The occurrence and distribution of Shigella species in water from the five river catchments in the North West province of South Africa were investigated. Shigella is a Gram-negative, non-motile, facultative anaerobic bacillus that causes shigellosis, an important cause of morbidity and mortality in high-risk populations (such as children, the elderly and immuno-compromised individuals) that depend on river water. A total of 54 water samples collected in winter (April 2007 to July 2007) and summer (December 2007 to March 2008 were cultured on Salmonella-Shigella agar by the spread-plate method. Suspected Shigella isolates obtained were characterised by primary biochemical (Triple Sugar Iron agar and agglutination) and molecular (polymerase chain reactions, PCR) tests. Amplification of the invasion plasmid gene (ipaH) by PCR was done to confirm the presence of Shigella spp. in water. In total, 214 Shigella boydii, 15 Shigella dysenteriae, 11 Shigella flexneri and 2 Shigella sonnei were confirmed by serotyping in both winter and summer samples. The ipaH gene (606 bp) was present in 176 and 49 of the winter and summer isolates, respectively. The presence of Shigella spp. in water was confirmed with over 90% specificity. The need for more effective management of these river catchments and the provision of potable water and sanitation facilities is needed to minimise the occurrence and transmission of water-borne diseases caused by these and other pathogenic bacteria.http://www.sajs.co.za

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The aim of this study was to examine and compare the levels of bacterial contamination in water obtained from the five river catchments in the North West Province with water quality guidelines. A total of 54 water samples collected during winter and summer seasons were cultured on m-FC and m-Endo agar plates using membrane filtration, and on Plate Count and Eosin Methylene Blue agar plates using spread-plate techniques. Biochemical characterisation of suspected Escherichia coli and Klebsiella isolates by Triple Sugar Iron (TSI) and serotyping using E. coli poly D1-D8 and Klebsiella capsular Types 1-6 antisera were performed for confirmatory identification. Results showed significantly high levels of contamination when using heterotrophic, total and faecal coliform counts as an indicator in all catchments in summer and winter seasons. In winter season, E. coli and Klebsiella were maximal in the Marico and Molopo catchment with 75 and 95% prevalence, respectively. The Crocodile and Elands and Marico and Hex catchments during summer also showed high levels of E. coli (63%) and Klebsiella (76%) contamination, respectively. Contamination levels were widespread and above the South African Department of Water Affairs' guidelines for domestic, recreational and irrigation water were used. The consumption of such untreated water sources directly or indirectly, poses a health risk to consumers. Strict measures to ensure the discharge of properly treated effluent into the rivers should be put in place, to minimise the spread of potential pathogenic bacteria and the occurrence of water borne disease outbreaks.