease: Syphilis. Primary syphilis- causes genital ulcer. Secondary syphilis- rash (serological test for antibodies). Tertiary syphilis- lumbar puncture (csf).

Chxs: Spirochetes. Not seen on Gram stain.

Habitat: Human genital tract. Transmission by sexual contact and from mother to fetus.

Lab Dx: Dark-field microscopy. Serologic tests.

Front 34

Borrelia burgdorferi

Back 34

Disease: Lyme disease

Chxs: Spirochestes. Not seen on Gram stain.

Habitat: Reservoir is white-footed mouse. Transmission is by ticks (needs to be attached for at least 24 hrs)

Lab dx: Serologic tests. Confirmed by Western Blot

Front 35

Mycoplasma pneumoniae

Back 35

Disease: Atypical pneumonia. Ear infections.

Chxs: Smallest free living organisms. No cell wall therefore not seen on Gram stain.

Habitat is the respiratory tract. Transmission is via respiratory droplets

Lab Dx: Diagnosed serologically – complement fixation test and Agglutinin. (Usually clinical dx)

Front 36

Chlamydia trachomatis

Back 36

Dis: Urethritis, cervicitis, pelvic inflammatory disease, conjunctivitis, lymphogranuloma venereum and trachoma. Also pneumonia in infants.

Chxs: Obligate intracellular parasite. Not seen on Gram stain.

Lab dx: Most often “DNA probes.” Others: cell culture, serologic and antigen tests.

Front 37

Chlamydia pneumoniae

Back 37

Disease: Atypical pneumoniae (most common in young ppl)

Habitat: Human respiratory tract. Transmission is via respiratory droplets.

Lab dx: Serologic tests. Usually clinical dx.

Front 38

Rickettsia rickettsii

Back 38

Disease: Rocky Mountain spotted fever

Chxs: Obligate intracellular parasites. Not seen on Gram stain.

Lab Dx: Stain and culture not useful. Usually serologic dx or clinical only.

Front 39

Mycobacterium tuberculosis

Back 39

Disease: Tuberculosis

Chxs: Aerobic, acid-fast rods. Does not Gram stain. Grows slowly.

Habitat: Human lungs. Transmission via respiratory droplets.

Lab dx: Acid-fast stain (Ziehl-Nelson, Kinyoun). AFB culture x3- separated by 3 days (only way to make definitive dx- takes 3-4 wks). Rapid identification using DNA probes.

Front 40

Human Immunodeficiency Virus (HIV)
Retrovirus

Back 40

Dis: HIV disease, acquired immunodeficiency syndrome (AIDS)

Transmission: Transfer of body fluids. Also transplacental and perinatal.

Pathogenesis: Attaches to CD4 cell on helper T cells and other cells.

Lab dx: HIV antibody by Elisa, confirmed with Western
Blot. HIV RNA by PCR

Front 41

Herpes simplex virus (HSV)
Type 1 (DNA virus)

Back 41

Dis: Fever blisters, cold sores, keratitis (eye infx). Primary infx is more serious and causes encephalitis (no antigens for virus)

Transmission: By saliva or direct contact with vesicle

Pathogenesis: Latent in trigeminal ganglia

Lab dx: Cell culture. Serologic tests.

Front 42

Herpes simplex virus (HSV)
Type 2 (DNA virus)

Back 42

Diseases: Herpes genitalis, asceptic meningitis, neonatal infection (primarily for primary infx in mother).

Transmission: Sexual contact, through birth can in neonates

Pathogenesis: Vesicular lesions on genitalia. Latent in ganglia.

Lab dx: Cell culture. Serologic tests. PCR test.

Front 43

Varicella-Zoster virus
(DNA virus)

Back 43

A. Diseases: Chickenpox (vairicella) and shingles (Herpes zoster)

Transmission: Varicella by respiratory droplets. Herpes zoster is not transmitted but occurs by reactivation of latent virus.

Pathogenesis: Latent in ganglia after chickenpox.

Lab dx: Cell culture.

Front 44

Epstein-Barr Virus (EBV)
(DNA virus)

Back 44

Diseases: Infectious mononucleosis (Mono), Burkett’s lymphoma in East African children. A case where virus can cause cancer (B-cell lymphoma). Can also give u a hepatitis.

Transmission: By saliva. Starts in oropharynx (presents as sore throat) then gets into blood and into B-cells. Symptomatic Mono usually only occurs once, and children r usually asymptomatic.

Pathogenesis: Establishes latency in B lymphocytes.

