Changing trends in frequency of extended spectrum beta lactamase producing gram negative bacilli in intensive care units of a tertiary care hospital

ABSTRACT

To determine the frequency of isolation of extended spectrum beta lactamase [ESBL] producing Gram negative bacteria from intensive care units [ICUs] of a tertiary care hospital. Retrospective descriptive study. The study was carried out at the department of microbiology Army Medical College Rawalpindi from Dec 2003 to Nov 2007. This study was carried out from Dec 2003 to Nov 2007. A total of 590 consecutive Gram-negative bacilli were recovered during the four year study period from various samples including urine, blood, pus, sputum, high vaginal swabs [HVS], ascitic fluid, central venous lines [CVP], chest tubes, catheter tips, NBL [nasobronchial lavage], CSF, tissue, endotracheal tube [ETT] tip and pleural fluid in ICUs. Extended spectrum Beta-lactamase detection in these isolates was carried out by Kirby- Bauer double disc synergy method. The frequency of ESBL producing organisms was 84 [66%] [December 03 to November 04], 80[54%] [December 04 to November 05], 80[57%] [December 05 to November 06] and 82 [47%] [December 06 to November 07] [p<0.0001] Our study shows a decrease in the frequency of ESBL producing organisms. However there is an increase in the resistant organisms having same resistance pattern, but not detected as ESBL producers, therefore we need to improve the methods for ESBL detection