ITE Infectious Disease Management 2 — Questions and Answers
Question 1: A 45-year-old man with HIV (CD4 50 cells/µL) presents with fever, headache, and neck stiffness. CSF shows elevated protein, low glucose, and India ink positive organisms. What is the first-line treatment?
- Fluconazole 400mg daily
- Liposomal amphotericin B plus flucytosine (Correct answer)
- Voriconazole IV
- Micafungin IV
Correct answer: Liposomal amphotericin B plus flucytosine
Cryptococcal meningitis in HIV patients is treated with induction therapy using liposomal amphotericin B plus flucytosine for 2 weeks, followed by fluconazole consolidation.
Question 2: A 30-year-old woman presents with dysuria and urinary frequency. Urine culture grows >100,000 CFU/mL of E. coli sensitive to all agents. She is 10 weeks pregnant. What is the appropriate antibiotic?
- Ciprofloxacin 500mg BID x 3 days
- Nitrofurantoin 100mg BID x 5 days (Correct answer)
- Trimethoprim-sulfamethoxazole DS BID x 7 days
- Doxycycline 100mg BID x 7 days
Correct answer: Nitrofurantoin 100mg BID x 5 days
Nitrofurantoin is safe in the second trimester and is first-line for uncomplicated UTI in pregnancy; TMP-SMX and fluoroquinolones are avoided due to fetal risks.
Question 3: A 60-year-old man with COPD is hospitalized with healthcare-associated pneumonia. He has no prior antibiotic exposure. What empiric coverage is most appropriate?
- Azithromycin monotherapy
- Piperacillin-tazobactam plus vancomycin (Correct answer)
- Levofloxacin monotherapy
- Ceftriaxone plus azithromycin
Correct answer: Piperacillin-tazobactam plus vancomycin
Healthcare-associated pneumonia requires broad-spectrum coverage for MRSA and Pseudomonas, making piperacillin-tazobactam plus vancomycin the appropriate empiric regimen.
Question 4: A 55-year-old patient develops fever and diarrhea 4 days after starting clindamycin for a skin infection. Stool testing is positive for C. difficile toxin. She has her first episode. What is the preferred treatment?
- Metronidazole 500mg TID x 10 days
- Oral vancomycin 125mg QID x 10 days
- Fidaxomicin 200mg BID x 10 days (Correct answer)
- Rifaximin 400mg TID x 10 days
Correct answer: Fidaxomicin 200mg BID x 10 days
Current IDSA guidelines recommend fidaxomicin as preferred first-line therapy for initial C. difficile infection due to lower recurrence rates compared to vancomycin.
Question 5: A 25-year-old man presents with a painless penile ulcer with indurated borders and bilateral inguinal lymphadenopathy. Dark-field microscopy confirms the diagnosis. What is the treatment of choice?
- Doxycycline 100mg BID x 14 days
- Benzathine penicillin G 2.4 million units IM single dose (Correct answer)
- Ceftriaxone 250mg IM single dose
- Azithromycin 1g PO single dose
Correct answer: Benzathine penicillin G 2.4 million units IM single dose
Primary syphilis is treated with benzathine penicillin G 2.4 million units IM as a single dose, which is curative for early syphilis.
Question 6: A 40-year-old woman from Southeast Asia presents with fever, night sweats, weight loss, and a productive cough for 3 months. AFB smear is positive. She starts RIPE therapy. After 2 months, cultures show full susceptibility. What is the total treatment duration?
- 4 months total
- 6 months total (Correct answer)
- 9 months total
- 12 months total
Correct answer: 6 months total
Drug-susceptible pulmonary tuberculosis is treated with 2 months of RIPE followed by 4 months of rifampin and isoniazid, for a total of 6 months.
Question 7: A 35-year-old man with a dog bite to his hand 8 hours ago presents for evaluation. He is up to date on tetanus and the wound has been thoroughly irrigated. What organism most commonly causes infection in dog bites?
- Staphylococcus aureus
- Pasteurella multocida (Correct answer)
- Capnocytophaga canimorsus
- Eikenella corrodens
Correct answer: Pasteurella multocida
Pasteurella multocida is the most common pathogen isolated from dog and cat bite wounds, typically causing rapid-onset cellulitis within 24 hours.
ITE Infectious Disease Management 2
A 45-year-old man with HIV (CD4 50 cells/µL) presents with fever, headache, and neck stiffness.
CSF shows elevated protein, low glucose, and India ink positive organisms.
What is the first-line treatment?