[Morphological changes in human embryonic lung fibroblasts caused by cytotoxins of various Clostridium species].

A total of 243 strains of 35 Clostridium species were tested for cytotoxin production in cooked meat medium or liver broth within 48-72 h at 37 degrees C, using human embryonal lung fibroblasts in tissue-culture as indicator cells. Cytotoxin could be detected in the culture-filtrates of all toxigenic strains of C. chauvoei, C. difficile, C. histolyticum, C. novyi types A and B, C. septicum and C. tetani, but not in the atoxigenic ones. The cytotoxin of C. novyi correlated with alpha-toxin in the culture filtrate. All strains of C. perfringens and C. novyi D tested were not cytotoxic for lung fibroblasts despite their pathogenicity for guinea-pigs. Further cytotoxigenic strains were found among C. hastiforme, C. limosum, C. oceanicum, C. putrificum, C. ramosum, C. sordellii, C. sporogenes, and C. subterminale. The morphological changes in lung fibroblasts caused by the culture filtrates were characteristic and species-specific and corresponded with pathogenicity for guinea-pigs and/or mice. No cytotoxin was produced by C. absonum, C. barati, C. bifermentans, C. botulinum (atoxic), C. butyricum, C. cadaveris, C. carnis, C. clostridioforme, C. cochlearium, C. glycolicum, C. innocuum, C. malenominatum, C. mangenotii, C. paraputrificum, C. putrefaciens, C. rectum, C. tertium, and C. tyrobutyricum.