Title:Phenotypic and Molecular Detection of BlaNDM Gene Among Drug-Resistant Klebsiella Isolates
Volume: 16
Issue: 2
Author(s): Taqdees Malik*Asma Naim
Affiliation:
- Department of Microbiology, Jinnah University for Women, Karachi,Pakistan
Keywords:
NDM, carbapenemase, Klebsiella, drug resistance, molecular, MDR.
Abstract:
Background: In the past few centuries, a widespread increase in antimicrobial
resistance has been observed among Klebsiella species. The antibiotic-
resistant strains of the genus Klebsiella are becoming a serious threat in clinical
settings due to their involvement in severe invasive and non-invasive infections.
The emergence of resistance among these strains is associated with their
strong enzymatic activity against several broad-spectrum antibiotics. These enzymes
include beta-lactamases, extended-spectrum beta-lactamases (ESBL), AmpC
beta-lactamases, and carbapenemases. These resistance enzymes are capable
of hydrolyzing various broad-spectrum drugs like extended-spectrum cephalosporin
and carbapenems.
Objective: The present study was conducted to determine the emerging resistance
among Klebsiella strains by identifying the production of carbapenemase
enzyme phenotypically and the frequency of the NDM resistance gene by a polymerase
chain reaction.
Methods: In this study, 236 Gram-negative isolates from different clinical laboratories
were identified. Out of which, 125 isolates were found as Klebsiella species
by using standard microbiological techniques. Minimum inhibitory concentrations
(MIC) were determined using eight representative antibiotics by the
Macro broth dilution method. Phenotypic detection of carbapenemase producing
Klebsiella species was performed by Modified Hodge Test. Phenotypic findings
were then checked and compared with genotypic results obtained by using the Polymerase
chain reaction (PCR) for the detection of resistance genes responsible
for the production of carbapenemase.
Results: In this study, carbapenemase production was found only in 6 (5%) Klebsiella
isolates by using the phenotypic method; however, 3 isolates out of 125
were screened positive for the gene NDM-1.
Conclusion: Since we are considering carbapenems as the last therapeutic option
for treating infections, mainly caused by Gram-negative isolates, the prevailing
resistance against this drug is widely disseminating. It is better to evaluate the
antibiotic susceptibility, phenotypic screening as well genotypic screening
(where possible) for implementing strict antibiotic control policies in health care
settings, hospitals, laboratories, etc.
