Qbank - Microbiology

Front 1

"white yellow membrane like plaques" with fibrin deposits (caused by enterotoxin B)

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C. diff - can present up to 4 wks after antibiotics

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envelope glycoprotein 22 nm in diameter forming spheres & tubules
infected hepatocytes may excrete enormous quanities

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HBsAg

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bacteria transmitted from animals (pets, farms, lab workers)

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campylobacter can be

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necrotic skin wound with erythematous & edematous border, necrotic center
gram positive rods

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cutaneous anthrax -

Front 5

acute bacterial arthritis - in sexually active --> ______ , in children/non-active --> ______

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in sexually active --> n. gonnorhea, in children/non-active --> staph aureus

Front 6

ETEC toxin is similar to what other toxin?

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LT is similar to cholera toxin ETEC causes diarrhea, LT & ST toxins

Labile in the Air (cAMP) Stable on the Ground (cGMP)

Front 7

latex agglutination tests for polysaccharide capsule
cryptococcus will show budding yeast
does not have mold form

Back 7

Cryptococcus meningitis in HIV patients

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endocarditis
catalase negative, grows in 6.5% NaCl & bile (think enteric, bile) --> ______
what kind of procedure might this be associated with

Back 8

enterococcus, endocarditis (distinguish this from mutans by 6.5% NaCl)
"genitourinary manipulation has been known to cause enterococcal endocarditis"

Front 9

necrotic skin patches in pt receiving chemo
presents w/fever, chills, sob

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ecthyma gangrenosum - occurs in neutropenic patients, pseudomonas colonizes perivascular area, toxins destroy & cause vascular insufficiency,

Front 10

african immigrant - patchy areas of skin anesthesia, hypopigmentation of UE, nerve biopsy many bacteria invading shwann cells -->

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Mycobacterium Tuberculosis
Tuberculoid TB --> skin thickening, patchy hypopigmentation, lionine facies, paresthesis / regional anesthesia, testicular destruction, blindness

Front 11

gram neg sepsis

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LPS causes gram neg sepsis not actively excreted but released w/lysis,Lipid A is the toxic part
activates macrophages to release TNF-alpha & IL-1 widespread

Front 12

tetanus - what route does toxin take?

Back 12

toxins travel retrograde in motorneurons to the spinal cord (Tetanus goes to the Top) to inhibit release of inhibitory neurotransmitters

Front 13

Tzank test positive -->
Tx w/what drug? What is MOA?

Back 13

herpes
tx active flairs with nucleoside analogs (acyclovir), which incorporate themselves into the viral DNA & terminate replication
phosphorylation by viral thymidine kinase required for activity

Front 14

Serum testing for treponema -->

Back 14

screening with nontreponema test looking for cardiolipin (VRDL, RPR)
confirmatory test with treponemous test for antigen (FTA-ABS, MHA-TP)

Front 15

facial pain, headache, black necrotic eschar in nasal cavity of diabetic --> ? How do you confirm dx / what will you see?

Back 15

mucormycosis
confirm dx w/mucosal biopsy
broad non-septate hyphae w/rt angle branching (WIDE branching in diabetics [associate w/overweight])

Front 16

foreign child w/febrile maculopapular rash starting head spreads to trunk & extremities -->

Back 16

rubella or rubeola
add postauricular lymphadenopathy --> rubella (german measles)
rubella is a togavirus (togas rub horses)

Front 17

HBV vaccine - what do you see?

Back 17

ppl vaccinated for HBV are positive for anti-HBsAg, negative for HBsAg
if they had actually contracted HBV and cleared it would also have anti-HBcAg IgG

Front 18

DIC & bilateral hemmorhagic destruction of adrenal glands -->

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Waterhouse Friedrichson Syndrome
meningococcal sepsis (neisseria)

Front 19

Pseudomons & Diphtheria toxin both act by:

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ribosylating and inactivating elongation factor 2 (exotoxin A)

Front 20

Strept bovis endocarditis is associated with:

