Micro Flashcards
1
Q
2 bac w/ weird cell walls?
A
Mycoplasma - contains sterols, no cell wall
Mycobacteria - contains mycolic acid, high lipid content
2
Q
Bugs that don’t Gm stain well
A
“These Rascals May Microscopically Lack Color”
Treponema (to thin, use fluorescent Ab)
Rickettsia (IC)
Mycobac (high lipid content, use carbolfuchsin in acid-fast stain)
Mycopl (no cell wall)
Legionella (mainly IC, use silver stain)
Chlamydia (IC, no muramic acid in cell wall)
3
Q
Do Giemsa stain on…
A
“Certain Bugs Really TRY my Patience”
Chlamydia, Borrelia, Rickettsiae, TRYpanosomes, Plasmodium
4
Q
PAS stains what?
- used to dx?
A
“PAS the sugar”
glycogen, mycopolysaccharides
- Whipple’s dz (Tropheryma whipplei)
5
Q
Ziehl-Neelsen (carbol fuchsin) stains?
A
acid-fast org’s (Nocardia, Mycobac)
6
Q
India ink stains?
- Can also use for this bug?
A
Cryptococcus neoformans
- mucicarmine to stain thick polysacch. cap red
7
Q
Silver stain is used for?
A
Fungi (PCP), Legionella, H. pylori
8
Q
How do you culture H. influenzae?
A
chocolate agar w/ factors V (NAD+) and X (hematin)
9
Q
How do you culture Neisseria (gonorrhoeae and meningitidis)?
A
Thayer-Martin (or VPN) media:
Vanc (inhib’s Gm+)
Polymixin (inhib’s Gm- except Neisseria)
Nystatin (inhib’s fungi)
10
Q
How do you culture B. pertussis?
A
Bordet-Gengou (potato) agar
11
Q
How do you culture C. diphtheriae?
A
Tellurite plate, Loffler’s media
12
Q
How do you culture M.Tb?
A
Lowenstein-Jensen agar
13
Q
How do you culture M. pneumoniae?
A
Eaton’s agar
14
Q
How do you culture lac-fermenting enterics?
- Can also grow E.coli on?
A
Pink colonies on MacConkey’s agar (fermentation makes acid to turn it pink)
- On EMB (eosin-methylene blue) agar as colonies w/ green metallic sheen
15
Q
How do you culture Legionella?
A
charcoal yeast extract agar buffered w/ Cys and Fe
16
Q
How do you culture fungi?
A
“SAB’s a FUN GUY”
Sabouraud’s agar
17
Q
Obligate aerobes?
Obligate anaerobes?
A
“Nagging Pests Must Breathe”
Nocardia, Pseudomonas, MTb, Bacillus
“Can’t Breathe Air”
Clostridium, Bacteroides, Actinomyces
18
Q
Obligate IC bugs
A
Rickettsia and Chlamydia
19
Q
Facultative IC bugs
A
“Some Nasty Bugs May Live FacultativeLY”
Salmonella, Neisseria, Brucella, Mycobac, Listeria, Francisella, Legionella, Yersinia pestis
20
Q
Positive quelling rxn is for who?
A
Encap’d bac (cap’s swells w/ antisera)
“SHiNE SKiS”
Strep. pneumo, Hib, Neisseria meningitidis, E. coli, Salmonella, Klebsiella, GpBStrep
21
Q
Cat(+) bugs
A
“PLACESS for your cats”
Pseudomonas, Listeria, Aspergillus, Candida, E.coli, S.aureus, Serratia
and Nocardia
22
Q
Urease-pos bugs
A
“CHuck norris hates PUNKSS”
Cryptococcus, H.pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, S.epidermidis, S.saprophyticus
23
Q
Protein A virulence factor:
exp’d by who? does what?
A
S.aureus
- binds Fc of Ig to prevent opsonization and phagocytosis
24
Q
IgA protease virulence factor:
exp’d by who? does what?
these org’s also have ability to?
A
SHiN = S.pneumo, HiB, Neisseria
- cleaves IgA -> can colonize resp mucosa
- take up naked DNA = transformation = competence
25
M pr virulence factor:
exp'd by who? does what?
- Abs to it can cause what?
