Detecting Carbapenemase Production amongst Gram Negative Isolates and its Role in Appropriate Antibiotic Selection

Iva Chandola,Anamika Ojha,Nidhi Negi,Dimple Raina

doi:10.22207/jpam.14.3.37

Abstract

Multidrug resistance has been increasing world wide amongst most microrganisms, and adding to increased rate of both hospital and community acquired infections. Of all resistance mechanisms the alarming spread of carbapenemase producers is most worrisome and needs to be tackled head on. The present study was undertaken with the objective of determining the prevalence of carbapenemase producers and its significance in selecting the appropiate antibiotic for clinical use.The study was undertaken by the department of Microbiology and Immunology of SGRRIM&HS, Dehradun over a period of six months. A total of 1918 varied clinical specimens were subjected to Bacterial identification and antibiotic sensitivity determination. Further carbapenemase production was detected phenotypically using modified carbapenemase inactivation method (mCIM) for randomly selected 152 carbapenem resistant gram negative isolates. Total of 58.55% isolates tested mCIM test positive of which the highest percentage (71.4%) were Pseudomonas spp, while 17.2% isolates were not found to be carbapenemase producers i.e mCIM negative. These results substantiate the importance of differentiating the carbapenemase producers from non producers to aid in rational use of antibiotics.

Highlights

Multidrug resistance amongst most bacterial species has been increasing at an alarming rate adding to increased rate of both hospital and community acquired infections
Pseudomonas 222 spp Authors from various parts of India have reported varying resistance rates of carbapenem in Enterobacteriaceae ranging from 5.75 % to 51% in various gram negative isolates (8,9).In our study raised MIC for carbapenems was detected in 27.4% (171/624) of E.coli, 58.72%(138/235) of Klebsiella and 36.5% (81/222) of Pseudomonas
Through the course of the study we found that 17% of our tested isolates had raised MIC for either of the carbapenems but tested negative for carbapenemase production via modified carbapenemase inactivation method (mCIM)

Summary

Introduction

Multidrug resistance amongst most bacterial species has been increasing at an alarming rate adding to increased rate of both hospital and community acquired infections. The resistance could be the result of either decreased outer membrane permeability combined with hyperexpression of betalactamases pocessing week carbapenemase activity or due to pocession of carbapenemase gene itself[1,2,3]. The Carbapenem-hydrolysing β-lactamases such as KPC, VIM, IMP, NDM and OXA-48 types are the most potent of all β-lactamases with the ability to hydrolyse almost all β-lactams Besides these enzymes carry several resistance genes, conferring resistance to many other classes of antibiotics apart from carbapenems including other aminoglycosides, fluoroquinolones, tetracyclines, trimethoprim, sulphonamides and phenicols[4,5]

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Discussion

Conclusion