6/4/25, 12:55 PM USMLE Step 1 Microbiology 2025 COMPLETE EXAM QUESTIONS AND VERIFIED ANSWERS |RECENTLY TESTING REAL EXA…
USMLE Step 1 Microbiology 2025 COMPLETE
EXAM QUESTIONS AND VERIFIED ANSWERS
|RECENTLY TESTING REAL EXAM QUESTIONS|
100% SOLVED!!
Save
Terms in this set (177)
BACTERIOLOGY -
OVERVIEW
These Rascals May Microscopically Lack Color -
Bugs that don't G stain
Treponema, Rickettsia, Mycobacteria, Mycoplasma,
well?
Legionella, Chlamydia.
Bugs visualized by Giemsa Borrelia, Plasmodium, trypanosomes, Chlamydia.
stain?
Bug visualized by PAS Tropheryma whippelii.
stain?
Organisms identified by Acid-fast organisms (Mycobacterium > Nocardia).
Siehl-Neelsen (carbol
fuchsin) stain?
Bug visualized by India Cryptococcus.
ink?
Bugs visualized by silver Pneumocystis, Legionella, (H. pylori?).
stain?
Culture requirement for H Chocolate agar w/ factors V and X.
flu?
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,6/4/25, 12:55 PM USMLE Step 1 Microbiology 2025 COMPLETE EXAM QUESTIONS AND VERIFIED ANSWERS |RECENTLY TESTING REAL EXA…
Thayer-Martin media (VPNT - vancomycin for G+,
Culture requirement for N.
Polymyxin for G-, Nystatin for fungi; TMP-SMX for
gonorrhea?
Proteus).
Culture requirement for B. Bordet-Gengou potato agar ("Bordet")
pertussis?
Culture requirement for C. Tellurite agar, Loffler's media.
diphtheria?
Culture requirement for Lowenstein-Jensen agar.
Mycobacterium TB?
Culture requirement for Eaton's agar ("Eatin' the fried eggs")
Mycoplasma
pneumoniae?
Culture requirement for Pink colonies on MacConkey's agar (pink due to acid
lactose-fermenting production) - macConKEE'S - Citraus, Klebsiella, E.
enterics? coli, Enterobacter, Serratia.
Culture requirement for E. MacConkey agar or eosin-methylene blue (EMB) -
coli? blue-black colonies w/ green metallic sheen.
Charcoal yeast extract w/ cysteine and iron (old men
Culture requirement for
with silver hair in the hot tub kept warm by the
Legionella?
charcoal fire).
Culture requirement for Sabouraud's agar.
fungi?
"Can't Breathe Air" - Clostridium, Bacteroides,
Obligate anaerobes? Actinomyces. Aminoglycosides require O2 for uptake
and won't work on these guys. (Pasteurella?)
"Nagging Pests Must Breathe" - Nocardia,
Obligate aerobes?
Pseudomonas, Mycobacterium, Bacillus.
Obligate intracellular Chlamydia and Rickettsiae (includes Erlichia and
parasites? Coxiella) - can't make their own ATP.
https://quizlet.com/1051242751/usmle-step-1-microbiology-2025-complete-exam-questions-and-verified-answers-recently-testing-real-exam-question… 2/19
, 6/4/25, 12:55 PM USMLE Step 1 Microbiology 2025 COMPLETE EXAM QUESTIONS AND VERIFIED ANSWERS |RECENTLY TESTING REAL EXA…
"Some Nasty Bugs May Live FacultativeLY" -
Facultative intracellular
Salmonella, Neisseria, Brucella, Mycobacterium,
parasites?
Listeria, Francisella, Legionalla, Yersinia pestis.
SHiNSKiES - S. pneumoniae, H flu B, N meningitides,
Salmonella, Klebsiella, E. coli, S. Epidermidis, Strep
Encapsulated bacteria? agalactiae. Also Pseudomonas aeruginosa,
Cryptococcus neoformans (latex agglutination). Are
also competent and secrete IgAse.
(This is the First Aid list) SSPACE for the cats and
Catalase-positive
granulomas - S. aureus, Serratia, Pseudomonas,
organisms?
Actinomyces, Candida, E. coli.
PUNCH-K - Proteus, Ureaplasma, Nocardia,
Urease-positive bugs?
Cryptococcus, H. pylori, Klebsiella.
Virulence factors of group M protein - prevents phagocytosis. Erythrogenic
A strep? toxin.
Exotoxins are encoded on plasmids or
Location of genes for
bacteriophages. Endotoxins are encoded on the
exotoxin vs. endotoxin?
bacterial chromosome.
Vaccine application of Toxoids used to stimulate T-cells to make attached
exotoxins? capsules antigenic.
2 toxins and bugs that Diphtheria toxin and exotoxin A (Pseudomonas).
inhibit elongation factor
2?
2 toxins that deactivate Shiga toxin (Shigella → dysentery and HUS; DOES
60S ribosome by cleaving invade) and Shiga-like toxin (EHEC O157:H7 → HUS;
rRNA? does NOT invade host)
"Labile in the Air, Stable in the Ground" - heat labile
2 toxins of ETEC and
toxin↑ cAMP (→ Cl secretion), heat stable toxin ↑
mechanisms?
cGMP (→ ↓ NaCl reabsorption).
2 bugs w/ heat-stable ETEC and Yersinia enterolytica (↑ cGMP)
toxin?
https://quizlet.com/1051242751/usmle-step-1-microbiology-2025-complete-exam-questions-and-verified-answers-recently-testing-real-exam-question… 3/19
USMLE Step 1 Microbiology 2025 COMPLETE
EXAM QUESTIONS AND VERIFIED ANSWERS
|RECENTLY TESTING REAL EXAM QUESTIONS|
100% SOLVED!!