GAS
- helps prevent phagocytosis by inhib'ing C'
- RF
26
Diphtheria toxin -> ?
inact's EF2 -> inhib's pr syn via ADP-ribosylation of EF2 -> pharyngitis w/ pseudomem's in throat and severe lymphadenopathy (bull neck)
- AB toxin
27
Pseudomonas Exotoxin A -> ?
| - also has what other toxin?
inact's EF2 -> host cell death (AB toxin)
| - endotoxin -> F, shock
28
Shigella Shiga toxin -> ?
inact's 60S by removing A from rRNA -> GI mucosal damage, dysentery; cytokine release -> HUS
29
EHEC O157:H7 Shiga-like toxin (SLT) -> ?
inact's 60S by removing A from rRNA -> cytokine release causing HUS; doesn't invade host cells (unlike Shigella)
30
ETEC (enterotoxigenic E.coli) LT (heat-labile toxin) -> ?
incr'd cAMP -> incr'd Cl and H2O out into gut -> watery D
[Labile in the Air (cAmp)]
- AB toxin
31
ETEC ST (heat-stable toxin) -> ?
incr'd cGMP -> decr'd reab'n of NaCl and water in gut -> watery D
[Stable on the Ground (cGmp)]
- AB toxin
32
Bacillus anthracis Edema factor -> ?
| Lethal factor also contributes to this sx
like AC, incr's cAMP -> edematous borders of black eschar in cut anthrax
33
Vibrio cholerae, Cholera toxin -> ?
permanently act's Gs -> incr'd AC and cAMP -> incr'd Cl and water efflux into gut -> "rice-water D"
- AB toxin
34
Bordatella pertussis, pertussis toxin -> ?
disable's Gi -> incr's AC and cAMP -> impairs phagocytosis -> Whooping cough
- AB toxin
35
Clostridium tetani, tetanospasmin -> ?
cleaves SNARE pr needed for nt release -> m. rigidity and lock jaw bc prevents release of inhib GABA and Gly nt's from Renshaw cells in SC
36
Clostridium botulinum, Botulinum toxin -> ?
heat labile toxin that cleaves SNARE pr needed for nt release -> flaccid paralysis (floppy baby) bc prevents release of ACh at NMJ
37
Clostridium perfringens, alpha toxin -> ?
phospholipase (lecithinase) that degrades tissue and cell mem's -> degrades phospholipid C -> myonecrosis (gas gangrene) and hemolysis (2x zone of hemolysis on bl agar)
38
Strep.pyogenes, Streptolysin O -> ?
- ASO Abs used to dx?
Strep.pyogenes, Exotoxin A -> ?
pr that degrades cell mem -> lyses RBCs (b-hemolysis)
- RF
brings MHC-II and TCR together -> release of IFN-g and IL-2 -> shock (F, rash, shock)
39
S.aureus, TSST-1 -> ?
- sx?
- exfoliative toxin ->
- enterotoxin ->
brings MHC-II and TCR together -> polyclonal Tcell act'n -> release of IFN-g and IL-2 -> shock
- sx: F, rash, shock
- scalded skin syndrome
- food poisoning
40
Endotoxin (LPS on Gm-):
- act's Mphage ->
- act's C' ->
- act's TF ->
- IL-1 (F), TNF (F and hypotension), NO (hypotension)
- C3a (hypotension, edema), C5a (N's)
- coag cascade -> DIC
41
Endotoxin -> what sx?
"ENDOTOXIN"
| Edema, NO, DIC/Death, Outer mem, TNF-a, eXtremely heat stable, IL-1, N chemotaxis
42
5 bac toxins encoded in a lysogenic phage:
```
"ABCDE"
ShigA-like toxin (EHEC O157:H7)
Botulinum toxin
Cholera toxin
Diphtheria toxin
Erythrogenic toxin of S.pyogenes (Streptolysin O, brks dwn cell mem's, inc'ing of RBCs)
```
43
S. pneumo is most common cause of?
```
"MOPS"
Meningitis
Otitis media in kids
Pneumonia
Sinusitis
```
44
Scarlet fever
- caused by?
- sx?
S. pyogenes (GAS)
- scarlet sandpaper-like rash sparing face, strawberry (scarlet) tongue after white exudate peels off, scarlet sore throat, F
45
GBS makes CAMP factor which does what?
| - Test for GBS?
