Featured Research

from universities, journals, and other organizations

Detecting pathogens in waterways: An improved approach

Date:
February 8, 2011
Source:
USDA/Agricultural Research Service
Summary:
U.S. scientists have come up with a way to detect pathogenic Escherichia coli and Salmonella bacteria in waterways at lower levels than any previous method. Similar methods have been developed to detect pathogenic E. coli in meat products, but this latest approach represents a first for waterways.

U.S. Department of Agriculture (USDA) scientists have come up with a way to detect pathogenic Escherichia coli and Salmonella bacteria in waterways at lower levels than any previous method. Similar methods have been developed to detect pathogenic E. coli in meat products, but the approach by the scientists with USDA's Agricultural Research Service (ARS) represents a first for waterways.

ARS is USDA's principal intramural scientific research agency, and this research supports the USDA priority of ensuring food safety.

When health officials test a public beach or lake for Salmonella or E. coli 0157:H7, they use two types of non-pathogenic bacteria, Enterococci and generic E. coli, as indicators. But while the indicators are often detected in contaminated waterways, their abundance doesn't guarantee the presence of either pathogen, according to Michael Jenkins, a microbiologist at the ARS J. Phil Campbell Sr. Natural Resource Conservation Center in Watkinsville, Ga.

These indicator organisms are often reliable, but investigators have detected the indicators in pathogen-free waters and have failed to find them in waters that contained sufficient levels of the pathogens to make someone sick.

The indicators are used as signals because both pathogens are hard to detect directly at levels that will make someone ill: just 100 cells of Salmonella and just 10 to 100 cells of E. coli 0157:H7, the toxic strain of the bacterium. Organic matter in a water sample will throw off current PCR (polymerase chain reaction) technology when it is used as a tool for detection. Salmonella and E. coli outbreaks are often attributed to agricultural operations, so improving ways to track down sources of outbreaks is a major priority.

Jenkins and his ARS colleagues Dinku Endale and Dwight Fisher at Watkinsville combined techniques previously developed to assess water quality and detect pathogens in laboratory settings: a water filtration technique to concentrate the pathogens; a special medium for growing and measuring the number of pathogenic cells; a biochemical testing process; and PCR technology.

They collected water samples from a pond at the Watkinsville site, ran them through a special filter, removed the filter contents and used a centrifuge to spin the filtered contents into a pellet form. They used the suspended pellets to develop cell cultures, confirmed their identity with a genetic method, and determined the concentration found in the original samples.

Their results, published in the Journal of Applied Microbiology, showed the process can be used to detect just a few cells of pathogenic E. coli and Salmonella in a 10-liter water sample, lower levels than any previously detected. Because the system involves collecting cell cultures, it also may lead to developing culture collections that-like a fingerprint database-could be used to identify bacterial strains that are potential sources of future outbreaks.


Story Source:

The above story is based on materials provided by USDA/Agricultural Research Service. Note: Materials may be edited for content and length.


Journal References:

  1. M.B. Jenkins, D.M. Endale, D.S. Fisher, P.A. Gay. Most probable number methodology for quantifying dilute concentrations and fluxes ofEscherichia coliO157:H7 in surface waters. Journal of Applied Microbiology, 2009; 106 (2): 572 DOI: 10.1111/j.1365-2672.2008.04028.x
  2. M.B. Jenkins, D.M. Endale, D.S. Fisher. Most probable number methodology for quantifying dilute concentrations and fluxes of Salmonella in surface waters. Journal of Applied Microbiology, 2008; 104 (6): 1562 DOI: 10.1111/j.1365-2672.2007.03677.x

Cite This Page:

USDA/Agricultural Research Service. "Detecting pathogens in waterways: An improved approach." ScienceDaily. ScienceDaily, 8 February 2011. <www.sciencedaily.com/releases/2011/02/110208144124.htm>.
USDA/Agricultural Research Service. (2011, February 8). Detecting pathogens in waterways: An improved approach. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/2011/02/110208144124.htm
USDA/Agricultural Research Service. "Detecting pathogens in waterways: An improved approach." ScienceDaily. www.sciencedaily.com/releases/2011/02/110208144124.htm (accessed August 23, 2014).

Share This




More Plants & Animals News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Endangered Red Wolves Face Uncertain Future

Endangered Red Wolves Face Uncertain Future

AP (Aug. 22, 2014) A federal judge temporarily banned coyote hunting to save endangered red wolves, but local hunters say that the wolf preservation program does more harm than good. Meanwhile federal officials are reviewing its wolf program in North Carolina. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Farm Resurgence Grows With Younger Crowd

Farm Resurgence Grows With Younger Crowd

AP (Aug. 22, 2014) New England farms are seeing a surge in younger farm hands as the 'buy local' food movement grows across the country. (Aug. 22) Video provided by AP
Powered by NewsLook.com
Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Terrifying City-Dwelling Spiders Are Bigger And More Fertile

Newsy (Aug. 21, 2014) According to a new study, spiders that live in cities are bigger, fatter and multiply faster. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins