Epidemiology of community-associated methicillin-resistant Staphylococcus aureus in San Francisco children

Article type: Research Article

Authors: Hermos, Christina R. | Shiau, Rita | Hsiang, Michelle | Chambers, Henry F. | Pan, Erica^;

Affiliations: Department of Pediatrics, University of California San Francisco, San Francisco, CA, USA | Department of Public Health, Communicable Disease Control & Prevention Section, University of California San Francisco, San Francisco, CA, USA | Department of Medicine, Division of Infectious Diseases, University of California San Francisco, San Francisco, CA, USA | Department of Pediatrics, Division of Infectious Diseases, University of California San Francisco, San Francisco, CA, USA

Note: [] Correspondence: Dr. Erica Pan, Department of Public Health, Communicable Disease Control & Prevention Section, University of California San Francisco, 101 Grove Street, Room 204, San Francisco, CA 94102, USA. Tel.: +1 415 554 2652; Fax: +1 415 554 2854; E-mail: [email protected]

Abstract: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in children is increasing worldwide, yet limited prospective studies have assessed epidemiologic risk factors for CA-MRSA infection in children. Our aim is to describe the clinical and microbiological characteristics of and potential epidemiologic risk factors for pediatric CA-MRSA infection in San Francisco. S. aureus isolate information from subjects 0–18 years old were prospectively collected over 6~months. Demographics and clinical details were gathered for subjects by chart review. Patients and/or guardians were interviewed about underlying conditions and potential risk factors for CA-MRSA such as a) previous MRSA/skin or soft tissue infection (SSTI) in patient or household; b) direct or indirect exposure to healthcare setting (recent antibiotics, emergency room visits, chronic disease or healthcare worker in household); c) community exposures (daycare, team sports, history of homelessness/group home, injection drug use or incarceration). Among S. aureus isolates from 216 subjects, 180 isolates from 170 subjects had community-acquired SA, 85 (50%) of whom had CA-MRSA. 91% of CA-MRSA patients had a SSTI. CA-MRSA resistance to clindamycin and ciprofloxacin were 7.8% and 50% respectively. Compared to community-associated methicillin-sensitive Staphylococcus aureus (CA-MSSA) patients, a significantly higher proportion of CA-MRSA patients were African-American, a smaller proportion were Asian/Pacific Islander, and a larger proportion were hospitalized. Among deep SSTI, 60/62 (97%) were MRSA. Over 50% of CA-MRSA patients were < 4 years old. 97% of interviewed MRSA patients had at least one potential risk factor; 85% of whom had an exposure to healthcare setting, 47% had or lived with someone who had previous MRSA or SSTI; and 60% had a potential community exposure. Fifty percent had an underlying atopic condition. This pediatric population had a high prevalence of potential epidemiologic risk factors for CA-MRSA and underlying conditions. Future studies comparing exposures of patients with CA-MRSA to those with CA-MSSA are needed to determine if these exposures are unique to subjects with CA-MRSA in this population.

Keywords: Staphylococcus aureus, methicillin resistance, community-associated infections, soft tissue infections, risk factors

DOI: 10.3233/JPI-2009-0169

Journal: Journal of Pediatric Infectious Diseases, vol. 4, no. 3, pp. 247-259, 2009