3/31 micro Flashcards
1
Q
All acid fast = gram+/-?
A
gram +
2
Q
Which gram - bug grows in alkaline media?
A
vibrio cholera
3
Q
Neisseria
- what gram stain?
- what shape?
A
gram - diplococci
4
Q
Which neisseria ferments maltose?
A
meningitidis ferments maltose
-M ferments M.
5
Q
Lactose-fermenting enteric bacteria:
-mnemonic:
A
Test with MacConKEE’S agar.
-Citrobacter, Klebsiella, E. coli, Enterobacter, and Serratia
6
Q
β-galactosidase
- what reaction does it catalyze?
- which bug has it?
A
- breaks down lactose into glucose and galactose.
- e.coli
7
Q
EMB agar
- what color are lactose fermenters?
- what color is E.coli?
A
- lactose fermenters grow as purple/black colonies.
- E. coli grows purple colonies with a green sheen.
8
Q
The gram-negative outer membrane layer inhibits entry of:
A
- penicillin G and vancomycin.
* Although they may be susceptible to penicillin derivatives like ampicillin or amoxicillin.
9
Q
N. gonorrhea:
- capsule?
- maltose fermenter?
- glucose fermenter?
- vaccine available?
A
goNOrrhea has NO capsule, NO maltose ferm, NO vaccine.
-it DOES ferment glucose.
10
Q
N. gonorrhoeae is often intracellular:
-inside which cell?
A
neutrophils
11
Q
Why is there no vaccine against gonorrhea?
A
Due to rapid antigenic variation of pilus proteins.
12
Q
Neonates given what ointment in their eyes to prevent gonorrhea conjunctivitis?
A
Erythromycin
13
Q
Gonorrhea
-Tx:
A
Tx: ceftriaxone + (azithromycin or doxycycline) for possible chlamydia coinfection.
14
Q
Fitz Hugh Curtis syndrome
- caused by what bug?
- what is it?
A
- gonorrhea
- rare complication of PID.
- Can form “violin string adhesion” that attach to capsule of liver.
15
Q
N. Meningitidis
- vaccine? for all serotypes?
- maltose fermenter?
- glucose fermenter?
- capsule?
A
- yes vaccine but not for type B.
- yes, ferments maltose & glucose.
- yes, polysacc capsule.
16
Q
N. Meningitidis
-hows it spread?
A
respiratory droplets.
17
Q
N. Meningitidis
-prophylaxis for close contacts:
A
Rifampin, ciprofloxacin, or ceftriaxone prophylaxis in close contacts.
18
Q
N. Meningitidis
-Tx:
A
ceftriaxone or penicillin G
19
Q
N. meningitidis
-path to meninges?
A
pharynx -> blood -> choroid plexus -> meninges
20
Q
N. meningitidis
-main endotoxin?
A
- lipooligosaccharide (LOS) = major endotoxin of n. meningitidus.
- LOS titers associated w/disease severity & outcomes. Blood conc. of this is correlated to pt’s morbidity & mortality.
21
Q
Haemophilus influenzae
- gram stain?
- shape?
A
Small gram-negative (coccobacillary) rod.
22
Q
Haemophilus influenzae
-nontypable strains cause which diseases?
A
-Mucosal infections otitis media, conjunctivitis, bronchitis.
23
Q
Haemophilus influenzae
- which agar?
- whats agar need in it?
A
-chocolate agar requires factors V (NAD+) and X (hematin) for growth.
24
Q
Haemophilus influenzae
- Sxs:
- mnemonic:
A
HaEMOPhilus
-Epiglottitis (“cherry red” in children), Meningitis, Otitis media, and Pneumonia.
*like s. pneumo except instead of sinusitis, here you get epiglottitis.
25
Haemophilus influenzae
| -can cause otitis _____.
media
26
Haemophilus influenzae
| -Tx for mucosal infections:
Treat mucosal infections with amoxicillin
| +/- clavulanate.
27
Haemophilus influenzae
- Tx for meningitis:
- Prophylaxis for meningitis close contact:
- Treat meningitis with ceftriaxone.
| - Rifampin prophylaxis in close contacts.
