杂交鳢(斑鳢♀×乌鳢♂)溃疡病病原菌的分离、鉴定及其防治中草药的筛选

针对2014年发生在广东省中山市三角镇的杂交鳢(Channa maculate♀×Channa argus♂)溃疡病,开展了病原的分离鉴定和致病性研究、药物敏感性试验和中草药抑菌、杀菌试验。实验从杂交鳢脾脏中分离到一个菌株S8,该菌株为革兰氏阴性短杆菌,菌体直、两端钝圆。对该菌进行生理生化鉴定、16S rRNA和gyr B序列和系统发育分析结果表明,此致病菌株为温和气单胞菌(Aeromonas sobria)。人工感染试验结果显示,当人工感染剂量大于1.0×107CFU/尾时,能引起杂交鳢100%发病死亡。抗菌药物敏感性试验表明,温和气单胞菌S8对阿米卡星、头孢拉啶等药物高度敏感,对头孢他啶、氨苄西林、复方新诺明等抗菌药物不敏感。应用二倍稀释法测定了18种中草药对温和气单胞菌S8的最小抑菌浓度和最小杀菌浓度,结果显示:石榴皮、五倍子、黄芩对温和气单胞菌S8的抑菌杀菌效果最佳,其次为山茱萸、地榆和芦荟。

Isolation and identification of Aeromonas sobria S8 from hybrid snakehead (Channa maculate♀× Channa argus♂) with ulcerative disease and screening of Chinese herbal medicine for prevention and treatment

In 2014, ulcer disease incident occurred in a hybrid snakehead (Channa maculate♀× Channa argus♂) farm located in Zhongshan, Guangdong Province. A bacterial strain named S8 was isolated from the spleen of infected hybrid snakehead. The results of artificial infection test showed that dosage over 1. 0 × 107 CFU would cause 100% mortality of hybrid snakehead. The strain was gram-negative short bacilli, with a straight body and blunt ends. The artificial infection test, physiological and biochemical analysis, 16S rRNA and gyrB genes sequence and phylogenetic analysis all showed that the strain belonged to Aeromonas sobria. Drug sensitivity test showed that S8 was highly sensitive to amikacin and ce-phradine, and was not sensitive to ceftazidime, ampicillin and cotrimoxazole. The minimal inhibitory concentration and minimum bactericidal concentration of the 18 kinds of Chinese herb against S8 were determined by tube double dilution method. The results suggested that the best inhibitory and bactericidal effects were obtained by Punica granatum, Gallnut and Radix Scutellariae, followed by Fructus Corni, Radix Sanguisorbae and Aloe.