Lab dx: Heterophil antibody positive (Mono-spot test). Lymphocytosis with atypical lymphocytes. EBV antibodies.

Front 45

Cytomegalovirus (CMV)
(DNA virus)

Back 45

Diseases: Congenital abnormalities. Mononucleosis-like illness, hepatitis

Transmission: By body fluids. Transmitted across placenta and by organ transplantation.

Lab dx: Cell culture. Acute and convalescent antibody titers.

Front 46

Adenovirus (DNA virus)

Back 46

Diseases: Upper and lower respiratory tract infections; common cold (URI), pharyngitis, pneumonia. Also enteric strains.

Transmission: Respiratory droplets.

MOST COMMON CAUSE OF PNEUMONIA IN KIDS IS VIRAL PNEUMONIA.

Pathogenesis: Infects epethelium of respiratory tract and eyes.

Lab dx: Usually clinical diagnosis for URI and pharyngitis.cell culture. Acute and convalescent antibody titers.

Front 47

Human Papillomavirus
(DNA virus)

Back 47

Diseases: Warts (verrucae), genital warts (condyloma acuminata). Associated with cervical cancer and cancer of penis.

Transmission: Direct contact of skin or genital lesions.

Lab dx: Clinical diagnosis. DNA hybridization tests.

Front 48

Parvovirus B 19
(DNA virus)

Back 48

Diseases: Erythema infectiosum (Fifth’s disease- "slap cheek"), aplastic anemia, Arthritis and hydrops fetalis.

Transmission: Respiratory droplets and transplacental.

Lab dx: Serologic tests.

Front 49

Influenza Virus (RNA}

Back 49

Disease: Influenza A (most severe), B and C. (aka FLU) - not the same as the common cold

Chxs: Segmented genome

Transmission: Respiratory droplets

Pathogenesis: Infects epethelium of respiratory tract

Clinical diagnosis, rapid antigen tests, cell cultures of naso-pharyngeal washing.

Front 50

Parainfluenza Virus (RNA)

Back 50

Diseases: Common cold, bronchiolitis and croup in children (upper respiratory disease "barking cough").

Transmission: Respiratory droplets

Lab dx: Clinical, cell culture, acute and convalescent antibody titers

Front 51

Respiratory Syncytial Virus (RSV)
(RNA)

Back 51

Diseases: Bronchiolitis and pneumonia in infants.

Transmission: Respiratory droplets

Lab dx: Cell culture, rapid antigen test - nasopharyngeal culture "wash"

Front 52

Coronavirus (RNA)

Back 52

Diseases: Common cold and SARS (Severe Acute Respiratory Syndrome)

Transmission: Respiratory droplets

Lab dx: Clinical diagnosis.

Front 53

Coxsackieviruses (RNA)

Back 53

Diseases: Herpangina (mouth blisters in infants and young chidren- soft pallet of the mouth), pericarditis, asceptic meningitis, possibly type 1 diabetes mellitus.

Transmission: Fecal-oral route

Pathogenesis: Initial site of infection is orophaynx, then settles in GI tract.

Lab dx: Cell culture, acute and convalescent antibody titers.

Front 54

Rhinoviruses (RNA)

Back 54

Diseases: Common cold

Transmission: Respiratory droplets and hand to-nose contact

Lab dx: Clinical dx

Front 55

Norwalk Virus (Norovirus)
(RNA)

Back 55

Diseases: Gastroenteritis (diarrhea on cruise ships), very common in nursing homes.

Transmission: Fecal-oral route.

Lab dx: Clinical diagnosis, PCR

Front 56

Rotavirus (RNA)

Back 56

Gastroenteritis (diarrhea) especially in children. Common deaths by diarrhea bc of dehydration.

Transmission: Fecal-oral route.

Lab dx: Clinical diagnosis.

Front 57

Hepatitis A Virus (HAV)
(RNA)

Back 57

Diseases: Hepatitis A

Transmission: Fecal-oral route. Person-to-person. Children are most likely t get it at day care.Common to get from shell-fish.

Pathogenesis: Replicates in GI tract and then spreads to liver. No chronic form of hepatitis. Chxs for pt to be jaundiced.

Lab dx: Serologic tests.

Front 58

Hepatitis B Virus (HBV)
(DNA)

Back 58

Diseases: Hepatitis B. Both acute (95%)/chronic (5% = >6 mo) forms. A % of ppl will develop hepatocellular cancer from chronic form.

Transmission: Blood, sexual intercourse, during birth (All pregnant women r tested). IV drug users.

Pathogenesis: About 5% of cases progress to chronic hepatitis B.

