Table 3.
Analytical performance of assays for detection of Ambler Class A β-lactamases-producing Enterobacterales isolates in positive blood cultures.
| Method | Result | Class A b-lactamase* | Sensitivity (95% CI) | Specificity (95% CI) | PPV (95% CI) | NPV (95% CI) | Accuracy (95% CI) | Youden | |
|---|---|---|---|---|---|---|---|---|---|
| Resistant (n = 37) | Susceptible (n = 113) | ||||||||
| BL-REDTM | Positive | 31 | 1 | 83.8% (68.9–92.4) | 99.1% (95.2–99.8) | 96.9% (84.3–99.5) | 94.9% (89.4–97.7) | 95.3% | 82.9% |
| Negative | 6 | 112 | |||||||
| β-LACTATM | Positive | 37 | 0 | 100% (90.6–100) | 100% (96.7–100) | 100% (90.6–100) | 100% (96.7–100) | 100% | 100% |
| Negative | 0 | 113 | |||||||
*
IMI-producing E. cloacae strain susceptible to 3GC was excluded.
PPV, Positive Predictive Value; NPV, Negative Predictive Value.