TABLE 2.
Risk factors for community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections
| Risk categories and factors | References |
|---|---|
| High-risk populations | |
| Young people | Age distribution for CA-MRSA younger than for hospital-associated MRSA (38) High rate of CA-MRSA in children younger than two years (61) CA-MRSA more common in Canadian children than adults (62) |
| Minority populations | |
| Native or Aboriginal, and African-American people | Higher risk in Aboriginal communities in midwestern United States (23,63,64) Higher risk in Alaskan natives (65) More common in African-Americans (61,66,67) Aboriginal communities in Canada (48,49,62,68,69) |
| Athletes – mainly those involved in contact sports | Outbreaks in football teams (70–74) Outbreak in wrestling team (75) Outbreaks in other competitive sports (71,76) |
| Intravenous drug users | San Francisco intravenous drug users (77) Western Canadian report of USA300 strain outbreak documents higher risk in intravenous drug users (78) |
| Men who have sex with men | CA-MRSA described in HIV-positive population of men who have sex with men (79,80) |
| Military personnel | 3% of United States army soldiers colonized (81) |
| Inmates of correctional facilities | Reports of outbreaks in United States prisons (82–86) Two outbreaks (total of 10 inmates) in Hamilton, Ontario (87) |
| Previous positive MRSA cultures | |
| MRSA carriage | Colonized soldiers more likely to get CA-MRSA disease (81) |
| Past MRSA infection | Prior abscess a risk factor for CA-MRSA (88) |
| Medical history | |
| Chronic skin disorder | Dermatological condition most common underlying medical disorder for CA-MRSA infection (38) Classroom contact of an index CA-MRSA case had chronic dermatitis (51) |
| Recurrent or recent antibiotic use | Antibiotic use associated with CA-MRSA infection in rural Alaska (65) |
| Environmental risks | |
| Low socioeconomic status | Medically underserved populations at higher risk of CA-MRSA (88,89) |
| Overcrowding | Close contact implicated in jail outbreak (84), neonatal intensive care unit transmission (90) |
| Contact with colonized pet | Family dog a source of recurrent infection (91) |
| Veterinary work | Cases documented in veterinarians working with horses (92–94), small animal veterinarians (95,96) and pig farmers (97) |