Clinical utility of sonication for diagnosing infection and colonization of cardiovascular implantable electronic devices.

Our study aimed to evaluate the sensitivity of the sonication tool for the microbiological diagnosis of cardiovascular implantable electronic device infections (CIEDIs). The extracted cardiac implants of 52 patients were assessed: 19 with CIEDI and 33 with elective generator replacement or revision without clinical infection. Sonication fluid culture of explanted CIEDs yielded higher numbers of microorganisms than pocket tissue or swab cultures. The sensitivity of sonication fluid culture was significantly higher than that of pocket swab and tissue culture for microbiological diagnosis of CIEDI. The microorganisms isolated most frequently via sonication of explanted CIEDs were Gram-positive cocci (70%), of which 50% was coagulase-negative Staphylococcus. Sonication fluid culture detected colonization in 36.4% of the non-infected patients. Sonication fluid culture represents a promising diagnostic strategy with increased sensitivity compared to conventional culture methods for microbiological diagnosis of cardiac devices associated with infection and colonization.

Molecular and Serological Diagnostic Approach to Define the Microbiological Origin of Blood Culture-Negative Infective Endocarditis.

Blood culture-negative infective endocarditis (BCNIE) poses a significant challenge in determining the best antibiotic regimen for this life-threatening infection, which should be treated with as specific and effective a regimen as feasible. The goal of this study was to determine the prevalence of BCNIE among definite infective endocarditis (IE) cases and to study the impact of a molecular and serological diagnostic approach in defining the microbiological origin of BCNIE. This study included 94 definite IE cases. Serum and blood samples from BCNIE patients were tested using serological, broad-range PCR, and sequencing assays. Valve tissue sections obtained from 42 operated patients were subjected to culture and molecular studies. BCNIE accounted for 63 (67%) of the cases. Of these cases, blood PCR followed by sequencing could diagnose 11 cases. Zoonotic infective endocarditis was detected in 7 (11%) patients by serology and PCR (four Brucella, two Bartonella, and one Coxiella). Sequencing of valve PCR bands revealed 30 positive cases. Therefore, the percentage of BCNIE with unidentified etiology was reduced from 67% to 27.7% through a combination of all diagnostic procedures utilized in our study. Blood and valve PCR and sequencing assays are valuable techniques for the etiological diagnosis of BCNIE, especially in cases with previous antibiotic therapy. However, these tests should be used as part of a larger diagnostic strategy that includes serology, microscopy, and valve culture. The use of an automated blood culture system, and proper blood culture collection before ordering antibiotics, will guide IE etiological diagnosis.