Staphylococcus

The bacterial genus Staphylococcus is split into two main groups:

• S. aureus: A cause of soft tissue infections, as well as toxic shock syndrome (TSS). It can be distinguished from other species of Staphylococcus by a positive result in a coagulase test - ability to clot plasma (all other species are negative).
• Non-aureus species such as S. epidermidis (coagulase-negative).

Staphylococci are non-motile, Gram-positive cocci, ~1 µm in diameter. The spherical cells occur in irregular clusters [Greek staphyle = bunch of grapes]. The term staphylococcus is also used for any bacteria with such a growth pattern. Staphylococcus epidermidis are Gram-positive cells ~1 µm diameter, arranged like "bunches of grapes".

S. epidermidis is a normal microbial inhabitant of human skin and mucosal surfaces but may spread to the blood through breaks in mucosal and skin integrity. This bacterium is an opportunistic pathogen. Those most susceptible to infection are intravenous drug users, newborns, elderly, and those using catheters or other artificial appliances. The organism produces a glycocalyx "slime" that acts as a glue adhering it to plastic and cells, and also causes resistance to phagocytosis and some antibiotics.

Microbiology
by L.M.Prescott et al.
A balanced, comprehensive introduction to all major areas of microbiology. The sixth edition has been updated extensively to reflect the latest discoveries in the field.
(Amazon.co.UK)