Prevalence of clinical strains resistant to various beta-lactams in a tertiary care hospital in India.

The incidence of infection due to extended spectrum beta-lactamases (ESBLs) producing Enterobacteriaceae has markedly increased in recent years. The traditional susceptibility methods lack sensitivity and/or specificity and this issue has prompted the search for an accurate test to detect the presence of ESBL. The present study included 300 bacterial strains and was undertaken to determine the prevalence of ESBL-producing strains. Here, compared three tests: a double disk synergy test (DDS), a three-dimensional test (3-D), and an inhibitor potentiated disk diffusion test (IPT); each test employed three different antibiotic discs, i.e., ceftazidime, ceftriaxone, and cefotaxime, in order to screen for ESBL strains. A strain was said to be an ESBL producer if it showed positive result(s) on any one of the three tests. The prevalence rate of ESBL in our hospital was 12.6% (38/300). IPT detected the most strains (34/38), followed by 3-D (23/38), and then DDS (15/38). The ceftriaxone disc was found to detect more ESBLs than either the ceftazidime or the cefotaxime disc.