Molecular characterization of multi-drug resistant Escherichia coli isolated from urine samples in Mater Hospital, Nairobi, Kenya

Abstract

Multi-drug resistance among Gram negative bacteria is on the increase due to acquisition and expression of extended spectrum β-lactamases (ESBL). The presence of ESBL producing organisms have been reported to affect the course and the outcome of infections. Therefore, infections due to ESBL-positive strains pose a major challenge in the management of infections worldwide. The aim of this study was to determine the antimicrobial susceptibility patterns and the genetic basis of antibiotic resistance in uropathogenic E.coli isolates from Mater hospital, Kenya. These isolates were tested for antimicrobial susceptibility and analyzed for the presence of ESBL genes. Polymerase chain reaction (PCR) was conducted to confirm the presence of ESBL enzymes and pulsed field gel electrophoresis (PFGE) was performed to determine the genetic relatedness of the strains. Of the 384 isolates submitted for analysis, 56 (14.6%) tested positive for ESBL. Out of these 56 isolates 9 (16%) had both TEM and SHV and 12 (21%) had TEM alone. The difference in resistance levels between ESBL and non-ESBL producing isolates for ciprofloxacin, ceftriaxone, cefuroxime, ceftazidime, ampicillin, cotrimoxazole, augmetin and nalidixic acid (p≤0.001) was statistically significant. This study reports a prevalence of (14.6%) ESBL producers among uropathogenic E.coli isolates from Mater Hospital. There are two predominant genes TEM and SHV among uropathogenic strains circulating in this hospital, presumably, this could have been the cause of resistance among these pathogens. The PFGE confirmed that the E.coli pathogenic strains were genetically diverse since the majority of the isolates came from community-acquired infections where the patients were not demographically related.