Table 1 Biochemical characteristics of Yersinia ruckeri isolates from fish in aquaculture in north west Germany
Test | Reference strain (DSM 18,506) | Number of the field isolates tested positive (%) | ||||
|---|---|---|---|---|---|---|
Total | Isolates from rainbow trouts in H | Isolates from rainbow trouts in N | Isolates from rainbow trouts in L | Isolates from other fish in L | ||
|  |  | (n = 82) | (n = 8) | (n = 49) | (n = 19) | (n = 6) |
Motility | + | 16 (19.5) | 1 (12.5) | 4 (8.2) | 6 (31.6) | 5 (83.3) |
Nitrate reduction | + | 77 (93.9) | 8 (100.0) | 47 (95.9) | 17 (89.5) | 5 (83.3) |
Nitrate reduction * | - | 72 (87.8) | 8 (100) | 45 (91.8) | 14 (73.7) | 5 (83.3) |
Citrate utilization | + | 59 (72.0) | 6 (75.0) | 32 (65.3) | 15 (78.9) | 6 (100) |
Citrate utilization * | + | 50 (61.7) | 6 (75.0) | 29 (59.2) | 10 (52.6) | 5 (83.3) |
Voges-Proskauer | - | 48 (58.5) | 5 (62.5) | 29 (59.2) | 10 (52.6) | 4 (66.7) |
Voges-Proskauer* | - | 52 (63.4) | 4 (50.0) | 37 (75.5) | 7 (36.8) | 4 (66.7) |
Gelatine hydrolysis | - | 81 (98.8) | 8 (100.0) | 49 (100.0) | 19 (100.0) | 5 (83.3) |
Gelatine hydrolysis* | - | 77 (93.9) | 8 (100.0) | 48 (98.0) | 16 (84.2) | 5 (83.3) |
Methyl-red | + | 76 (92.7) | 7 (87.5) | 48 (98.0) | 18 (94.7) | 3 (50.0) |
Tween 20 hydrolysis | + | 16 (19.5) | 1 (12.5) | 4 (8.2) | 6 (31.6) | 5 (83.3) |
Tween 80 hydrolysis | + | 16 (19.5) | 1 (12.5) | 4 (8.2) | 6 (31.6) | 5 (83.3) |
Acid from sorbitol | - | 5 (6.1) | 1 (12.5) | 1 (2.0) | 0 (0.0) | 3 (50.0) |