Back 20

GI lesions (colon cancer

Front 21

flat red skin lesion with central clearing

Back 21

erythema chronica migrans
borrelia burgdorferi

Front 22

hyper or hypo-pigmented skin patches becoming more noticeable after tanning

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malesthesia furfur
pityriasis (aka tinea) versicolor
KOH scraping --> "spaghetti & meatball" hyphae "cigar butt"
selenium shampoo

Front 23

MCC acute otitis media, sinusitis, & bacterial conjunctivitis in childhood:

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1.) stept pneumo, 2.) Non-typable haemoph infl, 3.) moraxella cataralis

Front 24

Haemophilus influenza B vaccine reduces:

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meningitis, pneumonia, sepsis, epiglotitis in children
given at 2 mos

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cherry red epiglottitis

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haemophilus influenza B

Front 26

fever, sore throat, drooling, progressive airway obstruction, & stridor in infant

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presenting sx of epiglottitis
haemophilus influenza B

Front 27

Shigella vs Salmonella vs E. Coli

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Shigella is non-motile (where Salmonella is motile & produces H2S)
Shigella produces acid (where E. Coli produces gas)

Front 28

penile lesions, draining ulcers, painful inguinal lymph nodes, fever, red eyes
cell scrapings --> inclusion bodies

Back 28

chlamydia trachomatis, lymphogranuloma venerum (L1-L3 serotypes)
Africa, Asia, Carribean, South America

Front 29

gram positive clustered bacteria (oropharynx)
POLAR GRANULES staining with ANILINE dye

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Corynebacterium Diphtheria

Front 30

young male w/joint / long bone pain

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hematogenous osteomyelitis
staph aureus most commonly in kids, followed by strept group A

Front 31

CSF: high WBC, lymphocyte predominant, glucose nl or slightly decreased, protein elevated but < 150

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Viral Meningitis

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MCC Viral Meningitis

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Enteroviruses (Coxsackievirus, Echovirus, Poliovirus, Enterovirus)

Front 33

HBV is in what body secretions?

Back 33

All except stool

Front 34

When does anti-HBsAg ab level rise?

Back 34

After virus is cleared, once HBsAg levels have dropped
asymptomatic

Front 35

HDV requires HBV for?

Back 35

envelop coating
once acquired it can penetrate hepacocytes & replicate

Front 36

Picornoviridae - Rhinovirus, Coxsackie, Echo, Polio, Hep A - which is acid sensitive?

Back 36

rhinovirus is acid sensitive
picornoviridae = rhinovirus & enteroviruses (others)
enteroviruses can withstand acid, colonize GI

Front 37

22 yo male, atypical lymphocytes, fever & joint pain
partially dbl stranded circular DNA virus w/RNA dependent DNA polymerase

Back 37

HBV

Front 38

HIV viral protein glycosylated & cleaved into 2 smaller prtns
what is it responsible for?

Back 38

absorption by target cells (gp160 --> gp120 + gp41)
gp120 binds CD4 for absorption
gp41 stabilizes gp120

Front 39

6 day old infant w/HBsAg & HBeAg positive
risk for chronicity, replication speed, and liver damage?

Back 39

high risk for chronic infection, high replication rate, histologically mild liver damage
typically transmission from mother occurs in birth canal, may occur transplacentally

Front 40

where do Kaposi's sarcomas first present?

Back 40

HIV associated
present as multiple blue-violet plaques on feet & legs before spreading proximally
can also develop on mucosal membranes of face & genitals

Front 41

34 yo female 2 days postpartum via spontaneous vaginal delivery
lower abdominal pain, temp 37.9, BP 110/70, pulse 110, resp 18, tender uterus & foul-smelling discharge - what's going on? What organism?

Back 41

Endometritis
Bacteroides most common organism, but can be mixed aerobic/anaerobics
can complicate both spontaneous & C-sections

Front 42

painful erupted vesicles on an erythematous base

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herpes zoster, reaction of VZV in dorsal root ganglion
neuropathic pain & isolated to single dermatome

Front 43

meningitis w/sx of seizures, personality changes, & psychosis?

