Epidemiologia e caracterização molecular de Pseudomonas aeruginosa, Klebsiella pneumoniae e Escherichia coli multirresistentes carreando determinantes de resistência às quinolonas mediada por plasmídeos

Abstract

The study conducted was comprehensive, including classical epidemiology and molecular aspects of infections by P. aeruginosa, K. pneumoniae and E. coli resistant to fluoroquinolones and/or carbapenems. Molecular analysis included determining the profile clonal, identification of genes of interest by PCR-based assays and sequencing of target gene. Case-control study was conducted to evaluate the prognostic and the impact of inappropriate therapy in patients with bacteremia and VAP (ventilator-associated pneumonia), as well as for the determination of the risk factors by multiresistant (MDR) P. aeruginosa infections. We observed a high rate of MDR P. aeruginosa isolates (40.7%), being 51.0% independently associated with inappropriate antibiotic therapy. In patients with VAP, significant rates were related to inappropriate therapy, especially by MDR and resistant to fluoroquinolones isolates. Besides, bacteremia was detected in 66.9% of patients, and prolonged hospital stay was expressive in those resistant to fluoroquinolone. Plasmid-mediated quinolone resistance genes (PMQR), were detected in two (5.3%) nosocomial isolates of P. aeruginosa (qnrS1 and aac(6 )Ib-cr), while those of K. pneumoniae and E. coli, from community or nosocomial origin, the presence of this gene was higher (55.3%; qnrA, qnrB, qnrD, qnrS and aac(6 )Ib-cr). In addition, we could verify the presence of the aac(6 )-Ib7 variant, with significant frequency to those of P. aeruginosa. Independently of the presence of PMQR genes, the minimum inhibitory concentration (MIC50 and MIC90) for ciprofloxacin were high, as well as, a high frequency of MDR isolates, and among those of the Enterobacteriaceae family were mainly community-acquired infection s agents (55.0%) and urinary tract (72.9%). Most isolates (90%) showed class 1 integron, but there is the necessity of further investigation to determine its relationship with PMQR genes. There was detection of genes encoding metallo-β-lactamase in 21.9% of the P. aeruginosa isolates, predominantly blaSPM gene and a polyclonal profile. Moreover, there was not a prevalent clone associated with the presence of PMQR determinants. Our data show for the first time the presence of PMQR determinants in clinical isolates of P. aeruginosa in Brazil, with a higher frequency of patients with inappropriate therapy; and multidrug-resistant K. pneumoniae and E. coli isolates with plasmid-mediated quinolone resistance. Although studies of classical and molecular epidemiology in hospitals are very important in the country, it is necessary that the infection control practices result in reducing these infections based on this data, considering the additional burden of participation of MDR micro-organism and its importance in terms of morbidity, mortality and cost.