ENVR 182 |
| 16S rRNA genes of certain Bacteroides spp. are host-specific and may act as biomarkers in distinguishing sources of fecal pollution. Examination of the abundance of all or specific Bacteroides spp. may, thus, be essential for performing fecal source tracking. To do so, a new molecular method, termed hierarchical oligonucleotide primer extension (HOPE), is developed to determine relative abundance of Bacteroides spp. present in fecal microbiota and wastewaters. Genomic DNA in feces of humans and swines and in wastewaters were extracted, and total bacterial 16S rRNA genes were PCR-amplified and used as a DNA template in HOPE. Ten oligonucleotide primers were designed to detect a total of six Bacteroides spp. at different hierarchical levels (domain, order, cluster and species), arranged and used in three multiplexing HOPE reactions. Using species-specific primers, B. vulgatus, B. thetaiotaomicron, B. caccae, B. uniformis and B. fragilis were individually detected in human feces and at abundances down to 0.29% of PCR-amplified 16S rRNA genes. Bacteroidales in human feces was further observed to account for 34% of PCR-amplified 16S rRNA genes and was six- and three-fold, respectively, higher than that observed in swine fecal microbiota and in wastewaters. Besides providing qualitative and quantitative analyses of biotic contaminants, HOPE has also shown clear advantages in terms of its throughput, versatility, specificity and sensitivity. Therefore, by further complementing this method, which determines abundances of host-specific Bacteroides spp., to conventional fecal indicator tests, a better understanding of fecal contamination in drinking water sources can potentially be achieved. |
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Sensors for Detection and Quantification of Contaminants in Drinking Water and the Environment
1:30 PM-5:10 PM, Wednesday, April 9, 2008 Morial Convention Center -- Rm. 235, Oral
Division of Environmental Chemistry |