Back 43

temporal lobe encephalitis
MCC is HSV-1
may also have seizure/olfactory hallucination
tx: IV acyclovir

Front 44

MCC infectious arthritis? In kids < 2? Teenagers? Sickle cell?

Back 44

N. gonorrhoeae, Staph, strept, haem inf, gram - bacilli (e coli, salmonella, pseudomonas)
kids <2 - Haem influ, kids > 2 staph aureus
teenagers & early adulthood (espec women) - N gon
sickle cell - salmonella

Front 45

bacterial resistance to antibiotic is diminished by addition of protons, what mechanism?

Back 45

drug efflux pump
usually coupled to H+ moving along concentration gradient OUT of the cell (some use Na or ATP though)

Front 46

rapid infusion of IV drug for endocarditis causes immediate pruritis & rash
this drug characteristically has a linear relationship between rate of infusion & histamine release, what drug?

Back 46

Vancomycin
"red man syndrome"
NOT IgE mediated, prevented by slower infusion rate

Front 47

56 yo woman on recent cruise, 2 days fever, productive cough, crackle in left lung, lobar consolidation -- what is it?

Back 47

Legionella
suspect legionella in water supplies - cruise, hotel
cough high fever confusion, diarrhea

Front 48

Characteristic lab finding with legionella?

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Hyponatremia
2nd to inappropriate secretion of ADH

Front 49

3 mos infant - irritable, feeds poorly, frequently vomits
wt 45% head circ 96%
CT - enlarged ventricles, scattered intracranial calcifications
fundoscopy - white-yellow chorioretinal lesions both eyes

Back 49

Congenital toxoplasmosis (in utero)
triad - hydrocephalus, intracranial calcifications, chorioretinitis

Front 50

fungus in pigeon droppings?

Back 50

Cryptococcus neoformans

Front 51

fungus in lungs showing "spherules packed with endospores"?

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Coccidioides imiitis
(spherules rupture, endospores disseminate, each can form new spherule) - mold form at 25-30 C, endospore at 37-40 C

Front 52

where is coccidioidomycosis found?

Back 52

Arizone, New Mexico, western Texas, central California, northern Mexico, some regions of South & Central America

Front 53

how is coccidiodis immitis transmitted?

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spore inhalation

Front 54

Histoplasma capsulatum associations?

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River Basins - Ohio & Mississippi, hx of cleaning bird coops or caving

Front 55

fungus that colonizes old lung cavities? (hx of TB)

Back 55

Aspergillus fumigatus, forms fungal ball (aspergilloma)

Front 56

what fungus are long hx of asthmatics at risk for?

Back 56

aspergillus fumigatus

Front 57

motile gram positive rods w/beta hemolysis?

Back 57

Lysteria
cell mediated immunity is necessary to eliminate

Front 58

infant born to 25 yo IV drug users develops prominent oral thrush, interstitial pneumonia, & severe lymphopenia during 1st year life - what would have prevented this condition?

Back 58

baby has HIV
viral enzyme inhibitor would have helped

Front 59

mucicarmine staining of lung tissue in immunocompromised pt w/cough & chest pain, turns red?

Back 59

Cryptococcus neoformans

Front 60

why does penicillin tx of group A strep prevent RF but not APSGN?

Back 60

rheumatic fever (antigen mimicry)
NOT post-strept glomerulonephritis (immune complex deposition)

Front 61

septate hyphae 45 degree angle?

Back 61

aspergillus fumigatus

Front 62

what gram positive cocci produces dextrans from glucose?

Back 62

Viridins streptococci
this helps them attach to damaged valves

Front 63

mayonaisse associated food poisoning?

Back 63

Staph aureus
usually getting at preformed heat-stable exotoxin

Front 64

what CV defects are seen in tertiary syphillus?

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AORTIC - aortitis, aortic aneurysm, aortic regurgitation

Front 65

what defense protein does staph aureus have? How does it work?

Back 65

Protein A - binds the Fc portin of IgG at the complement binding site, preventing complement activation

Front 66

what is done to minimize risk of transmission of active Hep B from mother to fetus?

