Mionecroses: estudos epidemiológicos e moleculares

Abstract

A study of natural cases of myonecroses by Clostridium chauvoei, Clostridium septicum and Clostridium sordellii was performed. In addition, a retrospective study employing the streptavidin-biotin peroxidase technique was made on formalin-fixed, paraffin-embedded tissues of 33 field cases from cattle and swine suspected of myonecrosis. A multiplex PCR tecnique for detection of C. chauvoei and C. septicum was standardized, and sequencing and phylogenetic analyses of five isolates and four vaccine strains of C. septicum was made. The results of the retrospective study revealed the presence of C. chauvoei, C. septicum, C. chauvoei plus C. septicum, C. chauvoei plus Clostridium novyi type A and C. chauvoei plus C. sordelli in 21, eight, two one and one cases, respectively. The multiplex PCR technique showed to be efficient for amplifyng genomic sequences of C. chauvoei and C. septicum isolates presenting a sensitivity of 45pg/uL, respectively. No cross reactions were observed toi other Clostridia, other bacterial species or between both agents. By the sequencing and phylogenetic analyses, the existence of two different genotypic groups of C. septicum was determined.