The comparison of DDST and NCCLS methods in detecting ESBL production of E. coli and K. pneumonia

There are few gram-negative bacteria which possess resistance to the antimicrobial drugs like extended spectrum cephalosporins and aztreonam. This has been attributed to the production of the extended spectrum beta-lactamases enzyme by these bacteria. There are few methods available from which the production of ESBL can be detected. We have performed earlier, the studies about the detection of ESBL separately by using the double disk synergy test (DDST) and the national committee for clinical laboratory standards phenotypic confirmatory tests (NCCLS-PCT). The objective of the present investigation was to tabulate and compare the results of the DDST and NCCLS-PCT methods. From the comparison, it has been observed that the NCCLS-PCT test is more efficient in detecting ESBL production than the DDST method. We also opine that the resistant strains of E. coli and K. pneumoniae should be confirmed for ESBL production by using the NCCLS-PCT phenotypic confirmatory test.