Detection of virulence gene of Shiga toxin-producing Escherichia coli (STEC) strains from animals with diarrhoea and water samples in the North-West Province, South Africa

Shiga toxin-producing Escherichia coli (STEC) strains have the potential to produce Shiga-toxins, which may lead to enterohemorrhagic diarrhoea and kidney failure in individuals. Moreover, virulence genes of E. coli correlate to their pathogenic nature causing severe morbidity and mortality in humans and animals. Hemolytic-uremic syndrome (HUS), hemorrhagic colitis, might lead to life-threatening hemolytic anemia, thrombocytopenia, and acute renal failure. Escherichia coli (E. coli) are well-known as gastrointestinal bacteria of humans and warm-blooded animals. The current paper was aimed at molecularly identifying virulent STEC strains from “animal with diarrhoea” and water samples from farms in the North-West Province, South Africa. A total of 25 samples (water, animals with diarrhoea such as pig, piglet, sheep, and rabbit) from two farms were used to isolate E. coli using standard microbiological methods. Molecular method was used to detect the virulent gene. Gram staining and biochemical assays were utilized for presumptive identification of E. coli and the results supported our findings. Out of 25 samples, 23 isolates tested positive for E. coli using molecular techniques targeting the uidA specific primers at 556 bp. Prevalence of E. coli was 92%. Virulence genes were detected, specifically stx2, hlyA, eaeA, was present in 48% (11/23), 43% (10/23) and 52% (12/23) respectively. Shiga toxin type 1 was not investigated since shiga toxin type 2 is more potent. We conclude that the animals suffering from diarrhoea are carriers and/or source of pathogenic E. coli, specifically STEC. There is an urgent need to identify and characterize the isolates that were found to be responsible for the wide distribution of STEC virulence genes detected showed the potential pathogenic nature of the E. coli stains and serves a massive healthcare concern.