Profiles of antibiotic susceptibilities of bacterial isolates and physico-chemical quality of water supply in rural Venda communities, South Africa

The Venda region of South Africa is predominantly rural and residents rely on untreated water sources for daily water needs. The physico-chemical quality of these water sources including antibiotic susceptibilities of enteric bacterial isolates which would guide clinicians in the empiric management of diarrhoea have received cursory attention. This study therefore sought to document the physico-chemical parameters and antibiograms of bacterial isolates from water sources in order to determine the safety for human consumption and to provide updated antibiotic data for empiric treatment of patients. Water samples were obtained on a weekly basis from Ngwedi, Mutale, Tshinane, Mutshindudi and Mudaswali Rivers and Makonde, Mudaswali and Thamathama Fountains between August 2000 and July 2002. Physico-chemical parameters such as turbidity, temperature, pH, lead, fluoride, cyanide, iron, sulphate, chromate and nitrate were determined. Antibiograms of bacterial isolates were ascertained using the disk diffusion method. Results obtained revealed that all the physico-chemical variables of the water sources analysed were within normal recommended limits for safety of drinking water except for turbidity, which exceeded recommended limits and hence precludes the rivers from direct domestic use. Antibiogram profiles showed multiple antibiotic resistances of Salmonella, Shigella, Campylobacter, Aeromonas, Vibrio cholera, Enterobacter and Plesiomonas to ampicillin, tetracycline, chloramphenicol, cotrimoxazole and erythromycin. In contrast virtually all the enteric bacterial isolates showed marked susceptibilities to ciprofloxacin, nalidixic acid, gentamicin, ceftriazone and amikacin. These effective antibiotics are therefore indicated in the empiric treatment of diarrhoeal cases or water-borne diseases of bacterial aetiology.