Back 66

passive immunization of all newborns w/HBIG, followed by active immunization w/recombinant HBV
typically transmission occurs in birth canal (but can cross placenta), HBeAg increases risk (from 20% to 95%)
if fetus is infected 80% chance to progress to chronic

Front 67

infection characteristic of sickle cell patients? Why?

Back 67

salmonella osteomyelitis - b/c fxnlly asplenic (followed by e. coli)

Front 68

bacteria - Vi antigen? K antigen?

Back 68

capsule antigens
Vi - salmonella (virulence)
K - E. coli

Front 69

why are envelop IgG antibodies not protective against HCV?

Back 69

envelop proteins vary their antigenic structure
HCV has hypervariable region, also lacks 3'-5' exonuclease proofreading (virion encoded RNAP)

Front 70

bacillus anthracis toxin is similar to what other bacterial toxin?

Back 70

lethal factor & edema factor
edema factor is adenylate cyclase causing massive increases in intracellular cAMP

similar to bordetella pertussis toxin called "extracellular adenylate cyclase"

Front 71

2 MC sites of flora that cause infection of central venous catheters?

Back 71

patient's skin flora and bacteria on health care worker's hands

Front 72

what are motile gram negative rods turning pink on MacKonkey? What is their virulence factor?

Back 72

E. Coli - (context of meningitis)

capsule of E. Coli, K-1 antigen (present in 20-40% of intestinal E. coli isolates)
virulence factor that aloows bacteria to survive hematogenous spread, establish meningeal infection

Front 73

what is verotoxin?

Back 73

another name for the shiga-like toxin of EHEC

Front 74

what is the O antigen (bacteria)?

Back 74

cell wall Outer membrane polysaccharide used to classify gram-negative bacteria

Front 75

MCC of viral acute hemorrhagic cystitis outbreaks in children?

Back 75

Adenovirus (males in particular)

Front 76

what mediates liver injury in HBV?

Back 76

cytotoxic CD8 t lymphocytes responding to viral antigen on cell surface

virus does not have direct cytotoxic effect (though in integrative phase integration of DNA increases risk of HCC)

Front 77

acute orchitis bacterial cause?

Back 77

young adults - c. trachomatis, n. gonorrhoeae

older pts - e. coli

Front 78

MCC e coli bacteremia in 72 yo man from skilled nursing facility?

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UTI

Front 79

MCC of bacteria infecting biliary tree?

Back 79

E. Coli, Klebsiella, Enterobacter, Enterococci

Front 80

wound with a fruity odor?

Back 80

Pseudomonas aeruginosa
gram negative rod

pigments would also give wound exudates in a blue-green hue

Front 81

what is the morphology of Haemophilus influenza? What makes its capsule different from other encapsulated H. influenza?

Back 81

gram negative rod

capsule contains RIBOSE instead of hexose for it's carbohydrate component

PRP capsule
polyribosyl-ribitol-phosphate

Front 82

bug grown on special medium, colonies appear black in color, intracellular polyphosphate granules detected on microscopy after methylene blue staining?

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C. diphtheria
metachromatic granules
grown on cysteine-tellurite agar (or Loffler's medium)

Front 83

use of blood agar containing bile & hypertonic saline?

Back 83

culture enterococci - E. faecalis & E. faecium

differentiates these from non-enterococci Group D strep including Strep bovis & Strep equinus
(grow in bile but NOT hypertonic saline)

Front 84

what is a viral capsid?

Back 84

nucleocapsid protein surrounds viral genome

Front 85

Tzank smear positive indicates?

Back 85

HSV or VZV

must obtain from base of vesiculoulcerative lesion
epithelial cells scraped prepared w/Wright-Giemsa & examined for multinucleated giant cells & intranuclear inclusions

Front 86

papanicolaou smear positive indicats?

Back 86

HPV, "pap" smear

Front 87

cryoglobulins indicate?

Back 87

HCV most commonly

cryoglobulins are cold-precipitable serum proteins containing immunoglobulins

Front 88

hemadsorption indicates?

