What are the implications of Staphylococcus epidermidis bacteremia in a patient with a pacemaker (permanent artificial cardiac pacemaker)?

From the Guidelines

For Staphylococcus epidermidis bacteremia in a patient with a pacemaker, complete device removal is generally necessary for cure, as biofilms form on the pacemaker hardware that antibiotics cannot effectively penetrate, and this approach is supported by the most recent guidelines 1.

Key Considerations

• Immediate treatment with vancomycin (15-20 mg/kg IV every 8-12 hours, adjusted based on renal function and to achieve trough levels of 15-20 μg/mL) is recommended, initiated after obtaining at least two sets of blood cultures.
• The standard treatment duration is 4-6 weeks of intravenous antibiotics, with timing of device removal and replacement determined by clinical stability and extent of infection.
• If the patient is stable, the infected system should be completely removed, followed by placement of a temporary pacing system if needed, with reimplantation of a permanent device after blood cultures remain negative for at least 72 hours, as suggested by guidelines 1.
• For patients who cannot undergo device removal due to high surgical risk, long-term suppressive antibiotic therapy may be considered, though this is less effective.
• Infectious disease and cardiology consultation is essential for optimal management of these complex infections, as S. epidermidis forms biofilms and frequently demonstrates methicillin resistance, making eradication without device removal extremely difficult, as noted in 1.

Management Approach

• Complete removal of all hardware, regardless of location, is the recommended treatment for patients with established CIED infection, including cases where a localized pocket infection occurs without signs of systemic infection 1.
• Antimicrobial therapy is adjunctive in patients with CIED infection, and complete device removal should not be delayed, regardless of the timing of initiation of antimicrobial therapy.
• Selection of the appropriate antimicrobial agent should be based on identification and in vitro susceptibility testing results, with vancomycin as the initial empirical antibiotic coverage until microbiological results are known 1.

Special Considerations

• The optimal timing of device replacement is unknown, but factors such as blood culture results and the type of pathogen identified can influence this decision, with some advocating for waiting until blood cultures are negative before placing a new device 1.
• The approach to hardware removal, including percutaneous lead extraction, should be individualized based on the patient's clinical parameters and the extractor's evaluation, with consideration of the risks involved, as discussed in 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, accounting for 70% to 95% of cases 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.
• Clinical manifestations of Staph epidermidis bacteremia in patients with pacemakers can vary from mild chronic non-specific symptoms to septic shock with marked localizing signs, and septic embolization to the lungs is common 2, 3.

Diagnosis and Treatment

• Blood culture and trans-oesophageal echocardiography (TOE) are the most important investigations for diagnosing Staph epidermidis bacteremia in patients with pacemakers, with TOE having a sensitivity of >90% 2.
• Antimicrobial therapy is an important part of treatment, with vancomycin being suitable as initial therapy, covering both S. aureus and coagulase-negative staphylococci 2, 4.
• The addition of low-dose gentamicin may improve bacterial killing, and 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.
• In cases of methicillin-resistant Staphylococcus epidermidis, alternative therapies such as daptomycin may be effective 4.

Bacteriology and Antibiotic Resistance

• Staphylococcus epidermidis is the most frequently isolated bacterial strain in pacemaker and implantable cardioverter defibrillator infections, followed by Gram-positive flora, Staphylococcus aureus, and Candida parapsilosis 5.
• Retained sensitivity to antibiotics was reported as follows: teicoplanin/vancomycin 100%, doxicyclin 96%, amikacin 94%, piperacillin-tazobactam 58%, cotrimoxazole 78%, gentamycin 65%, quinolones 47%, rifampicin 44%, cephalosporins 25%, and oxacillin 25% 5.
• Staphylococci, including S. epidermidis, show poor susceptibility to antibiotics, presenting three out of four methicillin-resistant features, and systemic antibiotics, mainly glycopeptides, must not be delayed awaiting the complete removal of the implanted system 5.