The 131st Annual Meeting (November 15-19, 2003) of APHA

Abstract #62807

Ralph Groves, MD¹, Cheryl L. Mason, MPH¹, Dave Boxrud², and James Cheek, MD, MPH¹. (1) National Epidemiology Program, Indian Health Service, 5300 Homestead Rd. NE, Albuquerque, NM 87110, 505-248-4226, ralph.groves@mail.ihs.gov, (2) Public Health Laboratory Division, Minnesota Department of Health, 717 Delaware St. Southeast, P.O. Box 9441, Minneapolis, MN 55440-9441

Background: Community-associated MRSA (CA-MRSA) is an emerging public health problem for both the American Indian/Alaska Native (AI/AN) and general US populations. CA-MRSA caused an outbreak of skin infections associated with sweat lodge use in AN communities, and an investigation of MRSA carriage rates in a rural AI community yielded higher than expected prevalence. The recent occurrence of four pediatric deaths (one American Indian) from systemic CA-MRSA infection demonstrates the consequences can be severe. We investigated a cluster of MRSA skin infections occurring in nine otherwise healthy newborns over an 8-month period at an IHS hospital to determine the source of their infections. Methods: We employed a case-control study to evaluate for potential hospital and community sources. Hospital staff (N=58) with potential for contact with case-patients and household members of case and control infants (N=80) underwent nasal sampling for MRSA and were assessed for risk factors. Pulsed-field gel electrophoresis (PFGE) was performed on cluster-associated MRSA isolates. Results: The only health-care worker (HCW1) colonized with MRSA was significantly more likely to be the primary caregiver for cases (seven of nine) in the peripartum period (OR = 63, 95% CI = 3.74-2984). MRSA isolates from seven cases and HCW1 displayed identical PFGE patterns (community-associated pattern MR391, Minnesota Department of Health laboratory). Additionally, HCW1 wore a nose stud; no other staff had nasal piercing. Repeat swabs from the nares and external piercing site of HCW1 grew MR391. Household sampling demonstrated MRSA carriage in two family members of HCW1 and the mother of one patient.

Learning Objectives:

At the conclusion of the session, the participant in this session will be able to:
• Recognize the importance of community-associated MRSA (ca-MRSA)as an emerging public health problem.
• Describe the epidemiology of ca-MRSA, particularly among AI/AN communities, and how it differs from the epidemiology of hospital-associated MRSA (ha-MRSA).
• Identify and evaluate strategies to prevent and contain further spread of ca-MRSA.

Keywords: Antibiotic Resistance, Outbreaks

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.