Microbiology of Cardiac Implantable Electronic Device Infections

Objectives: This study reports a high-volume tertiary care center experience with the microbiology of cardiac implantable electronic devices (CIED) infections with assessment of temporal trends and profiles of late versus early infections.

Background: The rates of CIED infections have been increasing. With changing demographics, patient and device characteristics, prophylactic measures, and the wide use of broad-spectrum antibiotics, there is need for updated contemporary data on the microbiology of CIED infections.

Methods: The study included 816 consecutive patients with confirmed CIED infections who underwent transvenous lead extraction at our institution between the years 2000 and 2011. Blood cultures were obtained in addition of pocket swabs, pocket capsule, and leads.

Results: Staphylococcal species remained the most common pathogens in CIED infections (68.4%), especially coagulase-negative species (37.6%). Methicillin-resistant staphylococci were the pathogens in 33.8% of all CIED infections and accounted for 49.4% of all staphylococcal infections. Gram-negative pathogens were identified in 8.9% of cases, whereas 13.2% were with negative cultures. CIED infections related to streptococci (2.5%), enterococci (4.2%), anaerobes (1.6%), fungi (0.9%), and mycobacteria species (0.2%) were less common. Of pocket infections, 49.5% occurred more than 1 year after pocket manipulation, and 53.6% of these were related to coagulase-negative staphylococci. In contrast, most endovascular infections were related to Staphylococcus aureus. The proportions of culture negative infections have increased (p < 0.0001).

Conclusions: The study provides contemporary data on the microbiology of CIED infections. The rates of methicillin resistance seem to be greater than those reported from the preceding decade.