USMLE STEP 1 MICROBIOLOGY PRACTICE QUIZ UPDATED
QUESTIONS AND ANSWERS
organisms known for causing endocarditis - CORRECT ANSWER✅✅✅S. aureus, Staph
epididermis, viridans strep, VRE, Strep. bovis, HACEK organisms
four drug regimen used to treat TB - CORRECT ANSWER✅✅✅isoniazid, ethambutol,
rifampin, pyrazinamide
used to treat Trichomonas or Gardnerella - CORRECT ANSWER✅✅✅metronidazole
used to treat Plasmodium vivax or ovale - CORRECT ANSWER✅✅✅chloroquine +
primaquine
used to treat Pediculosis capitis or pubus - CORRECT ANSWER✅✅✅permethrin, pyrethrin
organisms most commonly responsible for otitis media - CORRECT ANSWER✅✅✅Strep
pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
organism most commonly responsible for otitis externa - CORRECT
ANSWER✅✅✅Pseudomonas aeruginosa
fungus that causes San Joaquin Valley fever - CORRECT ANSWER✅✅✅Coccidioides
fungus found in rural Latin America - CORRECT ANSWER✅✅✅Paracoccidioides
fungus associated with plant thorns and cutaneous injury - CORRECT
ANSWER✅✅✅Sporothrix
,fungus found in states east of the Mississippi River - CORRECT
ANSWER✅✅✅Blastomycosis
fungus found in bird and bat droppings - CORRECT ANSWER✅✅✅Histoplasmosis
mold form contains barrel-shaped arthroconidia - CORRECT ANSWER✅✅✅Coccidioides
encapsulated bacteria (8) - CORRECT ANSWER✅✅✅E. coli, Strep pneumoniae, N.
meningitidis, Klebsiella pneumoniae, Haemophilus influenae, Pseudomonas aeruginosa,
Salmonella, group B Strep
steeple sign on X-ray - CORRECT ANSWER✅✅✅croup, parainfluenza virus
thumb sign on x-ray - CORRECT ANSWER✅✅✅epiglottitis, Haemophilus influenza
treatment of chronic hepatitis B and C - CORRECT ANSWER✅✅✅IFN-alpha, ribavirin
most abundant bacteria in the colon of most individuals - CORRECT
ANSWER✅✅✅Bacteroides fragilis
likely organisms in a patient with chronic granulomatous disease - CORRECT
ANSWER✅✅✅S. aureus, E. coli, K. pneumoniae, Aspergillus, Candida (all are catalase +)
organisms that cause infections in the mouth of AIDS patients - CORRECT
ANSWER✅✅✅HSV, C. albicans, EBV, CMV
three structural genes that code for HIV proteins - CORRECT ANSWER✅✅✅gag (p24)
pol (reverse transcriptase, integrase)
, env (gp120, gp41)
dark purple nodules on the skin in an HIV patient - CORRECT ANSWER✅✅✅HHV-8,
Kaposi sarcoma
large cells with owl's eye inclusions - CORRECT ANSWER✅✅✅CMV
treatment for CMV - CORRECT ANSWER✅✅✅ganciclovir
most common opportunistic infection in HIV patients - CORRECT
ANSWER✅✅✅Pneumocystis jirovecii
drug used to prevent Pneumocystis pneumonia - CORRECT ANSWER✅✅✅TMP-SMX
causes hemolytic-uremic syndrome - CORRECT ANSWER✅✅✅EHEC: 0157:H7
medications used to treat C. diff colitis - CORRECT ANSWER✅✅✅metronidazole and oral
vancomycin
food poisoning as a result of mayonnaise sitting out too long - CORRECT
ANSWER✅✅✅S. aureus
diarrhea caused by Gram (-) nonmotile organism that does not ferment lactose - CORRECT
ANSWER✅✅✅Shigella
Rice-water stools - CORRECT ANSWER✅✅✅Vibrio cholera
Diarrhea caused by an S-shaped organism - CORRECT ANSWER✅✅✅Campylobacter
