Detection of extended spectrum beta-lactamase production in clinical isolates of Klebsiella spp.

BACKGROUND & OBJECTIVE Clinical laboratories need to develop quick screening methods for detection of extended spectrum beta-lactamase (ESBL) producing strains, so that the appropriate medication can be started without delay. In this study, we report the screening sensitivity of four representative antimicrobial agents i.e., cefpodoxime, cefotaxime, ceftazidime and aztreonam, commonly used for ESBL detection in Klebsiella spp. METHODS A total of 100 clinical isolates of Klebsiella spp. from the cases of neonatal septicaemia at a tertiary care hospital from north India, were screened for ESBL production by Kirby- Bauer's disc diffusion (cefpodoxime, cefotaxime, ceftazidime and aztreonam) and minimum inhibitory concentration (MIC) test by agar dilution methods. Confirmation was done by double disc method. RESULTS Results showed that 58 of the 100 isolates tested were ESBL positive by confirmatory test and cefpodoxime was more efficient ESBL screening antimicrobial agent than ceftazidime, cefotaxime and aztreonam. INTERPRETATION & CONCLUSION Using the standard disk diffusion as screening test for identifying ESBL producers, cefpodoxime was found to be the most efficient antimicrobial agent in screening isolates as potential ESBL producers followed by ceftazidime in Klebsiella spp. isolates.