Plays a major role in decreasing resistance to glycopeptide antibiotics. Overexpression confers oxacillin hypersusceptibility, without affecting the levels of resistance towards vancomycin. Could be involved in virulence. Overexpression increases the levels of teicoplanin susceptibility. Overexpression also increased susceptibility to oxacillin in methicillin-resistant strains. Strongly up-regulated by teicoplanin and vancomycin even at lower concentrations (10 ug/ml). Induced by oxacillin at a very high concentration of over 1000 ug/ml. Increased resistance against glycopeptide antibiotics, especially teicoplanin. Belongs to the TcaA family.