Characterization of Bacterial Isolates from Bronchoalveolar Lavage and Their Antimicrobial Resistance Patterns in a Tertiary Care Hospital in Bangladesh: A VITEK 2-Based Cross-Sectional Study

Open Access

Abstract

Background: Lower respiratory tract infections (LRTIs) cause significant morbidity and mortality. Bronchoalveolar lavage (BAL) helps identify pathogens and guide therapy. This study determined the bacteriological profile and antimicrobial resistance patterns of BAL isolates in a Bangladeshi tertiary care hospital. Methods & Materials: This retrospective laboratory-based study was conducted at Bangabandhu Sheikh Mujib Medical University, Dhaka, from January 2024 to December 2024. A total of 245 BAL specimens from patients with suspected pulmonary infections were processed. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK 2 automated system and interpreted per CLSI guidelines. Results: Of 245 BAL specimens, 161 (65.7%) showed significant bacterial growth. Culture positivity was higher in males (55.9%) and in the 51-60 years age group (29.2%). Gram-negative bacteria comprised 98.1% of isolates. Pseudomonas aeruginosa (49.1%) was most common, followed by Klebsiella pneumoniae (26.7%), Escherichia coli (13.0%), Acinetobacter baumannii (6.8%), Enterobacter cloacae (2.5%), and Staphylococcus aureus (1.9%). Colistin showed 100% susceptibility among Gram-negatives. Amikacin and imipenem were the most active non-polymyxin agents. High resistance was seen to cephalosporins and ciprofloxacin. All S. aureus isolates were methicillin-sensitive and fully susceptible to vancomycin and linezolid. Conclusions: Gram-negative bacteria, especially P. aeruginosa, predominate in BAL isolates from pulmonary infection patients. High antimicrobial resistance highlights the need for routine surveillance, local antibiograms, and antimicrobial stewardship. BAL remains valuable for targeted therapy.