Coagluase-Negative Staphylococci
last authored: Feb 2010, David LaPierre
last reviewed:
Introduction
universally present on skin; virutually impossible to eradicate. S. epidermidis is the most ubiqutious Staphylococcus species,
The Case of...
Epidemiology
S. epidermidis is found on the skin of most people, but only infrequently causes disease.
Classification and Characteristics
Slime production (peptidoglycan) is found in most pathogenic S. epidermidis and allows adhesion to synthetic material and inhibits phagocytosis and chemotaxis.
Transmission and Infection
Found on skin; affinity for synthetic materials results in frequent infection of devices inserted though skin
Clinical Manifesations
Disease is uncommon with coagulase-negative Staph, except in some conditions and in particular with immunocompromised patients.
S. epidermiditis is a common cause of peritonitis in patients with peritoneal dialysis. It can also cause infections on implanted objects such as catheters, vascular grafts, and artifical joints.
S. lugdenensis is similar in virulence to S. aureus, . It is an uncommon cause of endocarditis.
S. saphrophyticus is a UTI pathogen in young women.
Diagnosis
All Staph are gram positive cocci which form clusters, similar to grapes.
Colonies are large and creamy on agar, with color tending to be white or light gray.
Coagulase-negative Staph are distingished from S. aureus by the absence of coagulase production. The exception is S. lugdenensis, which produces sufficient clumping factor to be positive on a slide but negative in a tube.
Many methods, including DNA analysis, can be done to identify specific species.
Treatment
Resources and References
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