Civil and Environmental Engineering Department, Villanova University, 800 Lancaster Ave, Villanova, PA 19085, USA.
Water Sci Technol. 2009;60(10):2659-68. doi: 10.2166/wst.2009.656.
The primary objective of this study was to investigate the effects of choice of the indicator organisms on the accuracy of classifying the fatty acid methyl ester (FAME) profiles of the known-source library isolates. First, a known-source library containing the FAME profiles of Enterococcus isolates cultured from six different possible sources of microbial pollution was developed. A total of 511 Enterococcus isolates were profiled: 120 isolates from sewage samples representing humans; 69 from dairy and cattle cow; 74 from chicken; 76 from swine; 94 from deer; and 78 from waterfowl. Classification of known-source Enterococcus isolates into their respective host categories resulted with a 66% average rate of correct classification (ARCC) in a six-way discriminant analysis (DA). The ARCC increased to 75% when the individual hosts were pooled into larger categories of human, livestock, and wildlife. The accuracy was 80% when isolates of human origin were discriminated against those of non-human origins. Recently, several studies reported the ARCCs for various classification schemes associated with total coliform (TC), fecal coliform (FC), and Escherichia coli of the known-source isolates. When the accuracy of classification of Enterococcus isolates was compared to those reported for TC, FC, and E. coli isolates, the lowest ARCCs were associated with classification of E. coli isolates, the only species level indicator organism among the four compared. It was found that the degree of discrimination increases as the indicator becomes more inclusive of bacteria from different genus. In addition, random cluster formation analysis indicates that known-source libraries with isolate numbers between 300 and 500 might be sufficient for MST by FAME.
本研究的主要目的是探讨选择指示生物对分类已知来源文库分离物脂肪酸甲酯 (FAME) 图谱准确性的影响。首先，开发了一个包含 6 种不同微生物污染来源的粪肠球菌 FAME 图谱的已知来源文库。共对 511 个粪肠球菌分离物进行了分析：120 个来自人类污水样本；69 个来自奶牛和牛；74 个来自鸡；76 个来自猪；94 个来自鹿；78 个来自水禽。将已知来源的粪肠球菌分离物按其各自的宿主类别分类，在 6 向判别分析 (DA) 中平均正确分类率 (ARCC) 为 66%。当将个体宿主归入更大的人类、家畜和野生动物类别时，ARCC 增加到 75%。当将人类来源的分离物与非人类来源的分离物区分开来时，准确性达到 80%。最近，有几项研究报告了与总大肠菌群 (TC)、粪大肠菌群 (FC) 和已知来源分离物的大肠杆菌相关的各种分类方案的 ARCC。当将粪肠球菌分离物的分类准确性与 TC、FC 和大肠杆菌分离物的报告进行比较时，与大肠杆菌分离物相关的 ARCC 最低，大肠杆菌是这四种比较的指示生物中唯一的种水平指示生物。结果发现，随着指示生物对不同属细菌的包容性增加，区分度增加。此外，随机聚类分析表明，对于 MST 而言，具有 300 到 500 个分离物数量的已知来源文库可能就足够了。
