Detailed bacteriologic tests to identify the origin of transvenous pacing system infections indicate a high prevalence of multiple organisms

Abstract

The reported incidence of pacing system-related infections (PSIs) varies widely, and the roles of leads and blood cultures remain poorly defined. Leads and blood cultures were obtained prospectively in 224 patients with suspected PSIs, and the results of cultures of blood and extravascular and intravascular lead fragments were compared. In 12.3% of the patients, no microorganism was found on the leads. Lead cultures with > or =1 microorganism cultured on the extravascular and intravascular fragments of the leads were found in 88.5% of the positive lead cultures. Infection was caused by Staphylococcus epidermidis and coagulase-negative staphylococci in 66.0% and 29.5%, respectively. Only 33 patients had positive blood cultures according to the Duke criteria with the same microorganism found by lead cultures in 30 cases. Infection was caused by multiple organisms in 39 (25%) patients. (1) Regardless of the clinical presentation, the extravascular and intravascular body of the lead is infected, even when the infection is local. More than one microorganism may be implicated. (2) Bacteriologic analyses must be performed on several segments of each implanted lead. (3) More than 2 positive blood cultures are a reliable clinical criterion for the diagnosis of pacemaker lead-related infection, but blood cultures alone are an insensitive method to identify the cause of infection. (4) Up to 50% of microorganisms isolated in a single blood culture are also recovered in lead cultures.