Table 1.
Evaluation of the Algorithm to report positive and negative plates with a detection threshold of 100 CFU/ml.
| Sample type | Media | N Se | Se | CI (se) | N Sp | Sp | CI (Sp) | N PPV | PPV | CI (PPV) | N NPV | NPV | CI (NPV) | N Prev | Prev | CI (Prev) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All | All | 1562 | 97.1 | (96.2, 97.8) | 234 | 93.6 | (90.1, 96.5) | 1531 | 99.0 | (98.4, 99.5) | 265 | 82.6 | (77.9, 87) | 1796 | 87.0 | (85.4, 88.6) |
| All | CHROM | 582 | 93.6 | (91.7, 95.6) | 119 | 95.0 | (90.7, 98.4) | 551 | 98.9 | (98, 99.6) | 150 | 75.3 | (67.8, 82.2) | 701 | 83.0 | (80.2, 85.6) |
| All | COL | 703 | 98.9 | (98, 99.6) | 24 | 83.3 | (67.9, 96.6) | 699 | 99.4 | (98.7, 99.9) | 28 | 71.4 | (54.2, 87.5) | 727 | 96.7 | (95.3, 97.9) |
| All | MAC | 277 | 99.6 | (98.6, 100) | 91 | 94.5 | (89.5, 98.9) | 281 | 98.2 | (96.6, 99.6) | 87 | 98.9 | (96.1, 100) | 368 | 75.3 | (70.9, 79.9) |
| Isolates | All | 1292 | 97.1 | (96.2, 98) | 100 | 96.0 | (91.4, 99.1) | 1259 | 99.7 | (99.4, 99.9) | 133 | 72.2 | (64.7, 79.6) | 1392 | 92.8 | (91.5, 94.1) |
| Isolates | CHROM | 476 | 93.9 | (91.5, 96) | 89 | 96.6 | (92.3, 100) | 450 | 99.3 | (98.4, 100) | 115 | 74.8 | (66.4, 82.2) | 565 | 84.2 | (81.2, 87.1) |
| Isolates | COL | 584 | 98.8 | (97.8, 99.7) | 5 | 80.0 | (33.3, 100) | 578 | 99.8 | (99.5, 100) | 11 | 36.4 | (7.7, 66.7) | 589 | 99.2 | (98.3, 99.8) |
| Isolates | MAC | 232 | 99.6 | (98.7, 100) | 6 | 100.0 | (61, 100) | 231 | 100.0 | (98.4, 100) | 7 | 85.7 | (50, 100) | 238 | 97.5 | (95.4, 99.2) |
| Urines | All | 270 | 96.7 | (94.5, 98.5) | 134 | 91.8 | (86.6, 96) | 272 | 96.0 | (93.2, 98.1) | 132 | 93.2 | (88.7, 97) | 404 | 66.8 | (62.4, 71.8) |
| Urines | CHROM | 106 | 92.5 | (86.9, 97.2) | 30 | 90.0 | (77.8, 100) | 101 | 97.0 | (93.2, 100) | 35 | 77.1 | (63.2, 90.3) | 136 | 77.9 | (70.6, 84.6) |
| Urines | COL | 119 | 99.2 | (97.3, 100) | 19 | 84.2 | (65.2, 100) | 121 | 97.5 | (94.3, 100) | 17 | 94.1 | (81.2, 100) | 138 | 86.2 | (80.4, 91.3) |
| Urines | MAC | 45 | 100.0 | (92.1, 100) | 85 | 94.1 | (88.1, 98.7) | 50 | 90.0 | (80.8, 97.9) | 80 | 100.0 | (95.4, 100) | 130 | 34.6 | (26.9, 43.1) |
Abbreviations: All: all sample types or all media types; CHROM: BD BBL CHROMagar Orientation; COL: BD Columbia Agar with 5% Sheep Blood; MAC: BD MacConkey II Agar; N Se: Number of sample analyzed for sensitivity; Se: Sensitivity; CI (Se): 95% confidence interval for Se; N Sp: Number of sample analyzed for specificity; Sp: Specificity; CI (Sp): 95% confidence interval for Sp; N PPV: Number of sample analyzed for PPV; PPV: positive predictive value; CI (PPV): 95% confidence interval for PPV; N NPV: Number of sample analyzed for NPV; NPV: Negative predictive value; CI (NPV): 95% confidence interval for NPV; N Prev: Number of sample analyzed for Prev (i.e. total number of samples per condition); Prev: Prevalence; CI (Prev): 95% confidence interval for Prev.