Detection of Staphylococcus aureus adhesion and biofilm-producing genes and their expression during internalization in bovine mammary epithelial cells

PEREYRA E.A.L.; RENNA M.S.; BARAVALLE C.; PIECCH F.; CALVINHO L.F.; DIEZ C.; ANDREOTTI C.S.; RUSSI R; DALLARD B.E.

VETERINARY MICROBIOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 183 p. 69 - 77

0378-1135

Staphylococcus aureus is the most prevalent major pathogen isolated frombovine mastitis, causing chronic intramammary infections (IMI) that limitprofitable dairying. Persistent infections are often associated with animpairment of the immune response, due to factors related both to the bacteriumand the host. Aims of this study were to select S. aureus isolates from bovine IMI with different genetic profilesand harboring genes involved in adherence and biofilm production, to determinethe behavior of these strains in contact with mammary epithelial cells and theexpression of those genes during bacterial-cell early interactions. The geneticdiversity of 20 S. aureus strainsthat were isolated from milk samples taken from cows with persistent-P and non-persistent-NPIMI was high, discriminated into 13fingerprint groups. The occurrence of genes coding for S. aureus surface proteins (clfA,clfB, fnbA, fnbB, fib, cna) and biofilm formation (icaA, icaD, icaC, bap) and invitro biofilm-forming ability was not related to strain epidemiologicalorigin (NP or P). Internalization ability in MAC-T cells of S. aureus was strain-dependent and internalizedbacteria overexpressed adherence and biofilm-forming genes compared with thosethat remained in the supernatant of co-cultures; particularly those genesencoding FnBPs and IcaD. Strains yielding highest invasion percentages werethose able to overexpress fnBP, irrespectivelyof the presence of other evaluated genes. Strains from NP IMI showed a greatermultiplication capacity in vitrocompared with strains from P IMI. These results provide new insights about S. aureus differential gene expression of adhesion-internalizationfactors during early interaction with mammary epithelial cells.