The results of the drug susceptibility test showed that the resistance rate of five strains to 14 types of drug susceptibility tests exceeded 50.00%. Y1301 is resistant to 9 drugs: CH, E, CAZ, K, AMP, PIP, CMZ, K, P, S300, SXT, and C. The drug resistance rate is 56.25% (9/16). No. 2 is resistant to 11 drugs: AZI, CH, E, AN, CAI, AMP, CMZ, P, K, P, E, S300, and SXT, with a drug resistance rate of 68.75% (11/16). No. 3 has resistance to 10 drugs, AZI, CH, PIP, AMP, K, P, S300, SXT, and C, with a drug resistance rate of 62.50% (10/16). No. 4 has resistance to 9 drugs: CH, AN, CAZ, TE, TM, CMZ, P, SXT, and C. The drug resistance rate is 56.25% (9/16). No. 5 is resistant to five drugs, AZI, CH, E, AMP, P, and S300, with a resistance rate of 31.25% (5/16). The results of the drug sensitivity test showed that the isolate was highly sensitive to two drugs, gentamicin and tobramycin, but resistant to penicillin. Therefore, these high-sensitivity drugs can be selected for prevention and control in production. This result is different from the drug sensitivity characteristics of Yersinia isolated from spot fork tails infected by Y.e. The possible reason for the difference in drug sensitivity characteristics is that the strains in different regions and different water environments are exposed to the effects of different drug environmental effects, resulting in differences in drug resistance variations.
Because biochemical characteristics of Y.e are more complex, accurate biochemical test results are essential to identify Y.e. The isolates tested in this test were sucrose-positive, raffinose-negative, VP (26 ℃) positive, and VP (37 ℃) negative, all of which were in line with typical Ye characteristics. In addition, the biochemical characteristics of other bacteria belonging to the genus Enterobacteriaceae were used. The biochemical characteristics of indole-positive and fermented sucrose can be distinguished from Yersinia pseudotuberculosis. At the same time, according to the biochemical characteristics of the isolates and the typical culture characteristics on CIN-1 and modified Y medium, it can be clearly distinguished from the genera Proteus, Salmonella and Shigella. Finally, according to the Berger's Bacteria Identification Manual and Cai Miaoying's "Enterobacteriaceae Retrieval Line", the isolate was determined to be Y.E. Because this bacterium is a psychrophilic pathogen, it brings great difficulty to the isolation and identification. According to the National Standard for "Yersinia enterocolitica Test" (GB4789.8-2008) issued by the Ministry of Health of the People's Republic of China, by using the alkali treatment method in combination with CIN-1 to select media and improve Y, a better Separate selection effects was succeeded. The detection medium for naked carp's solid organ Y.e shortened the inspection time by 3d, saved about 40% of raw materials, and improved the detection rate. On the one hand, it demonstrates the superiority of this method, and on the other hand, it also suggests the carrier rate in local naked carps. Five Y.e were isolated from the organs and gills of 75 naked carps collected, and the positive rate was 6.67% (5/75).