Study of extended spectrum beta lactamase producing uropathogens and their antibiotic susceptibility pattern

Escherichia coli and Klebsiella pneumoniae are major uropathogenic isolates producing Extended spectrum beta lactamases (ESBL) which confer high resistance to common antibiotics. This study was done to know the antibiogram pattern of ESBL producing isolates from urine samples.

Culture and Antibiotic susceptibility tests (AST) were done from midstream urine samples (MSU) collected from patients. AST was done by Kirby-Bauer disc diffusion method and the isolates resistant to ceftriaxone and cefotaxime were subjected to phenotypic double disc diffusion test as per CLSI guidelines using cefotaxime (30μg) disc alone and cefotaxime plus clavulanic acid (30/10μg) combined disc for confirmation of ESBL production.

Out of 726 urine samples, 172 showed significant growth. Among 172 isolates, most predominant isolate was Escherichia coli (81%) and then klebsiella species(10.4%). Total ESBL producers among these isolates were 68 (39.5%). Of which 63(92.6%) E.coli and 5 (7%) Klebsiella spp. These ESBL producing E.coli showed maximum resistance to Ampicillin and sensitivity to Nitrofurantoin. Similarly Klebsiella spp. showed maximum resistance to Ampicillin and sensitivity to Amikacin. These ESBL producing E.coli & Klebsiella spp. were also minimally resistant to Meropenem, about 14% and 20% respectively.

ESBL producing E.coli was high among uropathogens and most of them were highly resistant. So antibiotic sensitivity testing should be routinely done in order to prevent antibiotic resistance and treatment failure. Treatment should be followed according to the local antibiogram to specific ESBL producing isolates.