Acidity and intestinal bacteria: an in-vitro assessment of the bactericidal activity of hydrochloric acid on intestinal pathogens

Abstract

The bactericidal activity of hydrochloric acid (HQ) on different intestinal bacteria was evaluated at various pi I values and time intervals. The effect of HCI was highest at pH 2 and pH 3 on strains of Campylobacter jejuni, Aeromonas hydrophila, Plesiomorias shigelloides, Yersinia enterocolitica, Salmonella spp. and Shigella spp., producing complete killing after 60 min incubation. However, at higher pH values (pi I 4 and above), these organisms not only survived but they also showed evidence of rapid multiplication. In contrast, clinical and standard strains of Escherichia colt and Staphylococcus aureus were resistant to all the PH values. Highest sensitivity to HCI was observed with strains of Shigella spp. and Salmonella spp. It is conceivable that patients with normal gastric acidity should not suffer from gastroenteritis caused by these intestinal pathogens.