九龙江口沉积物TCBS(Thiosulfate Citrate Bile Salts Sucrose)菌群的分布

摘要

[Objective]To investigate potential pathogens in waters of Xiamen from Jiulong River, and to provide useful information for the prevention and control of potential pathogen infections. [Methods] All samples were spread on Thiosulfate Citrate Bile Salts Sucrose (TCBS) agar plates, and then incubated at 26 ± 1℃ for 24 ±2 h. In total 158 TCBS strains were isolated from TCBS agar plates and pure-cultivated on 2216E agar plates. All strains were identified using the 16S rRNA gene- Restriction fragment length polymorphism (RFLP) , 16S rRNA sequence analysis, GenBank database Basic Local Alignment Search Tool (BLAST) and phylogenetic analysis. [Results] The results show that 158 TCBS strains from the sediments of Jiulong River estuary were classfied as 7 genus, which were Pseudomonas (28%), Aeromonas (24%) , Pseudoalteromonas (19%) , Shewanella (13%) , Bacillus (11%) , Vibrio (4%) and Psychrobacter (1%). The composition and distribution of TCBS bacteria groups varied with stations. Non-halophilic or haloduric bacteria groups were dominant in the upper area of Jiulong River estuary, and halophilic and haloduric bacteria were dominant in the lower area, which characterized a typical estuary feature. The salinity played a key role in the distribution of TCBS groups. Vibrios did not constitute a significant proportion (6% - 19%) of the total TCBS strains at different stations, and most of the them distributed at the lower region. [Conclusion] There were a lot of potential pathogens in Jiulong River estuary. Aeromonas, a typical genus of halotolerant bacteria, was the potentially terrigenous bacteria contamination to the waters of Xiamen. Most Vibrio specieses were marine aborigines, which was not directly contaminated from the runoff of Jiulong River.%[目的]调查九龙江流域对厦门海域潜在的病原菌“污染”,为相关侵染性病害的预防和控制提供有价值的资料.[方法]通过TCBS(Thiosulfate Citrate Bile Salts Sucrose)培养基从九龙江河口沉积物中分离到158株细菌,应用16S rRNA基因-RFLP(限制性酶切图谱多样性分析)及16S rRNA基因序列分析等方法对158株细菌进行分子鉴定.[结果]研究结果表明九龙江口沉积物中分布的TCBS菌群分别属于7个属,其中假单胞菌属(Pseudomonas)占28％,气单胞菌属(Aeromonas)占24％,假交替单胞菌属(Pseudoalteromonas)占19％,希瓦氏菌属(Shewanella)占13％,芽孢杆菌属(Bacillus)占11％,弧菌属(Vibrio)占4％,嗜冷杆菌属(Psychrobacter)占1％.不同站位TCBS菌群的组成及各菌群的相对差异明显,其中上游区域以非嗜盐或耐盐细菌为主,下游区域以嗜盐细菌和耐盐细菌为主,具有典型的河口细菌分布特征.盐度对各TCBS菌群的分布具有重要的影响.弧菌在整个河口区所占的比例不大(6％-19％)且集中在下游区域.[结论]九龙江口存在大量的条件致病菌,其中以气单胞菌属为代表的耐盐菌,对厦门海域存在陆源性污染的风险；绝大多数弧菌属于海洋土著细菌,正常情况下(非流行性弧菌病期间)非来源于九龙江冲淡水的直接污染.