Gram-Negative Bacterial Infections in Cardiac Implantable Electronic Devices: Insights from a Retrospective Analysis of Multidrug-Resistant and Non-Multidrug-Resistant Isolates

Cardiac implantable electronic device (CIED) infections caused by Gram-negative bacteria are uncommon but potentially life-threatening. This study examined patients with Gram-negative CIED infections, investigating the clinical characteristics of patients harboring multidrug-resistant (MDR), versus non-MDR, isolates. A retrospective observational analysis was conducted at two tertiary Greek University Hospitals from 2015 to 2020. Patients were identified through microbiological cultures from device-related sites (pocket, lead, generator), with infections classified as MDR or non-MDR based on antimicrobial susceptibility profiles. Comprehensive data were collected, including demographic characteristics, clinical parameters, procedural details-on both the last device procedure and subsequent extraction procedure-infection-related findings, and microbiological profiles. In total, 18 patients were identified, with an equal distribution of 9 MDR and 9 non-MDR cases. The study population had a median age of 78 years, with 33.3% female patients, and a median Charlson Comorbidity Index of four. <i>Pseudomonas aeruginosa</i> was the most prevalent isolated species. Comparative analysis revealed that MDR patients had higher median SOFA (Sequential Organ Failure Assessment) scores (2 vs. 0, <i>p</i> = 0.07), longer time to device extraction (50% vs. 88.9% extracted within one month, <i>p</i> = 0.079), and higher blood culture positivity (80% vs. 37.5%, <i>p</i> = 0.135). Despite similar demographic characteristics, MDR infections demonstrated more complex clinical profiles, with a trend towards increased disease severity.