Background: The species-specific risk of cardiac device infection (CDI) among bacteremic patients is incompletely understood.
Methods: We conducted a prospective cohort study of hospitalized patients from 2004 to 2014 with an implantable CD and either S. aureus bacteremia (SAB) or gram negative bacteremia (GNB). Implantable CDs were defined as either cardiac valves, permanent pacemakers/defibrillators, or left ventricular assist devices (LVADs). CDI was defined by echocardiography, culture, or removal of the CD due to clinical suspicion of CDI. Multi-drug resistance (MDR) was defined as resistant to ³3 antibiotic classes.
Results: During the study period, a total of 306 patients with ³1 implantable CD developed either SAB (n=155 patients) or GNB (n=151 patients). Among the 306 patients, 83 had prosthetic valves, 168 had permanent pacemakers/defibrillators, 6 had LVADs, and 49 had > 1 device present. Overall, 50% of 155 patients with SAB and 13% of 151 patients with GNB had a CDI. Multivariable logistic regression analysis revealed that patients with either SAB (Odds ratio: 19.1, 95% CI 4.4-83) or Pseudomonas aeruginosa bacteremia (OR: 19.6, 3.2-121) had similar risks for CDI (Figure 1). By contrast, risk for CDI was lower in patients with bacteremia due to Serratia marcescens (7.22; 1.2-43), Enterobacter species (3.55, 0.43-29), Klebsiella species (2.13; 0.27-17), and other GN bacilli (0.85; 0.07-10). In the subset of patients with GNB, age (OR 0.89, 95% CI 0.84-0.95), and MDR species (11.3, 1.47-87.5) was associated with CDI. CDI in the SAB subset was associated with a surgical procedure within the last 30 days (2.66, 95% CI 1.09-6.47), male gender (0.46, 0.22-0.96), malignancy (0.25, 0.07-0.87), and hospital-acquisition of BSI (0.28, 0.11-0.73), but did not differ with methicillin susceptibility.
Figure 1: Microbiology of CDIs
Conclusion: Risk of CDI among bacteremic patients varies by species. CDI risk is highest in patients with bacteremia due to S. aureus or Pseudomonas. By contrast, it is lower in patients with bacteremia due to other species of GN bacilli.
F. Ruffin, Merck: Grant Investigator , Grant recipient
V. G. Fowler Jr, None