Molecular Identification of Aminoglycoside-Modifying Enzymes and Plasmid-Mediated Quinolone Resistance Genes among<i> Klebsiella pneumoniae</i> Clinical Isolates Recovered from Egyptian Patients

Abstract

Inappropriate use of antibiotics in clinical settings is thought to have led to the global emergence and spread of multidrug-resistant pathogens. The goal of this study was to investigate the prevalence of genes encoding aminoglycoside resistance and plasmid-mediated quinolone resistance among clinical isolates of <i>Klebsiella pneumoniae</i>. All <i>K. pneumoniae</i> isolates were phenotypically identified using API 20E and then confirmed genotypically through amplification of the specific <i>K. pneumoniae phoE</i> gene. All isolates were genotyped by the enterobacterial repetitive intergenic consensus polymerase chain reaction technique (ERIC-PCR). Antibiotic susceptibility testing was done by a modified Kirby-Bauer method and broth microdilution. All resistant or intermediate-resistant isolates to either gentamicin or amikacin were screened for 7 different genes encoding aminoglycoside-modifying enzymes (AMEs). In addition, all resistant or intermediate-resistant isolates to either ciprofloxacin or levofloxacin were screened for 5 genes encoding the quinolone resistance protein (Qnr), 1 gene encoding quinolone-modifying enzyme, and 3 genes encoding quinolone efflux pumps. Biotyping using API 20E revealed 13 different biotypes. Genotyping demonstrated that all isolates were related to 2 main phylogenetic groups. Susceptibility testing revealed that carbapenems and tigecycline were the most effective agents. Investigation of genes encoding AMEs revealed that <i>acc(6</i>'<i>)-Ib</i> was the most prevalent, followed by <i>acc(3</i>'<i>)-II</i>, <i>aph(3</i>'<i>)-IV,</i> and <i>ant(3</i>''<i>)-I</i>. Examination of genes encoding Qnr proteins demonstrated that <i>qnrB</i> was the most prevalent, followed by <i>qnrS</i>, <i>qnrD,</i> and <i>qnrC</i>. It was found that 61%, 26%, and 12% of quinolone-resistant <i>K. pneumoniae</i> isolates harbored <i>acc(6</i>'<i>)-Ib-cr</i>, <i>oqxAB,</i> and <i>qebA</i>, respectively. The current study demonstrated a high prevalence of aminoglycoside and quinolone resistance genes among clinical isolates of <i>K. pneumoniae</i>.