II. Labs: Characteristics
- Shares common appearance with other Staphylococci
- Gram Positive Cocci in irregular clusters
- Facultative Anaerobes
- Beta hemolytic
- As with Beta Hemolytic Streptococcus, hemolyze RBCs on sheep blood agar plate (BAL)
- Catalase positive
- Catalase converts Hydrogen Peroxide (from Macrophages, PMNs) into water and oxygen
- Catalase positive organisms on a culture plate will bubble when exposed to Hydrogen Peroxide
- Unique Staphylococcus Epidermidis features
- Coagulase-Negative Organisms
- Contrast with the coagulase positive Staphylococcus Aureus
- Adherent Polysaccharide capsule
- Polysaccharide capsule adheres well to catheters and prosthethic devices
- Most common colonizer of tubes and devices (and related secondary infections)
- Staphylococcus Epidermidis commonly forms a biofilm around these devices
- Coagulase-Negative Organisms
III. Pathophysiology
- Normal Bacterial colonization of human skin
- Frequently contaminates Blood Cultures
- Infects catheters and lines
- Catheter Associated Urinary Tract Infection
- Central Line-Associated Bloodstream Infection
- Prosthetic Infections
- Prosthetic Joint Infection
- Prosthetic Valve Endocarditis
- Peritoneal Dialysis Catheter Infections