Abstract:
BACKGROUND: Published data on the existence and magnitude of extended spectrum
beta-lactamase (ESBL) production in urinary pathogens in local setting is
limited. The aim of the present study was to determine the prevalence of
antimicrobial resistance and ESBL production among Escherichia coli and
Klebsiella spp from urine samples in a tertiary hospital. This was a cross
sectional study conducted at Muhimbili National Hospital in Dar es Salaam,
Tanzania.
FINDINGS: A total of 270 E.coli and Klebsiella spp urinary pathogens from
children and adults isolated from January to March 2010 were included in the
study. E. coli and Klebsiella spp isolates were tested for antimicrobial
susceptibility by the Clinical and Laboratory Standard Institute's disc diffusion
method. These isolates were further screened for ESBL phenotype using cefotaxime
and ceftazidime discs. Isolates with reduced sensitivity were confirmed using
ESBL E-test strips. Of 270 isolates, 138 (51.1%) were E. coli and 132 (48.9%)
were Klebsiella spp. ESBL was detected in 122 (45.2%) of all the isolates. ESBL-
producing E. coli strains were significantly more resistance to cotrimoxazole
(90.7%), ciprofloxacin (46.3%) and nalidixic acid (61.6%) than strains that did
not produce ESBL (p < 0.05). Similarly, ESBL- producing Klebsiella spp strains
were significantly more resistance to cotrimoxazole (92.6%), ciprofloxacin
(25.0%), nalidixic acid (66.2%), and gentamicin (38.2%) than strains that did not
produce ESBL (P < 0.05). Multi-drug resistance was found to be significantly (P <
0.05) more in ESBL producing isolates (90.5%) than non ESBL producers (68.9%).
The occurrence of ESBL was significantly higher among isolates from inpatients
than outpatients [95 (50.5%) vs. 27(32.9%)] (p = 0.008). The occurrence of ESBL
was significantly higher among isolates from children than in adults [84 (54.9%)
vs. 38(32.5%)] (p < 0.001).
CONCLUSIONS: High prevalence of ESBL-producing E. coli and Klebsiella spp strains
was found among inpatients and children. Most of the ESBL- producing isolates
were multi-drug resistant making available therapeutic choices limited. We
recommend continued antibiotic surveillance as well comprehensive multi-center
studies to address the emerging problem of ESBL-associated infections in order to
preserve the continued usefulness of most antimicrobial drugs. Further more
conducting molecular studies will help to evaluate the various ESBL types.
