Urban Runoff May Be Responsible For More E. coli Contamination Than Animal Production Facilities
ARS is USDA's chief intramural scientific research agency, and this work supports the USDA priority of ensuring food safety.
Even though most strains of E. coli are non-pathogenic, the bacterium is monitored by public health officials as an indicator of water quality. Cows are often seen as the culprits when E. coli is found in local lakes, rivers and other bodies of water.
Ibekwe, who works at the ARS U.S. Salinity Laboratory in Riverside, Calif., and his colleagues collected 450 water and sediment samples from 20 sites throughout California's middle Santa Ana River Watershed. The collection sites included urban areas, livestock feeding areas, parks, National Forest lands, and three wastewater treatment plants.
Then the scientists extracted E. coli bacteria from each sample and identified 600 different isolates of E. coli in their samples, many of which could be placed into six clonal populations. They found the greatest variety of different types of E. coli in runoff discharged from areas dominated by urban development or human activities.
Ibekwe also tested all the E. coli isolates for resistance to various antibiotics. He found that from 88 to 95 percent of the isolates were resistant to rifampicin, and that around 75 percent were resistant to tetracycline. Tetracycline resistance was by far the most common type of resistance observed in E. coli isolates collected near wastewater treatment plants.
The scientists also found that 24 percent of E. coli collected in sediment samples associated with urban runoff - a total of 144 isolates - showed resistance to as many as seven antibiotics. Results from this work were published in PLOS ONE.
Source: EurekAlert!, the online, global news service operated by AAAS, the science society
Visit our Infectious Diseases / Bacteria / Viruses category page for the latest news on this subject, or sign up to our newsletter to receive the latest updates on Infectious Diseases / Bacteria / Viruses.
Please use one of the following formats to cite this article in your essay, paper or report:
United States Department of Agriculture. "Urban Runoff May Be Responsible For More E. coli Contamination Than Animal Production Facilities." Medical News Today. MediLexicon, Intl., 3 Dec. 2012. Web.
25 May. 2017. <http://www.medicalnewstoday.com/releases/253439.php>
United States Department of Agriculture. (2012, December 3). "Urban Runoff May Be Responsible For More E. coli Contamination Than Animal Production Facilities." Medical News Today. Retrieved from
Please note: If no author information is provided, the source is cited instead.
Contact our news editors
For any corrections of factual information, or to contact our editorial team, please see our contact page.
Copyright Medical News Today: Excluding email/sharing services explicitly offered on this website, material published on Medical News Today may not be reproduced, or distributed without the prior written permission of Medilexicon International Ltd. Please contact us for further details.