摘要
从广东省某市池塘采集商品规格(体重2 0～2 5kg)的草鱼(Ctenoharyngodonidellus),利用加有头孢哌酮的麦康凯琼脂培养基,对其肠道中细菌进行选择性分离与鉴定。结果显示,12尾草鱼的肠道中,5尾可分离到具有以下特征的细菌:两端生鞭毛,菌体弯曲似海鸥状,革兰氏染色阴性,过氧化氢酶、氧化酶、尿酶和精氨酸双水解酶阳性,还原硝酸盐,不发酵、氧化或同化葡萄糖、甘露醇等15种常见的糖醇类,细菌形态、生化特性与报道的香港海鸥型菌相似,阳性率为41 7%。但在肌肉中未分离到此菌。进行分离细菌的16SrRNA基因序列分析,与GenBank中登录的4株香港海鸥型菌序列的同源性为99 7%～99 9%。由菌的培养特征、形态特点、理化特性、16SrRNA基因序列分析等多元鉴定的结果表明,从草鱼肠道中选择分离的细菌为香港海鸥型菌。药敏实验结果表明,所分离菌株对奥格门丁和亚胺培南的敏感性与报道的香港海鸥型菌有一定区别。
Laribacter hongkongensis,a novel genus and species associated with community-acquired gastroenteritis and traveler's diarrhea was first isolated in Hongkong in 2001 from the blood and empyemic pus of a cirrhotic patient with bacteremia and empyema. Then it was sought in faecal specimens of six patients with community-acquired gastroenteritis. And then it was isolated in freshwater fishes such as grass carp(Ctenoharyngodon idellus),big head carp(Aristichthys nobilis), mud carp (Cirrhina molitorella) and largemouth bass (Micropterus salmoides) and also in minced freshwater fish meat by Lau et al in 2004. Since L. hongkongensis is harmful to human health, the research of L. hongkongensis is necessary. In this study, Cefoperazone Macconkey agar was used for selective isolation of bacteria from the intestine of grass carp (body weight 2.0-2.5kg) cultured in some farms of Guangdong Province. Five strains of typical shaped bacteria colonies were obtained named GRA1, GRA2, GRB1, GRB2 and GRC1 from five grass carp respectively. They were identified by biochemical characteristics, scanning and transmission electron microscope and 16S rRNA gene sequence analyses. The sensitivities of the 5 strains to 14 antibiotics were tested by filter paper diffusion method. The results showed that the culture-positive of the typical shaped bacteria colonies was 41.7% (5/12) from the intestines of the fish. All strains could grow on normal nutrition agar, as colonies about 1mm in diameter at 48h incubation at 28℃. And their colonies were non-hemolytic, gray and 1.2-1.5mm in diameter on 5% sheep blood agar. The forms of all colonies on the three kinds of agar were circular with smooth face and swelled-like center. All the five strains were motile with bipolar flagellae,seagull in shape,1.6-2.5μm in length, 0.43-0.57μm in diameter under scanning and transmission electron microscope. They were gram-negative bacteria, oxidase, catalase,urease and arginine dihydrolase positive. And they reduced nitrate but did not ferment, oxidize, or
出处
《中国水产科学》
CAS
CSCD
北大核心
2005年第3期307-313,共7页
Journal of Fishery Sciences of China
关键词
香港海鸥型菌
草鱼
选择分离
鉴定
Laribacter hongkongensis
Ctenoharyngodon idellus
selective isolation
identification
