Molecular epidemiology of Carbapenemase-encoding genes and comparative evaluation of carbapenem MIC with genotypic carbapenem resistance in Klebsiella isolates from neonatal sepsis cases

Abstract

The objective of this study was to determine the molecular epidemiology of Carbapenemase-encoding genes in Klebsiella isolates from neonatal sepsis cases and comparative evaluation of carbapenem minimum inhibitory concentration (MIC) with genotypic carbapenem resistance. One hundred cases of neonatal sepsis with blood cultures positive for Klebsiella spp. were included in the study. MIC for imipenem and meropenem was determined by Epsilometer-test. Antimicrobial susceptibility testing (AST) was performed by modified Kirby Bauer disc diffusion method. All the isolates of Klebsiella spp. were tested for the presence of beta-lactamase Klebsiella pneumoniae carbapenemase (blaKPC ), beta-lactamase New Delhi metalloβ-lactamase-1(blaNDM-1), beta-lactamase imipenemase (blaIMP), beta-lactamase Verona imipenemas e (blaVIM) genes by multiplex polymerase chain reaction (PCR) and uniplex PCR for beta-lactamase oxacillinase-48 (blaOXA-48). Comparison of individual antibiotic susceptibility between carbapenemase-encoding gene positive and negative Klebsiella spp. isolates was performed. Statistical analysis was done using the Fisher’s exact test. P < 0.05 was considered significant. The prevalence of carbapenemase-encoding genes in Klebsiella spp. was 16%. Most predominant carbapenemase-encoding gene was blaOXA-48 gene (12%) followed by blaNDM-1 gene (6%). Coexpression of both blaOXA-48 and blaNDM-1 was observed in 2% of isolates. All the Klebsiella spp. isolates harboring the carbapenemases gene (100%) had resistant MIC values for Meropenem, whereas, for imipenem, only 75% of isolates had resistant MIC values. Determination of prevalence of carbapenemase-encoding genes is of paramount importance in the development of effective antibiotic policies at various levels.