Objective: To detect the production of ESBLs in MDR Enterobacteriaceae by using different phenotypic methods and to know the coexistence of these enzymes in the isolates. Gene detection of most dominant ESBL producer CTX-M gene in these isolates.
Methodology: A total of 100 MDR isolates from various clinical samples received during June- November 2018 for culture and sensitivity at the Department of Microbiology, BMCRI were included in the study. Specimens were processed according to the standard protocol.
ESBL and AmpC production was detected by using inhibitory based methods. Cefotaxime and cefotaxime+Clavulanate, ceftazidime and ceftazidime+Clavulanate for ESBLs, Cefoxitin along with Phenyl boronic acid was used for AmpC detection. An improved method for better detection of ESBL in presence of AmpC by utilizing Aztreonam +Clavulanate was also performed. Ctx-M gene was also detected by conventional PCR technique.
Results: Out of 100 MDR isolates tested for ESBL production, 54% were positive by using cefotaxime and ceftazidime with clavulanate, while 83% were positive by using Aztreonam as substrate and clavulanic acid as inhibitor for ESBL production. Out of 100 MDR isolates 26% (26/100) were found to be AmpC producers. 58% isolates were found positive for ESBL- blaCTX-M gene.
Discussion and conclusion: The study concludes that ESBL detection by newer method is more effective. Using Aztreonam and clavulinic acid for detection of ESBLs gives the advantage of detecting ESBLs which are masked by AmpC beta-lactamases.
Impact Factor
2022: 6.012
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