Resistance landscape and clonal dynamics of ESKAPE pathogens in bloodstream infections: A multicenter study from Mexico

Antimicrobial resistance in healthcare-associated infections represents one of the greatest threats to global health. The COVID-19 pandemic disrupted infection control and antimicrobial stewardship, potentially affecting the prevalence of pathogens and the development of resistance. This study aimed to investigate the prevalence, antimicrobial resistance, and clonal dissemination of ESKAPE pathogens isolated from bloodstream infections during the second year of the COVID-19 pandemic in four tertiary-care hospitals in Mexico. A total of 926 isolates were analyzed: <i>Staphylococcus aureus</i> (22.4%), <i>Klebsiella pneumoniae</i> (22%), <i>Acinetobacter baumannii</i> (21.5%), <i>Pseudomonas aeruginosa</i> (12.5%), <i>Enterobacter cloacae</i> (9.4%), <i>Enterococcus faecalis</i> (8.4%), and <i>Enterococcus faecium</i> (3.8%). High rates of multidrug resistance were observed in <i>A. baumannii</i> (70.9% XDR) and <i>K. pneumoniae</i> (71% XDR plus MDR with 79% ESBL). <i>P. aeruginosa</i> and <i>E. cloacae</i> showed the highest susceptibility rates (53% and 48%, respectively) to all antimicrobials. The main β-lactamases involved in resistance were <i>bla</i>_SHV,<i>bla</i>_CTX-M, and<i>bla</i>_TEM in <i>K. pneumoniae</i> while the predominant carbapenemases were <i>bla</i>_OXA-24<i>, bla</i>_{<em>OXA-23</em>} <i>in A. baumannii</i><i>, bla</i>_<em>NDM</em> in <i>K. pneumoniae</i> and <i>bla</i>_VIM in <i>P. aeruginosa</i> Among Gram-positives, methicillin-resistant <i>S. aureus</i> accounted for 33.8% of isolates, and vancomycin resistance was higher in <i>E. faecium</i> (28%) than in <i>E. faecalis</i> (1.3%). Pulsed-field gel electrophoresis revealed endemic circulation of <i>A. baumannii</i> clones (Pulsotypes 1AC, 2AM), persistent for over a decade, and interhospital dissemination of <i>S. aureus</i> and <i>K. pneumoniae</i> clones. These findings underscore the epidemiological relevance of MDR ESKAPE pathogens during the COVID-19 pandemic and highlight the urgent need to optimize empirical therapy and maintain continuous genomic surveillance to enhance infection control in Mexican hospitals.