Nurse Practitioner Infectious Diseases Test
Bank – 150 Questions with Correct Answers
And Rationale
2025/2026
1. A 35-year-old patient presents with fever, malaise, and a
maculopapular rash after returning from travel in sub-Saharan
Africa. Which infectious disease should be highest on your
differential?
• A. Measles
• B. Dengue
• C. Malaria
• D. Lyme disease
Rationale: Malaria is endemic in sub-Saharan Africa. Fever with
systemic symptoms and travel history should raise suspicion for
malaria.
2. Which antibiotic is the first-line treatment for community-
acquired methicillin-resistant Staphylococcus aureus (MRSA) skin
infections?
• A. Amoxicillin
• B. Ceftriaxone
• C. Trimethoprim-sulfamethoxazole (TMP-SMX)
• D. Azithromycin
Rationale: TMP-SMX is effective against MRSA skin infections
and is commonly used as first-line oral therapy.
,3. A patient presents with watery diarrhea after recent antibiotic
use. The most likely causative organism is:
• A. Salmonella
• B. Giardia
• C. Clostridioides difficile
• D. E. coli
Rationale: C. difficile often causes antibiotic-associated diarrhea
due to disruption of normal gut flora.
4. Which of the following vaccines is recommended for all adults
over 50 years to prevent shingles?
• A. Influenza
• B. MMR
• C. Pneumococcal
• D. Recombinant zoster vaccine (Shingrix)
Rationale: Shingrix is recommended for adults over 50 to prevent
herpes zoster and its complications.
5. A patient presents with fever, cough, night sweats, and weight
loss. Chest X-ray shows upper lobe cavitary lesions. The most
likely diagnosis is:
• A. Tuberculosis
• B. Pneumocystis jirovecii pneumonia
• C. Bacterial pneumonia
• D. Sarcoidosis
Rationale: Cavitary lesions in the upper lobes along with
systemic symptoms are classic for tuberculosis.
,6. Which laboratory test is the most sensitive for early detection of
HIV infection?
• A. Western blot
• B. Rapid antibody test
• C. HIV RNA PCR (viral load)
• D. CD4 count
Rationale: HIV RNA PCR can detect infection within 10–14 days
post-exposure, before antibodies develop.
7. A 22-year-old male presents with urethral discharge and dysuria.
Gram stain shows intracellular gram-negative diplococci. The most
likely organism is:
• A. Chlamydia trachomatis
• B. Neisseria gonorrhoeae
• C. Treponema pallidum
• D. Mycoplasma genitalium
Rationale: Gram-negative intracellular diplococci in urethral
discharge is diagnostic for gonorrhea.
8. Which is the treatment of choice for latent tuberculosis infection
in adults?
• A. Isoniazid for 6–9 months
• B. Rifampin for 1 month
• C. Pyrazinamide for 3 months
• D. Ethambutol for 2 months
Rationale: Isoniazid monotherapy for 6–9 months is standard for
latent TB.
, 9. A patient with advanced HIV presents with fever, cough, and
diffuse interstitial infiltrates on CXR. The most likely pathogen is:
• A. Streptococcus pneumoniae
• B. Pneumocystis jirovecii
• C. Mycobacterium tuberculosis
• D. Influenza virus
Rationale: Pneumocystis pneumonia is common in
immunocompromised patients with CD4 <200 cells/mm³.
10. Which of the following is the first-line therapy for
uncomplicated urinary tract infection in women?
• A. Ciprofloxacin
• B. Amoxicillin
• C. Nitrofurantoin
• D. Doxycycline
Rationale: Nitrofurantoin is effective for uncomplicated UTIs and
has a low risk of promoting resistance.
11. A patient presents with fever and a bull’s-eye rash after
hiking in the northeastern U.S. The most likely diagnosis is:
• A. Lyme disease
• B. Rocky Mountain spotted fever
• C. Ehrlichiosis
• D. Tularemia
Rationale: Erythema migrans (bull’s-eye rash) is characteristic of
early Lyme disease caused by Borrelia burgdorferi.
