TABLE 2.
Sensitivities, specificities, PPVs, and NPVs of Spectra MRSA and SBA for detection of MRSA at 24 and 48 h for the individual clinical trial sites
| Clinical trial site and incubation period (h) | Medium | No. of samples with the following result: |
Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) | |||
|---|---|---|---|---|---|---|---|---|---|
| TPa | FP | TN | FN | ||||||
| Site A | |||||||||
| 24 | Spectra MRSA | 29 | 0 | 91 | 0 | 100.0 | 100.0 | 100.0 | 100.0 |
| SBA | 29 | 0 | 91 | 0 | 100.0 | 100.0 | 100.0 | 100.0 | |
| 48 | Spectra MRSA | 29 | 0 | 91 | 0 | 100.0 | 100.0 | 100.0 | 100.0 |
| SBA | 29 | 0 | 91 | 0 | 100.0 | 100.0 | 100.0 | 100.0 | |
| Site B | |||||||||
| 24 | Spectra MRSA | 29 | 2 | 171 | 1 | 96.7 | 98.8 | 93.5 | 99.4 |
| SBA | 28 | 0 | 173 | 2 | 93.3 | 100.0 | 100.0 | 98.9 | |
| 48 | Spectra MRSA | 30 | 4 | 169 | 0 | 100.0 | 8.2 | 88.2 | 100.0 |
| SBA | 28 | 0 | 173 | 2 | 93.3 | 100.0 | 100.0 | 98.9 | |
| Site C | |||||||||
| 24 | Spectra MRSA | 15 | 0 | 155 | 1 | 93.8 | 100.0 | 100.0 | 99.4 |
| SBA | 16 | 0 | 155 | 0 | 100.0 | 100.0 | 100.0 | 100.0 | |
| 48 | Spectra MRSA | 16 | 1 | 154 | 0 | 100.0 | 99.4 | 94.1 | 100.0 |
| SBA | 16 | 0 | 155 | 0 | 100.0 | 100.0 | 100.0 | 100.0 | |
| Site D | |||||||||
| 24 | Spectra MRSA | 31 | 0 | 239 | 3 | 91.2 | 100.0 | 100.0 | 98.8 |
| SBA | 29 | 0 | 239 | 5 | 85.3 | 100.0 | 100.0 | 97.6 | |
| 48 | Spectra MRSA | 32 | 5 | 234 | 2 | 94.1 | 97.9 | 86.5 | 99.2 |
| SBA | 32 | 1 | 238 | 2 | 94.1 | 99.6 | 97.0 | 99.2 | |
a
A TP result is defined as a denim blue colony on Spectra MRSA that demonstrated characteristic features on the gold standard media (as described in Materials and Methods) and that was identified as MRSA by the Oxoid PBP 2′ test and the oxacillin Etest (≥4 μg/ml).