Table 2.
Compiled PZA results for 14 susceptible and 3 resistant isolatesa tested in duplicate by 9 laboratoriesb.
| Outcome | Predicted total | Number (%) by inoculation method | ||
|---|---|---|---|---|
| BD | A | C | ||
| True-susceptible | 252 | 186 (61.2) | 226 (76.4) | 230 (79.2) |
| True-resistant | 54 | 52 (17.1) | 42 (14.2) | 42 (14.5) |
| False-resistant | 0 | 64 (21.1) | 17 (5.7) | 8 (2.8) |
| False-susceptiblec | 0 | 2 (0.7) | 11 (3.7) | 9 (3.1) |
|
| ||||
| Total valid tests | 306 | 304d | 296d | 289d |
| Timed Oute | 0 | 2 (0.7) | 10 (3.3) | 17 (5.6) |
|
| ||||
| Total testsf | 306 | 306 | 306 | 306 |
aResults from three isolates categorized as “inconclusive” not included. bResults for one laboratory excluded due to <70% reproducibility. c18 of the false-susceptible results occurred in isolate 17. The remaining 4 occurred in isolate 14, all in the same laboratory. dDenominators used to calculate outcome percentage. eTest result not achieved within the 21-day instrument protocol. 19 of these events occurred in one strain (isolates 11 and 23). fDenominator used to calculate Timed-Out percentages.