Antimicrobial susceptibility patterns in Jalisco, Mexico: a snapshot of regional resistance (2021-2023)

Antimicrobial resistance (AMR) is a major global public health threat, responsible for an estimated 4.9 million deaths worldwide and associated with increased morbi-mortality, and healthcare costs. The burden is particularly high in hospital settings, where multidrug-resistant pathogens, including ESKAPE group, are prevalent. However, in Mexico, epidemiological data remain limited. This study aimed to determine the prevalence and distribution of AMR among clinically relevant bacterial pathogens isolated in three hospitals in Guadalajara, Jalisco, Mexico, and to compare resistance patterns across hospital wards and clinical specimen types.

A retrospective multicenter study was conducted from January 2021 to December 2023. Bacterial identification and susceptibility tests were performed using VITEK 2 and MicroScan WalkAway systems. Results were analyzed using WHONET and interpreted according to CLSI criteria. Clinical specimens included urine, blood, biopsies, abscesses, lower respiratory tract (LRT) specimens, and sterile fluids. Species analyzed included, Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter baumannii and Escherichia coli. Statistical comparisons were performed using R Statistical Software Studio.

A total of 13,336 clinical isolates were analyzed, with E. coli (n= 5,737) and K. pneumoniae (n= 1,738) as the most predominant pathogens. Urine samples were the most frequently collected (n= 4,247). Bloodstream isolates exhibited the highest resistance levels for E. coli and K. pneumoniae. Non-fermenting pathogens showed high resistance in LRT isolates, especially for P. aeruginosa and A. baumannii, with elevated carbapenem resistance. Resistance levels were higher the ICU, particularly for K. pneumoniae, E. cloacae, P. aeruginosa, and A. baumannii. In contrast, the non-ICU settings showed a greater prevalence of ESBL-producing E. coli.

This study reveals substantial AMR burden in Guadalajara, with particularly high levels among bloodstream pathogens, non-fermenters in LRT specimens, and carbapenem-resistant K. pneumoniae and A. baumannii. Resistance patterns varied across hospital wards and specimen types, with higher resistance in ICU. These findings contribute valuable regional data to national AMR monitoring efforts.