EN
Twelve Clostridium perfringens strains were isolated in 12 calves that had died with diarrhoea on two farms. On the basis of seroneutralization of antitoxins by diagnostic sera, 10 strains were classified into serotype A and 2 into serotype C. Most of the strains (7) were isolated from the small intestines of calves that died 7-18 h from the onset of diarrhoea. Characterization of the toxins revealed the presence of alpha, beta, kappa, mi and ni toxins, as well as enterotoxin. Pathogenic areobic microflora was absent. The results point to the presence (for the first time) in Poland of nonenterotoxigenic strains of C. perfringens A, and in some cases together with C. perfringens C in the etiology of diseases in calves. Such cases were also found in other countries.