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105 Cards in this Set
- Front
- Back
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unique components of the bacterial cell wall
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1. murein (peptidoglycan)
2. lipopolysaccharide (LPS) 3. teichoic acids (in some types) |
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1) 2 functions of bacterial capsules
2) type of colonies formed by encapsulated bacteria |
1)antiphagocytic (S. pneumoniae), promote adherence (S. mutans)
2) smooth, mucoid like colonies |
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Gram + Cell Wall
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-thick peptidoglycan
-cross-linked NAG and NAM make up murien sac -teichoic acids (promote adhesion) -purple in gram stain |
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Gram - Cell Wall
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-thin peptidoglycan layer
-murein forms periplasmic gel with very little crosslinking -outer membrane present externial to periplasm -Braun's/murein lipoprotein attaches periplasm to OM -negatively charged outer surface -pink in Gram stain |
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Structure of Outer Membrane of Gram -
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-phospholipid bilayer with LPS endotoxoin as its outer leaflet
-LPS is made up of lipid A (causes toxic immune rxn), core polysaccharide, and O Ag (surface Ag) |
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Bacterial Ribosomes
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70S made up of 30S and 50S subunits
-target of many antimicrobials |
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Spores
1)What are they? 2)Who makes them? 3)What do they cause? 4)What can they withstand |
1)small, dehydrated, metabolically inactive bacterial forms
2)G+ bacilli (Clostridium, Bacillus spp) 3)anthrax, gag gangrene, tetanus, botulism 4)extreme pH and temperature, chemicals, and some radiation |
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What is a virus?
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set of RNA or DNA wrapped into a protein shell (capsid)
-all together forms a virion |
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Viral Envelope
1)what is it? 2)it's derived from...? 3)what deactivates it? 4)how does it compare to non-enveloped viruses |
1)lipid membrane coating of some viruses
2)cytoplasmic or nuclear membranes of host cell 3)detergents, soaps, disinfectants (rarely makes it through GI) 4)non-enveloped viruses are tougher |
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What are the receptors for the following viruses?
1) influenza A 2)adenovirus 3)EBV 4)HIV 5)rabies 6)rhinovirus |
1)sialic acid
2)integrins 3)CR2 4)CD4 5)Ach receptor 6)ICAM-1 |
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Interferons
1) what makes gamma INF? 2) what do alpha and beta INF inhibit? 3)what proteins do they alter? |
1. Ag stimulated T cells
2. RNA and DNA viruses 3. Mx proteins, protein kinase, ribonuclease |
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Interferons
1) what makes gamma INF? 2) what do alpha and beta INF inhibit? 3)what proteins do they alter? |
1. Ag stimulated T cells
2. RNA and DNA viruses 3. Mx proteins, protein kinase, ribonuclease |
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Retroviridae
1. what is it? 2. example 3. Tx (4 inhibitors) |
1. enveloped ss+RNA
2. HIV 3. a) RT inhibitors (nucleoside inhibitors-AZT and non nucleoside inhibitors-bind near active site) b)protease inhibitors c) fusion inhibitors |
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Herpes Viruses
1. what is it? 2. Tx (4 meds)in order of use |
1. enveloped DS DNA
2. Acyclovir (HSV, VZV), Ganciclovir (CMV), Foscarnet, Cidofovir |
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1. Acyclovir
2. Ganciclovir 3. Foscarnet 4. Cidofovir |
1. HSV, VZV, inhibits viral DNAp
2. nucleoside analog of guanosine, bone marrow supression 3. non-nucleoside inhibits DNAp, renal impairment (>25%) 4. nucleoside analog, highly nephrotoxic |
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Orthomyxoviridae
1. what is it? 2. example 3. Tx |
1. enveloped ss-segmented RNA
2. influenza virus (A and B) 3. A&B: zanamivir(intranasal), oseltamivir (orally) only A: Amantadine, Rimantidine |
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Paramyxoviridae
1. what is it? 2. 3 examples 3. Tx |
1. enveloped ss-nonsegmented RNA
2. RSV, measles, mumps 3. ribavirin(only RSV)-nucleoside analog of guanine |
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Picornaviridae
1. what is it? 2. example |
1. naked ss+RNA
2. enteroviruses (Coxsackie, Echoviruses - polio, meningitis, mycarditis, skin leasions, hepatitis A) |
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Adenovirus
1. what is it? 2. what's it cause? 3. Tx |
1. naked ds DNA
2. respiratory/conjunctival infections, diarrhea 3. no treatment |
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Flavivirus
1. what is it? 2. example 3. Tx |
1. enveloped ss+RNA
2. Hep C 3. alpha INF and ribavirin |
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Hepadnavirus
1. what is it 2. example 3. Tx |
1. enveloped partially dsDNA
2. Hep B 3. alpha INF and lamivudine |
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Rotavirus (Reovirus)
1. what is it? 2. what's it cause? |
1. naked ds-segmented RNA
2. diarrhea |
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What grows on . . .
