Abstract: A dominant bacterium was isolated from brain of eruptive diseased red tilapia Oreochromismossambicus×O.niloticus collected from a farm in Zhangzhou, Fujian Province in 2017 using traditional method, and identified by morphological observation and 16S rRNA gene sequence analysis.Genetic characteristics of the isolated strain were analyzed by molecular serotyping, multilocus sequence typing (MLST) and virulence-related gene sequencing, and the susceptibility of the isolated strain to 26 kinds of antimicrobial drugs was measured using Kirby-Bauer disc diffusion method to seek out the aetiological agent and to provide a theoretical foundation for effective treatment of the disease.It was found that the strain isolated from the diseased fish was a non-hemolysis (γ-hemolysis), type Ⅰa-ST7 Streptococcusagalactiae with pathogenicity, and virulence-related genotype of bac+-bca+-cfb+-hylB+-fbsA+-fbsB+-lmb--scpB- -cpsE+-sip+.The strain was shown to be highly sensitive to 13 kinds of antibiotics including cephalosporin drugs, doxycycline, and ampicillin, intermediately sensitive to 4 antibiotics including fleroxacin, penicillin G, and polymyxin B, and resistant to 9 antibiotics including neomycin, gentamicin, and amikacin.The finding provides a theoretical basis for the epidemiology, vaccine development and disease treatment of Streptococcosisin red tilapia in Fujian Province.
王巧煌. 福建红罗非鱼源无乳链球菌的分离鉴定及其分子特征[J]. 大连海洋大学学报, 2019, 34(1): 63-69.
WANG Qiao-huang. Isolation, identification, and molecular characteristics of Streptococcus agalactiae from cultured red tilapia in Fujian Province. Journal of Dalian Ocean University, 2019, 34(1): 63-69.
2019, Vol. 34 