Back 88

suggests hemagglutinins or glycoproteins w/high affinity for RBC being expressed on host cell surface

characteristic of influenza & parainfluenza viruses

Front 89

continuous proliferation of B-cells while maintaining ability to secrete immunoglobulin?

Back 89

EBV

immortalization, or transformation
controlled by T-cell response

Front 90

what is tazobactam? Sulbactam?

Back 90

beta-lactamase inhibitors, like clavulanic acid

Front 91

proximal bronchiectasis in 34 yo woman w/recurrent transient pulmonary infiltrates who suffers from bronchial asthma?

Back 91

Aspergillus fumigatus (Allergic Bronchopulmonary Aspergillosis - ABPA)

occurs w/hypersensitivity reaction, very high IgE and eosinophilia

5-10% of steroid dependent asthmatics

Front 92

parasite that causes cough, asthma-like bronchospasm, and hemoptysis?

Back 92

Strongyloidiasis

transient pneumonia also, as larvae migrate thru lungs on way to laryngopharynx

Front 93

HIV pt lost to follow up 3 yrs returns, pain & itching in perirectal area, exam shows ulcerative mass?

Back 93

Squamous cell carcinoma of the anus
(anal cancers ulcerative in > 50% cases)

HPV associated

Front 94

fever w/GI upset, hepatosplenomegaly, & "rose spots" on abdomen?

Back 94

typhoid fever - Salmonella typhi & paratyphi
travel associated

can have possible hemorrhagic enteritis w/bowel perforation later in course

salmonella penetrate both enterocyte transporters & via phagocytosis by M cells in Peyer's patches
phagocytosed by macrophages and survive intracellularly
can go to liver, spleen, & bone marrow

Front 95

MCC of bacteriemia in sickle cell patients? Osteomyelitis?

Back 95

Streptococcus pneumo
followed by hemophilus influenza

(asplenic)

MCC of osteomyelitis is salmonella > s aureus or e coli

Front 96

"rust colored sputum"?

Back 96

strept pneumo

"lancet-shaped gram positive diplococci"
optichin sensitive (?)

Front 97

what is expected to accompany blue/white spots on buccal mucosa in immigrant child?

Back 97

this is measles, rubeola

CCCK - cough, coryza, conjunctivities, koplik spots

Front 98

people w/active leprosy have what response to heat killed M. leprae injection? (lepromin skin test)

Back 98

if tuberuloic leprosy will have positive test
-well contained, good Th1 CD4 response (& macrophages)

if lepromatous leprosy, won't be positive?
-poor cell mediated response, get limbs falling off and so on

Front 99

mutation of the HIV pol and env genes confer what?

Back 99

pol mutation - resistance to reverse transcriptase and protease inhibitors

env (structural glycoproteins) - enables escape from host neutralizing antibodies

Front 100

metallic sheen on eosin methylene blue agar, & hemolysis on blood agar? Motile

Back 100

E. coli

Front 101

most important virulence factor for e. coli causing UTI? Meningitis?

Back 101

UTI - fimbriae, adhesion to uroepithelial cells

meningitis - K-1 capsular antigen

Front 102

what is the O antigen?

Back 102

cell wall Outer membrane polysaccharide used to classify gram-negative bacteria

Front 103

CMV causing the following conditions are present in which populations?

mononucleosis
retinitis
hepatitis
pneumonia
odynophagia

Back 103

mononucleosis - MC manifestation of CMV in immunocompetent hosts (but still less common than EBV)

retinitis - CMV in HIV patients

diarrhea & hepatitis - disseminated CMV in immunocompromised

CMV pneumonitis - organ transplant

esophagitis - HIV pts

Front 104

growth media for telling what strep is what?

Back 104

all strep are gram positive cocci, catalase negative

Alpha Hemolytic
--optochin resistant, grows in bile --> Strep Viridans
--optochin sensitive, NOT grow in bile --> Strep pneumo

Beta Hemolygic
--bacitracin resistant --> Group B strep
--bacitracin sensitive --> Group A strep

Gamma (no) Hemolysis
--grows in bile AND NaCl --> Enterococci (E. faecium)
--grows in bile, NOT NaCl --> Non-Enterococci (S. bovis)

Front 105

common cause & route of a hepatic abscess?

