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

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.