1. blood agar 2. MacConkey |
1. yeasts, gram +, gram - uropathogens
2. only G- (selective) |
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MIC
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minimum inhibitory concentration: what's the least amount of antimicrobial you need to inhibit growth
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community acquired pneumonia
1. usually caused by (3)... 2. more rarely caused by (2)... 3. can also be caused by (3)... |
1. S. pneumoniae, H. influenzae, M. catarrhalis
2. S. aureus, Enterobacteriaceae 3. C. pneumoniae, M. pneumonieae, Legionella pneumophila |
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How does normal flora of mouth change in the hospital?
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more G- bacilli (Enterobacteriaceae, P. aeruginosa) which become the predominant cause of nosocomial pneumoniae
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What are the most common blood culture isolates?
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Coagulase-neg staphylococci (S. epidermidis)
-usually contaminant |
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Common causes of meningitis (6)
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S. pneumoniae, N. meningitidis, L. monocytogenes, S. agalactiae (newborns), E. coli (newborns), H. influenzae
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media used for culturing owunds and aseptically obtained body fluids
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anaerobic
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Fungal cultures
1. use bacterial cultures for... 2. use fungal cultures for ... |
1. yeasts (chlamydia, C. neoformans)
2. molds (aspergillus, tinea agents), dimorphic fungi (Histoplasma, Coccidioides, Blastomyces, Sporothrix), slow growing bacteria (Nocardia) |
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Mycobacteria
1. initial tests 2. digest specimen with... |
1. PPD skin test and AFB smear
2. mucolytic agent and NaOh=H |
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Use culture independent methods for difficult to grow or slow frowing organisms
1. DFA 2. ELISA 3. nucleic acid hybridization 4. PCR 5. Latex agglutination |
1. legionella, cryptosporidium, giardia, pneumocystis
2. gonorrhea, chlamydia, HIV, hepatitis, legionella 3. chlamydia, gonorrhea 4. HIV, hepatitis, mycobacteria, chlamydia 5. agents of meningitis (for CSF) |
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What do R groups of antibiotics affect?
What do they determine? |
-affect susceptibility of Ab to B-lactamase
-determine ability of Ab to pass trough OM of G- |
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peptodglycan is synthesized in (1)...as a unit of (2)...and the final step is (3)...catalyzed by (4)...
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1. cytoplasm
2. GlcNac-MurNac pentapeptide 3. crossliking via transpeptidase rxn 4. PBPs |
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What percent of staph are B-lactamase resistant?
What antibiotics does this make them R to? |
95-98%
-penicllin, ampicillin, amoxicillin |
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MRSA
1. resistance does not involve... 2. it is mediated by.. |
1. B-lactamase
2. altered PBP-2 involved in PG synthesis |
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2 ways vancomycin inhibits PG synthesis
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1. addition of GlcNac to MurNac
2. transpeptidation (crosslinking) rxn |
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can be used as a substitute in penicillin allergic pts
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erythromycin
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antibiotic with a significant potential for renal and ototoxicity
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aminoglycosides
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favorite antibiotic for treating community acquired pneumonia
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levofloxacin
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one of few oral agents with activity against P. aeruginosa
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ciprofloxacin
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what are the functions of topoisomerase II and IV?
What inhibits them? |
-topoisomerase II: temporarily breaks DNA strand allowing DNA to unwide, converting from a + to a - supercoil
-topo IV: separates daughter DNA once replicaiton is complete -quinolones inhibit them |
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how does metronidazole work?
What does it have important activity against? |
-enters cell by passive diffusion and produces metabolites that damage bacterial DNA (requires low O2)
-important activity against obligate anaerobes |
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What is SMX and what does it inhibit?
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sulfamethoxazole, a component of Bactrim
-structural analog of PABA -inhibits folic acid synthesis (can't make DHF) |
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What is TMP and what does it inhibit?
