Escherichia—E. coli is a major member of the enteric group. It is also the most studied and familiar bacterial species used in biological research. Tests to detect its presence in water or food are important because this is considered an indication of fecal contamination. Although regular strains of E. coli are normal and harmless in the intestinal tract, there are exceptions:Regular strains cause many urinary tract infections—they are OK in the intestines but pathogenic in other locationsCertain strains produce enterotoxins, which cause travelers' diarrheaOne specific strain, E. coli O157:H7 produces a toxin which causes a severe or fatal foodborne diseaseSalmonella—these enterics are not normal flora, and their presence in the intestinal tract of humans is not considered normal. Animals, especially poultry and cattle, frequently do carry
This is the end of the preview.
access the rest of the document.