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

• Infected cardiac devices were more associated with previous local complications.
• Gram-positive cocci (CoNS, Streptococcus, and S. aureus) were frequently isolated.
• Compared to traditional cultures, sonication was more sensitive and less specific.
• Sonication identified a higher number of organisms in colonized cardiac devices.
• Previous use of antibiotic reduces microbial identification, mainly tissue cultures.

SummaryObjectivesThe clinical utility of sonication as an adjunctive diagnostic tool for the microbial diagnosis of cardiac implantable device-associated infections (CIDAIs) was investigated.MethodsThe 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 performedResultsGenerator 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.ConclusionsSonication fluid culture from the removed cardiac implants has the potential to improve the microbiological diagnosis of CIDAIs.