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trimethoprim, a component of Bactrim
-inhibits conversion of DHF to THF preventing folic acid synthesis and DNA synthesis (b/c THF is used for making purines, pyrimidines, and DNA) |
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5 clinical uses of Bactrim
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1. UTI
2. otitis media 3. pneumocystis pneumonia 4. traveler's diarrhea 5. acute exacerbations of chronic bronchitis |
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Daptomycin
can't get into (1)...so it should NOT be used for (2)... |
1. alveoli
2. pneumonia |
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Nitrofurantoin
only used for (1)...so do NOT use for (2) -it appears to damage (3)... |
1. uncomplicated cystitis
2. pyelonephritis (kidney infection) 3. bacterial DNA |
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Erysipelas
1. what is it? 2. where does it present? 3. history often includes... |
1. rapid spreading S. pyogenes infection of the deeper layers of the dermis
2. often on face 3. sore throat |
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Unusual organisms seen with...
1. human bites 2. animal (esp cat bites) 3. freshwater injuries 4. saltwater injuries |
1. Eikenella corrdens
2. Pasteurella multisided 3. Aeromonas hydrophilic 4. Vibrio vulnificus |
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3 causes of Granulomatous skin lesions
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Mycobacterium, disseminated fungal infections, sporothrix
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5 S. aureus toxins
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1. alpha toxin: inserts in lipid bilayer to form pores
2. exfoliatin: intercellular splitting of epidermis 3. pyrogenic toxin super antigens (PTSAgs): bind MHC II, induce massive cytokine release 4. enterotoxin: food poisoning 5. toxic shock syndrom toxin-1 |
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Antiphagocytic mechanisms of S. aureus
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1. protein A competes with phagocytes for available IgG-Fc sites, diminishing opsonization
2. coagulase retards migration of phagocytes to site of infection |
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Bullous impetigo
1. what causes it? 2. localized form of what? |
1. Exfoliatin-producing strains of S. aureus
2. scalded skin sydrome |
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Cause of more than 90% of acute osteomyelitis cases in children
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S. aureus
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Manifestations caused by S. aureus toxins
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1. scalded skin syndrome: exfoliatoxin
2. toxic shock syndrom: TSST-1 3. food poisoning: enterotoxin |
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Treatment of S. aureus
1. 80-90% of strains are resistant to what? 2. commonly use... 3. if strain is reistant to beta lactams, what is used? |
1. penicillin
2. penicillinase resistant beta-lactams (methicillin, nafcillin, 1st gen cephalosporins) 3. vancomycin, clindamycin, erythromycin |
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3 drugs given as chemoprophylaxis during high risk surgery (hip and cardiac valve replacements)
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methicillin, cephalospoirns, vancomycin
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S. epidermidis (coag neg staph)
1. common colonizers of... 2. most common...in cultures |
1. skin and medically implanted devices (catheters, valves, etc)
2. skin contaminant |
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Streptococci
1. significant portion of normal flora in... 2. O2 requirements 3. gtown on what type of agar? |
1. oropharynx
2. falculatative anaerobes 3. blood agar (hemolysis very evident) |
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3 Classifications of Strep
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1. Pyogenic: group A (S. pyogenes), group B (S. agalactiae), beta hemolytic
2. Pneumococci: S. pneumoniae, alpha hemolytic, antigenic polysaccharide capsule 3. Viridans: S. salivarius, S. mitis, alpha hemolytic |
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Group A strep
1. example 2. type of hemolysis 3. surface proteins 4. products |
1. S pyogenes
2. beta hemolysis 3. M protein, protein F, lipoteichoic acid (LTA) 4. streptolysin O, SPEs, C5a peptidase, streptokinase |
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most common bacterial cause of pharyngitis in school age children
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group A strep (S. pyogenes)
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2 examples of poststreptococcal sequelae
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1. acute rheumatic fever: follow respiratory inf, can make Abs that react with both heart tissue and strep Ags
2. acutre glomerulonephritis: follows respiratory or skin infection, deposition of Ag-Ab complexes in glomeruli |
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expression of M protein and protein F in S. pyogenes is environmentally regulated
1. high O2 favors... 2. high CO2 favors |
1. protein F adherence to Langerhans cells
2. M protein interaction with keratinocytes |
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Puerperal infection
1. caused by 2. infection of... |
1. S. pyogenes
2. endometrium at or near delivery |
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Scarlet fever
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S. pyogenes with cimcumoral pallor rash (red all over face ezcept pale area around mouth/nose) and strawberry tongue
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Tx of group A strep (S. pyogenes)
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penicillin G, or if allergic, erythromycin
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Enterococci
1. posses....Ag 2. type of hemolysis 3. normal flora of... 4. cause... 5. best choice of treatment 6. often R to... |
1. Lancefield group D
2. non or alpha hemolysis 3. intestine 4. opportunistic UTI and some wound/soft tissue infections 5. amplicillin 6. beta-lactams, aminoglycosides, sulfonamides, tetracyclines, erythromycin, and cephalosporins |
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Clostridia
1. what are they? 2. what exotonis do medically important strains produce? |
1. large, spore-forming G+ bacilli anaerobe
2. C. perfringens: hemolytic C. tetani/botulinm: neurotoxin C. difficile: enterotoxin |
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Nonsporulating G+ bacilli
1. normal skin flora 2. normal colon flora |
1. Proprionibacterium
2. Eubacterium |
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Anaerobic infections are often treated empirically.
