Detection and analysis of different interactions between resistance mechanisms and carbapenems in clinical isolates of Klebsiella pneumoniae

Abstract

Carbapenems are considered last-line agents for the treatment of serious infections caused by Klebsiella pneumoniae, and this microorganism may exhibit resistance to β-lactam antibiotics due to different mechanisms of resistance. We evaluated 27 isolates of K. pneumoniae resistant to carbapenems recovered from inpatients at the University Hospital of Santa Maria-RS from July 2013 to August 2014. We carried out antimicrobial susceptibility, carbapenemase detection, testing for the presence of efflux pump by broth microdilution and loss of porin by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Genetic similarity was evaluated by ERIC-PCR. High levels of resistance were verified by the minimum inhibitory concentration for the antimicrobials tested. The blaKPC gene was present in 89% of the clinical isolates. Blue-Carba and combined disk with AFB tests showed 100% concordance, while the combined disk test with EDTA showed a high number of false-positives (48%) compared with the gold-standard genotypic test. Four isolates showed a phenotypic resistance profile consistent with the overexpression of the efflux pump, and all clinical isolates had lost one or both porins. The ERIC-PCR dendrogram demonstrated the presence of nine clusters. The main mechanism of resistance to carbapenems found in the assessed isolates was the presence of the blaKPC gene.

Analysis of Antibiotic Resistance and Virulence Traits (Genetic and Phenotypic) in Klebsiella pneumoniae Clinical Isolates from Pakistan: Identification of Significant Levels of Carbapenem and Colistin Resistance

“…In this study, the MICs determined for fluoroquinolone, aminoglycoside, and polymyxin were notably higher for the carbapenemase-producing K. pneumoniae . CRKP frequently harbors a combination of resistance mechanisms including carbapenemases, drug efflux, and loss of porin function 32 , 33 leading to higher levels of resistance to antibiotics, as observed here in the carbapenemase-producing isolates. Molecular screening for the resistance markers in 200 K. pneumoniae isolates in this study confirmed bla NDM-1 as the predominant (39% occurrence) carbapenemase-encoding gene followed by bla OXA-48 (24%) and bla KPC , (5%).…”

Emerging Transcriptional and Genomic Mechanisms Mediating Carbapenem and Polymyxin Resistance in Enterobacteriaceae : a Systematic Review of Current Reports

“…Carbapenem resistance in Enterobacteriaceae is mediated mainly by the production of carbapenemases ( 11 ). However, elevated carbapenem resistance in carbapenemase-producing Enterobacteriaceae is usually through the overproduction of carbapenemases and/or alteration of membrane permeability ( Table 1 ) ( 32 ).…”

Research Article Characterization and molecular epidemiology of extensively prevalent nosocomial isolates of drug-resistant <i>Klebsiella pneumoniae</i>

“…In addition, the rapid detection of patients colonized or infected with KPC-containing strains is very important since these microorganisms can cause serious infections that have high morbidity and mortality rates (Yan et al, 2017). ERIC-PCR is a fast, inexpensive method that gives good results for the genetic characterization of Klebsiella spp (Dalmolin et al, 2017). Genetic techniques are increasingly being used for the identification of microorganisms; one of these techniques is complete genome sequencing.…”