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COMSAE Phase 1 ASA 113– The Complete 176 Question Test
Bank All questions with correct verified answers & detailed
rationales – graded A+ for the newest 2026 actual exam
SECTION 1: MICROBIOLOGY & PHARMACOLOGY (Q1–40)
1. A 68-year-old woman with COPD is hospitalized with fever, productive cough,
and a right lower lobe infiltrate. Gram stain shows numerous neutrophils and
lancet-shaped gram-positive diplococci. She has a history of anaphylaxis after
taking amoxicillin. Which antibiotic is contraindicated?
A) Levofloxacin
B) Vancomycin
C) Cefazolin
D) Doxycycline
E) Azithromycin
: Correct Answer : C
Full Rotation & Rationale:
• A (Levofloxacin): Fluoroquinolone; safe in penicillin allergy.
• B (Vancomycin): Glycopeptide; no beta-lactam cross-reactivity.
• C (Cefazolin): Correct. Cephalosporins share a beta-lactam ring with
penicillins; cross-reactivity occurs in ~1-10% of penicillin-allergic patients.
With anaphylaxis to amoxicillin, cephalosporins are contraindicated unless
skin testing confirms no allergy.
• D (Doxycycline): Tetracycline; safe.
• E (Azithromycin): Macrolide; safe.
2. A 20-year-old college student presents with a sore throat, fever, and posterior
cervical lymphadenopathy. Examination reveals exudative tonsillitis and
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splenomegaly. CBC shows lymphocytosis with atypical lymphocytes. A
Monospot test is positive. Which medication should be avoided due to the risk
of a severe morbilliform rash?
A) Penicillin V
B) Amoxicillin
C) Azithromycin
D) Clindamycin
E) Cephalexin
: Correct Answer : B
Full Rotation & Rationale:
• A (Penicillin V): Treatment for strep pharyngitis; does not commonly cause
rash in EBV.
• B (Amoxicillin): Correct. In EBV infection, amoxicillin/ampicillin causes a
characteristic morbilliform rash in up to 90% of patients. This is a Type IV
hypersensitivity, not a true allergy.
• C (Azithromycin): Macrolide; not associated with EBV rash.
• D (Clindamycin): Not associated with EBV rash.
• E (Cephalexin): Cephalosporin; may cross-react in penicillin allergy but does
not cause EBV rash.
3. A 45-year-old HIV-positive patient (CD4 50 cells/µL) presents with confusion,
headache, fever, and multiple ring-enhancing brain lesions on MRI. What is the
most likely cause?
A) Cryptococcus neoformans
B) Toxoplasma gondii
C) Mycobacterium tuberculosis
D) Progressive multifocal leukoencephalopathy (PML)
E) Herpes simplex virus encephalitis
: Correct Answer : B
Full Rotation & Rationale:
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• A (Cryptococcus): Soap-bubble lesions in basal ganglia, not typically
ring-enhancing.
• B (Toxoplasma gondii): Correct. In AIDS with CD4 <100, the most common
cause of ring-enhancing lesions is reactivated toxoplasmosis.
• C (M. tuberculosis): Can cause tuberculomas but less common.
• D (PML): Non-enhancing white matter lesions.
• E (HSV): Temporal lobe, hemorrhagic.
4. A 4-year-old child presents with high fever, difficulty swallowing, drooling,
and an erythematous throat with a grayish-white membrane that bleeds when
scraped. What is the most likely causative organism?
A) Epstein-Barr virus
B) Corynebacterium diphtheriae
C) Streptococcus pyogenes
D) Respiratory syncytial virus
E) Bordetella pertussis
: Correct Answer : B
Full Rotation & Rationale:
• A (EBV): Exudative pharyngitis but no tough membrane.
• B (C. diphtheriae): Correct. Pseudomembrane that bleeds, bull neck,
potential myocarditis from exotoxin.
• C (S. pyogenes): Strep throat, not tenacious membrane.
• D (RSV): Bronchiolitis in infants.
• E (B. pertussis): Paroxysmal coughing.
5. Which antibiotic works by inhibiting the 50S ribosomal subunit and is highly
associated with pseudomembranous colitis?
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, 4
A) Clindamycin
B) Doxycycline
C) Gentamicin
D) Vancomycin
E) Ciprofloxacin
: Correct Answer : A
Full Rotation & Rationale:
• A (Clindamycin): Correct. Inhibits 50S and is strongly linked to C.
difficile colitis.
• B (Doxycycline): 30S inhibitor.
• C (Gentamicin): 30S inhibitor.
• D (Vancomycin): Treats C. diff.
• E (Ciprofloxacin): DNA gyrase inhibitor.
6. A 25-year-old woman with dysuria, urinary frequency, and suprapubic
tenderness has a urine dipstick positive for leukocyte esterase and nitrite. What
is the most common causative organism?
A) Proteus mirabilis
B) Klebsiella pneumoniae
C) Escherichia coli
D) Pseudomonas aeruginosa
E) Enterococcus faecalis
: Correct Answer : C
Full Rotation & Rationale:
• C (E. coli): Correct. >80% of community-acquired UTIs; nitrate-positive.
• A (Proteus): Complicated UTIs.
• B (Klebsiella): Less common.
