Some membesrs of the CNS group, primarily S. epidermidis, are common nosocomial pathogens, and the presence of regulatory elements, involved in the control of virulence factor synthesis, has been recently identified. Remarkably, strains of S. xylosus were isolated from patients who had an underlying disease. The same species has been reported to be involved in infections of poultry (Aarestrup et al. 2000).