Frequency of Extended Spectrum Β-lactamase Producing Klebsiella Pnumoniae and Escherichia Coli Isolates

Extended spectrum beta lactamases (ESBLs) that mediate resistance to 3rd generation cephalosporins are now observed worldwide in all species of Enterobacteriaceae especially Klebsiella pneumoniae and Escherichia coli. ESBL producing organisms are responsible for nosocomial infections and may result in hospital outbreaks. Present study is a descriptive study. It was planned to determine the frequency of extended-spectrum β-lactamase (ESBL) production among Klebsiella pneumoniae and Escherichia coli isolated from different clinical specimens from patients admitted to different teaching hospitals of Lahore (Services Hospital, Mayo Hospital and Sir Ganga Ram Hospital). It was carried out in Department of Pathology, Services Institute of Medical Sciences (SIMS), Lahore from October 2005 to August 2006. A total of 324 clinical isolates of Klebsiella pneumoniae and Escherichia coli recovered from different clinical specimens like blood, urine, sputum, pus / wound swabs were included in this study. All isolates were screened and confirmed for extended spectrum beta lactamase (ESBL) production by Kirby-Bauer disk diffusion method on Mueller Hinton agar using NCCLS guidelines. Out of a total of 324 isolates, 184 were Klebsiella pneumoniae and 140 were Escherichia coli. Among these, 47.82% were Klebsiella pneumoniae and 38.57% Escherichia coli isolates were ESBL producer. ESBL production was the highest among isolates from blood (50%) isolates from Mayo Hospital, Lahore (56.25%). It is concluded that there is a high frequency of ESBL production among nosocomial isolates of Klebsiella pneumoniae and Escherichia coli. These isolates being resistant to 3rd generation cephalosporins and many other classes of antibiotics pose a special therapeutic challenge. Therefore, these isolates should be routinely tested for ESBL production.