STAPHYLOCOCCUS
Clinically, the most important genus of the Micrococcaceae family is Staphylococcus. The Staphylococcus genus is classified into two major groups: aureus and non-aureus. S. aureus is a leading cause of soft tissue infections, as well as toxic shock syndrome (TSS) and scalded skin syndrome. It can be distinguished from other species of Staph by a positive result in a coagulase test(all other species are negative).
The pathogenic effects of Staph are mainly asssociated with the toxins it produces. Most of these toxins are produced in the stationary phase of the bacterial growth curve. In fact, it is not uncommon for an infected site to contain no viable Staph cells. The S. aureus enterotoxin causes quick onset food poisoning which can lead to cramps and severe vomiting. Infection can be traced to contaminated meats which have not been fully cooked. These microbes also secrete leukocidin, a toxin which destroys white blood cells and leads to the formation of pus and acne. Particularly, S. aureus has been found to be the causative agent in such ailments as pneumonia, meningitis, boils, arthritis, and osteomyelitis (chronic bone infection). Most S. aureus are penicillin resistant, but vancomycin and nafcillin are known to be effective against most strains.
Of the non-aureus species, S. epidermis is the most clinically significant. This bacterium is an opportunistic pathogen which is a normal resident of human skin. Those susceptible to infection by the bacterium are IV drug users, newborns, elderly, and those using catheters or other artificial appliances. Infection is easily treatable with vancomycin or rifampin.
S.Epidermis: Babies often get pustules which when swabbed contain staph. It causes paronychia & 'sticky eyes' plus impetigo in infants/chidren. Highly contagious & passes quickly between children, good hand-washing is essential. I wouldn't agree that it's harmless babies can get qite sick esp if it affects their umbi& it requires antibiotic therapy.
S. aureus gets into wounds & can become really nasty. You have all heard of MRSA & Golden Staph (which can kill a baby due to septic shock as can Streptococcus).