Save
Terms in this set (177)
BACTERIOLOGY -
OVERVIEW
These Rascals May Microscopically Lack Color -
Bugs that don't G stain
Treponema, Rickettsia, Mycobacteria, Mycoplasma,
well?
Legionella, Chlamydia.
Bugs visualized by Giemsa Borrelia, Plasmodium, trypanosomes, Chlamydia.
stain?
Bug visualized by PAS Tropheryma whippelii.
stain?
Organisms identified by Acid-fast organisms (Mycobacterium > Nocardia).
Siehl-Neelsen (carbol
fuchsin) stain?
Bug visualized by India Cryptococcus.
ink?
Bugs visualized by silver Pneumocystis, Legionella, (H. pylori?).
stain?
Culture requirement for H Chocolate agar w/ factors V and X.
flu?
https://quizlet.com/1051242751/usmle-step-1-microbiology-2025-complete-exam-questions-and-verified-answers-recently-testing-real-exam-question… 1/19
,6/4/25, 12:55 PM USMLE Step 1 Microbiology 2025 COMPLETE EXAM QUESTIONS AND VERIFIED ANSWERS |RECENTLY TESTING REAL EXA…
Thayer-Martin media (VPNT - vancomycin for G+,
Culture requirement for N.
Polymyxin for G-, Nystatin for fungi; TMP-SMX for
gonorrhea?
Proteus).
Culture requirement for B. Bordet-Gengou potato agar ("Bordet")
pertussis?
Culture requirement for C. Tellurite agar, Loffler's media.
diphtheria?
Culture requirement for Lowenstein-Jensen agar.
Mycobacterium TB?
Culture requirement for Eaton's agar ("Eatin' the fried eggs")
Mycoplasma
pneumoniae?
Culture requirement for Pink colonies on MacConkey's agar (pink due to acid
lactose-fermenting production) - macConKEE'S - Citraus, Klebsiella, E.
enterics? coli, Enterobacter, Serratia.
Culture requirement for E. MacConkey agar or eosin-methylene blue (EMB) -
coli? blue-black colonies w/ green metallic sheen.
Charcoal yeast extract w/ cysteine and iron (old men
Culture requirement for
with silver hair in the hot tub kept warm by the
Legionella?
charcoal fire).
Culture requirement for Sabouraud's agar.
fungi?
"Can't Breathe Air" - Clostridium, Bacteroides,
Obligate anaerobes? Actinomyces. Aminoglycosides require O2 for uptake
and won't work on these guys. (Pasteurella?)
"Nagging Pests Must Breathe" - Nocardia,
Obligate aerobes?
Pseudomonas, Mycobacterium, Bacillus.
Obligate intracellular Chlamydia and Rickettsiae (includes Erlichia and
parasites? Coxiella) - can't make their own ATP.
https://quizlet.com/1051242751/usmle-step-1-microbiology-2025-complete-exam-questions-and-verified-answers-recently-testing-real-exam-question… 2/19
, 6/4/25, 12:55 PM USMLE Step 1 Microbiology 2025 COMPLETE EXAM QUESTIONS AND VERIFIED ANSWERS |RECENTLY TESTING REAL EXA…
"Some Nasty Bugs May Live FacultativeLY" -
Facultative intracellular
Salmonella, Neisseria, Brucella, Mycobacterium,
parasites?
Listeria, Francisella, Legionalla, Yersinia pestis.
SHiNSKiES - S. pneumoniae, H flu B, N meningitides,
Salmonella, Klebsiella, E. coli, S. Epidermidis, Strep
Encapsulated bacteria? agalactiae. Also Pseudomonas aeruginosa,
Cryptococcus neoformans (latex agglutination). Are
also competent and secrete IgAse.
(This is the First Aid list) SSPACE for the cats and
Catalase-positive
granulomas - S. aureus, Serratia, Pseudomonas,
organisms?
Actinomyces, Candida, E. coli.
PUNCH-K - Proteus, Ureaplasma, Nocardia,
Urease-positive bugs?
Cryptococcus, H. pylori, Klebsiella.
Virulence factors of group M protein - prevents phagocytosis. Erythrogenic
A strep? toxin.
Exotoxins are encoded on plasmids or
Location of genes for
bacteriophages. Endotoxins are encoded on the
exotoxin vs. endotoxin?
bacterial chromosome.
Vaccine application of Toxoids used to stimulate T-cells to make attached
exotoxins? capsules antigenic.
2 toxins and bugs that Diphtheria toxin and exotoxin A (Pseudomonas).
inhibit elongation factor
2?
2 toxins that deactivate Shiga toxin (Shigella → dysentery and HUS; DOES
60S ribosome by cleaving invade) and Shiga-like toxin (EHEC O157:H7 → HUS;
rRNA? does NOT invade host)
"Labile in the Air, Stable in the Ground" - heat labile
2 toxins of ETEC and
toxin↑ cAMP (→ Cl secretion), heat stable toxin ↑
mechanisms?
cGMP (→ ↓ NaCl reabsorption).
2 bugs w/ heat-stable ETEC and Yersinia enterolytica (↑ cGMP)
toxin?
https://quizlet.com/1051242751/usmle-step-1-microbiology-2025-complete-exam-questions-and-verified-answers-recently-testing-real-exam-question… 3/19
