Virulence and phylogenetic groups of Escherichia coli cultured from raw sewage in Kuwait

In Kuwait, some untreated sewage is discharged into the sea which poses health risks. Therefore, we determined the virulence traits and the phylogenetic groups of E. coli cultured from raw sewage. Sewage was collected once every month for 12 months with culturing of a total of 140 E. coli isolates. E. coli was typed by the methods of Clermont. The five pathotypes of diarrheagenic E. coli (DEC), and extra-intestinal pathogenic E. coli (ExPEC) were detected by specific PCR assays. Four virulence genes which correlate with pathogenicity in animal models, were used for the first time for detection of ExPEC-vat (vacuolating auto-transporter toxin), fyuA (yersiniabactin receptor), chuA (heme-binding protein), and yfcV (major subunit of putative chaperon-usher fimbria). Most E. coli belonged to phylogenetic groups A (65[45%]) and B1 (34[24.3%]). Three (2.1%) isolates were DEC, while 14 (10%) isolates were ExPEC mostly in group B2 (57.1%). A relatively high prevalence of ExPEC in sewage has public health implications.