Asian Journal of Microbiology, Biotechnology & Environmental Sciences Paper

ANTIMICROBIAL RESISTANCE, BLACTX-M GENES AND GENETIC DIVERSITY OF ESCHERICHIA COLI ISOLATES FROMTAIF HOSPITALS REGION, SAUDI ARABIA

MOSTAFA M. FARAG, ALI K. ALZAHRANI, KARIM F. ABDALLAH, AYMAN K. ISMAIL, ISMAIL A. ISMAIL, FAROOQ A. GANAI AND WALAA F. ALSANIE

Abstract

Beta-lactam antibiotics have been discussed as options for the treatment of infections caused by multi resistant extended-spectrum beta-lactamase (ESBL)-producing bacteria. The objective of this study was to investigate the in vitro activity of different beta-lactam antibiotics against CTX-Mproducing Escherichia coli. Twenty isolates of 100 E. coli with the ESBL phenotype were studied. A large percentage of the E. coli was susceptible to meropenem (100%), imipenem (95%) and gentamicin (75%), but resistant to Ampicillin (95%), ceftazidime (90%) and cefepime (90%). Polymerase chain reaction (PCR) amplification of CTX-M genes was performed. These isolates were demonstrating resistance to either oxyimino-cephalosporin, and were found to harbor blaCTX-M genes by PCR. All the twenty isolates harboredbla CTX-M genes belonging to the blaCTX-M-1, blaCTX-M-2, blaCTX-M-3 and blaCTXM- 4 clusters, respectively. The antibiotics susceptibility of isolates was tested and fingerprinting of these isolates was done using fiverep-PCR primers, and Dendrogram based on rep-PCR was grouped the E. coli isolates into two different clusters with about 57% genetic similarity. The first cluster contained E. coli isolates E19 and E20, while the second cluster contained other E. coli isolates. This study shows significant differences insusceptibility to different beta-lactam antibiotics among the CTX-Mproducing E. coli isolates and a significant difference for many antibiotics tested between the CTXMproducing groups 1 and 5. The good in vitro activity of other beta-lactam antibiotics compared to carbapenems indicate that clinical studies are warranted in order to examine the potential role of these beta-lactam antibioticsin the treatment of infections caused by multiresistant ESBLproducing E. coli.