This adds ArlRS and MgrA to the short list of skin virulence regulators (Agr, SaePQRS, and CodY) and expands other reports of ArlRS or MgrA being involved in systemic infections, such as staphylococcal sepsis, endocarditis, arthritis following bacteremia, and muscle infection (Benton et al., 2004; Chen et al., 2009; Crosby et al., 2016b; Gupta et al., 2013; Jonsson et al., 2008; Li et al., 2019; Liu et al., 2014; Radin et al., 2016; Walker et al., 2013). The gene discussed is MAS1; the disease is arthritic joint disease.