Lab dx: Serologic tests, DNA viral load (PCR)

Front 59

Hepatitis C Virus (HCV)
(RNA)

Back 59

Diseases: Hepatitis C, associated with hepatocellular cancer. Both acute and chronic. Acute presentation is not very severe, most ppl will not see MD

Transmission: Blood is responsible for most cases. Sexual and perinatal transmission accounts for small number of cases. IV drug users.

Pathogenesis: Approximately 75% of cases are chronic.

Lab dx: Serologic tests, RNA viral loads (PCR)

Front 60

Hepatitis D Virus
(RNA)

Back 60

Diseases: Hepatitis D (hepatitis delta). Defective virus, cannot multiply unless infected person also had Hep B. Acute form most common among pregnant women.

Transmission: Blood, sexually and mother to child.

Pathogenesis: Defective virus that uses surface antigen of hepatitis B. Replicates only in cells already infected with hepatitis B. Chronic hepatitis develops.

Lab dx: Serologic tests.
Cannot tell 1 form of Hep from another w/o serologic test

Front 61

Hepatitis E Virus

Back 61

Diseases: Hepatitis E

Transmission: Fecal-oral route.

Pathogenesis: No chronic form of hepatitis.

Front 62

West Nile Virus

Back 62

Disease: West Nile Fever (not very severe), meningitis and encephalitis (only a small % of older ppl get it), flaccid paralysis (tends to be in younger ppl - paralysis is temporary).

Transmission: bite of infectious mosquito, Birds r the reservoir.

Lab dx: Serological tests: serum or CSF for WNV IgM and/or IgG

Front 63

Dermatophytes: Genus Trichophyton
Microsporum and Epidermophyton

Back 63

FUNGI CAUSING CUTANEOUS MYCOSES

Diseases: Tinea capitis (ring worm) - fungal infx on head), tinea cruris (jockage) - groin area, tinea corporis - on trunk or extremities, tinea pedis - athletes foot

Chxs: Molds-not dimorphic. Habitat = human skin. (Microsporum infects dogs and cats also)

Transmission: Direct contact with skin scales.

Lab dx: KOH wet mount for presence of hyphae. Fungal culture (Sabouraud’s agar).

Front 64

Candida albicans and other species

Back 64

FUNGI CAUSING CUTANEOUS MYCOSES

Diseases: Candidiasis of skin, diaper rash, chronic paronychia (under nails). Also vaginitis.

Chxs: Yeast (likes to be warm and moist).

Lab dx: KOH wet mount. Fungal culture.

Front 65

Sporothrix schenckii

Back 65

FUNGI CAUSING SUBCUTANEOUS MYCOSES

Disease: Sporotrichosis

Chxs: Thermally dimorphic. Lives in soil and vegetation.

Transmission: Spores enter skin in puncture wounds by rose thorns and other sharp objects in garden.

Lab dx: Gram stain: cigar-shaped budding yeasts in pus. Culture on Sabouraud’s agar.

Front 66

Coccidioides immitis

Back 66

FUNGI CAUSING SYSTEMIC MYCOSES

Disease: Coccidioidomycosis (Valley fever)

Chxs: Thermally dimorphic. Habitat = soil of aid regions.

Transmission: Inhalation of airborne spores.

Lab dx: Fungal culture of sputum or tissue. Serologic tests.

Front 67

Histoplasma capsulatum

Back 67

FUNGI CAUSING SYSTEMIC MYCOSES

Disease: Histoplasmosis

Chxs: Thermally dimorphic Ohio and Mississipi areas

Transmission: Inhalation of airborne spores

Lab dx: Fungal culture of sputum or tissue.

Front 68

Blastomyces dermatitidis

Back 68

FUNGI CAUSING SYSTEMIC MYCOSES

Disease: Blastomycosis

Chxs: Thermally dimorphic. Upper Midwest of the US.

Transmission: Inhalation of airborne spores

Lab dx: Fungal culture of sputum or skin lesions.

Front 69

Candida albicans

Back 69

FUNGI CAUSING OPPORTUNISTIC MYCOSES

Diseases: Thrush (yeast infx in mouth common in children), disseminated candidiasis, esophagitis

Chxs: Normal flora of mucous membranes as a yeast. Forms pseudohyphae and hyphae when invades tissue.

Transmission: Part of normal flora. No person to person Transmission.

Lab dx: KOH wet mount or Gram stain (Gram positive). If only yeasts are found = colonization.