Back 105

staph aureus thru hematogenous seeding

other routes include:
-portal vein
-arterial supply
-ascending biliary tract infection (usually enteric gram neg bacilli & enterococci)
-direct invasion from adjacent source (usually enteric gram-negative bacilli & enterococci)
-penetrating injury

Front 106

patient w/mycoplasma pneumonia is tx and develops sequelae, what might that be? Pathophys?

Back 106

can get mild anemia

some antigens are shared between RBC and m. pneumoniae wall

antibodies that cross react are called "cold agglutinins" - able to agglutinate RBCs in vitro at low temp

steven johnson syndrome & joint pain are other rare sequelae

Front 107

pseudomonas toxin is similar to? Shiga toxin is similar to?

Back 107

Pseudomons & Diptheria exotoxin A act on EF-2

Shig-like toxins (vero toxins) are produced by EHEC, they inhibit the 60S ribosomal subunit preventing tRNA binding

Front 108

deficiency in forming complement membrane attack complex exposes particular risk to what infection?

Back 108

Neisseria (meningitidis)

Front 109

petechial skin rash on trunk, spreading to include palms & soles?

Back 109

Neisseria-induced small-vessel vasculitis
especially affects palms & soles

Front 110

Echinococcus is? Causes? Tx? Risk w/tx?

Back 110

MCC hydatid cysts in humans
-sheep & dog exposure, part of tapeworm life cycle

encapsulated calcified cyst "eggshell calcification"

surgery to remove cyst could result in spillage --> ANAPHYLAXIS

adjunctive chemo w/mebendazole or albendazole then surgery is tx of choice
-also they talk about injecting et-OH

Front 111

where does HSV-1 encephalitis occur? What signs are noticed? If fatal, what does autopsy show?

Back 111

occurs in TEMPORAL lobe

sx - aphasia, olfactory hallucinations, personality changes

macroscopic examination shows edema & hemorrhagic necrosis

Front 112

23 yo male 2 day hx of fevere, confusion - impaired speech, change in personality, and olfactory hallucinations?

Back 112

temporal lobe encephalitis --> HSV-1

Front 113

the lesions of syphilis?

Back 113

Primary - chancre - painless ulceration

Secondary - condylomata lata - large gray wart like growths

Tertiar - Gummas - begin as painless indurated granulomatous lesions progressing to white-gray rubbery lesion, may ulcerate

Front 114

condylomata acuminata vs condylomata lata?

Back 114

condylomata acuminata - anogenital warts caused by HPV

condyloma lata - wart-life genital lesion caused by syphilis

Front 115

essential virulence factor for nesseriea?

Back 115

pili

also has capsule, but pili are essential for establishing infeciton

Front 116

homosexula man w/abdominal pain & diarrhea, guiac positive, occasional trophozoites w/phagocytosed RBCs seen?

Back 116

Entamoeba histolytica

usually bloody

common in homosexual population b/c can be transmitted oral-anally

Front 117

E coli that does not ferment sorbitol nor produce glucoronidase?

Back 117

E. coli O157:H7

Front 118

bacteria producing toxins that…

-activate adenylate cyclase?

-activate guanylate cyclase?

-inactivate EF2?

-disrupt cytoskeleton?

Back 118

active adenylate cyclase - b. pertussis (pertussis toxin), B. anthracis (edema factor), ETEC (heat labile), campylobacter, bacillus cerus (heat labile) & v cholera

activate guanylate cyclase - ETEC (heat stable), Yersinia enterocolitica

inactivate EF2 - corynebacterium diphtheriae, Pseudomonas aeruginosa (ADP-ribosylation)

disrupt cytoskeleton - C difficile (toxin B, cytotoxin)

Front 119

what RNA viruses replicate inside the nucleus? (only a few)

Back 119

Influenza A (orthomyxovirus)

Retroviruses