1. tx for oral infections 2. tx for infections below diaphragm |
1. penicillin
2. beta-lactamase resistant drugs(clindamycin, metronidazole, cepalosporan) |
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Clostridium perfringens
1. what is it? 2. type of hemolysis? 3. produces... 4. causes 5. Tx |
1. large,G+ bacilli
2. double zone 3. gas, exotoxins (alpha, theta, enterotoxin) 4. gas gangrene, food poisoning, anaerobic cellulitis, endometritis 5. massive penicillin dose (give clindamycin and cephalosporins to take care of Enterobacteriaceae contaminants) |
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Bacteroides Fragilis
1. what is it? 2. surface features 3. most strains produce... 4. most distinctive feature is... 5. Tx |
1. anaerobic G- bacilli
2. LPS (less toxic), polysaccharide capsule, pili 3. superoxide dismutase (relatively tolerant of O2) 4. ability to produce abscess 5. clindamycin, metronidazole, chloramphenicol |
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Rocky Mt Spotted fever
1. caused by 2. transmitted by 3. symptoms 4. diagnostic feature 5. Tx |
1. R. rickettsi
2. ticks 3. headache, fever, rash, mental confusion, myalgia 4. rash on palms/soles then spreads to trunk 5. doxycycline (chloramphenical if that doesn't work) 3. |
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Louse-borne Typus Fever
1. caused by 2. transmitted via 3. symptoms 4. complications |
1. R. prowazzeki
2. body louse 3. fever, headache, malaise, myalgia, rash that spreads from trunk to extremities 4. CNS dysfunction, myocarditis |
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Endemic Typhus
1. caused by 2. transmitted via 3. symptoms 4. tx 5. mortality |
1. R. typhi
2. rat flea (Xenopyslla cheopsis) 3. fever, headache, myalgia, rash that spreads from trunk to extremities 4. tetracycline (chloramphenicol only if that doesn't work) 5. rare |
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Scrub typhus
1. caused by 2. transmitted via 3. symptoms |
1. Orientia tsutsugamushi
2. rodent mite larvae (chiggers) 3. local eschar, fever, headache, rash, lymphadenopathy |
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Q fever
1. caused by 2. transmitted by...via... 3. symptoms |
1. Coxiella burnetti
2. goats, sheep, cattle...inhalation 3. abrupt onset of fever, headache, chills, NO rash |
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Ehrlichia
1. includes several species of...E. chaffeensis: 2. 2 examples 3. observation of... 4. symptoms 5. Tx |
1. WBC-associated bacteria
2. E. chaffeensis: HME Anaplasma phagocytophilum: HGE (2nd most common tickborne infection in US) 3. morulae inclusions in granulocytes/mononuclear cells 4. leukopenia, thrombocytopenia, anemia 5. doxycyclin |
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Bartonella
1. B. quinitana 2. B. bacilliformis 3. B. henselae |
1. trench fever
2. acute Oroya fever (sand fly) 3. cat scratch fever (tx: azithromycin or erythromycin) |
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Lyme disease
1. caused by 2. transmitted via 3. Osp in ticks; OSp in host 4. characteristic symptom 5. other symptoms 6. Tx |
1. Borellia burgedorfi
2. ixodes tick in nymph stage 3. OspA, OspC 4. bulls eye rash 5. fever, fatigue, arthralgia, neck stiffness 6. doxycycline, amoxicillin |
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Measles
1. what causes it? 2. what's found in lymphoid tissue? 3. transmitted via... 4. symptoms 5. complication |
1. enveloped ssRNA- (paramyxovirus)
2. Warton-Finkeldey cells 3. respiratory route 4. Koplik spots, rash 5. subacute sclerosing panencephalitis |
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Subacute Sclerosing Panencephalitis
1. begins..Measles 2. causes... 3. tx |
1. 2-10 years after measles infecction
2. slow onset of personality change, intellectial deterioration, motor dysfunction 3. none; gonna die |
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Rubella
1. what is it? 2. major concern is... 3. aka |
1. enveloped togavirus with ssRNA+
2. congenital rubella (mom gets infected in 1st trimester) 3. German/3-day measles |
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Parvovirus B19
1. what is it? 2. receptor is... 3. causes what in pts already compromised by chronic hemolytic process 4. manifests as what disease |
1. naked ssDNA virus
2. P Ag on progenitor RBC cells 3. aplastic anemia 4. erythema infectiosum (fifth disease) |
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erythema infectiosum
1. aka 2. caused by... 3. characteristic symptom 4. fetal infection can cause... |
1. fifth disease
