Characterization of an Enterococcus faecium strain in a lactating mouse model of mastitis

MONTIRONI I; MOLIVA M; CAMPRA NA; RAVIOLO J; BAGNIS G; CARIDDI LN; REINOSO E

JOURNAL OF APPLIED MICROBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2019

1364-5072

Aim: The aim of the study was to characterize phenotypically andgenotypically Enterococcus faecium strains collected from bovine mastitis milkand to evaluate one of them for its virulence in a murine mastitis model.Methods and Results: A total of five E. faecium isolates were collected fromcows with subclinical mastitis. EF-7A showed resistance to antibiotics tested, itpresented alpha haemolysin and did not present gelatinase activity. It yieldedcyA, efafm and gelE1 genes and it could be characterized as a moderate biofilmproducer. It was able to internalize in MAC-T cells and 19108 colony formingunit ml-1 was able to establish an intramammary infection in mice. The straincould be recovered from liver, kidney and blood samples. RAPD profilesshowed different bands with respect to the inoculated strain. Histopathologyanalyses showed different grades of polymorphonuclear neutrophils infiltrationin mammary glands.Conclusion: This is the first report that studied E. faecium strain in a lactatingmouse model of mastitis and showed that the experimental inoculation wasable to stimulate an inflammatory response resulting in mastitis. Resultscontribute to a better understanding of intramammary infections caused by E.faecium.Significance and Impact of the Study: This investigation shows that micerepresent a valuable model for the study of the mastitis pathogenesis caused byE. faecium considering the high costs of using cows for mastitis research.