Enlarges area of hemolysis formed by S.aureus
| - hippurate test positive (can hydrolyse sodium hippurate)
46
Bac for meningitis <2yo?, for adults?
Listeria > E.coli > GBS
| N. meningitidis > H.flue
47
How do you dx C. diphtheriae?
| - grows on?
Gm+ rods w/ metachromatic (blue and red) granules and Elek's test for exotoxin
- blk colonies on cystine-tellurite agar OR on Loeffler's coag'd bl serum then stain w/ methylene blue to see bac
48
C. diphtheriae properties?
```
ABCDEFG
ADP-ribosylation (of EF2 to inact it)
B-prophage (carries exotoxin)
Corynebacterium
Diphtheria
EF2 (what exotoxin inact's) (Elek's test for it toxin)
Granules (metachromatic)
```
49
Which Gm+ bac form spores (found in soil)?
| What are 3 others?
Bacillus anthracis, C.perfringens, C.tetani
| - B.cereus, C.botulinum, Coxiella burnetii
50
Only bac w/ polypep capsule (containing D-Glutamate)?
Bacillus anthracis
51
Woolsorters' dz =
inhal of B. anthracis (anthrax) spores from contaminated wool; flu sx that rapidly progress to pulm hemorrhage, mediastinitis and shock
52
Actinomyces vs. Nocardia
- air? acid fast?
- found in?
- causes?
- trt w/?
- anaerobe vs. aerobe; no vs. partially
- nl oral flora vs. soil
- oral/facial abscesses that drain thr sinus tracts -> yellow sulfur granules VS. pulm infec's in immcomp'd and cut infec's post trauma in nl ppl
- Pn vs. sulfonamides
53
Mycobac:
- M. kansaii causes?
- M.avium-intracellulare causes? drug?
- Cord factor inhib's?
- Sulfatides inhib?
- pulm TB-like sx
- disseminated non-TB dz in AIDS; prophylaxis w/ azithromycin
- inhib's Mphage maturation and induces release of TNF-a
- are surface gp's that inhibs phagolysosomal fusion
54
Mycobac leprae
- infects where?
- which type has pos lepromin skin test?
- trtmt
- likes cool T's -> infec's skin and superficial n's -> glove and stocking loss of sensation
- Tuberculoid type bc high CMI and lg Th1 response vs. low CMI w/ humoral Th2 response in lepromatous
- Tuberculoid: dapsone + rifampin for 6mo
Lepromatous: dapsone + rifampin + clofazimine for 2-5yrs
55
Lactose fermenting bac (pink on MacConkey's agar) (5 bac)
| - on EMB agar they grow as?
CEKES lactose
Citrobacter, Enterobacter, Klebsiella, E.coli, Serratia
- purple/blk colonies; E.coli grows purple w/ green sheen
56
What abx do not work on Gm- bugs? Which do?
PnG and vanc (can't X outer mem)
| - Pn deriv's like amp/amox
57
Trtmt of N. meningitidis vs. N. gonorrhoeae?
Ceftriaxone or PnG AND trt close contacts w/ rifampin, cipro or ceftriaxone
vs. Ceftriaxone (+ azithromycin or doxycycline for possible Chlamydia coinfec)
58
H.flue
- Causes?
- Non typable strains cause?
- Grow it on?
- Trt w/?
- HaEMOPhilus: Epiglottitis, Meningitis, Otitis media, Pneumo
- mucosal infec's: otitis media, conjunctivitis, bronchitis
- "When you get the flu, mom goes to the 5&dime to buy chocolate" = Chocolate agar + Factor V (NAD+, S.aureus can make) and X (hematin)
- Meningitis w/ ceftriaxone and rifampin to close contacts
59
Legionella
- grows on?
- labs show?
- trt w/
- charcoal yeast extract w/ Fe and Cysteine
- hypoNa
- quinolone or macrolide
60
Pseudomonas can cause?
| - Trtmt?
BE PSEUDDO = Burn wound infec's, Endocarditis, Pneumo (esp in CF, biofilm), Sepsis (blk lesions on skin), Ext. otitis media, UTI (pyelo), Drug use, Diabetic Osteomyelitis
- aminoglycosides + big Pn (Piperacillin, ticarcillin)
61
3 E.coli VFs?
1) fimbriae (cystitis and pyelo)
2) K capsule (pneumo, neonatal meningitis)
3) LPS endotox (septic shock)
62
4 A's of Klebsiella:
Aspiration pneumo
Abscess in lungs/liver
Alcoholics
di-A-betics
63
Typhoid F
- caused by?