2. parvovirus B19 3. slapped cheek rash 4. severe anemia leading to hydrops fetalis |
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Roseola Infant (exanthem subitum)
1. seen in what age group? 2. caused by... 3. clinical presentation |
1. 6mo-4yrs
2. HHV-6 (sometimes HHV-7) 3. sudden onset of high fever(3-5 days) and as soon as its gone, rash develops |
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Brucella
1. 3 types 2. enter and multiply inside.. 3. manifests as.. 4. tx |
1. B. abortus (cow), mellintis (sheep/goats), suis (pig)
2. macrophages of RES; cause granulomas 3. undulant fever 4. tetracycline/doxycycline |
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what kind of viruses are herpesviruses?
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large, enveloped dsDNA
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Varicella-zoster
1. characteristic symptom 2. becomes latent in.. 3. reactivation presents as.. 4. treatment |
1. rash with lesions in different stages of developent
2. sensory ganglion cells 3. zoster/shingles: rash over 1-3 dermatomes 4. acyclovir in 18+ yo |
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fungal cell wall
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mannan, glucan, chitin, ergosterol
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Diagnosis of fungal infection
1. use...solution 2. some yeasts are...with Gram stain 3. dye used to enhance detection 4. selective media used |
1. KOH
2. usually G+ 3. calciflour white 4. Sarbouraud's |
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only encapsulated fungus
-Ab plays a role in controlling infection |
Cryptococcus neoformans
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what symptom is characteristic of a fungal infection
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Neutropenia
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Antifungals that affect membrane sterols
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1. Polyenes (nystatin, amphotericin B): bind ergosterol
2. Azoles (ergosterol synthesis inhibitors): inhibit cytochrome P450 that converst LAN stero to ergosterol 3. Allylamines (terbinafine, naftitine): inhibit squalene epoxidase in early ergosterol synthesis |
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Antifungals affecting nucleic acid synthesis
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5-flucytosine (5-FC): inhibits protein synthesis, analog of cytosine, active against yeasts (CAndida)
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Antifungals affecting cell wall synthesis
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-Griseofulvin: only active against superficial mycoses
-Postassium iodide: cutaneous sporotrichosis -Tolnaftate: topic tx of dermatophytoses |
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most common tx of serious systemic fungal infections
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amphotericin B (despite toxicity) usually followed by an azole
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Dermatophytes
1. what are they? 2. caused by... 3. various skin sites are labeled as... |
1. superficial mycoses
2. Microsporum, Trichophyton, Epidermophyton 3. tinea diseases |
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Causes and symptoms of superficial mycoses
1. Pityriasis 2. Tinea nigra 3. Piedra |
1. Malassezia furfur; abnormal pigmentation, induration, scaling on trunk/arms
2. Hortaea werneckii; black macular lesions on plams/soles 3. Tricosporum cutaneum (white), Piedraia hortae (black; hair infection |
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Sporothricosis
1. caused by...found in.. 2. manifests as.. 3. look for...on diagnosis |
1. Sporothrix schenkii (dimorphic fungus) found in hay, moss, soil
2. painless papulaes that eventually ulcerate (usually on hand) 3. assteroid bodies |
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Chromoblastomycosis
1. caused by 2. symptoms 3. tx |
1. fonsecaea, phiolophora, cladophialophora
2. papules that develop into scaly, wartlike structures (usually under feet) 3. 5FC, itraconazole |
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Mycetoma
1. associated with 2. causes 3. tx |
1. foot trauma
2. massive induration with draining sinuses 3. none |
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nCandida albicans
1. what is it? 2. normal flora in... 3. bind to...with... 4. resistant to phagocytosis by... 5. manifestations |
1. yeast, can produce hyphae in invasive form
2. oropharynx, GI, female genital tract 3. keratinocytes...mannan proteins 4. neutrophils 5. thrush, vaginal candidiasis, diaper rash |
