Microbial diagnosis of infection and colonization of cardiac implantable electronic devices by use of sonication

OBJECTIVES: The clinical utility of sonication as an adjunctive diagnostic tool for the microbial diagnosis of cardiac implantable device-associated infections (CIDAIs) was investigated. METHODS: The implants of 83 subjects were investigated, 15 with a CIDAI and 68 without a clinical infection. Clinical data were analyzed prospectively and sonication fluid cultures (83 patients, 100%) and traditional cultures (31 patients, 37.4%) were performed RESULTS: Generator pocket infection and device-related endocarditis were found in 13 (86.7%) and four (26.7%) subjects, respectively. The mean numbers of previous technical complications and infections were higher in the infected patients compared to the non-infected patients (8 vs. 1, p<0.001; 2 vs. 0, p<0.031, respectively). The sensitivity and specificity for detecting CIDAI was 73.3% (11/15) and 48.5% (33/68) for sonication fluid culture, and 26.7% (4/15) and 100% (16/16) for traditional culture (p<0.001), respectively. A higher number of organisms were identified by sonication fluid than by tissue culture (58 vs. 4 specimens; p<0.001). The most frequent organisms cultured were Gram-positive cocci (66.1%), mainly coagulase-negative staphylococci (35.5%). Thirty-five (51.5%) non-infected subjects were considered colonized due to the positive identification of organisms exclusively through sonication fluid culture. CONCLUSIONS: Sonication fluid culture from the removed cardiac implants has the potential to improve the microbiological diagnosis of CIDAIs.