Front 70

Pneumocystis jiroveccii
(previously Pneumocystis carinii)

Back 70

FUNGI CAUSING OPPORTUNISTIC MYCOSES

Disease: Pneumonia (only seen in immunodepressed ppl, especially in HIV positive patients)

Chxs: Previously classified as protozoan. Molecular evidence suggests it is a yeast but medically with characteristics of protozoan.

Transmission: inhalation

Lab dx: Sputum stain (not Gram stain) Examination of bronchial lavage, bronchoscopy

Front 71

Cryptococcus neoformans

Back 71

FUNGI CAUSING OPPORTUNISTIC MYCOSES

Disease: Cryptococcal meningitis

Chxs: Encapsulated yeast. Not dimorphic. Associated with pigeon droppings.

Pathogenesis: Influenza-like illness then spread via bloodstream to meninges.

Lab dx: Latex agglutination test detects antigen in CSF. India ink preparation of CSF. Fungal culture of CSF or sputum.

Front 72

Aspergillus fumigatus

Back 72

FUNGI CAUSING OPPORTUNISTIC MYCOSES

Disease: Invasive aspergilllosis

Chxs: Mold (grows on food only causes infection in immunocompromised). "Fungus Balls in Lungs" - restricting lung disease, hardening of lungs (not very elastic).

Transmission: Inhalation of airborne spores.

Pathogenesis: Opportunistic infection.

Lab dx: Fungal culture

Front 73

Mucor and Rhizopus
species

Back 73

FUNGI CAUSING OPPORTUNISTIC MYCOSES

Disease: Mucormycosis (sinuses- in elderly diabetic pts, malignant otitis externa - "swimmers ear" not common in young ppl)

Characteristics: Mold.

Transmission: Inhalation of airborne spores

Lab dx: Microscopic examination for hyphae. Fungal culture.

Front 74

Giardia lambia

Back 74

Disease: Giardiasis - diarrhea and other gastrointestinal symptoms. "Travelers Diarrhea", "Backpackers Disease"

Transmission: ingestion of the cyst in fecally contaminated food and water. Asymptomatic carriers pass cyst in stools.

Lab dx: Ova and parasites (trophozoites and cysts) Stool antigen (ELISA)

Front 75

Entamoeba histolytica

Back 75

Disease: Amebic dysentery and liver abscess

Transmission: Fecal-oral transmission of cysts. Common to have asymptomatic carriers. Human resevoir.

Pathogenesis: Trophozoites invade colon epethelium, can spread to liver.

Front 76

Cryptosporidium parvum

Back 76

Disease: Cryptosporidiosis (diarrhea)

Transmission: Fecal oral. Human and animal resevoir.

Pathogenesis: Attach to wall of small intestine – no invasion.

Lab dx: Acid fast stain of stool to see oocysts.

Front 77

Trichomonas vaginalis

Back 77

Disease: trichomoniasis - women causes vaginitis, in men may cause urethritis.

Transmission: sexual contact

Lab dx: Wet mount (trophozoites)

Front 78

Toxoplasma gondii

Back 78

Disease: Toxoplasmosis

Transmission: Ingestion of cysts from cat feces or raw meat.

Pathogenesis: infect brain, eyes, liver

Lab dx: Serologic tests. Radiology: CT scan of brain.

Front 79

Plasmodium species

Back 79

Disease: P. falciparum causes Malaria

Pathogenesis: Life cycle involves infection of liver cells and red blood cells (hemolytic anema).

Transmission: female Anopheles mosquitoes.

Lab dx: Thick and thin blood smears. Also PCR test & ELISA.

Front 80

Ascaris lumbricoides

Back 80

Disease: Ascariasis - may cause abdominal pain or ascaris pneumonia
Transmission: Humans are infected by eating eggs in soil contaminated with soil containing eggs. Re-infection common

Lab dx: Ova and parasites (eggs seen) Eosinophilia

Front 81

Enterobius vermicularis

Back 81

Disease: pinworm infection -perianal pruritis (common in kids- scratching the butt)

Transmission: By ingesting eggs. Humans only host. At night female worm will exit anus and deposit eggs on skin.

Lab dx: “Scotch tape” test

Front 82

Taenia saginata

Back 82

Disease: Taeniasis (beef tapeworm) = muscle disease

Lab dx: Gravid proglottids visible in stool. Eggs infrequently seen.

Front 83

Taenia solium

Back 83

Disease: Taeniasis ande cysticercosis (if pt ingests eggs- larvae will get into brain tissue, body will wall them off and not multiply, but space occupying lesion causes seizers and heachaches

Lab dx: Gravid proglottids visible in stool. Eggs infrequently seen.