Genetic heterogeneity of CTX-M type extended-spectrum β-lactamase producing Escherichia coli strains from diverse sources in Saudi Arabia

Background: The rise of CTX-M extended spectrum β-lactamase (ESBLs)-producing E. coli in non-human sources is a growing concern of public health. Understanding the extent of public health risk attributed to CTX-M type ESBLs-producing strains from different sources is critical for effective control. Objective: This study focuses on detection and molecular typing of CTX-M type ESBL-producing E. coli isolated from various sources in Taif, Western Saudi Arabia.  Material and Methods: A total of 24 E. coli ESBLs-producing isolates from multiple sources were assessed for the presence of CTX-M groups gene by PCR, and subsequently their clonal relatedness by random amplifid of polymorphic DNA (RAPD) analysis. Isolates were selected according to a resistance phenotype consistent with production of ESBL-type beta-lactamase using double disk diffusion method. Results: A CTX-M gene was detected in all 24 isolates. RAPD typing of E. coli isolates bearing CTX-M gene showed 24 patterns verifid into two major clusters (A, B) and three sub-clusters (A1 – A3). Phylogenetic analysis indicating a degree of similarity among clustering isolates from human, sheep and raw milk origins. Identical profie was observed between three isolates obtained from pet bird and chicken.