Identification of human fecal pollution:: detection and quantification of the human specific HF183 Bacteroides 16S rRNA genetic marker with real-time PCR

A real-time PCR assay for the detection and quantification in fecal and environmental samples of the human specific HF183 Bacteroides 16S rRNA genetic marker previously found by Bernhard & Field (2000a), was developed and proved to be more sensitive than the conventional HF183 PCR. The limit of detection in canal water was 1.94 x 10(2) copies per mul DNA extract and the limit of quantification was 5.83 x 10(2) copies per mul DNA extract. The intra- and intervariability coefficients of the real-time assay were less than 1% and 3%, respectively. The amount of marker copy number present per g of wet human feces varied from 10(2) to 10(8) between different individuals. The amount of marker copy number present in wastewater treatment plant influent varied from 10(8) to 10(9) per liter. The marker persisted upto 6 days at 28degreesC. Whereas, the limit of detection was not reached after 24 days of incubation at 4 and 12degreesC.