Table 2.
Occurrence of nasal carriage, mean daily prevalence and carriage states for Staphylococcus aureus outcomes among 22 industrial hog operation workers based on 327 nasal swabs, North Carolina
| Carriage states, N (%) | |||||
|---|---|---|---|---|---|
| Outcome | Ever carriage N* (%) |
Mean daily prevalence (% (range)) | Persistent | Intermittent | Non-carrier |
| S. aureus | 19 (86.4) | 65.3 (47.4–72.7) | 12 (54.5) | 7 (31.8) | 3 (13.6) |
| scn-negative S. aureus† | 16 (72.7) | 50.6 (36.8–56.8) | 10 (45.5) | 6 (27.3) | 6 (27.3) |
| scn-positive S. aureus | 6 (27.3) | 14.7 (10.5–18.2) | 2 (9.1) | 4 (18.2) | 16 (72.7) |
| MRSA‡§ | 1 (4.5) | 4.0 (0.0–4.5) | 1 (4.5) | 0 | 21 (95.5) |
| MDRSA§ | 10 (45.5) | 32.7 (21.1–36.4) | 6 (27.3) | 4 (18.2) | 12 (54.5) |
| scn-negative MDRSA† | 9 (40.9) | 31.6 (21.1–36.4) | 6 (27.3) | 3 (13.6) | 13 (59.1) |
| scn-positive MDRSA | 1 (4.5) | 1.1 (0–2.3) | 0 | 1 (4.5) | 21 (95.5) |
*It was possible for participants to carry both scn-positive and scn-negative S. aureus and MDRSA during the study period; therefore, the sum of these subclassifications may not equal the total number of participants ever colonised by S. aureus and MDRSA.
†scn-negative isolates were considered to be livestock associated.
‡All MRSA isolates were scn-negative.
§MRSA and MDRSA are subsets of S. aureus.
MDRSA, multidrug-resistant S. aureus; MRSA, methicillin-resistant S. aureus.