Antimicrobial resistance evolution over time during pre-and post-COVID-19 periods at a major tertiary care center in...

The increasing rates of AMR have been tolling the healthcare systems globally. This study aims to explore the evolution of AMR patterns against commonly encountered clinical bacterial pathogens at a major tertiary care center in Lebanon during pre-COVID (2019) and post-COVID (2023) periods.

Consecutive non-duplicate isolates of Gram-positive (e.g., Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus spp.) and Gram-negative pathogens (e.g., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii) were analyzed using MALDI-TOF identification and CLSI-standardized disk diffusion/Etest methods.

Key findings revealed persistent methicillin-resistant S. aureus (MRSA) rates (36%), increased vancomycin-resistant Enterococci (VRE; 7% to 10%), and high penicillin susceptibility among S. pneumoniae. Gram-negative isolates exhibited concerning trends: ESBL prevalence rose in E. coli (32% to 36%) but remained stable (35% to 34%) in K. pneumoniae. Carbapenem-resistant Enterobacterales (CRE) rates remained unchanged for E. coli (6% to 5%) but declined for K. pneumoniae (15% to 6%). A. baumannii susceptibility remained critically low (18-55%), while P. aeruginosa showed stable susceptibility (76-92%).

An overall increase in the resistance profiles among different bacterial species is noted in comparison with earlier studies from this institution. These findings align with prior multidrug-resistant strains and underscore the need for robust surveillance, antibiotic stewardship, and infection control measures.