The objective of this study was to investigate the host-specific differences in fatty acid
methyl ester (FAME) profiles of fecal coliforms (FC). A known-source library was
constructed with 314 FC isolates cultured from 6 possible sources of fecal pollution; 99
isolates from sewage; 29 from bovine; 29 from poultry; 50 from swine; 46 from waterfowl;
and 61 from deer. It was found that the hydroxy FAMEs 12:0 2OH, 12:0 3OH, and 14:0 2OH
were exclusively associated with isolates of human origin. On the other hand, 3 saturated
FAMEs, 10:0, 15:0, and 18:0 were found only in isolates from non-human sources, 15:0 being
associated with livestock samples only. In addition to the presence of these signature
FAMEs, the mean relative masses of 16:1 o7c and 16:1 ISO/14:0 3OH were significantly
different between the isolates of human and non-human origins. A linear discriminant
function differentiated FC isolates of human origin from those of livestock and wildlife
origin at 99% accuracy. These results strongly suggest that the FAME profiles of FC show
statistically significant host specificity and may have the potential to be used as a
phenotypic microbial source tracking tool.