Phenotypic and genotypic detection of ESBL mediated cephalosporin resistance in Klebsiella pneumoniae: Emergence of high resistance against cefepime, the fourth generation cephalosporin S.S. Grover a , Meenakshi Sharma a, *, D. Chattopadhya b , Hema Kapoor c , S.T. Pasha a , Gajendra Singh d a Department of BiochemistryeBiotechnology, National Institute of Communicable Diseases, 22-Shamnath Marg, New Delhi-110054, India b Department of Microbiology, National Institute of Communicable Diseases, 22-Shamnath Marg, New Delhi-110054, India c Department of Microbiology, Safdarjung Hospital, New Delhi-110029, India d Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar, Punjab-143005, India Accepted 5 December 2005 Available online 20 February 2006 KEYWORDS Klebsiella pneumoniae; Cephalosporin; ESBL; PCR Summary Objectives: Cephalosporins belonging to second and third generation are commonly used in India for the treatment of Klebsiella pneumoniae. Report on resistance among K. pneumoniae strains to second and third generation cepha- losporins are on rise in this country, which has been attributed to emergence of strains expressing extended-spectrum b-lactamases (ESBLs). The aim of this study was to evaluate the in vitro susceptibility of K. pneumoniae to broad-spectrum cephalosporins particularly to cefepime, a recently introduced fourth generation cephalosporin in relation to ESBL production. Methods: This study has been carried out in two phases among K. pneumoniae strains isolated between October 2001 and September 2002 (phase I, before mar- keting of cefepime in India) and between August 2003 and July 2004 (phase II, after marketing of cefepime in India). Minimum Inhibitory Concentration (MIC) was * Corresponding author. Indian Council of Medical Research, Ansari Nagar, New Delhi-110029, India. Tel.: þ91 11 26589544; fax: þ91 11 26588381. E-mail address: sharmam@icmr.delhi.nic.in (M. Sharma). 0163-4453/$30 ª 2006 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2005.12.001 Journal of Infection (2006) 53, 279e288 www.elsevierhealth.com/journals/jinf