Abstract

Extended-spectrum-beta-lactamase (ESBL) producing Escherichia coli that cause urinary tract infection (UTI) is a burning issue. This study was carried out to detect extended spectrum beta lactamase producing E. coli isolated from patients presented with UTI. This cross sectional study was conducted in the Department of Microbiology at Dhaka Medical College, Dhaka from January to December 2005, a period of one year. Clinically diagnosed cases of infected (UTI) patients were included in this study. The clean catch mid‑stream (CCMU) technique was employed to collect urine sample. Microscopical examination of urine was done and pus cell ≥5/HPF was included in the study. Urine samples were inoculated into blood agar and MacConkey agar media. All the organisms were identified by their colony morphology, staining character, pigments production, haemolysis, motility and other relevant biochemical tests as per standard methods. Antibiogram for all bacterial isolates were done by disc diffusion method of modified Kirby‑Bauer technique using Mueller­ Hinton agar plates. Detection of ESBL producers was performed by double disc diffusion test. Phenotypic confirmatory test was done by E test. A total of 250 samples of urine were collected and within this, 103 (41.2%) samples were shown in positive culture. Out of 103 positive urine samples, majority were E. coli (67.0%) followed by Klebsiella species (19.4%), Pseudomonas species (7.8%) and Proteus species (5.8%). Out of 69 E. coli isolates, ESBL producers were found in 22 (31.9%) urine samples. The difference between the rate of isolation of E. coli with ESBL and other than E. coli with ESBL is statistically significant (p=0.0001). E. coli strains showed 100.0% resistance to amoxicillin, aztreonam, cefotaxim, ceftazidime, ceftriaxone and cephradine. However, more than 80.0% resistant was observed in cotrimoxazole, amikacin and nalidixic acid. Nitrofurasntoin and mecillinam were more than 50.0% resistant. All strains were sensitive to imipenem. A considerable number of ESBL producing E. coli was detected from UTI cases, indicating it as the major challenge for future antibiotic therapy.

Key words: Extended-spectrum-beta-lactamase (ESBL), bacterial agents, urinary tract infection, antimicrobial susceptibility.