The present disclosure provides recombinant Staphylococcus bacterium (e.g. S. epidermidis) that are dependent on D-alanine for growth. In one aspect, the disclosure features a recombinant Staphylococcus bacterium comprising two inactivated alanine racemase genes (Δalr1Δalr2); and an inactivated D-alanine aminotransferase (dat) gene. In another aspect, the disclosure features a method of making the recombinant Staphylococcus bacterium.