Table 2.
Multivariate ORs for risk of methicillin resistance and multidrug resistance among Staphylococcus aureus and methicillin-resistant S. aureus isolates recovered from cultures of samples obtained while the person was as an outpatient or within 72 h of hospital admission.
| Outcome, exposure | No. of patient isolates | OR (95% CI) | P | % MRSA or % R-MRSAa |
|---|---|---|---|---|
| Risk of methicillin resistance among S. aureus (N = 4685) | ||||
| Previous LTCF residence | 55 | 2.1 (1.1–3.9) | .02 | 27.3 |
| Previous hospitalization, duration | ||||
| 0–6 months | 1061 | 3.5 (2.9–4.3) | <.0001 | 23.3 |
| >6–12 months | 234 | 2.2 (1.5–3.2) | <.0001 | 15.8 |
| >12–24 months | 185 | 1.5 (0.9–2.4) | .11 | 11.4 |
| >24–36 months | 68 | 0.7 (0.3–2.1) | .57 | 5.9 |
| None in previous 3 years | 3137 | Reference | … | 7.8 |
| Risk of multidrug resistance among MRSA (N = 553) | ||||
| Previous LTCF residence | 15 | 3.5 (1.2–10.5) | .02 | 60.0 |
| Previous hospitalization, duration | ||||
| >0–6 months | 247 | 1.7 (1.1–2.5) | .009 | 37.7 |
| >6–12 months | 37 | 0.4 (0.2–1.1) | .083 | 13.5 |
| >12–24 months | 21 | 0.3 (0.1–1.4) | .12 | 9.5 |
| >24–36 months | 4 | 0.9 (0.1–9.6) | .98 | 25.0 |
| None in previous 3 years | 244 | Reference | … | 25.8 |
NOTE. LTCF, long-term care facility; MRSA, methicillin-resistant S. aureus.
a
For the first outcome, the percentages (% MRSA) refer to the percentage of S. aureus isolates that were MRSA, and for the second outcome, the percentages (% R-MRSA) refer to the percentage of MRSA isolates that were multidrug resistant.