28
Haemophilus influenzae
- conjugated to what?
- given to kids at what age?
- Vaccine contains type B capsular polysacc.(polyribosylribitol phosphate) conjugated to diphtheria toxoid or other protein.
- Given between 2 and 18 months of age.
29
Which bug can grow if plated w/s. aureus?
Haemophilus influenzae
30
Legionella pneumophila
- gram stain?
- shape?
- oxidase +/-
- Gram-negative rod
| - oxidase +
31
Best way to stain for Legionella?
silver stain
32
Legionella
| -how do you Dx?
Detected clinically by presence of antigen in urine.
33
Legionella
| -is there person-to-person transmission?
No
| -only from aerosol from environment - water sources.
34
Legionella
| -Tx:
macrolide or quinolone.
35
Legionnaire's disease
| -what will CXR show?
-patchy infiltrate w/consolid. of one lobe.
36
Pseudomonas aeruginosa
- gram stain?
- shape?
- lactose fermenter?
- oxidase +/-?
- gram (-) rod.
- non-lactose fermenter
- oxidase (+)
37
Pseudomonas aeruginosa
| -odor?
grape-like odor
38
Pseudomonas aeruginosa
| -what are its toxins?
endotoxin (fever, shock) and exotoxin A (inactivates EF-2).
39
Pseudomonas aeruginosa
- mechanism of exotoxin?
- same as what other bug's toxin?
- exotoxin A inactivates EF-2.
| - diphtheriae
40
Pseudomonas aeruginosa
- Sxs:
- mnemonic:
PSEUDOmonas is associated with wound and burns.
- Pneumonia (especially in CF)
- Sepsis
- External otitis (swimmer’s ear)
- UTI
- Drug use and Diabetic Osteomyelitis
- hot tub folliculitis
- Malignant otitis externa in diabetics.
- Ecthyma gangrenosum
41
Pneumonia in CF pts?
| -which bug?
Pseudomonas aeruginosa
42
Hot tub folliculitis
| -which bug?
Pseudomonas aeruginosa
43
Pseudomonas aeruginosa
| -causes otitis _____
externa
44
Malignant otitis externa in diabetics
- which bug?
- what will it look like?
- Pseudomonas aeruginosa
| - graulation tissue usually seen w/in ear canal in malignant otitis externa.
45
Diabetic Osteomyelitis
| -which bug?
Pseudomonas aeruginosa
46
Which bugs are from water source?
Legionella & pseudomonas.
47
Ecthyma gangrenosum
- what is it?
- what bug causes it?
-rapidly progressive, necrotic cutaneous lesions caused by Pseudomonas bacteremia. Typically seen in immunocompromised patients.
48
Pseudomonas aeruginosa
| -Tx:
-aminoglycoside plus extended-spectrum penicillin (e.g., piperacillin, ticarcillin, cefepime, imipenem, meropenem)
49
Pseudomonas aeruginosa
- encapsulated?
- motile?
- catalse +/-
- encapsulated & motile.
| - catalase (+).
50
E.coli: pneumonia & meningitis
| -main virulence factor?
K capsule—pneumonia, neonatal meningitis.
51
E.coli: septic shock
| -main virulence factor?
LPS endotoxin—septic shock.
52
ETEC
- what type of diarrhea?
- invasive?
- watery
| - not invasive (or it would be called EIEC).
53
EPEC
- how does it work?
- whats it cause?
-No toxin produced. Adheres to apical surface,
flattens villi, prevents absorption.
-Diarrhea usually in children (Pediatrics).
54
EHEC
| -aka?
STEC
| -Shiga toxin–producing E. coli.
55
EHEC
| -how to distinguish it vs all other E.coli strains?
- Does not ferment sorbitol (distinguishes it from other E. coli).
* doesn't have glucoronidase.
56
E. coli
| -catalase +/-?
catalse (+)
57
Klebsiella
- what gives it such a mucoid appearance?
- Red “currant jelly” sputum.
-abundant polysaccharide capsules.
58
Klebsiella
| -what are the 4 A's?
