Epidemiology and Infection

Original Papers

Community-associated methicillin-resistant Staphylococcus aureus is prevalent in wounds of community-based injection drug users

E. LLOYD-SMITHa1a2, M. W. HULLa1a3, M. W. TYNDALLa1a3, R. ZHANGa1, E. WOODa1a3, J. S. G. MONTANERa1a3, T. KERRa1a3 and M. G. ROMNEYa4a5 c1

a1 British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, BC, Canada

a2 School of Public and Population Health, University of British Columbia, Vancouver, BC, Canada

a3 Department of Medicine, University of British Columbia, Vancouver, BC, Canada

a4 Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada

a5 Medical Microbiology Laboratory, St Paul's Hospital, Vancouver, BC, Canada

SUMMARY

Injection drug users (IDUs) have an elevated risk for carriage of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). Cutaneous injection-related infections are common in IDUs but detailed studies are few. Based on a subsample of 218 individuals from a community-recruited cohort of IDUs at a supervised injection facility, we investigated the microbiology and related antibiotic susceptibility profiles of isolates from 59 wounds. Twenty-seven percent of subjects had at least one wound and 25 (43%) were culture positive for S. aureus alone [14 MRSA and 11 (19%) methicillin-susceptible (MSSA) isolates]. Sixteen of 18 MRSA isolates were classified as community associated (CA) by the presence of genes encoding for PVL. MRSA and MSSA occurred in mixed infection with other organisms on three and six occasions, respectively. All CA-MRSA isolates were susceptible to tetracycline, vancomycin and linezolid but only 13% were susceptible to clindamycin compared to 63% of MSSA isolates. The frequency of CA-MRSA is a cause for concern in wound infection in the IDU setting.

(Accepted February 12 2010)

Correspondence:

c1 Author for correspondence: M. G. Romney, MD, FRCPC, DTM&H, Medical Microbiologist, Medical Director, Infection Prevention and Control, St Paul's Hospital/Providence Health Care, Vancouver, BC, Canada. (Email: mromney@providencehealth.bc.ca)

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