NP Infectious Diseases Exam Ready:
150 Practice Items Answers And
Rationales
2025/2026
1. Which pathogen is most commonly associated with community-
acquired pneumonia in adults?
• Streptococcus pneumoniae
• Haemophilus influenzae
• Mycoplasma pneumoniae
• Legionella pneumophila
Rationale: Streptococcus pneumoniae is the leading cause of
community-acquired pneumonia, particularly in adults, due to its
prevalence and virulence factors.
2. A 25-year-old presents with urethral discharge and dysuria. Gram
stain shows gram-negative intracellular diplococci. The most likely
diagnosis is:
• Chlamydia trachomatis
• Neisseria gonorrhoeae
• Trichomonas vaginalis
• Mycoplasma genitalium
Rationale: Gram-negative intracellular diplococci in urethral discharge
strongly suggest Neisseria gonorrhoeae infection.
, 3. Which of the following is the first-line treatment for latent
tuberculosis infection?
• Isoniazid for 6–9 months
• Rifampin for 2 months
• Isoniazid for 6–9 months
• Pyrazinamide for 3 months
Rationale: Isoniazid for 6–9 months is the standard therapy for latent
TB to prevent progression to active disease.
4. Which virus is most commonly associated with cervical cancer?
• Herpes simplex virus
• Human papillomavirus (HPV)
• Epstein-Barr virus
• Cytomegalovirus
Rationale: High-risk HPV strains, especially types 16 and 18, are the
primary cause of cervical cancer.
5. A patient presents with fever, headache, and a stiff neck. The
most appropriate empiric antibiotic therapy for suspected
bacterial meningitis in an adult is:
• Ampicillin alone
• Ceftriaxone plus vancomycin
• Ciprofloxacin
• Azithromycin
,Rationale: Empiric therapy with ceftriaxone plus vancomycin covers
the most likely pathogens including Streptococcus pneumoniae and
Neisseria meningitidis.
6. Which antibiotic is contraindicated in pregnancy due to the risk of
fetal bone growth abnormalities?
• Penicillin
• Tetracyclines
• Cephalosporins
• Macrolides
Rationale: Tetracyclines can cause permanent tooth discoloration and
inhibit bone growth in the developing fetus.
7. A patient presents with acute watery diarrhea after travel to a
developing country. The most likely causative organism is:
• Salmonella typhi
• Enterotoxigenic Escherichia coli (ETEC)
• Shigella dysenteriae
• Clostridium difficile
Rationale: ETEC is the leading cause of traveler's diarrhea and
typically presents with watery, non-bloody stools.
8. Which hepatitis virus is primarily transmitted via the fecal-oral
route?
• Hepatitis B
• Hepatitis C
• Hepatitis A
, • Hepatitis D
Rationale: Hepatitis A virus is transmitted through contaminated food
and water, leading to acute hepatitis.
9. A patient with HIV presents with oral thrush. The most likely
causative organism is:
• Streptococcus mutans
• Staphylococcus aureus
• Candida albicans
• Aspergillus fumigatus
Rationale: Candida albicans is the most common fungal pathogen
causing oral thrush in immunocompromised patients, including those
with HIV.
10. Which of the following infections is most commonly
associated with neutropenia?
• Influenza
• Tuberculosis
• Bacterial sepsis
• Viral hepatitis
Rationale: Neutropenic patients are at high risk for bacterial infections
due to impaired innate immune response.
11. A 3-year-old child presents with a barking cough and stridor.
The most likely diagnosis is:
• Asthma exacerbation
• Croup (laryngotracheitis)
150 Practice Items Answers And
Rationales
2025/2026
1. Which pathogen is most commonly associated with community-
acquired pneumonia in adults?
• Streptococcus pneumoniae
• Haemophilus influenzae
• Mycoplasma pneumoniae
• Legionella pneumophila
Rationale: Streptococcus pneumoniae is the leading cause of
community-acquired pneumonia, particularly in adults, due to its
prevalence and virulence factors.
2. A 25-year-old presents with urethral discharge and dysuria. Gram
stain shows gram-negative intracellular diplococci. The most likely
diagnosis is:
• Chlamydia trachomatis
• Neisseria gonorrhoeae
• Trichomonas vaginalis
• Mycoplasma genitalium
Rationale: Gram-negative intracellular diplococci in urethral discharge
strongly suggest Neisseria gonorrhoeae infection.
, 3. Which of the following is the first-line treatment for latent
tuberculosis infection?
• Isoniazid for 6–9 months
• Rifampin for 2 months
• Isoniazid for 6–9 months
• Pyrazinamide for 3 months
Rationale: Isoniazid for 6–9 months is the standard therapy for latent
TB to prevent progression to active disease.
4. Which virus is most commonly associated with cervical cancer?
• Herpes simplex virus
• Human papillomavirus (HPV)
• Epstein-Barr virus
• Cytomegalovirus
Rationale: High-risk HPV strains, especially types 16 and 18, are the
primary cause of cervical cancer.
5. A patient presents with fever, headache, and a stiff neck. The
most appropriate empiric antibiotic therapy for suspected
bacterial meningitis in an adult is:
• Ampicillin alone
• Ceftriaxone plus vancomycin
• Ciprofloxacin
• Azithromycin
,Rationale: Empiric therapy with ceftriaxone plus vancomycin covers
the most likely pathogens including Streptococcus pneumoniae and
Neisseria meningitidis.
6. Which antibiotic is contraindicated in pregnancy due to the risk of
fetal bone growth abnormalities?
• Penicillin
• Tetracyclines
• Cephalosporins
• Macrolides
Rationale: Tetracyclines can cause permanent tooth discoloration and
inhibit bone growth in the developing fetus.
7. A patient presents with acute watery diarrhea after travel to a
developing country. The most likely causative organism is:
• Salmonella typhi
• Enterotoxigenic Escherichia coli (ETEC)
• Shigella dysenteriae
• Clostridium difficile
Rationale: ETEC is the leading cause of traveler's diarrhea and
typically presents with watery, non-bloody stools.
8. Which hepatitis virus is primarily transmitted via the fecal-oral
route?
• Hepatitis B
• Hepatitis C
• Hepatitis A
, • Hepatitis D
Rationale: Hepatitis A virus is transmitted through contaminated food
and water, leading to acute hepatitis.
9. A patient with HIV presents with oral thrush. The most likely
causative organism is:
• Streptococcus mutans
• Staphylococcus aureus
• Candida albicans
• Aspergillus fumigatus
Rationale: Candida albicans is the most common fungal pathogen
causing oral thrush in immunocompromised patients, including those
with HIV.
10. Which of the following infections is most commonly
associated with neutropenia?
• Influenza
• Tuberculosis
• Bacterial sepsis
• Viral hepatitis
Rationale: Neutropenic patients are at high risk for bacterial infections
due to impaired innate immune response.
11. A 3-year-old child presents with a barking cough and stridor.
The most likely diagnosis is:
• Asthma exacerbation
• Croup (laryngotracheitis)