```
4 A’s:
Aspiration pneumonia
Abscess in lungs and liver
Alcoholics
di-A-betics
```
59
Salmonella
- how do you get it?
- which strain is unique?
Is unique among the enterics b/c it lives in the GI tract of animals and can infect humans anytime food or water is contaminated w/animal feces. (exception = salmonella typhi, which is only carried by humans).
60
Salmonella
| -In the U.S., most commonly found in which foods?
chickens and uncooked eggs.
61
Shigella
| -how does it cause diarrhea?
*Patients develop diarrhea because the inflamed colon, damaged by the Shiga toxin, is unable to reabsorb fluids and electrolytes. Plus the necrotic cells and blood/pus.
62
Why can salmonella disseminate hematogenously but shigella cant?
Bc salmonella is encapsulated (Vi capsule) and shigella is not.
63
Shigella
| -reservoir:
Only reservoirs are humans and primates.
64
Salmonella v. shigella
| -which one produces H2S?
salmonella
65
Salmonella v. shigella
| -ABx help shorten fecal excretion duration in which one?
Shigella
| -ABxs may prolong fecal excretion of salmonella.
66
Salmonella invades intestinal mucosa and causes what sort of response?
monocytic
| -macros
67
Shigella invades intestinal mucosa and causes what sort of response?
Neutros
68
Rose sports on abdomen + diarrhea.
| -which bug?
Salmonella typhi.
69
Salmonella typhi
| -where can this bug colonize?
gallbladder.
70
Hektoen agar: what color is:
- shigella
- salmonella
- shigella = green.
- salmonella = black.
*all motile enterics = H2S positive = black on hektoen agar.
71
All motile enterics are ___ positive and are _____ on hektoen agar.
all motile enterics = H2S positive = black on hektoen agar
72
Campylobacter jejuni
| -Tx:
erythromycin
73
Campylobacter jejuni
| -Common antecedent to:
-Guillain-Barré syndrome and reactive arthritis.
74
Which enteric bug transmitted thru puppy feces?
Yersinia entercolitica
75
Similarities btwn yersinia & listeria:
- transmitted thru milk
| - can resist cold temps
76
Yersinia
| -whats stain look like?
- gram (-)
- Bipolar staining (stains heaviest at the ends).
- makes it look like safety pin.
77
Yersinia
| -encapsulated?
yes
78
Yersinia entercolitica
| -Sxs:
Invasive, bloody diarrhea.
79
Signs of appendicitis but its a child thats playerd w/puppy poop:
Yersinia entercolitica
80
Yersinia pestis
- reservoir?
- vector?
- Praire dogs
| - fleas = vector
81
H. pylori
- catalase:
- oxidase:
- urease:
- catalase +
- oxidase +
- urease +
82
H. pylori
| -how to Dx:
Urea breath test or fecal antigen test for diagnosis
83
H. pylori
| -Tx: triple therapy:
triple therapy: PPI + clarithromycin + either amoxicillin or metronidazole.
84
Weil disease:
Icterohemorrhagic leptospirosis—severe form with jaundice and azotemia from liver and kidney dysfunction; fever, hemorrhage, and anemia.
85
conjuctival suffusion
| -which bug?
leptospira
86
Ixodes tick
| -natural reservoir?
Mouse
87
Lyme disease
| -Tx:
doxycycline, ceftriaxone.
88
Bilteral facial nerve palsy
| -think what disease?
Lyme disease
89
Whats unique about rash of secondary syphillis?
targets soles and palms
90
Syphillis
| -you get condyloma ___
lata
91
Congenital syphilis
| -signs:
Saber shins, saddle nose, CN VIII deafness, Hutchinson teeth, mulberry molars.
92
Congenital syphilis
| -prevention:
To prevent, treat mother early in pregnancy, as placental transmission typically occurs after first trimester.
93
HIV evasion of humoral immunity due to mutation in which gene?
env
| -codes for structural glycoproteins.
94
"cottage cheese" discharge from vagina
- which bug:
- Tx:
- candida
| - fluconazole
95
Inc. vaginal pH (aklaline environement)
| -present in which vaginal diseases?
