Status of Extended Spectrum Beta-Lactamase Producing Enterobacteriaceae among Bacterial Uropathogens
Date
2013
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Microbiology
Abstract
The prevalence of Extended Spectrum Beta Lactamases (ESBL), the main cause
of resistance to broad spectrum β-lactams, among uropathogenic bacteria have
increased over time raising a global concern in the therapeutic management of
infections caused by these organisms. This resistance poses difficulties with the
choice of therapeutic options for the treatment of severe infections. The study was
carried out in the Alka Hospital, Lalitpur between May to October 2012 with an
objective to determine the status of ESBL producing Enterobacteriaceae isolated
from the urine sample, collected from patients suspected of urinary tract infection.
During the study, the Enterobacteriaceae isolated were tested for the presence of
ESBL by double disc synergy test (DDST) and combination disk method and
antibiotic susceptibility testing was done by Kirby Bauer disc diffusion method
following Clinical and Laboratory Standard Institute (CLSI) guidelines.
Among the total 1054 mid-stream urine samples, 267 Enterobacteriaceae were
isolated. By screening test using third generation cephalosporins, 81 of the
isolates were suspected of ESBL producers. Among 81 isolates, 72 isolates were
positive for ESBL test by combination disk method and only 28 isolates were
positive by DDST method. Among the 72 (27%) isolates 67 (30.2%) Escherichia
coli, 3 (15.8%) of Klebsiella pneumoniae, 1 (25%) of Citrobacter spp. and 1
(14.3%) of Morganella morganii were found to be ESBL producers. Majority of
ESBL producer showed resistance to amoxicillin (100%), cotrimoxazole (79.2%)
followed by ciprofloxacin (76.4%). Imipenem (100%), tigecycline (98.6%),
amikacin (97.2%), piperacillin- tazobactam (98.6%) and nitrofurantoin (91.7%)
seemed to be the agent of choice for urinary tract infections when ESBL
producers are susceptible to it.
Combination disk method was found to be more sensitive than DDST method for
the detection of ESBL producing Enterobacteriaceae. The high level of ESBL
production found in these Enterobacteriaceae with the resultant microbial
resistance to the available cephalosporins and other agents may pose difficulties
with the choice of therapeutic options for the treatment of severe infections.
Efforts to prevent and/or control outbreaks of infections with ESBL producing
strains must emphasize on the judicious use of all antibiotics.
Description
Keywords
Urinary tract infection, Enterobacteriaceae, Extended spectrum beta lactamase (ESBL)