Antimicrobial resistance in clinical Gram-negative bacilli: phenotypic and genotypic characterization in Ecuador

Antimicrobial resistance (AMR) is a major global public health threat, hampering the use of antimicrobials for the treatment of bacterial infections. In this study, we characterized the phenotypic and genotypic profiles of antimicrobial resistance determinants in clinically derived bacteria from infectious processes in patients treated in hospitals in Quito, Ecuador. Nine bacterial isolates selected from the Catholic Bacterial Collection - Quito (CB-QCA) of the Microbiology Laboratory of the Pontifical Catholic University of Ecuador, preserved at -20ºC and -80ºC, were analyzed. One E. coli isolate, three Klebsiella pneumoniae isolates, two Proteus mirabilis isolates, and three Pseudomonas aeruginosa isolates were analyzed. Phenotypic antibiotic susceptibility testing and mCIM and eCIM tests were performed using the disk diffusion method. Genotypic characterization of beta-lactam and carbapenemase resistance genes was performed by polymerase chain reaction (PCR). The results revealed a high prevalence of resistance among isolates, with β-lactams, quinolones and aminoglycosides being the most commonly detected antibiotic classes. The findings highlight the need for continued surveillance of antimicrobial resistance patterns.