Staphylococcus hominis

Staphylococcus hominis is a coagulase-negative member of the bacterial genus Staphylococcus, consisting of Gram positive, spherical cells in clusters. It occurs very commonly as a harmless commensal on human and animal skin. However, like many other coagulase-negative staphylococci, S. hominis may occasionally cause infection in patients whose immune system is compromised, for example by chemotherapy or predisposing illness.

Laboratory identification of S. hominis is not difficult. It is one of only two species of Staphylococcus that display sensitivity to desferrioxamine, the other being S. epidermidis. Unlike S. epidermidis, S. hominis produces acid from trehalose, so the two tests together serve to identify the species.

Colonies of S. hominis are small, usually 1-2 mm in diameter after 24 hours' incubation at 35 degrees Celsius, and white or tan in colour. Occasional strains are resistant to Novobiocin and may be confused with other resistant species (eg. S. saprophyticus.)