The microbial quality of several, untreated surface water sources, used by rural communities in the Venda region of South Africa, was assessed to determine its safety for human consumption and to highlight the possible occurrence of water-borne diseases. The water sources studied were six sampling points on the Levubu River, Vuwani, Mutale, Ngwedi, Tshinane, Makonde, Mutshindudi and Mudaswali Rivers. Heterotrophic plate counts, faecal and total coliforms, enterococci and somatic coliphage counts were performed according to standard methods to determine the microbiological quality of the water sources. The presence of enteric pathogens such as Salmonella, Shigella, Campylobacter, Plesiomonas, Aeromonas and Vibrio was also determined. Results obtained showed that the minimum and maximum counts with regard to all the sampling points investigated were 1.5 x 10 3 cfu•ml-1 and 6.3 x 10 4 cfu•ml-1 for faecal coliforms, 6.0 x 10 2 cfu•ml-1 and 3.7 x 10 4 cfu•ml-1 for total coliforms, 1.8 x 10 2 cfu•ml-1 and 1.3 x 10 6 cfu•ml-1 for heterotrophic plate counts, 1.0 x 10 1 cfu•ml-1 and 2.5. x 10 4 cfu•ml-1 for enterococci and 0 and 13 pfu•100 ml-1 for somatic coliphages. The results for the indicators were higher than the acceptable maximum limits prescribed by the Department of Water and Forestry of South Africa. According to these guidelines, the maximum values are as follows: 0 cfu•100 ml-1 for faecal coliforms, 5 cfu•100 ml-1 for total coliforms, 1.0 x 10 2 cfu•ml-1 for heterotrophic plate count, 0 cfu•ml-1 for enterococci and 1 pfu•100 ml-1 for somatic coliphages. Salmonella, Shigella, Vibro, Campylobacter, Aeromonas and Plesiomonas species were isolated from several of the water sources investigated. These untreated water sources are used for drinking and domestic purposes and pose a serious threat to the health of the consumers and therefore calls for urgent intervention by government.

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River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was isolated and identified by standard cultural and biochemical methods. Pathogenicity of environmental and human isolates was determined by amplification of genes associated with virulence of E. coli, using specific primers.Of a total of 228 water and river sediment samples screened, E. coli was recovered from 200 (87.7%), and 135 (67.5%) of these had one or more genes associated with pathogenicity. The highest frequency of isolation of pathogenic strains was found in Ritavi River water and sediment (80.6%), followed by Lotanyanda River (76.9%), and the least (45.8%) in Nzhelele River 2. Escherichia coli was recovered from all of the 252 diarrhoeic stools tested (100%), and 119 (47.28%) of these had one or more genes associated with pathogenicity. The frequency of isolation of potential pathogenic E. coli from humans was highly significant (t = 6.3; pd•0.01) in comparison to water isolates. Cytotoxic necrotizing Factor 1 (cnf1) and cytotoxic necrotising Factor 2 (cnf2) coding for necrotoxigenic E. coli (NEC); bundle-forming pilus (bfpA) and enteropathogenic attachment and effacement (eaeA) coding for enteropathogenic E. coli (EPEC), occurred in 35% and 34% respectively of river isolates. Heat-stable (ST) and heat-labile (LT) toxin genes coding for enterotoxigenic (ETEC) and Shiga-like toxin 1 (Stx1) and Shiga-like toxin 2 (Stx2) coding for Shiga-like toxin-producing E. coli (STEC) were not encountered in the river isolates. Isolates from stool samples had 21.8% and 12.6% of EPEC and NEC strains respectively; while enterotoxigenic (ETEC), Shiga-like toxin-producing (STEC) and enteroaggregative E. coli (EAEC) had a prevalence of 5%, 5.8% and 5.8% respectively. One human isolate possessed stx2 and eaeA indicating E. coli O157: H7. No genes associated with pathogenicity were observed in human non-diarrhoeic stool isolates. Results have revealed a possibility of a recycling of pathogenic E. coli strains, particularly the EPEC and NEC strains, between the water sources and the local population.

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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.