SONICATION OF REMOVED DEVICES FOR MICROBIOLOGICAL DIAGNOSIS OF CARDIAC DEVICE INFECTIONS

BackgroundMicrobiologic diagnosis is essential for the optimal management of cardiac device infections (CDIs). Sonication of the devices before culture may represent an attractive tool to improve the diagnosis CDIs. We evaluated the role of ultrasonication for the detection of causative organisms of CIDs. diagnosis of CDIs.Methods A total of 24 explanted devices (7 generators, 7 grafts and 10 lead tips) were obtained from 11 patients with CDIs (9 with pocket infections, 2 with pacemaker-related endocarditis). Devices were inoculated in tripticase soy broth (TSB) for 24 h and analyzed for bacterial growth with traditional methods. In addition, they were were vortexed for 30 s and then sonicated for 5 min at a frequency >20kHz using the Ultrasonik 300 bath (Ney, BarkMeyer Division, Yucaipa, CA).Results Among the explanted generators, 6/7 (85%) cultured in TSB and 7/7 (100%) after sonication grew bacteria. The grafts cultured in TSB and after sonication were positive in 75% and 100%, respectively. The overall bacterial growth of lead tips (atrial and/or ventricular) was 7/10 (70%): 5/10 were positive after being cultured in TSB whereas 7/10 after sonication (table1). The bacterial counts was >1000000UFC/ml in 6/7 generator sonication fluids whereas in the one which grew only after sonication the count was 3000UFC/ml. Cell count was 1 fold lower in the lead tips sonication fluids. Swabs cultures were positive in only 2 subjects. ConclusionsSonication of the devices improves the microbiological diagnosis of CDIs both in pocket infections and in device-related endocarditis. This is of particular concern in subjects who have been treated with antibiotic therapy.