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A scanning and transmission electron microscopic study of an infected endocardial pacemaker lead
Abstract:
We studied the pacemaker lead that had been removed from a patient who suffered three sequential episodes of Staphylococcus aureus bacteremia. This organism was recovered from the surface of the lead. Scanning electron microscopy showed differential colonization of the pacemaker lead. The metal tip, the inner surface and the internal wires were covered with a heavy biofilm of bacteria. The outer silastic surface had no biofilm adherent to it; instead, well-spaced bacterial cells were seen. These observations illustrate why infection of implantable devices persists despite intensive antibiotic chemotherapy.
Insights
Pacemaker lead infections by Staphylococcus aureus biofilms explain persistent bacteremia. Differential bacterial colonization on lead surfaces hinders antibiotic treatment efficacy for implantable device infections.
Area of Science:
- Medical Microbiology
- Biomaterials Science
- Infectious Diseases
Background:
- Recurrent Staphylococcus aureus bacteremia in patients with pacemakers necessitates understanding device-related infection mechanisms.
- Investigating the physical and biological interactions between bacteria and pacemaker leads is crucial for managing chronic infections.
Observation:
- Scanning electron microscopy revealed distinct bacterial colonization patterns on a removed pacemaker lead.
- Heavy Staphylococcus aureus biofilm formation was observed on the metal tip, inner surfaces, and internal wires of the lead.
- The outer silastic surface exhibited sparse bacterial adherence without significant biofilm development.
Findings:
- Staphylococcus aureus preferentially colonizes specific lead components, forming robust biofilms.
- Differential colonization suggests that lead material and surface topography influence bacterial adhesion and biofilm formation.
- The presence of dense biofilms on internal and metallic components correlates with persistent bacteremia.
Implications:
- Understanding differential colonization is key to developing strategies against implantable device infections.
- Targeting biofilm formation on specific lead surfaces may improve treatment outcomes for Staphylococcus aureus bacteremia.
- This study highlights challenges in eradicating device-associated infections due to heterogeneous bacterial distribution.