Community-associated Methicillin-Resistant Staphylococcus aureus in Outpatients, United States, 1999–2006

• Main Authors: Eili Klein, David L. Smith, Ramanan Laxminarayan
• Format: Article
• Language: English
• Published: Centers for Disease Control and Prevention 2009-12-01
• Series: Emerging Infectious Diseases
• Subjects: Methicillin-resistant Staphylococcus aureus; community-associated MRSA; hospital-associated MRSA; phenotypic susceptibility; outpatients; staphylococci
• Online Access: https://wwwnc.cdc.gov/eid/article/15/12/08-1341_article
• ISSN: 1080-6040; 1080-6059

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a major problem in US hospitals already dealing with high levels of hospital-associated MRSA (HA-MRSA). Using antimicrobial drug susceptibility data for 1999–2006 from The Surveillance Network, we characterized the relationship between outpatient and inpatient levels of CA-MRSA nationally. In outpatients, the frequency of CA-MRSA isolates has increased >7× during 1999–2006, which suggests that outpatients have become a major reservoir for CA-MRSA. However, contrary to results in other reports, although CA-MRSA increases are associated with decreases in the frequency of HA-MRSA in hospitals, the decreases are only modest. This finding suggests that instead of replacing HA-MRSA in the hospital, CA-MRSA is adding to the overall presence of MRSA already found within the hospital population.