Staphylococcus epidermidis, and most other Staphylococcus spp. (e.g., S.aureus, S.haemolyticus, S.saprophyticus, S.hyicus, S.simulans), is oxidase negative. The oxidase test is a test used in microbiology to determine if a bacterium produces certain cytochrome c oxidases. The cytochrome system is usually only present in aerobic organisms that are capable of using oxygen as the terminal electron acceptor.