ABSTRACT
Escherichia coli [E. coli] are normal flora of the intestines of most animals, including humans. Most strains are harmless and beneficial to host by preventing the establishment of pathogenic bacteria within the intestine. However, some E. coli strains can cause a wide variety of intestinal and extra-intestinal diseases, such as diarrhoea, urinary tract infections, septicaemia, neonatal meningitis and renal complications
Several virulence factors including toxins, adhesins, serine proteases, etc. have been reported in these highly adapted clones
The present study was designed to enumerate toxin genotype through PCR assay in local clinical isolates of E. coli. A total of 37 E. coli strains were collected from different clinical laboratories of Karachi and examined for the presence of shiga toxin 1 [stxl] and shiga toxin 2 [stx2] genes of Eenterohemorrhagic E. Coli [EHEC] and heat stable [sf] and healt labile [If] toxin genes of enterotoxigenic E. Coli [ETEC]
It was observed that 16 strains out of 37 carried one or more type of toxin genes
The presence of stxl gene was significantly higher as it was positive in 10 isolates compared to others toxins
Two in above stxl positive strains were also carrying for stx2 gene. Six out of 37 isolates were positive for It gene, and none of the strains are carrying st gene
Although, the study was carried out with fewer isolates, yet it demonstrated the trend of dispersion of toxin genes and findings can be used to correlate the gastro-intestinal infections and their complications in Pakistan