A longitudinal seven-year multicenter study on the molecular epidemiology of carbapenemase-producing Enterobacterales in Taiwan: The burden of metallo-β-lactamases.

BACKGROUND: With the introduction of novel antimicrobial agents, the threat posed by multidrug-resistant organisms has rapidly emerged. Among these, metallo-β-lactamase-producing carbapenem-resistant Enterobacterales (MBL-CRE) represent a significant challenge, severely limiting therapeutic options for clinicians. Our aim is to investigate the current burden and molecular epidemiology of carbapenemase-producing Enterobacterales (CPE) in Taiwan, with a particular focus on MBL producers.

METHODS: We conducted a multicenter, seven-year longitudinal study from 2018 to 2024, collecting carbapenem-resistant Enterobacterales isolates, and screening them for carbapenemase genes.

RESULTS: A total of 1743 CPE isolates were included in this study. The most common species were Klebsiella pneumoniae (58.5 %), Escherichia coli (21.2 %), and Enterobacter cloacae complex (7.8 %), primarily recovered from urine and respiratory specimens. Among these isolates, 67.3 % harbored non-MBL genes and 32.7 % harbored MBL genes, with both types increasing significantly over time (both p < 0.001). In addition, a notable emergence of multiple-carbapenemase-producing Enterobacterales (M-CPE) was observed among various species, particularly K. pneumoniae, which exhibited the greatest diversity of carbapenemase gene combinations while E. coli co-harboring blaOXA-181 and blaNDM-5 accounted for the largest proportion of M-CPE isolates. Overall, the proportion of MBL producers among total CPE isolates increased from 22.3 % (95 % CI, 15.2-30.4 %) in 2018-40 % (95 % CI, 34.9-45 %) in 2024 with a statistical significance (p = 0.02). Among the six most frequently identified CPE species, K. pneumoniae and Citrobacter koseri were largely linked to non-MBL genes, while E. coli, Enterobacter cloacae complex, Citrobacter freundii, and Serratia marcescens were almost exclusively associated with MBL genes.

CONCLUSION: The rising prevalence of MBL-CPE underscores the urgent need for strengthened infection control measures, ongoing genomic surveillance, and robust antimicrobial stewardship programs to prevent further emergence and transmission.