UROVIRULENT ESCHERICHIA-COLI FROM SOUTH-AFRICA PRODUCE CYTOTOXIC NECROTIZING FACTOR TYPE-1 AND HAVE CELL ADHERENCE PROPERTIES

The frequent isolation (50.8%) in South Africa of Escherichia coli fro m urinary tract infections (UTI), producing cytotoxic necrotizing fact or type 1 was significant compared to faecal isolates from asymptomati c controls (6.4%). None of the 126 strains produced cytotoxic necrotiz ing factor type 2. Toxicity/ lethality (cytotoxic necrotizing factor a nd/or haemolysin production and/or mouse lethality) was exhibited by 6 5.1% of UTI isolates. P fimbriation (42.9% vs. 14.3%) and mannose-resi stant haemagglutination (68.3% vs. 20.6%) were both significantly asso ciated with the uropathic isolates. When the combination of properties in individual strains is considered, toxic/lethal strains with adhesi ve properties significantly occurred in UTI but those with toxicity/le thality or adhesiveness alone were not significantly different from fa ecal isolates. Our data suggest that both toxicity/lethality and adhes iveness are required for urovirulence in E. coli.