1252. Community-Onset Staphylococcus aureus Wound and Blood Infections from 2005-2010 in the US Department of Defense National Healthcare System
Session: Poster Abstract Session: Staphylococcal Resistance and Epidemiology
Saturday, October 22, 2011
Room: Poster Hall B1
Background: Recent population-based data for community-onset (CO) S. aureus skin and soft tissue infections (SSTIs) and bacteremia are largely unknown. This study sought to characterize the burden of these CO S. aureus infections in the US Department of Defense (DoD) healthcare system.

Methods: The study population included all DoD TRICARE beneficiaries seen at military treatment facilities from Jan 2005 through Dec 2010. All annual first positive S. aureus wound/abscess and blood cultures occurring in ambulatory settings or within 72 hours of hospital admission were identified from electronic medical record databases. Methicillin-resistant S. aureus (MRSA) isolates were defined by standard microbiologic techniques. Incidence rates per 100,000 person-years of follow-up (PY) were adjusted for age and gender and standardized to US Census data from 2000.

Results: A total of 79,801 wound/abscess and 2,094 blood annual first positive S. aureus cultures were identified, during approximately 56 million PY of observation, providing overall crude rates of 141 and 3.73 per 100,000 PY for wound/abscess infection and bacteremia, respectively. The adjusted rate for wound/abscess MRSA infections was 75/100,000 PY (95% CI, 73-76) in 2005, increased significantly to 106/100,000 PY (95% CI, 104-109) in 2008, then significantly decreased to 63/100,000 PY (95% CI, 62-65) in 2010. The adjusted annual rates of MRSA bacteremia also decreased significantly from 1.51/100,000 PY (95% CI, 1.27-1.76) in 2005 to 0.97/100,000 PY (95% CI, 0.79-1.16) in 2010. Similar annual trends were seen for MSSA wound/abscess infection and bacteremia. The rates of MRSA and MSSA wound/abscess infections were highest in those aged 18-24 years, on active duty, and in the southern US; while rates of MRSA and MSSA bacteremia were highest for those 0-4 and >65 years of age, but similar by active duty status and geographic region.

Conclusion: The burden of CO S. aureus SSTIs and bacteremia from both MRSA and MSSA remains substantial in this relatively young and healthy population. Although the annual rates continue to fluctuate, the incidence of CO S. aureus SSTIs and bacteremia may be decreasing, similar to recent trends observed for healthcare-associated MRSA infections.

Subject Category: C. Clinical studies of bacterial infections and antibacterials including sexually transmitted diseases and mycobacterial infections (surveys, epidemiology, and clinical trials)

Michael Landrum, MD1,2, Charlotte Neumann, MPH3, Courtney Cook, MS3, Uzo Chukwuma, MPH3, Duane Hospenthal, MD, PhD1, Michael Ellis, MD4 and Clinton K. Murray, MD5, (1)Brooke Army Medical Center, Fort Sam Houston, TX, (2)Infectious Disease Clinical Research Program, Uniformed Services University, Bethesda, MD, (3)EpiData Center Department, Navy and Marine Corps Public Health Center, Portsmouth, VA, (4)Uniformed Services University of the Health Sciences, Bethesda, MD, (5)Brooke Army Medical Center, Ft. Sam Houston, TX


M. Landrum, None

C. Neumann, None

C. Cook, None

U. Chukwuma, None

D. Hospenthal, None

M. Ellis, Forest Laboratories: Speaker's Bureau, Speaker honorarium

C. K. Murray, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.