[Cell cultures as a system for distinguishing between strains ofClostridium chauvoei and Clostridium septicum isolated in northeastern Mexico].

Clostridium chauvoei and C. septicum have similar characteristics as far as results from biochemical methods and gas chromatography (GC) are concerned. A total of 267 samples collected from sick or dead animals in the fields from Northeast Mexico, were bacteriologically analysed and differentiated by the GC technique. From these strains, 16 belong to the group of C. chauvoei/C. septicum. Studies on the effect of toxin on cell cultures of the lines EBL, 3T3, BHK21-BSR/PK5/88, CHO-K1 and MDCK were performed. The objective was to obtain further data for identification, as the results from GC do not allow exact differentiation between C. chauvoei and C. septicum species. The results were obtained in tests with BHK21-BSR/PK5/88 cells as this had proved to be the most sensitive cell line, closely followed by 3T3 and CHO-K1 cells. MDCK cells were of little sensitivity. Results of the cytotoxin test of the 16 strains were reproducible and suggested a differentiation between C. chauvoei and C. septicum other than indicated by GC. The cytotoxin test is a highly specific system that provides also an additional method to distinguish between C. chauvoei and C. septicum strains.