Feature | |
---|---|
Sucrose fermentation | sucrose-positive – yellow and matte colonies |
Possess acid phosphatase | change of color of the colony from yellow to pink in ammonium hydroxide vapors |
Feature | |
---|---|
Reduction of sulphites to sulphides | black or grey colonies |
Motility | none |
Reduction of nitrate to nitrites | orange/red-colored medium after the addition of the Nessler reagent |
Lactose fermentation | orange or yellow-colored medium with lactose (acidification of the medium and gas formation) |
Protease formation | gelatine liquefaction |
Characteristics of |
TSC ISO/CD 6461-2:2002 | mCP Directive 98/83/EC |
---|---|---|
Number of all confirmed colonies | 466 | 381 |
Typical colonies, confirmed positive (true positive) | 150 | 107 |
Atypical colonies, confirmed positive (false negative) | 33 | 11 |
Typical colonies, confirmed negative (false positive) | 196 | 79 |
Atypical colonies, confirmed negative (true negative) | 87 | 184 |
Typical colonies, non-detection error | 0.18 | 0.09 |
Performance parameters | TSC ISO/CD 6461-2:2002 | mCP Directive 98/83/EC |
---|---|---|
Sensitivity | 82.0% | 90.7% |
Specificity | 30.7% | 70.0% |
Selectivity | 32.2% | 28.1% |
False negative rate | 27.5% | 5.6% |
False positive rate | 56.6% | 42.5% |
Efficiency | 50.9% | 76.4% |