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Application of leftover sample material from waterborne protozoa monitoring for the molecular detection of Bacteroidales and fecal source tracking markers
Citation:
RYU, H., T. TRAN, M. W. WARE, B. Iker, S. GRIFFIN, A. EGOROV, T. Edge, N. Newmann, E. N. VILLEGAS, AND J. W. SANTO-DOMINGO. Application of leftover sample material from waterborne protozoa monitoring for the molecular detection of Bacteroidales and fecal source tracking markers. JOURNAL OF MICROBIOLOGICAL METHODS. Elsevier Science Ltd, New York, NY, 86(3):337-343, (2011).
Impact/Purpose:
To inform the public.
Description:
In this study, we examined the potential for detecting fecal bacteria and microbial source tracking markers in samples discarded during the concentration of Cryptosporidium and Giardia using USEPA Method 1623. Recovery rates for different fecal bacteria were determined using spiked samples and environmental waters and using different group-specific and host-specific PCR assays. Bacteroidales recovery ranged from 59 to 71% for aliquots of supernatant collected after the elution step. The recovery of human-specific Bacteroidales from sludge spiked samples was 54% in the elution step. An additional 1-7% Bacleroidales DNA was recovered after the immunomagnetic separation step, while recovery from the pellet left after the immunomagnetic separation of protozoa parasites was substantially lower. Comparison of Bacteroidales 16S rRNA gene sequences from elution and immunomagnetic separation discarded samples indicated that the distribution of clones was not statistically different, suggesting that there were no recovery biases introduced by these steps. Ruminant-specific Bacteroidales and fecal indicator bacteria (i.e., enterococci,) were also detected in environmental samples collected from different geographic locations. Overall, the results of this study demonstrated the potential application of leftover sample fractions that are currently discarded for the PCR detection of fecal bacterial indicators and molecular source tracking.
