Frequency and Antimicrobial Sensitivity Pattern of Extended Spectrum β-Lactamases Producing Escherichia coli and Klebsiella pneumoniae Isolated from urine at a Tertiary Care Hospital

Abstract

Background: Infections due to extended spectrum ?-lactamases (ESBL) producing Escherichia coli and Klebsiella pneumoniae have become an important clinical problem. These organisms are important regarding the infection control by the physicians.

Objective: The present study was undertaken to determine the prevalence of ESBLs along with their antimicrobial sensitivity pattern in Escherichia coli and Klebsiella pneumoniae.

Methodology: This cross sectional study was conducted in the Department of Microbiology at Sir Salimullah Medical College, Dhaka. Urine samples were collected from patients who were clinically suspected to have UTI. After incubation, plates were checked for presence of suspected pathogens. Organisms were identified to species level by conventional methods. All isolated E. coli and K. pneumoniae were included in the study. The susceptibility to antibiotics was determined by Kirby Bauer method on Muller Hinton agar. Isolates were screened for ESBL production by using disk diffusion of cefotaxime, ceftazidime, ceftriaxone and cefpodoxime placed on inoculated plates containing Muller Hinton agar according to the CLSI recommendations. Phenotypic confirmatory test for ESBL producers was done by combined disc diffusion for all the isolates that were screened positive for the ESBL production following CLSI guidelines. Combined disk diffusion method was also done in this study.

Result: A total of 220 non repeated urine samples were cultured of which 132(60%) cases had shown the bacterial growth. Among the 132 samples Escherichia coli had found in 103(78.0%) cases and Klebsiella spp. was found in 14(10.6%) cases. Out of 103 E coli 23(22.3%) cases was found as ESBL strain. On the other hand within 14 Klebsiella species, the ESBL strain was found in 5(35.7%) cases. Both E coli and Klebsiella species were 100% sensitive to imipenem. However, cephamycin was sensitive in 93.7% and 100% in E coli and Klebsiella species respectively.

Conclusion: Results indicate that routine ESBL detection should be made imperative and empirical use of third generation cephalosporins must be discouraged.

DOI: http://dx.doi.org/10.3329/jssmc.v4i1.11999

J Shaheed Suhrawardy Med Coll, 2012;4(1):22-25