NDM Production as a Dominant Feature in Carbapenem-Resistant Enterobacteriaceae Isolates from a Tertiary Care Hospital.

Fakhur Uddin,Zeinhom M. El-Bahy,Muhammad Sohail,Saeed Khan,Ashraf Y. Elnaggar,Ahmed M. Fallatah,Taseer Ahmed Khan,Zulfiqar Ahmed,Syed Hadi Imam

doi:10.3390/antibiotics11010048

Abstract

The worldwide spread and increasing prevalence of carbapenem-resistant Enterobacteriaceae (CRE) is of utmost concern and a problem for public health. This resistance is mainly conferred by carbapenemase production. Such strains are a potential source of outbreaks in healthcare settings and are associated with high rates of morbidity and mortality. In this study, we aimed to determine the dominance of NDM-producing Enterobacteriaceae at a teaching hospital in Karachi. A total of 238 Enterobacteriaceae isolates were collected from patients admitted to Jinnah Postgraduate Medical Centre (Unit 4) in Karachi, Pakistan, a tertiary care hospital. Phenotypic and genotypic methods were used for detection of metallo-β-lactamase. Out of 238 isolates, 52 (21.8%) were CRE and 50 isolates were carbapenemase producers, as determined by the CARBA NP test; two isolates were found negative for carbapenemase production by CARB NP and PCR. Four carbapenemase-producing isolates phenotypically appeared negative for metallo-β-lactamase (MBL). Of the 52 CRE isolates, 46 (88.46%) were blaNDM positive. Most of the NDM producers were Klebsiella pneumoniae, followed by Enterobacter cloacae and Escherichia coli. In all the NDM-positive isolates, the blaNDM gene was found on plasmid. These isolates were found negative for the VIM and IPM MBLs. All the CRE and carbapenem-sensitive isolates were sensitive to colistin. It is concluded that the NDM is the main resistance mechanism against carbapenems and is dominant in this region.

Highlights

Many Enterobacteriaceae species are the pathogens involved in hospital-associated and community-acquired infections, especially in urinary and respiratory tracts, the blood stream, and intra-abdominal and surgical sites [1]
The carbapenem resistance was higher in Klebsiella aerogenes (3; 23.1%), K. pneumoniae (20; 28.9%), E. cloacae (9; 22.5%) and E. coli (18; 21.4%) in comparison to other species of Enterobacteriaceae (Table 2)
The common mode for carbapenem resistance in Enterobacteriaceae is the production of carbapenemases, New Delhi metallo-β-lactamase (NDM-1), on the Indian subcontinent [14]

Summary

Introduction

Many Enterobacteriaceae species are the pathogens involved in hospital-associated and community-acquired infections, especially in urinary and respiratory tracts, the blood stream, and intra-abdominal and surgical sites [1]. The most commonly encountered pathogens of the family Enterobacteriaceae are Escherichia coli, Klebsiella pneumoniae, Proteus, Salmonella, Shigella and Enterobacter spp. These genera are reportedly very susceptible to carbapenems [2]. Enterobacteriaceae (CRE) and their inclusion in the list of priority pathogens, they have received attention globally [4,5,6,7,8,9]. CRE strains can spread resistance markers by horizontal transfer to other strains in hospitals and augment problems in healthcare sectors [4]

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