a Civil, Environmental & Sustainable Engineering, National Science Foundation Water & Environmental Technology Center, Arizona State University, Tempe, AZ 85287-5306, USA.
Can J Microbiol. 2013 Dec;59(12):771-7. doi: 10.1139/cjm-2013-0518. Epub 2013 Oct 24.
Bacteroides molecular markers have been used to identify human fecal contamination in natural waters, but recent work in our laboratory confirmed cross-amplification of several human-specific Bacteroides spp. assays with fecal DNA from fish. For identification of unique molecular markers, Bacteroides from human (n = 4) and fish (n = 7) fecal samples were cultured and their identities were further confirmed using Rapid ID 32A API strips. The 16S rDNA from multiple isolates from each sample was PCR amplified, cloned, and sequenced to identify unique markers for development of more stringent human-specific assays. In human feces, Bacteroides vulgatus was the dominant species (75% of isolates), whereas in tilapia feces, Bacteroides eggerthii was dominant (66%). Bacteroides from grass carp, channel catfish, and blue catfish may include Bacteroides uniformis, Bacteroides ovatus, or Bacteroides stercoris. Phylogenic analyses of the 16S rRNA gene sequences showed distinct Bacteroides groupings from each fish species, while human sequences clustered with known B. vulgatus. None of the fish isolates showed significant similarity to Bacteroides sequences currently deposited in NCBI (National Center for Biotechnology Information). This study expands the current sequence database of cultured fish Bacteroides. Such data are essential for identification of unique molecular markers in human Bacteroides that can be utilized in differentiating fish and human fecal contamination in water samples.
拟杆菌分子标记已被用于鉴定天然水中的人类粪便污染，但我们实验室最近的研究证实，几种人类特异性拟杆菌检测方法与鱼类粪便 DNA 存在交叉扩增。为了鉴定独特的分子标记，我们培养了来自人类（n=4）和鱼类（n=7）粪便样本的拟杆菌，并使用 Rapid ID 32A API 条带进一步确认了它们的身份。从每个样本的多个分离株中扩增了 16S rDNA，并进行克隆和测序，以鉴定用于开发更严格的人类特异性检测方法的独特标记。在人类粪便中，脆弱拟杆菌是优势物种（75%的分离株），而在罗非鱼粪便中，埃格特拟杆菌是优势物种（66%）。草鱼、斑点叉尾鮰和蓝鳃太阳鱼的拟杆菌可能包括普通拟杆菌、卵形拟杆菌或粪拟杆菌。16S rRNA 基因序列的系统发育分析显示，每个鱼类物种的拟杆菌都有明显的分组，而人类序列与已知的脆弱拟杆菌聚类。鱼类分离株与目前在 NCBI（美国国家生物技术信息中心）中储存的拟杆菌序列没有显著相似性。这项研究扩展了现有的养殖鱼类拟杆菌的序列数据库。这些数据对于鉴定人类拟杆菌中独特的分子标记至关重要，这些标记可用于区分水样中的鱼类和人类粪便污染。
