559. Risk factors and Outcomes of Gram-negative Cardiac Device Infections
Session: Poster Session: Hospital-acquired and Transplant Infections
Friday, October 30, 2009: 12:00 AM
Room: Poster Hall A
Background: Cardiac device (permanent pacemakers and implantable cardioverter-defibrillators) related infections (CDI) are predominantly due to gram-positive organisms. The risk factors and outcomes of CDI due to gram-negative bacteria have not been reported.
Methods: We performed a retrospective study of all patients with CDI at our institution from 1/1/00-12/31/08. Data were collected on demographics, underlying conditions, Charlson Comborbidity score, type of infection (local, systemic, or both), microbiology (results of blood cultures and local cultures), complications (endocarditis, metastatic infections) and outcomes. Patients with gram-negative and gram-positive infections were compared using χ2 analysis, Mann-Whitney U test, and Student’s t-test.
Results: Among 61 patients with CDI, 50 (82%) had local infections, 20 (32.8%) had systemic infections only and 9 (14.8%) had both. Blood cultures were performed in 54 (88.5%) patients and were positive in 21 (38.9%). Local cultures (pocket site and/or leads) were positive in an additional 32 cases. Infections included the following: 41 (67.2%) gram-positive (30 S. aureus, 10 coagulase-negative staphylococci, 1 Corynebacterium), 12 gram-negative (19.7%), and 8 culture-negative (13.1%). Patients with gram-negative and gram-positive infections were not different in terms of age, gender, race, or underlying conditions and the median time to infection after device placement. Gram-negative infections were more likely to be local (100% vs. 73.1% of gram-positive cases; p=0.05) and less frequently associated with systemic infections (8.3% vs. 45.2%, p=0.02). All six patients with vegetations on the tricuspid valve or the pacemaker leads (n=6) and all three deaths due to CDI (p=0.3) occurred in patients with gram-positive infections.
Conclusion: Patients with gram-negative and gram-positive CDI are similar in terms of time to infection, underlying conditions, and outcomes. CDI due to gram-negative organisms usually present with local infections and rarely cause systemic manifestations.
Leonard Johnson, MD, Jinson Jose, MD, Medicine, St. John Hospital and Medical Center, Grosse Pointe Woods, MI, Riad Khatib, MD, Susan Szpunar, PhD, St. John Hospital and Medical Center, Grosse Pointe Woods, MI and  J. Jose, None..
S. Szpunar, None..
R. Khatib, None. 
L. Johnson,
Pfizer Role(s): Speaker's Bureau, Received: Speaker Honorarium.