3/31 micro Flashcards Preview

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Flashcards in 3/31 micro Deck (192):
1

All acid fast = gram+/-?

gram +

2

Which gram - bug grows in alkaline media?

vibrio cholera

3

Neisseria
-what gram stain?
-what shape?

gram - diplococci

4

Which neisseria ferments maltose?

meningitidis ferments maltose
-M ferments M.

5

Lactose-fermenting enteric bacteria:
-mnemonic:

Test with MacConKEE’S agar.
-Citrobacter, Klebsiella, E. coli, Enterobacter, and Serratia

6

β-galactosidase
-what reaction does it catalyze?
-which bug has it?

-breaks down lactose into glucose and galactose.
-e.coli

7

EMB agar
-what color are lactose fermenters?
-what color is E.coli?

-lactose fermenters grow as purple/black colonies.
-E. coli grows purple colonies with a green sheen.

8

The gram-negative outer membrane layer inhibits entry of:

-penicillin G and vancomycin.
*Although they may be susceptible to penicillin derivatives like ampicillin or amoxicillin.

9

N. gonorrhea:
-capsule?
-maltose fermenter?
-glucose fermenter?
-vaccine available?

goNOrrhea has NO capsule, NO maltose ferm, NO vaccine.
-it DOES ferment glucose.

10

N. gonorrhoeae is often intracellular:
-inside which cell?

neutrophils

11

Why is there no vaccine against gonorrhea?

Due to rapid antigenic variation of pilus proteins.

12

Neonates given what ointment in their eyes to prevent gonorrhea conjunctivitis?

Erythromycin

13

Gonorrhea
-Tx:

Tx: ceftriaxone + (azithromycin or doxycycline) for possible chlamydia coinfection.

14

Fitz Hugh Curtis syndrome
-caused by what bug?
-what is it?

-gonorrhea
-rare complication of PID.
-Can form "violin string adhesion" that attach to capsule of liver.

15

N. Meningitidis
-vaccine? for all serotypes?
-maltose fermenter?
-glucose fermenter?
-capsule?

-yes vaccine but not for type B.
-yes, ferments maltose & glucose.
-yes, polysacc capsule.

16

N. Meningitidis
-hows it spread?

respiratory droplets.

17

N. Meningitidis
-prophylaxis for close contacts:

Rifampin, ciprofloxacin, or ceftriaxone prophylaxis in close contacts.

18

N. Meningitidis
-Tx:

ceftriaxone or penicillin G

19

N. meningitidis
-path to meninges?

pharynx -> blood -> choroid plexus -> meninges

20

N. meningitidis
-main endotoxin?

-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

Haemophilus influenzae
-gram stain?
-shape?

Small gram-negative (coccobacillary) rod.

22

Haemophilus influenzae
-nontypable strains cause which diseases?

-Mucosal infections otitis media, conjunctivitis, bronchitis.

23

Haemophilus influenzae
-which agar?
-whats agar need in it?

-chocolate agar requires factors V (NAD+) and X (hematin) for growth.

24

Haemophilus influenzae
-Sxs:
-mnemonic:

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 Ž 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!