Role of β-lactamases and efflux pumps in multidrug resistance inPseudomonas aeruginosaisolated from patients in the Intensive Care Unit in the northeast of Brazil

Abstract

AbstractPseudomonas aeruginosais an opportunistic pathogen of great clinical relevance in intensive care units (ICU), mainly due to its high resistance to various antimicrobials, which sometimes makes effective treatment impossible, leading to high morbidity and mortality in patients in critical situations. In this study, we aimed to detect variants of genes encoding β-lactamases and efflux pumps inP. aeruginosaisolates resistant to β-lactams, fluoroquinolones and aminoglycosides. All genes belonging to the subfamilies were included in the study:blaSHV,blaTEM,blaNDM,blaKPC,blaGES,blaCTX-M. In addition, we investigate the most relevant variants of theblaOXAsubfamily and genes belonging to the efflux pumps of the Mex family. We tested 54 isolates ofP. aeruginosa, finding a high prevalence of phenotypic resistance to the antimicrobials piperacillin with tazobactam, ceftazidime, cefepime, imipenem and meropenem, with a high positivity in the presence of resistance genes related to carbapenems and spectrum β-lactamases extended, mainly for theblaKPCgenes with 81.49%, followed byblaCTXM-2with 72.22% andblaCTXM-1with 66.66%. In relation to the presence of Mex family efflux pumps there was a rate of 100% of positivity. These results suggest that theP. aeruginosastrains isolated have an arsenal of genes encoding β-lactamases capable of inducing phenotypic patterns of resistance to several antimicrobials commonly used for these infections, making treatment difficult for the patients in this clinical ward.