| ORIGINAL ARTICLE |
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| Year : 2019 | Volume
: 149
| Issue : 4 | Page : 528-538 |
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Contribution of acrB upregulation & OmpC/Ompk36 loss over the presence of blaNDM towards carbapenem resistance development among pathogenic Escherichia coli & Klebsiella spp.
Arijit Pal, Lena Dhara, Anusri Tripathi
Department of Biochemistry & Medical Biotechnology, Calcutta School of Tropical Medicine, Kolkata, India
Correspondence Address:
Dr Anusri Tripathi
Department of Biochemistry & Medical Biotechnology, Calcutta School of Tropical Medicine, 108, C.R. Avenue, Kolkata 700 073, West Bengal
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/ijmr.IJMR_716_17
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Background & objectives: The global spread of carbapenem-resistant Enterobacteriaceae (CRE) is an emerging clinical problem. Hence, in this study, the plausible role of extended-spectrum beta-lactamases (ESBLs)/carbapenemases, OmpC/Ompk36, acrB and their combinations was explored among CRE.
Methods: The minimum inhibitory concentration (MIC) of meropenem, enzyme-phenotypes (ESBLs/IR and metallo-beta-lactamase (MBL)/non-MBL carbapenemase), genotypes (blaTEM, blaSHV and blaCTX-M; blaNDM and blaVIM; blaKPC and blaOXA-48-like variants), acrB and outer membrane protein (OMP) expressions were analyzed with a total of 101 non-duplicate clinical isolates, obtained from various samples of patients visiting two tertiary care units of Eastern India during May 2013 - October 2016. This included Escherichia coli (n=36) and Klebsiella pneumoniae (n=65), categorized into two groups, namely Group I (resistant to all carbapenems; n=93; E. coli=34 and Klebsiella spp.=59) and Group II (non-resistant to all the carbapenems; n=8; E. coli=2 and Klebsiella spp.=6).
Results: Though 88.17 per cent of Group I isolates exhibited ESBL property, the presence of carbapenemase activity (70.96%) and that of blaNDM gene (42/66: 63.63%) indicated their contributions towards the emergence of CRE. Further, porin loss and/or efflux pump activation among ESBL/carbapenemase-producing isolates heightened the MIC of meropenem from 64 to 256 mg/l (range exhibited by only ESBL/carbapenemase-producing isolates) to >256 mg/l.
Interpretation & conclusions: These findings implied the major contribution of porin loss and/or efflux pump activation over the presence of ESBLs/carbapenemases in imparting carbapenem resistance in pathogenic bacteria.
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