ABSTRACTWater quality monitoring techniques that target microorganisms in the orderBacteroidalesare potential alternatives to conventional methods for detection of fecal indicator bacteria.Bacteroidalesand members of the genusBacteroideshave been the focus of microbial source tracking (MST) investigations for discriminating sources of fecal pollution (e.g., human or cattle feces) in environmental waters. For accurate source apportionment to occur, one needs to understand both the abundance ofBacteroidesin host feces and the survival of these host-associated microbial markers after deposition in the environment. Studies were undertaken to evaluate the abundance, persistence, and potential for growth ofBacteroidalesoriginating from poultry litter under oxic and anoxic environmental conditions.Bacteroidalesabundance, as determined by quantitative PCR (qPCR) with GenBac primers and probe, increased 2 to 5 log gene copies ml−1and 2 log gene copies g litter−1under most conditions during incubation of poultry litter in a variety of laboratory microcosm and field mesocosm studies. DNA sequencing of theBacteroidalesorganisms in the litter identified taxa with sequences corresponding exactly to the GenBac primer and probe sequences and that were closely related toBacteroides uniformis,B. ovatus, andB. vulgatus. These results suggest that MST studies using qPCR methods targetingBacteroidalesin watersheds that are affected by poultry litter should be interpreted cautiously. Growth ofBacteroidalesoriginating from poultry litter in environmental waters may occur whileBacteroidalesgrowth from other fecal sources declines, thus confounding the interpretation of MST results.
Decomposition of Leaves, Stems and Roots of Transgenic Aspen with the Xyloglucanase (sp-Xeg) Gene under Laboratory Microcosm Conditions