Abstract 9718: Rising Antibiotic Resistance: Changes in Microbial Patterns in Cardiac Implantable Electronic Device Infections
Introduction: As the number of cardiac implantable electronic devices (CIEDs) implanted has risen, so has the number of CIED infections requiring extraction. We evaluated the type and sensitivity of microbial pathogens associated with CIED infections over a 16-year period.
Hypothesis: We hypothesized that antibiotic resistance in CIED infections has increased since 1995.
Methods: We reviewed 202 cases of infected CIEDs requiring extraction. The database was divided into two groups: Group I included the years 1995-2002 and Group II included 2003-2010. Each case was classified as resistant or sensitive. Resistance was present if cultures revealed a methicillin- or vancomycin-resistant organism; otherwise the organism was classified as sensitive. Groups were compared using chi-square analysis, with a p-value < 0.05 considered statistically significant.
Results: CIED pocket infection or erosion was present in 62.9% of cases, persistent bacteremia with or without obvious endocarditis in 28.7%, and both in 8.4%. Resistance was seen in 13.7% of cases (3/41) in Group I, increasing to 34.2% of cases (55/161) in Group II (p<0.0005). Cultures of hardware (device and/or lead material) increased the yield of resistant organisms to 36.6% (p<0.0001 compared to Group I). The rate of infection with methicillin-resistant Staph Aureus (MRSA) more than tripled in Group II (16.8%) as compared to Group I (4.9%). There were a total of 5 in-hospital deaths. In-hospital mortality for resistant infections was 6.4%, compared to 0.7% for sensitive organisms (p<0.05). Patients with organisms identified only from hardware samples represented 15.7% of the cases of resistant infections.
Conclusions: The incidence of antibiotic-resistant device infections has more than doubled over the past 16 years. Device infections with MRSA have tripled since 1995. Resistant infections are associated with a significantly higher in-hospital mortality. Over 15% of resistant infections were found based on hardware culture alone, stressing the importance of this practice for identifying resistance and tailoring antibiotic therapy for efficacy. More data is needed to aid in the selection of appropriate prophylactic antibiotics for new implants and generator changes.
- © 2011 by American Heart Association, Inc.