Assessment of Intra-Serotypic Diversity in Escherichia coli from Dogs Using ERIC-PCR

The scope of this study was to characterize the intra-serotypic genetic diversity in fecal Escherichia coli isolates obtained from dogs, using enterobacterial repetitive intergenic consensus (ERIC)-PCR. Serological typing of forty-seven E. coli isolates recovered from the rectal swabs (n=93) of different dog breeds in Andhra Pradesh revealed O141 (5 isolates), O128 (3 isolates), O126 (2 isolates), O9 (2 isolates), O15, O20, O35, O49, O63, O85, O101, O116, O117, O118 and O119 (1 isolate each) serotypes. A total of 10 and 14 isolates were found to be rough (R) and untypable (UT), respectively. ERIC-PCR genotyping allowed discrimination of 47 E. coli isolates into 46 ERIC-PCR genotypes. The numerical index of discrimination was 0.999. Dendrogram analysis discriminated 47 E. coli isolates into eight major clusters (C1 to C8) with 70% similarity between them and three isolates were found to be unclustered with other isolates. Our results showed high intra-serotypic diversity in fecal E. coli from dogs, as evidenced by the grouping of isolates of same ‘O’ serotype into different clusters. Furthermore, ERIC-PCR genomic fingerprinting was found to be a rapid, easy-to-perform genotyping tool to differentiate E. coli strains within serotype based on their genotype.