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QUESTIONS AND ANSWERS
organisms known for causing endocarditis - CORRECT ANSWER✅✅✅S. aureus, Staph
epididermis, viridans strep, VRE, Strep. bovis, HACEK organisms
four drug regimen used to treat TB - CORRECT ANSWER✅✅✅isoniazid, ethambutol,
rifampin, pyrazinamide
used to treat Trichomonas or Gardnerella - CORRECT ANSWER✅✅✅metronidazole
used to treat Plasmodium vivax or ovale - CORRECT ANSWER✅✅✅chloroquine +
primaquine
used to treat Pediculosis capitis or pubus - CORRECT ANSWER✅✅✅permethrin, pyrethrin
organisms most commonly responsible for otitis media - CORRECT ANSWER✅✅✅Strep
pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
organism most commonly responsible for otitis externa - CORRECT
ANSWER✅✅✅Pseudomonas aeruginosa
fungus that causes San Joaquin Valley fever - CORRECT ANSWER✅✅✅Coccidioides
fungus found in rural Latin America - CORRECT ANSWER✅✅✅Paracoccidioides
fungus associated with plant thorns and cutaneous injury - CORRECT
ANSWER✅✅✅Sporothrix
,fungus found in states east of the Mississippi River - CORRECT
ANSWER✅✅✅Blastomycosis
fungus found in bird and bat droppings - CORRECT ANSWER✅✅✅Histoplasmosis
mold form contains barrel-shaped arthroconidia - CORRECT ANSWER✅✅✅Coccidioides
encapsulated bacteria (8) - CORRECT ANSWER✅✅✅E. coli, Strep pneumoniae, N.
meningitidis, Klebsiella pneumoniae, Haemophilus influenae, Pseudomonas aeruginosa,
Salmonella, group B Strep
steeple sign on X-ray - CORRECT ANSWER✅✅✅croup, parainfluenza virus
thumb sign on x-ray - CORRECT ANSWER✅✅✅epiglottitis, Haemophilus influenza
treatment of chronic hepatitis B and C - CORRECT ANSWER✅✅✅IFN-alpha, ribavirin
most abundant bacteria in the colon of most individuals - CORRECT
ANSWER✅✅✅Bacteroides fragilis
likely organisms in a patient with chronic granulomatous disease - CORRECT
ANSWER✅✅✅S. aureus, E. coli, K. pneumoniae, Aspergillus, Candida (all are catalase +)
organisms that cause infections in the mouth of AIDS patients - CORRECT
ANSWER✅✅✅HSV, C. albicans, EBV, CMV
three structural genes that code for HIV proteins - CORRECT ANSWER✅✅✅gag (p24)
pol (reverse transcriptase, integrase)
, env (gp120, gp41)
dark purple nodules on the skin in an HIV patient - CORRECT ANSWER✅✅✅HHV-8,
Kaposi sarcoma
large cells with owl's eye inclusions - CORRECT ANSWER✅✅✅CMV
treatment for CMV - CORRECT ANSWER✅✅✅ganciclovir
most common opportunistic infection in HIV patients - CORRECT
ANSWER✅✅✅Pneumocystis jirovecii
drug used to prevent Pneumocystis pneumonia - CORRECT ANSWER✅✅✅TMP-SMX
causes hemolytic-uremic syndrome - CORRECT ANSWER✅✅✅EHEC: 0157:H7
medications used to treat C. diff colitis - CORRECT ANSWER✅✅✅metronidazole and oral
vancomycin
food poisoning as a result of mayonnaise sitting out too long - CORRECT
ANSWER✅✅✅S. aureus
diarrhea caused by Gram (-) nonmotile organism that does not ferment lactose - CORRECT
ANSWER✅✅✅Shigella
Rice-water stools - CORRECT ANSWER✅✅✅Vibrio cholera
Diarrhea caused by an S-shaped organism - CORRECT ANSWER✅✅✅Campylobacter
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