Bank – 150 Questions with Correct Answers
And Rationale
2025/2026
1. A 35-year-old patient presents with fever, malaise, and a
maculopapular rash after returning from travel in sub-Saharan
Africa. Which infectious disease should be highest on your
differential?
• A. Measles
• B. Dengue
• C. Malaria
• D. Lyme disease
Rationale: Malaria is endemic in sub-Saharan Africa. Fever with
systemic symptoms and travel history should raise suspicion for
malaria.
2. Which antibiotic is the first-line treatment for community-
acquired methicillin-resistant Staphylococcus aureus (MRSA) skin
infections?
• A. Amoxicillin
• B. Ceftriaxone
• C. Trimethoprim-sulfamethoxazole (TMP-SMX)
• D. Azithromycin
Rationale: TMP-SMX is effective against MRSA skin infections
and is commonly used as first-line oral therapy.
,3. A patient presents with watery diarrhea after recent antibiotic
use. The most likely causative organism is:
• A. Salmonella
• B. Giardia
• C. Clostridioides difficile
• D. E. coli
Rationale: C. difficile often causes antibiotic-associated diarrhea
due to disruption of normal gut flora.
4. Which of the following vaccines is recommended for all adults
over 50 years to prevent shingles?
• A. Influenza
• B. MMR
• C. Pneumococcal
• D. Recombinant zoster vaccine (Shingrix)
Rationale: Shingrix is recommended for adults over 50 to prevent
herpes zoster and its complications.
5. A patient presents with fever, cough, night sweats, and weight
loss. Chest X-ray shows upper lobe cavitary lesions. The most
likely diagnosis is:
• A. Tuberculosis
• B. Pneumocystis jirovecii pneumonia
• C. Bacterial pneumonia
• D. Sarcoidosis
Rationale: Cavitary lesions in the upper lobes along with
systemic symptoms are classic for tuberculosis.
,6. Which laboratory test is the most sensitive for early detection of
HIV infection?
• A. Western blot
• B. Rapid antibody test
• C. HIV RNA PCR (viral load)
• D. CD4 count
Rationale: HIV RNA PCR can detect infection within 10–14 days
post-exposure, before antibodies develop.
7. A 22-year-old male presents with urethral discharge and dysuria.
Gram stain shows intracellular gram-negative diplococci. The most
likely organism is:
• A. Chlamydia trachomatis
• B. Neisseria gonorrhoeae
• C. Treponema pallidum
• D. Mycoplasma genitalium
Rationale: Gram-negative intracellular diplococci in urethral
discharge is diagnostic for gonorrhea.
8. Which is the treatment of choice for latent tuberculosis infection
in adults?
• A. Isoniazid for 6–9 months
• B. Rifampin for 1 month
• C. Pyrazinamide for 3 months
• D. Ethambutol for 2 months
Rationale: Isoniazid monotherapy for 6–9 months is standard for
latent TB.
, 9. A patient with advanced HIV presents with fever, cough, and
diffuse interstitial infiltrates on CXR. The most likely pathogen is:
• A. Streptococcus pneumoniae
• B. Pneumocystis jirovecii
• C. Mycobacterium tuberculosis
• D. Influenza virus
Rationale: Pneumocystis pneumonia is common in
immunocompromised patients with CD4 <200 cells/mm³.
10. Which of the following is the first-line therapy for
uncomplicated urinary tract infection in women?
• A. Ciprofloxacin
• B. Amoxicillin
• C. Nitrofurantoin
• D. Doxycycline
Rationale: Nitrofurantoin is effective for uncomplicated UTIs and
has a low risk of promoting resistance.
11. A patient presents with fever and a bull’s-eye rash after
hiking in the northeastern U.S. The most likely diagnosis is:
• A. Lyme disease
• B. Rocky Mountain spotted fever
• C. Ehrlichiosis
• D. Tularemia
Rationale: Erythema migrans (bull’s-eye rash) is characteristic of
early Lyme disease caused by Borrelia burgdorferi.
