Antimicrobial resistance patterns of common Gram-negative microorganisms isolated from patients with lower respiratory tract infection in a Teaching Hospital in Vietnam.

This cross-sectional study investigated the antimicrobial resistance (AMR) patterns of Gram-negative pathogens isolated from 4,789 hospitalized patients with lower respiratory tract infections (LRTIs). Of the collected specimens, 1,325 (27.7%) specimens tested positive for Gram-negative bacteria. The most prevalent isolates were Acinetobacter baumannii (38.6%), Pseudomonas aeruginosa (33.5%), Klebsiella pneumoniae (18.7%), Escherichia coli (5.6%), and Klebsiella aerogenes (3.5%). Antimicrobial resistance analysis revealed high resistance rates among A. baumannii isolates, showing resistance (79.9%-100%) to multiple classes of antibiotics, except amikacin, trimethoprim/sulfamethoxazole, and colistin. P. aeruginosa displayed lower resistance to colistin (<10%), but resistance to other antibiotics was high. K. pneumoniae displayed elevated resistance rates against most penicillins, ranging from 90.0% to 100.0%. In contrast, the resistance rates were notably lower for colistin (7.1%) and amikacin (16.7%). K. aerogenes showed high resistance to various antibiotics, while sensitivity was observed for amikacin (95.1%), ampicillin (100.0%), and colistin (100.0%). E. coli exhibited resistance to ampicillin (96.9%) but showed maximum sensitivity to several antibiotics. The study identified significant antimicrobial resistance trends and highlighted the prevalence of multidrug-resistant strains (93.6% for K. aerogenes and 69.1%-92.4% for other isolates). These findings emphasize the urgent need for appropriate antibiotic stewardship practices to combat antimicrobial resistance in Gram-negative pathogens associated with LRTIs.