Abstract
We investigated coliphages from various fecal sources, including humans and animals, for microbial source tracking in South Korea. Both somatic and F+-specific coliphages were isolated from 43 fecal samples from farms, wild animal habitats, and human wastewater plants. Somatic coliphages were more prevalent and abundant than F+ coliphages in all of the tested fecal samples. We further characterized 311 F+ coliphage isolates using RNase sensitivity assays, PCR and reverse transcription-PCR, and nucleic acid sequencing. Phylogenetic analyses were performed based on the partial nucleic acid sequences of 311 F+ coliphages from various sources. F+ RNA coliphages were most prevalent among geese (95%) and were least prevalent in cows (5%). Among the genogroups of F+ RNA coliphages, most F+ coliphages isolated from animal fecal sources belonged to either group I or group IV, and most from human wastewater sources were in group II or III. Some of the group I coliphages were present in both human and animal source samples. F+ RNA coliphages isolated from various sources were divided into two main clusters. All F+ RNA coliphages isolated from human wastewater were grouped with Qbeta-like phages, while phages isolated from most animal sources were grouped with MS2-like phages. UniFrac significance statistical analyses revealed significant differences between human and animal bacteriophages. In the principal coordinate analysis (PCoA), F+ RNA coliphages isolated from human waste were distinctively separate from those isolated from other animal sources. However, F+ DNA coliphages were not significantly different or separate in the PCoA. These results demonstrate that proper analysis of F+ RNA coliphages can effectively distinguish fecal sources.