ESBL producing Nosocomial Enterobacteria isolated from clinical specimens detected by double disc diffusion method

ABSTRACT

To identify extended spectrum betalactamases [ESBL] producing organisms of Enterobacteriacae family from clinical specimens. Simple descriptive study Setting: The study was carried out in Microbiology Department of Army Medical College, Rawalpindi from 1 Jan 02 to 31 Dec 02 on clinical samples received from admitted patients in Military hospital, Rawalpindi Samples consisting of urine, blood, high vaginal swabs, catheter tips, fluids including CSF, sputum, chest tube, [HVS] and IV canula central vascular line specimens received for routine culture from outpatient as well as indoor cases of Rawalpindi/Islamabad. The samples were inoculated on Blood agar and Mac Conkeys agar [chocolate agar was also used for sputum and CSF]. Urine samples were cultured on CLED agar. The samples were incubated at 37C under aerobic conditions. The organisms were identified by standard techniques. Confirmation to the species level was done by API 20 E and API NE where required. Sensitivity testing was carried out by Modified Kirby Bauer disc diffusion method on Mueller Hinton agar incubated at 37°C in ambient air for 24 hrs. ESBL producing strains were identified by double disc diffusion method test according to Jarlier et al [1988]. Clavulanate was applied as the inhibitor of beta lactamases [AMO/CLAY disc].The results were tabulated as frequencies. 1. Forty seven percent of clinical isolates yielded ESBL producing enterobacteria. 2. Enterobacter cloacae, Klebsiella oxytoca, Proteus mirabilis and Klebsiella pneuumoniae were the most frequent ESBL producing bacteria. These bacteria were frequently recovered in fluids, drainage tubes/ catheter tips and canulas