Staph epidermidis thrive as Gram-positive cocci in clusters. 

-They are Coagulase-negative. Catalase-positive.

-Coagulase negative Staph are the most common cause of nosocomial bloodstream infections 

-They reside on the human skin and can enter the bloodstream at the site of intravenous catheters 

-They cause pyogenic infections on prosthetic implants such as heart valves, pacemakers, and hip joints

St-Treatment: Vancomycin plus either rifampin or an aminoglycoside.

Staph aureus gastroenteritis is a common cause of food poisoning when food is left at room temperature (e.g.at picnics) 

-Foods rich in sugar (custard, cakes, ice creams), dairy, mayonnaise, potato salads, meats such as ham favor Staph growth and enterotoxin production 

-After ingestion, patients develop nausea, vomiting, abdominal cramps, diarrhea and rarely fever.

-incubation period is around 6 hours 

-Diagnosis is by history or/and by isolating S aureus or enterotoxin from the suspected food, vomitus or stool 

-Recovery is rapid usually within 24 hours; hydration if there is dehydration