A 27-year-old woman presents to the emergency department with shortness of breath, cough, nausea, vomiting and fever for the past day. Her past medical history is notable for cystic fibrosis (CF), type 2 diabetes mellitus managed glargine insulin, chronic sinusitis, and CF-related pancreatic insufficiency. Due to worsening respiratory distress, the patient is intubated in the emergency department, and a bronchoalveolar lavage is performed which shows detectable influenza A infection. Sputum cultures obtained prior to intubation grow mucoid pseudomonal pneumonia. CT scan of the chest shows diffuse, bilateral peribronchovascular consolidative and nodular opacities on a background of ground-glass attenuation consistent with multifocal pneumonia.
B) Cefepime and oseltemivi
In a patient who has a cystic fibrosis with current sputum cultures growing Pseudomonas, treatment should be with an antibiotic that provides pseudomonal coverage, such as cefepime. Additionally, with a positive viral influenza test, it is imperative to treat with a course of oseltemivir.
Answer choice A: Cefepime, is incorrect. Given the positive influenza test, treatment with oseltemivir is also indicated.
Answer choice C: Linezolid, is incorrect. Linezolid is an antibioitic best used for gram-positive cocci, specifically methicillin-resistant Staphylococcus aureus (MRSA) lung infections. Patients with cystic fibrosis can have MRSA infections, especially at a younger age, which would require treatment with vancomycin or linezolid. In this case, the patient already had sputum cultures that were solely positive for Pseudomonas, which is a gram-negative rod, and she had a bronchoalveolar lavage BAL that detected influenza; therefore, treatment should target these two microbes.
Answer choice D: Oseltemivir, is incorrect. Given the patient’s immunocompromised state and pseudomonal pneumonia, treatment with cefepime is also indicated.
Answer choice E: Oseltemivir, linezolid, and cefepime, are incorrect. Given the identification of Pseudomonas and influenza, treatment with linezolid to cover for MRSA infection is not necessary.
Key Learning Point
Patients with cystic fibrosis are considered immunocompromised and should be aggressively treated for viral influenza and any other underlying infection with antimicrobials. Use the information from obtained sputum cultures to aid in antimicrobial selection and eventually de-escalation.
