Haemolytic Escherichia coli, including human intestinal and extraintestinal as well as porcine enterotoxigenic and edema disease isolates, and Proteus morganii strains were studied for their virulence. Hly+ wild-type strains and Hly+ transconjugants were more virulent than Hly+ derivatives as shown in mice and chick embryos. This enhanced virulence seems to be connected with the ability of diffusible alpha-hemolysin production because clones producing only non-diffusible, beta-hemolysin behaved as non-hemolytic ones. Hemorrhagic lung symptoms and haemoglobinuria were frequently observed after parenteral challenge of mice with alpha-haemolytic clones. Though the Hly- clone exhibited a high resistance against blood clearance, the number of circulating bacteria was significantly higher in the case of the alpha-haemolytic clone. A causal connection between this phenomenon and the leukocidin activity of alpha-haemolysin is suggested.
|Number of pages||10|
|Journal||Acta Microbiologica Academiae Scientiarum Hungaricae|
|Publication status||Published - 1980|
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