- gardernella vaginalis
- trichomonas vaginalis
*candida yeast infection = normal pH.
96
Most common cause of candida vaginitis:
| -what are other causes?
Antibiotic use
- will dec. # of gram (+) bacteria in the vagina.
- OCP use, systemic corticosteroid use, DM, immunosupression.
97
Which bugs can cause diarrhea w/a small inoculum?
Shigella, campylobacter, entamoeba histolytica, giardia.
98
Which drugs end w/-oxacin?
fluoroquinolones
99
Which cephalosporins are useful against pseudomonas?
cefepime, ceftazidime
100
erythema infectiosum
- aka?
- which bug?
- fifth disease
| - parvovirus B19
101
hepA
- which virus family?
- genome made of?
- envelope?
- picorniaviridae
- ssRNA
- no
102
hepB
- virus fam?
- genome?
- envelope?
- hepadnaviridae
- dsDNA
- yes
103
hepC
- virus fam?
- genome?
- envelope?
- Flaviviridae
- ssRNA
- yes
104
hepD
- virus fam?
- genome?
- envelope?
- deltaviridae
- ssRNA
- yes
105
hepE
- virus fam?
- genome?
- envelope?
- hepeviridae
- ssRNA
- no
106
Which hep virus is made of DNA?
hepB
107
germ tubes
| -think what?
candida albicans
108
intraabdominal infections
| -most commonly isolated bugs?
bacteroides, E.coli
109
Only pathogenic fungus w/polysacc capsule?
cryptococcus neoformans.
110
Does alcohol destroy spores?
No.
111
Strep pyogenes
| -main virulence factor?
Protein M.
| -its the target of humoral response to the bug.
112
Jarisch-Herxheimer reaction
- what is it?
- commonly seen in which disease?
- Flu-like syndrome after antibiotics are started—due to killed bacteria releasing pyrogens.
- syphillis Tx w/penicillin.
113
Jarisch-Herxheimer reaction
| -especially seen w/use of which drug?
penicillins.
114
Gardnerella vaginalis
| -How to Dx?
1) KOH whiff test. Adding the KOH makes the smell especially strong.
2) microscopic exam of discharge - you see Clue cells.
115
Treatment for all ricketssial infections:
doxycycline
116
Rickettsia rickettsii
- whats it cause?
- vector?
- Rocky Mountain spotted fever.
| - dermacenter tick
117
Rickettsia rickettsii
- causes which disease?
- describe the rash:
-rash begins on extremities and spreads centrally
| which is opposite of typhus.
118
Rocky Mountain spotted fever
| -seen most in which state?
North Carolina
119
Rocky Mountain spotted fever
| -where does rash spread to thats pretty unique?
palm/soles.
| *secondary syphillis & Coxsackievirus A infection also hit palms/soles.
120
Rickettsiae
- intracellular? extracellular?
- what do they need to surive?
-obligate intracellular organisms that need CoA and NAD+ because they cannot synthesize ATP.
121
Rocky Mountain spotted fever
| -classic triad:
-headache, fever, rash (vasculitis).
122
Palm/soles rash
- which diseases?
- mnemonic:
"You drive CARS using your palms and soles".
- Coxsackievirus A infection (hand, foot, and mouth disease)
- Rocky Mountain spotted fever
- 2° Syphilis
123
Rickettsiae
- Which Tx used to be given?
- What was potential side effect?
-chloramphenicol used to be given - can cause aplastic anemia.
124
Typhus
- endemic: which bug? which vector?
- epidemic: which bug? which vector?
- Endemic: fleas — R. typhi.
- Epidemic: human body louse—R. prowazekii.
*louse poops on our skin and gets scratched in. Whereas the tick in R. Rickettsia bites us.
125
Typhus
| -rash starts where & spread where?
Rash starts centrally and spreads out, sparing
| palms and soles.
126
Ehrlichiosis
- vector?
- what will you see on histology?
- tick
| - monocytes w/morulae.
