Diagnosis and management of staphylococcal infections of pacemakers and cardiac defibrillators

Abstract

Staphylococcal species, usually Staphylococcus aureus or Staphylococcus epidermidis, account for 70% to 95% of pacemaker and cardiac defibrillator infections. Infection limited to the generator pocket may cause pain, redness and swelling that is often accompanied by drainage or fistula formation. In this instance, the generator should be removed and reimplanted at another site as cure is rare with antimicrobial therapy alone. Infection of the leads usually tracks along the wire to include the endocardial surface and may involve the tricuspid valve and pocket. Clinical manifestations vary from mild chronic non-specific symptoms to septic shock with marked localizing signs. Septic embolization to the lungs is common and may cause cough, chest pain and shortness of breath that may be misdiagnosed. Blood culture and trans-oesophageal echocardiography (TOE) are the most important investigations. TOE has a sensitivity of >90%. Lead infection without vegetations may occur and these infections should be treated as for endocarditis. Antimicrobial therapy is an important part of treatment but lead infections are unlikely to cured unless the device is removed. Vancomycin is suitable as initial antimicrobial therapy as this covers both S. aureus and coagulase-negative staphylococci. Flucloxacillin, dicloxacillin or a first-generation cephalosporin are preferred if the organism is sensitive. The addition of low-dose gentamicin may improve bacterial killing. The duration of antimicrobial therapy and timing of replacement of the device have not been determined but 2 weeks treatment before removal and 2-4 weeks treatment after replacement is commonly administered.