• D (Pseudomonas): Nosocomial.
pg. 4
COMSAE Phase 1 ASA 113– The Complete 176 Question Test
Bank All questions with correct verified answers & detailed
rationales – graded A+ for the newest 2026 actual exam
SECTION 1: MICROBIOLOGY & PHARMACOLOGY (Q1–40)
1. A 68-year-old woman with COPD is hospitalized with fever, productive cough,
and a right lower lobe infiltrate. Gram stain shows numerous neutrophils and
lancet-shaped gram-positive diplococci. She has a history of anaphylaxis after
taking amoxicillin. Which antibiotic is contraindicated?
A) Levofloxacin
B) Vancomycin
C) Cefazolin
D) Doxycycline
E) Azithromycin
: Correct Answer : C
Full Rotation & Rationale:
• A (Levofloxacin): Fluoroquinolone; safe in penicillin allergy.
• B (Vancomycin): Glycopeptide; no beta-lactam cross-reactivity.
• C (Cefazolin): Correct. Cephalosporins share a beta-lactam ring with
penicillins; cross-reactivity occurs in ~1-10% of penicillin-allergic patients.
With anaphylaxis to amoxicillin, cephalosporins are contraindicated unless
skin testing confirms no allergy.
• D (Doxycycline): Tetracycline; safe.
• E (Azithromycin): Macrolide; safe.
2. A 20-year-old college student presents with a sore throat, fever, and posterior
cervical lymphadenopathy. Examination reveals exudative tonsillitis and
pg. 1
,2
splenomegaly. CBC shows lymphocytosis with atypical lymphocytes. A
Monospot test is positive. Which medication should be avoided due to the risk
of a severe morbilliform rash?
A) Penicillin V
B) Amoxicillin
C) Azithromycin
D) Clindamycin
E) Cephalexin
: Correct Answer : B
Full Rotation & Rationale:
• A (Penicillin V): Treatment for strep pharyngitis; does not commonly cause
rash in EBV.
• B (Amoxicillin): Correct. In EBV infection, amoxicillin/ampicillin causes a
characteristic morbilliform rash in up to 90% of patients. This is a Type IV
hypersensitivity, not a true allergy.
• C (Azithromycin): Macrolide; not associated with EBV rash.
• D (Clindamycin): Not associated with EBV rash.
• E (Cephalexin): Cephalosporin; may cross-react in penicillin allergy but does
not cause EBV rash.
3. A 45-year-old HIV-positive patient (CD4 50 cells/µL) presents with confusion,
headache, fever, and multiple ring-enhancing brain lesions on MRI. What is the
most likely cause?
A) Cryptococcus neoformans
B) Toxoplasma gondii
C) Mycobacterium tuberculosis
D) Progressive multifocal leukoencephalopathy (PML)
E) Herpes simplex virus encephalitis
: Correct Answer : B
Full Rotation & Rationale:
pg. 2
,3
• A (Cryptococcus): Soap-bubble lesions in basal ganglia, not typically
ring-enhancing.
• B (Toxoplasma gondii): Correct. In AIDS with CD4 <100, the most common
cause of ring-enhancing lesions is reactivated toxoplasmosis.
• C (M. tuberculosis): Can cause tuberculomas but less common.
• D (PML): Non-enhancing white matter lesions.
• E (HSV): Temporal lobe, hemorrhagic.
4. A 4-year-old child presents with high fever, difficulty swallowing, drooling,
and an erythematous throat with a grayish-white membrane that bleeds when
scraped. What is the most likely causative organism?
A) Epstein-Barr virus
B) Corynebacterium diphtheriae
C) Streptococcus pyogenes
D) Respiratory syncytial virus
E) Bordetella pertussis
: Correct Answer : B
Full Rotation & Rationale:
• A (EBV): Exudative pharyngitis but no tough membrane.
• B (C. diphtheriae): Correct. Pseudomembrane that bleeds, bull neck,
potential myocarditis from exotoxin.
• C (S. pyogenes): Strep throat, not tenacious membrane.
• D (RSV): Bronchiolitis in infants.
• E (B. pertussis): Paroxysmal coughing.
5. Which antibiotic works by inhibiting the 50S ribosomal subunit and is highly
associated with pseudomembranous colitis?
pg. 3
, 4
A) Clindamycin
B) Doxycycline
C) Gentamicin
D) Vancomycin
E) Ciprofloxacin
: Correct Answer : A
Full Rotation & Rationale:
• A (Clindamycin): Correct. Inhibits 50S and is strongly linked to C.
difficile colitis.
• B (Doxycycline): 30S inhibitor.
• C (Gentamicin): 30S inhibitor.
• D (Vancomycin): Treats C. diff.
• E (Ciprofloxacin): DNA gyrase inhibitor.
6. A 25-year-old woman with dysuria, urinary frequency, and suprapubic
tenderness has a urine dipstick positive for leukocyte esterase and nitrite. What
is the most common causative organism?
A) Proteus mirabilis
B) Klebsiella pneumoniae
C) Escherichia coli
D) Pseudomonas aeruginosa
E) Enterococcus faecalis
: Correct Answer : C
Full Rotation & Rationale:
• C (E. coli): Correct. >80% of community-acquired UTIs; nitrate-positive.
• A (Proteus): Complicated UTIs.
• B (Klebsiella): Less common.
• D (Pseudomonas): Nosocomial.
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