Isolation,Identification and Pathogenicity Analysis of Riemerella anatipestifer Strain LC1 and CX1
The aim of this study was to isolate,purify,identify and analyze the pathogenicity of the strains from the disease material of Muscovy ducks which suspected to be infected with infectious serositis from a farm in Putian,Fujian Province,China.Brain and liver tissues of 10-day-old diseased Muscovy ducks were collected for strain isolation and purification,and 16S rDNA PCR identification and serotyping were conducted,respectively.The isolates were subjected to 16S rDNA sequencing and genetic evolutionary analyses,and their drug resistance and pathogenicity to ducklings were determined.The results showed that 2 strains of Riemerella anatipestifer type 11 were obtained and named as LC1 and CX1.The 16S rDNA sequences of LC1 and CX1 showed that the isolates were in the same evolutionary branch as the reference strains of Riemerella anatipestifer Fujian strain RAf115 and Shanghai strain Yb2,with 99.9％similarity.The isolates were sensitive to β-lactams,chloramphenicol,and tetracyclines,but less sensitive to macrolides and aminoglycosides.The pathogenicity assay indicated that the mortality of the two strains(1.3 × 106 CFU·mL-1)was 100％,and the lethal ducks showed the typical Riemer's disease with pericarditis,perihepatitis,and enlarged spleen.The pathology results of the HE staining showed that the red-white medullary boundary of the spleen of the lethal ducks disappeared,and a large number of necrotic foci were presented.In addition,myocardial fibers of lethal ducks from the two isolates showed tear-like lesions.These datas demonstrated that two strains of Riemerella anatipestifer type 11 LC1 and CX1 were isolated and characterized,MLST to be ST111 and ST114,respectively,which provide reference basis for the prevention and control of Riemerella anatipestifer disease and subsequent research.
万方数据
维普
