Detection of the blaCTX-M1 gene, subgroup 15, in extended-spectrum beta-lactamase-producing Enterobacteriales isolates from two private healthcare institutions in Ecuador

Objective: to characterize the presence of the blaCTX-M1 gene, subgroup 15, in Enterobacterales isolates obtained from two private healthcare institutions in Cuenca, Ecuador, between August 2024 and January 2025. Study design: a total of 85 isolates were analyzed using the double-disk synergy test and PCR for the molecular detection of the resistance gene. Findings: all isolates were phenotypically confirmed as extended-spectrum β-lactamase (ESBL)-producing bacteria. The blaCTX-M1 gene, subgroup 15, was detected in 39 of the 85 isolates analyzed (45.88%). Escherichia coli was the predominant species (n=68; 80.0%), and urine was the most common specimen type (n=70; 82.35%). Conclusion: these findings provide information on the local presence of this genetic determinant and contribute to the understanding of molecular resistance mechanisms among ESBL-producing Enterobacterales in Ecuador.