TABLE 2.
Performance of CHROMagar (direct plating [DP]) method for the detection of total and pathogenic Vibrio parahaemolyticus and Vibrio vulnificusa
| Sample type/gene | No. of samples |
% (lower value, upper value) |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Total | True positive | False positive | False negative | True negative | Sensitivity | Specificity | False-positive rate | False-negative rate | Accuracy | |
| Oyster/tlh | 110 | 90 | 3 | 14 | 3 | 87 (78, 92) | 50 (19, 81) | 50 (19, 81) | 13 (7, 20) | 86 (78, 91) |
| Water/tlh | 110 | 58 | 2 | 46 | 5 | 56 (46, 65) | 71 (35, 92) | 29 (2, 55) | 44 (35, 54) | 57 (45, 66) |
| Oyster/tdh | 110 | 35 | 1 | 34 | 40 | 51 (39, 62) | 98 (86, 100) | 2 (0, 7) | 49 (38, 61) | 68 (60, 77) |
| Water/tdh | 110 | 12 | 5 | 30 | 64 | 29 (17, 44) | 93 (84, 97) | 7 (1, 13) | 71 (58, 84) | 69 (60, 77) |
| Oyster/trh | 110 | 18 | 2 | 30 | 60 | 38 (25, 52) | 97 (88, 100) | 3 (0, 7) | 63 (49, 76) | 71 (62, 79) |
| Water/trh | 110 | 7 | 3 | 30 | 71 | 19 (9, 35) | 96 (88, 99) | 4 (0, 8) | 81 (69, 93) | 70 (62, 79) |
| Oyster/vvhA | 110 | 93 | 0 | 17 | 0 | 85 (76, 90) | 0 (IDb ) | 0 (ID) | 15 (9, 22) | 85 (78, 91) |
| Water/vvhA | 110 | 63 | 1 | 46 | 0 | 58 (48, 67) | 0 (0, 71) | 100 (ID) | 42 (33, 51) | 57 (48, 66) |
| Oyster/vcgC | 110 | 31 | 1 | 71 | 7 | 30 (22, 40) | 88 (51, 99) | 13 (0, 31) | 70 (61, 78) | 35 (26, 43) |
| Water/vcgC | 110 | 21 | 1 | 77 | 11 | 21 (14, 31) | 92 (62, 100) | 8 (0, 22) | 79 (71, 87) | 29 (21, 38) |
a
True positive, positive by both methods; false positive, positive only by CHROMagar method; false negative, positive only by MPN-PCR method; true negative, negative by both methods. CHROMagar-negative and MPN-PCR-positive results were interpreted as CHROMagar false negative. MPN-PCR-negative and CHROMagar-positive results were considered CHROMagar false positive. Samples positive and negative for V. parahaemolyticus and V. vulnificus by both methods were considered true positive and true negative, respectively.
b
ID, indeterminate.