Abstract
BACKGROUND: Antimicrobial resistance and difficult-to-treat resistance (DTR) in ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) is a threat to human health. The aim of this study was to determine the prevalence of antimicrobial resistance and DTR rates in ESKAPE pathogens over six years in a third-level hospital from Monterrey, Mexico. METHODS: Antimicrobial susceptibility testing was determined by either disk diffusion or broth microdilution in strains from 2018 to 2023. Isolates were screened for carbapenemase genes. Multidrug resistance (MDR), extensively drug resistance (XDR), carbapenem resistance (CR), extended-spectrum cephalosporin-resistance (ESCR), fluoroquinolone resistance (FQR), and DTR were determined. RESULTS: From 3,239 strains, 48.5% were from respiratory infections, resistance was 87.5% to meticillin in Staphylococcus spp. and 39.8% in S. aureus, and 13.9% to vancomycin in Enterococcus spp. MDR, FQR and ESCR rates were between 54-90% in A. baumannii, 20-60% in Enterobacterales and 17-25% in P. aeruginosa. CR was 85.7% in A. baumannii, 33.3% in P. aeruginosa and <5% in Enterobacterales. Most frequent CR genes were OXA-24/40-like in A. baumannii and NDM and OXA-48 in carbapenem-resistant Enterobacterales. DTR rates were 59.7% in A. baumannii (49.2% in 2018 vs 62.9% in 2023), 8.9% in P. aeruginosa and <3% in Enterobacterales. XDR in A. baumannii was 14.4%. CONCLUSIONS: Antimicrobial resistance rates were high in Gram-negative pathogens. CR and DTR rates were higher in A. baumannii than P. aeruginosa and Enterobacterales. DTR surveillance in healthcare providers should be continuous updating local and regional DTR trends among Gram-negative bacteria.