Characterization of a Streptococcus uberis mutant strain deficient in the sua gene

CAMPRA NA; MOLIVA M; RAVIOLO J; PORPORATTO C; CARIDDI LN; REINOSO E

Congreso; 52th Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2016

Improving the quality of milk is a priority considering the increase of the export capacity of the sector, mainly in Mercosur. Agents causing of bovine mastitis have been classified in contagious and environmental pathogens.Streptococcus uberis is considered one of the most prevalent environmental pathogen. The aim of this study was to characterize pheno and genotypically asuamutant strain ofS. uberisand evaluate their behaviorin vivo. Previously, we obtainedS. uberismutant strains deficient insuagene using conditional replication vectors. Microtiter plate assay revealed that the mutant strain was categorized as strongly positive biofilm producer and showed adhesion capability in bovine mammary epithelial cell line (MAC-T). Intraperitoneal inoculation of the wild-type strain in Balb/c mice showed that 109CFU/ml was able to induce death and the strain could be cultured from kidneys, liver, spleen and heart. However, 108CFU/ml did not cause death but it could be cultured from the organs, except heard. While the mutant strain (108 and 109CFU/ml), did not cause death but it could be cultured from all organs. Genotyping by PFGE showed one different band in the mutant strain. The results obtained show new insights regarding tosuagene. Knowledge about specific virulence factors exploited by this pathogen is an important key to developing novel control strategies.