Table 2.
Comparison of sensitivity, specificity, and positive predictive value and negative predictive value, including the 95% confidence intervals, as well as numbers of very major and major errors of the different tests for the 50 CNS strainsa
| Method and drug(s) | % Sensitivityb (95% CI)f | % Specificityc (95% CI) | % PPV (95% CI) | % NPV (95% CI) | No. of: |
|
|---|---|---|---|---|---|---|
| VMEsd | MEse | |||||
| Disk diffusion | ||||||
| FOX | 90.9 (71.8; 96.6) | 100 (80.5; 100) | 100 (88.1; 100) | 85 (58.1; 94.6) | 3 | 0 |
| MOX | 100 (89.4; 100) | 100 (80.5; 100) | 100 (88.1; 100) | 100 (80.5; 100) | 0 | 0 |
| MOX + FOX | 100 (89.4; 100) | 100 (80.5; 100) | 100 (88.1; 100) | 100 (80.5; 100) | 0 | 0 |
| PC30 panel | ||||||
| OXA MIC | 100 (89.4; 100) | 94.1 (71.3; 99.8) | 97.1 (84.7; 99.9) | 100 (79.4; 100) | 0 | 1 |
| FOX test | 90.9 (75.7; 98.1) | 94.1 (71.3; 99.8) | 96.8 (83.3; 99.9) | 84.2 (60.4; 96.6) | 3 | 1 |
| OXA MIC + FOX test | 100 (89.4; 100) | 88.2 (63.5; 98.5) | 94.2 (80.2; 99.3) | 100 (78.2; 100) | 0 | 2 |
The different tests for the 50 CNS strains included cefoxitin (FOX) and moxalactam (MOX) alone or in combination in the disk diffusion method and the determination of oxacillin MIC (OXA MIC) and the FOX test alone or in combination in the PC30 panel. PPV, positive predictive value; NPV, negative predictive value.
Percentage of the 33 mecA-positive isolates for which positive test results were obtained.
Percentage of the 17 mecA-negative isolates for which negative test results were obtained.
False susceptibility.
False resistance.
95% exact binomial confidence intervals are shown.