Unexpected Prevalence of -Positive in the Animas River, Durango, Colorado.

Since 2014, biology students at Fort Lewis College have studied the water quality of the Animas River in Durango, Colorado. Environmental microbiology and molecular biology techniques have been employed to study isolates from the river and to define characteristics of the bacteria related to public health. was found in the river, as well as in culverts and tributary creeks that drain into the river within the Durango city limits. Concentrations of in the river occasionally exceeded the US EPA guideline of 126 CFU per 100 mL for recreational water use. Many of the isolates were able to be grown at 45 °C, an indication of mammalian origin. Unexpectedly, 8% of the isolates contained the intimin () gene, a virulence gene characteristic of two pathotypes of , the enterohemorrhagic and enteropathogenic Several isolates tested were resistant to multiple antibiotics commonly used in animal and human medicine. Further study is warranted to determine the source of these bacteria entering the Animas River, and to further characterize the possible disease potential of multi-antibiotic resistant and virulence gene-containing isolates found in a semi-rural/urban setting.