127
Ehrlichiosis & Anaplasmosis
- presentation:
- Tx:
- present like RMSF but w/o the rash.
| - Doxycycline
128
Anaplasmosis
- vector?
- what will you see on histology?
- tick
| - granulocytes w/morulae.
129
Ehrlichiosis vs Anaplasmosis
| -which one invades macros & which one invades granulocytes?
- anaplasmosis = granulos
| - ehrlichiosis = macros
130
Which vector born illness has no arthropod vector?
Coxiella burnetii => Q fever.
131
Q fever
- which bug?
- how you contract it?
- presentation:
-Coxiella burnetii
-Tick feces and cattle placenta release spores that are
inhaled as aerosols.
-Presents as pneumonia.
132
hepatitis + pneumonia in context of being around
animals
-which bug(s)?
coxiella burnetii (and possibly brucella).
133
Chlamydiae
- what are the 2 forms?
- which one is infectious?
1) Elementary body (small, dense) is “Enfectious” and Enters cell via Endocytosis; transforms into reticulate body.
2) Reticulate body Replicates in cell by fission; reorganizes into elementary bodies.
134
Chlamydiae
| -Tx:
- azithromycin (favored because one-time treatment) or doxycycline.
* give ceftriaxone as well in case of gonorrhea.
135
Why can't you use beta-lactams to treat chalmydiae?
Cell wall lacks peptidoglycan! muramic acid =
constituent of PG. This is why you can't use beta
lactams!
*Use macrolides or doxycycline instead. They target ribos.
136
Chalmydia trachomatis
- which serotypes => trachoma?
- where is it seen most commonly?
- Types A, B, and C.
| - Africa
137
Chalmydia trachomatis
| -which serotypes => Urethritis/PID
-Types D–K.
138
Chalmydia trachomatis
| -which serotypes => neonatal pneumonia (staccato cough), neonatal conjunctivitis.
- Types D–K.
* kind of a trick question: bc types D-K usually below waist, but since babys eyes touched moms vagina, baby gets these serotypes above the waist.
139
Chalmydia trachomatis
| -which serotypes => Lymphogranuloma venereum
-Types L1, L2, and L3.
140
Lymphogranuloma venereum
- painful?
- presentation?
- no, they're painless.
| - small, painless ulcers on genitals swollen, painful inguinal lymph nodes that ulcerate (“buboes”).
141
Mycoplasma
| -since they have no cell wall, what does their plasma membrane contain to inc. stability?
Bacterial membrane contains sterols for stability.
142
Only bacteria w/cholesterol in cell membrane:
Mycoplasma
143
Fungi: cell wall
| -is it exterior or interior to plasma membrane?
exterior
144
Fungi: capsule
| -is it exterior or interior to cell wall?
exterior.
| -its the most exterior thing.
145
What is unique about coccidioidomycosis shape in tissue?
The only exception is coccidioidomycosis, which
| is a spherule (not yeast) in tissue.
146
Systemic mycoses
- Tx for local infx:
- Tx for systemic infx:
- local = fluconazole/itraconazole
| - systemic = amphotericin B
147
Difference btwn contracting a systemic mycoses vs TB?
No person-to-person contraction of systemic mycoses.
148
Which systemic mycoses associated w/earthquakes?
Coccidioidomycosis
149
“Desert bumps” & “Desert rheumatism”
| -which fungus?
Coccidioidomycosis
150
Para coccidioidomycosis
- whats it look like?
- size compared to RBC?
Captains wheel
| -much larger than RBC
151
Para coccidioidomycosis
| -seen in which geographic location?
latin america
152
Tinea versicolor
- caused by what?
- Tx:
- Malassezia furfur
| - topical miconazole, selenium sulfide (Selsun)
153
Tinea versicolor
| -whats it look like?
“Spaghetti and meatball” appearance.
154
Tinea versicolor
- is there inflammation?
- itchy?
No - only superficial skin layer affected.
| -not itchy bc no inflammation.
155
Other tineae besides versicolor
- is there inflammation?
- itchy?
- yes, there is inflammation. Goes slightly deeper than superficial skin.
- yes, it is itchy bc there is inflammation.
