Occurrence of Plasmid-Mediated Quinolone Resistance and Carbapenemase-Encoding Genes in Pseudomonas aeruginosa Isolates from Nosocomial Patients in Aguascalientes, Mexico

<i>Pseudomonas aeruginosa</i> is a leading cause of healthcare-associated infections, which are related to substantial morbidity and mortality. The incidence of Plasmid-Mediated Quinolone Resistance (PMQR) determinants has been previously reported in this bacterium. However, there is limited information regarding the presence of PMQR and carbapenemase-encoding genes simultaneously. This study aims to analyze the prevalence of these determinants on <i>P. aeruginosa</i> strain isolated from clinical patients in the State of Aguascalientes, Mexico. Fifty-two <i>P. aeruginosa</i> isolates from nosocomial patients were collected from Centenario Hospital Miguel Hidalgo. This is a retrospective observational study conducted at a single center. Antibiotic susceptibility was tested using the Vitek-2 system. Only carbapenem-resistant isolates were included in this study. Carbapenemase-encoding genes and PMQR determinants were screened by polymerase chain reaction (PCR). Resistance rates of 100% were found on tigecycline and ceftriaxone. Of the 52 isolates, 34.6% were positive for the <i>qnr</i> genes, 46.2% for the <i>oqxA</i> gene, and 25% for the <i>aac-(6')-lb</i> gene. The most frequent carbapenemase genes found in the samples were <i>bla</i>_OXA-51 (42.3%), <i>bla</i>_OXA-1 (15.4%), and <i>bla</i>_VIM (15.4%). <i>bla</i>_OXA-51 co-carrying <i>oqxA</i> was detected in 21.1% of the isolates, <i>bla</i>_OXA-51 co-carrying <i>aac-(6')-lb</i> in 11.5%, <i>bla</i>_VIM co-carrying <i>aac-(6')-lb</i> in 3.8%, and <i>bla</i>_KPC co-carrying <i>oqxA</i> in 5.8%. Systematic surveillance to detect carbapenemase-encoding genes and PMQR determinants, and rational prescription using the last-line drugs could help in preventing the dissemination of multidrug-resistant determinants.