Escherichia coli
are known pathogenic organism that has caused diseases which has led to severe
morbidity and increased death rate. The occurrence of extended spectrum beta Lactamase (
bla) producing
Escherichia coli has been on the rise. Water samples were investigated as a potential reservoir for the Extended Spectrum Beta-
Lactamase (ESBL) - producing
E. coli using phenotypic (culture-based) and molecular methods. Double disc synergy
test was determined between a disc of amoxicillin-clavulanate (20μg/10μg) (augmentin) and a 30-μg disc of each thirdgeneration
cephalosporin antibiotic placed at a distance of 20 mm from centre to centre on a Mueller-Hinton Agar
plate streaked with the isolate. An isolate was considered to be ESBL negative if there was no enhancement between
any of the cephalosporin and the clavulanate-containing discs and were then subjected to specific Polymerase Chain
Reaction (PCR). Eighty-four environmental
E. coli was isolated. 58(69.04%) showed positivity for ESBL production.
E. coli isolates positive for ESBL-production selected and subjected to plasmid curing were all plasmid mediated. 16
isolates subjected to PCR to identify the presence of
blaSHV (Sulphydryl Variable),
blaTEM (Temoneira) and
blaCTX-M (Cefotaximase) genes revealed that 11(68.7%) of these had at least one ESBL gene (either
blaCTX-M or
blaTEM, or both), 5(31.3%) isolates do not have any of the three ESBL genes, and
blaSHV was not detected in any of
the isolates. The results of this study indicate the widespread prevalence of ESBLs in
E. coli. Therefore, beta-lactam
antibiotics and beta-lactamase inhibitors should be prescribed based on an antibacterial susceptibility test.
