Staphylococci Infections, Coagulase-Negative

Key Features

• An important cause of infections of intravascular and prosthetic devices and of wound infection after cardiothoracic surgery

• Less virulent than Staphylococcus aureus, and infections tend to be more indolent

• Normal flora of human skin

Clinical Findings

• Often associated with a foreign body

• Evidence of prosthetic valve infection

  • Fever

  • New murmur

  • Instability of the prosthesis

  • Signs of embolization

Diagnosis

• Infection (vs isolation as a contaminant) is more likely if

  • Patient has a foreign body or an intravascular device in place

  • Same strain is isolated from two or more blood cultures and from the foreign body site

• Contamination: more likely when a single blood culture is positive or if > 1 strain is isolated from blood cultures

  • Antimicrobial susceptibility and speciation can help determine whether multiple strains have been isolated

Treatment

• Remove the foreign body or intravascular device when possible

  • Sometimes treatment with antibiotics is preferable

  • Surgical management may become necessary

• Vancomycin

  • Dosage: 1 g every 12 hours intravenously

  • Treatment of choice for patients with normal kidney function until susceptibility to penicillinase-resistant penicillins or other agents has been confirmed

• Duration of therapy is not established for infections caused by foreign devices, which may be eliminated by simply removing the device

• Treat bone or a prosthetic valve infection for 6 weeks

• Vancomycin plus rifampin, 300 mg twice daily orally, and gentamicin, 1 mg/kg every 8 hours intravenously, is recommended for prosthetic valve endocarditis caused by methicillin-resistant strains