- sx?
- can stay in?
- Salmonella typhi
- rose spots on ab, F, HA, D
- GB -> carrier state (Typhoid Mary)
64
3x tx for H.pylori
| - pt's w/ it are at incr'd risk for?
PPI, clarithromycin, amox or metronidazole
| - PUD, gastric adenoca, lymphoma
65
What are the 3 spirochetes?
| How do you visualize them?
BIG = Borrelia (Big size), Leptospira, Treponema
- Borrelia - aniline dye (Wright's or Giemsa stain)
- Treponema by dark-field microscopy
66
Leptospirosis presents as?
| - Severe form is?
flu-like sx w/ jaundice and photophobia w/ conjunctivitis (surfers and tropics bc is from animal urine in water)
- Weil's dz = jaundice and azotemia (bad liver and kidney), F, hemorrhage, anemia
67
Lyme dz: 3 stages?
| Trtmt?
1) erythema chronicum migrans (red rash w/ central clearing), flu sx
2) neuro (facial n. palsy) and cardiac (AV node block)
3) MSK (chronic monoarthritis and migratory polyarthritis), neuro (encephalopathy and polyneuropathy), and cut sx
- Doxycycline or ceftriaxone
68
Congenital syphilis presents as?
| - Passes to fetus, when?
Saber shins, saddle nose, CN VIII deafness, Hutchinson's teeth, mulberry molars
- after 1st trimester
69
VDRL tests for?
- used to dx?
- false pos's?
nonsp Ab that rcts w/ beef cardiolipin
- syphilis
- VDRL: Viruses (mono, hepatitis); Drugs, Rheumatic f., Lupus/Leprosy
70
Jarisch-Herxheimer rxn =
flu-like synd immediately after starting abx due to killed bac releasing pyrogens
71
Syphilis: Rule of 6s:
```
Six - Sexual trans
6 axial filaments
6 wk incubation
6 wks for ulcer to heal
6 wks after ulcer heals progresses to 2* syph
6 wks for 2* syph to resolve
66% of latent stage pt's have resolution
6 yrs to develop 3* syph (at least)
```
72
RMSF =
- Bac needs what to grow?
- classic triad?
- rash is?
From Rickettsia rickettsii; obligate IC org
- CoA and NAD+
- HA, F, rash (vasculitis)
- starts at wrists/ankles, spreads to trunk, palms and soles
73
Typhus
- Endemic type spread by?
- Epidemic type spread by?
- Rash is?
- R. typhi on fleas
- R. prowazekii from human body louse
- Starts centrally on trunk, spreads out but NOT to palms and soles
74
Ehrlichiosis
- spread by
- histo shows
spread by tick
| - monocytes w/ morula (berry-like inclusions) in cyto
75
Anaplasmosis
- spread by
- histo shows
spread by tick
| - granuloctes w/ morula in cyto
76
Q fever
- spread by
- caused by
- presents as
spread by tick feces and cattle placenta releasing spores that are inhaled
- caused by Coxiella burnetii
- presents as pneumo
77
Chlamydiae
- how to dx?
- cell wall does not have?
- cyto inclusions (contain lots of reticulate bodies) on Giemsa or fluorescent Ab-stained smear
- no muramic acid
78
Chlamydia trachomatis serotypes:
A,B,C =
D-K =
L1, L2, L3 =
- ABC=Africa/Blindness/Chronic infec (blind from follicular conjunctivitis)
- everything else! urethritis/PID, ectopic preg, neonatal pneumo (staccato cough) or conjunctivitis
- lymphogranuloma venereum
79
Mycoplasma pneumoniae
- high titer of?
- grown on?
- bac mem contains?
- trtmt?
cold agglutinins (IgM) which can agglutinate or lyse RBCs
- Eaton's agar
- sterols for stability
- macrolide or FQ
80
Enterobius, Ascaris, Trichinella
- are what?
- how do they infect?
nematodes
| - ingested
81
Strongyloides, Ancylostoma, Necator
- are what?
