LAUSR

AIMS The DNA marker HF183 is a partial 16S rRNA gene sequence highly specific to human-associated Bacteroides including Bacteroides dorei. While HF183 is used to assess human fecal contamination in aquatic environments worldwide, little is known about the existence of HF183 and B. dorei in human microbiomes outside of the human gastrointestinal tract and feces. METHODS AND RESULTS Previously published human skin and urine microbiome datasets from 5 independent human body skin studies, the Human Microbiome Project (HMP), and three independent human urine studies were analyzed. The HF183 gene sequence was detected in all skin datasets, with the ratios of positive samples ranging from 0.5% to 36.3%. Popliteal fossa (knee), volar forearm and inguinal (groin) creases were identified as hot spots. HF183 was detected in 2 of 3 urine datasets, with ratios of positive samples ranging from 0% to 37.5%. All HF183-containing sequences from these datasets were classified as associated with B. dorei. CONCLUSIONS HF183 is widespread on human skin and present in urine. SIGNIFICANCE AND IMPACT OF STUDY Skin and urine microbiomes could be sources of HF183 to environmental waters. Such non-fecal sources of HF183 might explain low concentrations of HF183 in recreational waters when swimmers are present.