Development and small-scale validation of a novel pigeon-associated mitochondrial DNA source tracking marker for the detection of fecal contamination in harvested rainwater

摘要

AbstractThe current study was aimed at designing and validating (on a small-scale) a novel pigeon mitochondrial DNA (mtDNA) microbial source tracking (MST) marker for the detection of pigeon fecal matter in harvested rainwater. The pigeon mtDNA MST marker was designed to target the mtDNA Cytochromebgene by employing mismatch amplification mutation assay kinetics. The pigeon marker was validated by screening 69 non-pigeon and 9 pigeon fecal samples. The host-sensitivity of the assay was determined as 1.00 while the host-specificity of the assay was 0.96. Harvested rainwater samples (n=60) were screened for the prevalence of the marker with the mtDNA Cytochromebmarker detected in 78% of the samples. Bayes' theorem was applied to calculate the conditional probability of the marker detecting true pigeon contamination and the marker subsequently displayed a 99% probability of detecting true pigeon contamination in the harvested rainwater samples. In addition, the mtDNA Cytochromebmarker displayed high concurrence frequencies versus heterotrophic bacteria (78.3%),E. coli(73.3%), total coliforms (71.1%) and fecal coliforms (66.7%). This study thus validates that targeting mtDNA for the design of source tracking markers may be a valuable tool to detect avian fecal contamination in environmental waters.Graphical abstractDisplay OmittedHighlights•Pigeons are sources of fecal contamination of harvested rainwater.•Mitochondrial DNA MST marker specific to pigeons was designed using MAMA kinetics.•The marker was highly pigeon-sensitive (1.00) and -specific (0.96).•The marker showed a 99% probability of detecting true pigeon fecal contamination.•Targeting mtDNA for the design of avian source tracking markers is a valuable tool.