- how do they infect?
nematodes
| - thr skin
82
Brain cysts, seizures -> ? parasite
Taenia solium (cystericersosis) (pork tapeworm -> praziquentel)
83
Liver cysts -> ? parasite
Enchinococcus granulosus (dog tapeworm -> praziquantel; allergic to fluid in cysts)
84
VitB12 defic -> ? parasite
Diphyllobothrium latum (from raw freshwater fish -> praziquantel)
85
Biliary tract dz, cholangioca -> ? parasite
Clonorchis sinensis (from undercooked fish -> praziquantel)
86
Hemoptysis -> ? parasite
Paragonimus westermani (from undercooked crab meat -> lung inflamm and 2* bac infec -> praziquantel)
87
Portal HTN -> ? parasite
Schistosoma mansoni (from freshwater snails, eggs in liver/spleen -> fibrosis and inflamm -> praziquantel)
88
Hematuria, bladder ca -> ? parasite
Schistosoma haematobium (from freshwater snails -> lives in bladder -> eggs cause fibrosis and inflamm -> praziquantel)
89
Microcytic anemia -> ? parasite
Ancylostoma, Necator (hookworms, suck bl from GI wall -> anemia -> -bendazoles, pyrantel pamoate)
90
Perianal pruritus -> ? parasite
Enterobius (pinworm -> GI infec -> lay eggs at night outside anus -> Scotch tape test -> mebendazole or pyrantel pamoate)
91
Four vaccines for encap'd bugs?
pneumovax (PPV-23) has no conj'd pr, just polysacch (Strep.pneumo, >2yo at risk); Prevnar-13 is conj'd (kids d
92
JONES criteria for RF:
Jts (polyarthritis), Heart (carditis), Nodules (subcut), Erythema marginatum, Syndenham's chorea
93
Yersinia enterocolitica
| - causes what 2 things?
day-care outbreaks of bl'y D
| pseudoappendicities (actually is mesenteric adenitis)
94
Common causes of pneumo:
- in neonates?
- in kids 4wk - 18yrs
- GBS, E.coli
| - Mycopl, Chlamydia trachomatis (infants-3yrs), C. pneumo (school kids), S. pneumo
95
Common causes of pneumo:
- 18-40yo
- 40-65yo
- elderly
- Mycopl, C.pneumo, S.pneumo
- S.pneumo, H.flue, anaerobes, viruses, mycopl
- S.pneumo, influenza virus, anaerobes, H.flue, GNRs
96
Pneumo in:
- nosocomial?
- CF?
- post-viral?
- Staph, enteric GNRs
- Pseudomonas, S.aureus, S.pneumo
- Staph, H.flue, S.pneumo
97
Common causes of meningitis:
- 0-6mo
- 6mo-6yrs
- 6-60yrs
- 60+ yrs
- GBS, E.coli, Listeria
- S.pneumo, N.meningitis, HiB (if unvaccinated), enteroviruses
- S.pneumo, N.meningitis (#1 in teens), enteroviruses, HSV
- S.pneumo, GNRs, Listeria
98
Trtmt of meningitis?
Ceftriaxone + vanc empirically, add amp if Listeria is suspected
99
Viral causes of meningitis?
Enteroviruses (esp. coxsackie), HSV-2 (HSV-1 = encephalitis), HIV, WNV, VZV
100
Causes of meningitis in HIV+?
Cryptococcus, CMV, toxoplasmosis (brain abscesses), JC virus (PML)
101
Chancroid =
| - caused by?
painful genital ulcer, inguinal adenopathy
| - Haemophilus ducreyi
102
Trichomonas vaginalis causes?
vs.
Gardnerella vaginalis causes?
- Vaginitis: strawberry-colored mucosa, motile in wet prep, STD
- Vaginosis: no inflamm, bad fishy smell d/c, pos whiff test, clue cells, not and STD
103
7 bugs that cause bl'y D?
```
Can't Stop Shitting E ErYthrocytEs:
Campylobacter
Salmonella
Shigella
EHEC
EIEC
Yersinia
Entamoeba
```
104
4 bac, 2 protozoa and 2 viruses that cause watery D?
ETEC, V.cholerae, C.dif, C.perfringens
Giardia, Cryptosporidium
Rotavirus, norovirus
105
Neutropenic pt's will get?
Candida albicans (systemic), Aspergillus
