Background: Pulmonary infiltrates are a common radiographic finding with a broad differential diagnosis, including infectious, inflammatory, and neoplastic etiologies. Accurate identification of the causative pathogen is essential for targeted antimicrobial therapy, particularly in critically ill or immunocompromised patients. Bronchial washings, obtained via bronchoscopy, offer a valuable diagnostic sample for microbiological analysis. This study explores the clinical implications of antibiogram results derived from bronchial washings in patients presenting with pulmonary infiltrates.

Methods: We conducted a retrospective analysis of patients undergoing bronchoscopy for evaluation of pulmonary infiltrates over 12 months at a tertiary care centre. Culture and sensitivity data from bronchial washings were reviewed alongside clinical outcomes, antimicrobial adjustments, and radiologic progression. The impact of antibiogram-guided therapy on clinical response and hospital length of stay was assessed.

Results: Of the 142 patients included, bronchial washing cultures yielded significant pathogens in 68% of cases. The most commonly isolated organisms were Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus. In 72% of culture-positive cases, the initial empiric antibiotics were modified based on sensitivity patterns. Patients whose therapy was adjusted according to the antibiogram showed a statistically significant improvement in clinical parameters, including resolution of infiltrates and reduced length of hospital stay (p < 0.05). Notably, inappropriate empiric antibiotic use was associated with delayed recovery and increased risk of complications.