Expanded range beta-lactamase delivering uropathogenic Escherichia coli disease in Dhaka, Bangladesh

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.