K. K. Patela & Sarita Patelb
aDept. of Clinical Microbiology, Chhattisgarh Institute of Medical Sciences, Bilaspur (C. G.)
bDept. of Zoology, Govt. E. Raghwendra Rao (P.G.) Science College, Bilaspur, (C.G.)
Received 20th June,2011; Revised 25th August,2011
Abstract : Growing incidence of carbapenem resistance among gram-negative bacteria is a major cause of concern which threatens to disrupt therapeutic options. The production of extended spectrum â-lactamases (ESBLs) and AmpC â-lactamases are the most common mechanisms of antimicrobial resistance in Gram negative bacilli. The study was undertaken to know the occurrence of ESBL and AmpC producing strains and their antibiotic susceptibilities to newer agents to guide therapy for complicated urinary tract infections. The period of two years (January 2009 to December 2010), organisms grown in pure culture and in significant numbers from urine sample were identified by standard biochemical tests and antibiotic susceptibility determined by disc diffusion method. Uropathogens were isolated in significant numbers in 592 (23%) of the total 2575 samples, of which 136 (23 %) were HDRU. The highest positivist was found to be in Klebsiella 11, followed by E. coli 07, Enterobacter spp. 05 and Pseudomonas aeruginosa 02. These 71 HDRU isolates (both ESBL producers and non-producers) were tested for susceptibility to newer antibiotics and â-lactam b -lactamase inhibitor combinations. ESBL producing isolates showed a high degree resistance to piperacillin (92.1%), amoxycillin-clavulanic acid (91.1%), aztreonam (77.4%), cefepime (74.7%), ampicillin-sulbactam (73.7%) and ticarcillin (61.2%). The most effective antibiotics were imipenem (6.1% resistance), piperacillin-tazobactam (8.4%) and ceftazidime-clavulanic acid (22.1%). Overall, 23 % of our isolates were highly drug resistant, and ESBL producers could explain only 35% of HDRU in our study.