156
Other tineae besides versicolor
- caused by what?
- Tx:
- dermatophytes: Microsporum, Trichophyton, and Epidermophyton.
- Tx: griseofulvin, terbinafne.
157
Endocarditis in IV drug abusers
| -fungal
candida albicans
158
Does candida usually cause lung disease?
No!
159
Candida
- superficial infection prevented by:
- systemic infection prevented by:
- superficial ifx prevented by T cells.
| - systemic ifx prevented by neutrophils.
160
Candida albicans
| -what form will it be at body temp? (37deg)
germ tubes
161
Invasive aspergillosis
| -happens in which pt pops?
immunocompromised & CGD pts.
| *aspergillus = catalase (+).
162
Allergic bronchopulmonary aspergillosis (ABPA):
- which pt pop is it associated with?
- what can it cause?
- Associated with asthma and cystic fibrosis.
| - may cause bronchiectasis and eosinophilia.
163
Aflatoxins
- how do they cause HCC?
- found in what foods?
- Induce p53 mutations.
| - most often found in peanuts, rice, and cereal/grains.
164
Aspergillus
| -whats it look like?
```
Acute angles (45deg)
-septate hyphae
```
165
Whats most specific test for cryptococcus?
Latex agglutination test detects polysaccharide capsular antigen and is more specific India ink or mucicarmine.
166
Latex agglutination test is specific for what?
cryptococcus
167
cryptococcus
| -how are the lesions in the brain described?
“Soap bubble” lesions in brain.
168
cryptococcus
| -budding?
-narrow based buds.
169
cryptococcus
| -does it form hyphae?
does NOT form any hyphae or pseudohyphae, so if
you see something that looks like this but w/hyphae
its Candida albicans.
170
Mucor
- appearance?
- how to Dx?
- non-septate, typically at 90 degree angles.
| - Dx w/biopsy.
171
Pneumocystis jirovecii
| -what type of pneumonia does it cause?
Diffuse, interstitial, bilateral CXR appearance.
172
First marker detected in serum after Hep B infection:
HBsAg
173
Most specific marker for acute hep B?
IgM anti-HBc
| -present during window phase.
174
HBeAg
- what does it indicate?
- what if its present longer than 3 months?
indicates viral replication & infectivity.
- associated w/presence of HBV DNA.
- if it persists longer than 3 months - you prob have chronic hep B.
175
nontypable H. flu
| -what does that mean?
it has no capsule!
176
Skin infection
| -think what bugs?
S. aureus, strep pyogenes.
177
Whos capsule is made of PRP?
h. influenzae type B.
| - polyribosyl-ribitol-phosphate
178
Legionella
| -what will gram stain show?
Its faintly staining & facultative intracellular, gram staining will show lots of neutros but few if any microbes.
*its Dx using urinary Ag test.
179
colistin
| -aka?
polymyxin
180
cryptococcus can mimic the appearance of which fungus?
| -how to differentiate?
candida
| -but look for germ tubes to differentiate. Candida has germ tubes.
181
Pneumocystis jirovecii
| -how to Dx?
Diagnosed by lung biopsy or lavage.
182
Pneumocystis jirovecii
| -Tx:
TMP-SMX, pentamidine,
183
Pneumocystis jirovecii
| -prophylaxis
dapsone, atovaquone.
184
When should you start Pneumocystis jirovecii prophylaxis in HIV pts?
When CD4 count drops < 200 cells/mm3.
185
Diffuse interstitial pneumonia w/ground-glass appearance
| *cells look like rolled up condom
Pneumocystis jirovecii
186
sporothrix
| -what shape is it?
cigar-shaped budding yeast
| -dimorphic
187
sporothrix
| -Tx:
itraconazole or potassium iodide.
188
Protozoa
- which form is protective casing, like a spore?
- which form is infective?
- cyst
| - cyst
189
Protozoa
| -motile feeding form?
trophozoite
190
Do you get immunity against non-invasive bugs?
NO
191
Most common central nervous system infection in AIDS patients:
Toxoplasma encephalitis
192
Do protozoa elicit an eosinophilic response?
No!
