From the Guidelines
For Staphylococcus epidermidis bacteremia in a patient with a pacemaker, treatment typically requires 4-6 weeks of intravenous antibiotics, as recommended by the most recent guidelines 1. The preferred regimen is vancomycin (15-20 mg/kg IV every 8-12 hours, adjusted based on levels) or daptomycin (6-8 mg/kg IV daily) if the organism is methicillin-resistant. For methicillin-susceptible strains, nafcillin or oxacillin (2 g IV every 4 hours) is recommended. Complete device removal should be strongly considered whenever possible, as the pacemaker is likely infected and serves as a persistent source of bacteremia, as supported by previous studies 1. If the device cannot be removed, suppressive oral antibiotics may be needed indefinitely following the initial IV course. Blood cultures should be repeated to confirm clearance of bacteremia. Infectious disease consultation is valuable for optimizing therapy. This extended duration of treatment is necessary because S. epidermidis forms biofilms on prosthetic materials like pacemakers, making eradication difficult without device removal. The bacteria within biofilms are protected from both antibiotics and immune responses, requiring prolonged high-concentration antibiotic therapy to achieve cure. Key considerations in management include:
- Early source control
- Appropriate antibiotic choice and dosing
- Treatment duration of 4-6 weeks for bacteremia with high-risk features, such as the presence of a pacemaker 1.
From the Research
Staph Epidermidis Bacteremia in Patients with Pacemakers
- Staphylococcal species, including Staphylococcus epidermidis, are common causes of pacemaker and cardiac defibrillator infections 2.
- Infection limited to the generator pocket may cause pain, redness, and swelling, while infection of the leads can track along the wire to include the endocardial surface and may involve the tricuspid valve and pocket 2.
Duration of Treatment
- 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 2.
- Antimicrobial therapy is an important part of treatment, but lead infections are unlikely to be cured unless the device is removed 2.
- Vancomycin is suitable as initial antimicrobial therapy, as it covers both S. aureus and coagulase-negative staphylococci, including S. epidermidis 2, 3.
Antibiotic Tolerance and Resistance
- Staphylococcus epidermidis isolates from nosocomial infections are frequently resistant to methicillin, and cross-resistance between methicillin and cephalosporins occurs in vitro 3.
- Virtually all S. epidermidis isolates are susceptible in vitro to vancomycin and rifampin, but antibiotic tolerance can occur, making treatment difficult 3, 4.
- In-host evolution of S. epidermidis can result in increased antibiotic tolerance, making treatment failure more likely 5.