Pheno and genotypic characterization of an Enterococcus faecium strain and its virulence in a murine model of mastitis

MOLIVA MV; MONTIRONI I; CAMPRA N; RAVIOLO JM; CARIDDI L; REINOSO EB

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Reunión Conjunta de Sociedades de Biociencias

Bovine mastitis is a disease that causes significant economic losses to the dairy industry in the world, being streptococci and enterococci the main environmental bacteria involved. The aim of this work was to characterize pheno and genotypically an Enterococcus faecium strain collected from a bovine mastitis case. In addition, bacterial counts and histopathological alterations in the mammary tissue were evaluated using a mouse mastitis model. For phenotypic characterization bacteria growth curve, antibiotic susceptibility testing, enterococcal virulence factors and biofilm assays were performed. For genotypic characterization, amplification of virulence associated genes by PCR assays and PFGE assay were performed. The maximum cell growth was determined at 6 h. The strain only showed susceptibility to teicoplanin, presented gamma hemolysin and did not present gelatinase activity. It could be characterized as moderate biofilm producer and yielded gelE1 and efa genes. PFGE analysis showed the presence of 19 bands. Balb/c lactating mice were inoculated as follows: Control: 100 µl of PBS and Group 2: 100 μl of 1x10 8 CFU/ml of E. faecium. Animals were sacrificed 24, 48, 72, 96 and 360 h post-inoculation (p.i.). Bacterial count decreased at 48 hours (p