Abstract Introduction Pneumocystis jirovecii typically causes pneumonia in immunocompromised hosts. Its detection in immunocompetent children is rare and may represent colonization or transient infection. We report a pediatric case highlighting the diagnostic challenges and the possible role of indirect occupational exposure. Case Report A previously healthy 2-year-8-month-old boy presented with recurrent respiratory infections over 1.5 months, including persistent rhinorrhea, productive cough, sinusitis, otitis media, and recurrent fever despite antibiotic treatments (amoxicillin-clavulanic acid and cefalexin). Prolonged antibiotic use led to Clostridium difficile-associated colitis treated with metronidazole and nifuroxazide. Upon hospitalization, laboratory studies showed leukocytosis, neutrophilia, and elevated inflammatory markers (C-reactive protein and procalcitonin). Viral PCR tests (influenza, RSV, SARS-CoV-2) were negative. Chest CT revealed bilateral pneumonia with right lobar consolidation. Nasopharyngeal PCR detected adenovirus, coronavirus OC43, Moraxella catarrhalis, and Streptococcus pneumoniae. Bronchoscopy with bronchoalveolar lavage (BAL) confirmed adenovirus and coronavirus OC43, and BAL cultures grew beta-lactamase-positive Staphylococcus aureus. Cytological examination of the BAL identified structures consistent with Pneumocystis jirovecii cysts on Giemsa stain. PCR confirmation was not available. An immunologic workup (immunoglobulin levels and lymphocyte subsets) showed no abnormalities. HIV testing for both child and mother was negative. Epidemiologic investigation revealed the mother was a healthcare professional with frequent contact with HIV-positive patients, suggesting potential transient exposure. Given the absence of Pneumocystis-related symptoms and steady clinical improvement, no specific treatment was administered. The patient was discharged after 12 days and remained healthy at six-month follow-up. Discussion This case underscores the importance of considering atypical or opportunistic pathogens in pediatric pneumonia even in immunocompetent hosts. Detection of Pneumocystis jirovecii in this context may reflect transient colonization rather than true infection. The case also highlights the need for cautious interpretation of microbiologic findings, thorough immunologic assessment, and awareness of indirect occupational exposure. Judicious antibiotic use remains crucial to reduce secondary complications. This abstract is funded by: None
Leon et al. (Fri,) studied this question.