Phenotypic characteristics of clinical isolates of Klebsiella pneumoniae & evaluation of available phenotypic techniques for detection of extended spectrum beta-lactamases.

Abstract

Modified DDST using at least two different third generation cephalosporins was considered to be the best technique for detection of ESBL producing K. pneumoniae at our hospital. MIC reduction test with >2 doubling dilution reduction in MICs was found to be a better criterion than the presently recommended >3 doubling dilution reduction. For screening of potential ESBL producers, MIC determination using agar dilution was as good as that using broth dilution method. However, while performing MIC reduction test agar dilution method was found highly unreliable for detection of ESBL harbouring isolates.