Text Size Default Text SizeDefault Text Size Large Text SizeLarge Text Size Largest Text SizeLargest Text Size Print Print this Page

2012 News Releases

Longwood research finds Salmonella in waterways

December 3, 2012

Longwood professor Dr. David Buckalew found high levels of salmonella in the area watershed.Longwood professor Dr. David Buckalew found high levels of salmonella in the area watershed.
Dr. David Buckalew

Researchers at Longwood have identified a potential public health concern in the form of high levels of salmonella bacteria in the streams and rivers that run through the heart of Virginia.

"It was a surprise at first," said Dr. David Buckalew, associate professor of biology, who conducted the research with student Timothy Smith ’13 of South Boston. "I didn’t expect there to be so many of them."

Incidents of salmonella outbreaks in the United States have increased over the last three years, including one in peanut butter that originated with a company headquartered in nearby Lynchburg. Since then, lettuce, cantaloupe, ground beef and even dog food have been pulled off grocery store shelves.

Salmonella in area streams isn’t as immediate a risk as Salmonella in food, but it poses a risk to a number of segments of the population, said Buckalew. Farmers, fishermen, outdoor enthusiasts and people who live close to streams could be exposed to harmful amounts of the bacteria. Particularly at risk of infection, he said, are young children and older adults, if they were to drink enough of the water.

Every strain of Salmonella is potentially harmful, but some are more so than others. Buckalew and Smith isolated more than 30 different types of the Salmonella out of the water, and tested each of them for pathogenic markers, which is where Smith came in. With an expertise in molecular typing, he was able to extract DNA from each of the Salmonella strains and use PCR—a commonly used practice to amplify portions of DNA for testing and identification analysis—to identify different strains of the pathogen.

The results showed about 80 percent of the presumptive Salmonella isolates were confirmed as Salmonella—potentially harmful bacteria that cause diarrhea, abdominal cramps and fever, and potentially deadly to those with reduced immunity. "This gives us the biochemical and genetic data to say that we have Salmonella in our streams that could cause people harm," said Buckalew. "I hope this will open people’s eyes to the fact that we have a problem in the water around us and from recent reports, it’s common throughout the US."

Buckalew had to develop his own filtration procedure to both isolate and estimate the number of these bacteria. "When you are looking for bacteria other than E. coli in water, it’s difficult because there are so many other microorganisms in there," he said. "It’s very hard to filter only salmonella out of the water. So, we had to basically create our own protocol to isolate and enumerate Salmonella in the wild."

Raising awareness isn’t the only result to come out of this research. Buckalew predicts we are going to begin seeing a greater variety of bacteria that thrive in warmer climates in the coming years in more northern latitudes, specifically Campylobacter and Listeria.

"These are not harmless bacteria," said Buckalew. "Campylobacter is a neotropical organism that produces symptoms much like Salmonella; Listeria has been linked to instances of meningitis." Doing something about the problem is up to the people, he said. "In many areas, people should be aware that stories of disease outbreaks in the paper—Salmonella outbreaks, Listeria in lettuce—can be closer to them than they think."