Abstract:
Extended spectrum β-lactamase (ESBLs) producing bacteria are of great public
health concern. It is also recognized that detection of ESBLs constitutes a problem
for microbiological laboratories since detecting methods used in this context are
not sensitive enough to deal with all clinical isolates. The aim of this study was to
compare two methods used for detection of ESBLs, the double disc synergy test
(DDST) and phenotypic confirmatory test (PCT) on the recovered isolates.
Clinical specimens, including; urine, sputum, blood, wound swab, ear swab, high
vaginal swab, and knee aspirate were collected from hospitalized patients in
Khartoum State. The causative agents were characterized by phenotypic
procedures and molecular typing. ESBLs were detected by DDST and PCT
methods.
Out of 120 collected specimens, 54 bacterial species were recovered. These are E.
coli (46.3 %), K. pneumoniae (24.1%), K. oxytoca (3.7%), P. mirabilis (16.7%), P.
vulgaris (7.4%) and E. cloacae (1.9%). Of these 16 and 17 isolates were found to
be ESBLs- producers when tested by DDST and PCT respectively. On the other
hand, 18 out of 54 isolates were ESBLs-producers when examined by PCR.
The study concluded that there is no significant difference between DDST and
PCT. Moreover, the two tests were rapid, easy to perform and cost-effective in
screening ESBLs.
