Featured Research

from universities, journals, and other organizations

Antibiotic-resistant strains of Salmonella tracked from farm to fork

Date:
August 29, 2013
Source:
Penn State
Summary:
Continuing research on Salmonella may enable researchers to identify and track strains of antibiotic resistant bacteria as they evolve and spread, according to researchers.

Continuing research on Salmonella may enable researchers to identify and track strains of antibiotic resistant bacteria as they evolve and spread, according to researchers in Penn State's College of Agricultural Sciences.

Related Articles


Tracing the transmission of individual strains from agricultural environments to humans through the food system is difficult because of the rapid evolution of resistance patterns in these bacteria. Resistance patterns change so quickly that, until now, it has been impossible to determine where some highly resistant strains are coming from.

Michael DiMarzio, a doctoral candidate in food science working under the direction of Edward Dudley, associate professor and Casida Development Professor of Food Science, developed a method for identifying and tracking strains of Salmonella enterica serological variant Typhimurium as they evolve and spread.

Every year in the United States, the various strains of Salmonella together are responsible for an estimated 1 million illnesses, 20,000 hospitalizations and 400 deaths at an economic cost exceeding $3 billion. Salmonella Typhimurium accounts for at least 15 percent of clinically reported salmonellosis infections in humans nationally. The number of antibiotic-resistant isolates identified in humans is increasing steadily, suggesting that the spread of antibiotic-resistant strains is a major threat to public health.

"Typhimurium infections have exhibited a gradual decline in susceptibility to traditional antibiotics, a trend that is concerning in light of this pathogen's broad host range and its potential to spread antibiotic resistance determinants to other bacteria," DiMarzio said. "Now more than ever, it is imperative to effectively monitor the transmission of Salmonella Typhimurium throughout the food system to implement effective control measures."

Building on recent research done in Dudley's lab, DiMarzio developed the new approach to identify antibiotic resistant strains of Salmonella Typhimurium focusing on virulence genes and novel regions of the bacteria's DNA known as clustered regularly interspaced short palindromic repeats, or CRISPRs. They report their results in the September issue of Antimicrobial Agents and Chemotherapy.

CRISPRs are present in many foodborne pathogens. The researchers demonstrated that CRISPR sequences can be used to identify populations of Salmonella with common antibiotic-resistance patterns in both animals and humans.

"Specifically, we were able to use CRISPRs to separate isolates by their propensity for resistance to seven common veterinary and human clinical antibiotics," DiMarzio said. "Our research demonstrates that CRISPRs are a novel tool for tracing the transmission of antibiotic-resistant Salmonella Typhimurium from farm to fork."

DiMarzio found that several subtypes of Salmonella Typhimurium showed up repeatedly in the frozen collection of Salmonella samples taken from cows, pigs and chickens in Penn State's Animal Diagnostic Laboratory. In this case, researchers looked at 84 unique Salmonella Typhimurium isolates collected from 2008 to 2011.

"We know those strains are widely disbursed, and the thing they have in common is that they have noticeably higher levels of antibiotic resistance," he said. "So we examined clinical samples of Salmonella taken from humans, and it turned out that we see an overlap -- the ones we see in humans are the ones we see a lot in animals. You would expect that, but it is confirmation that our method works."

DiMarzio noted that the researchers identified subsets of the overall Salmonella bacteria population that seem to be more prone to acquiring antibiotic resistance.

"Our challenge now is to learn what makes those strains different -- why do some strains acquire resistance while others don't, even though both are circulating widely among animal populations?" he said. "We will need to know that to try to control them."


Story Source:

The above story is based on materials provided by Penn State. Note: Materials may be edited for content and length.


Journal Reference:

  1. M. DiMarzio, N. Shariat, S. Kariyawasam, R. Barrangou, E. G. Dudley. Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Associates with CRISPR Sequence Type. Antimicrobial Agents and Chemotherapy, 2013; 57 (9): 4282 DOI: 10.1128/AAC.00913-13

Cite This Page:

Penn State. "Antibiotic-resistant strains of Salmonella tracked from farm to fork." ScienceDaily. ScienceDaily, 29 August 2013. <www.sciencedaily.com/releases/2013/08/130829112850.htm>.
Penn State. (2013, August 29). Antibiotic-resistant strains of Salmonella tracked from farm to fork. ScienceDaily. Retrieved April 1, 2015 from www.sciencedaily.com/releases/2013/08/130829112850.htm
Penn State. "Antibiotic-resistant strains of Salmonella tracked from farm to fork." ScienceDaily. www.sciencedaily.com/releases/2013/08/130829112850.htm (accessed April 1, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, April 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Liberia Sees Resurgence of Drug Trafficking as Ebola Wanes

Liberia Sees Resurgence of Drug Trafficking as Ebola Wanes

AFP (Apr. 1, 2015) — The governments of Liberia and Sierra Leone have been busy fighting the menace created by the deadly Ebola virus, but illicit drug lords have taken advantage of the situation to advance the drug trade. Duration: 01:12 Video provided by AFP
Powered by NewsLook.com
Stigma Stalks India's Leprosy Sufferers as Disease Returns

Stigma Stalks India's Leprosy Sufferers as Disease Returns

AFP (Apr. 1, 2015) — The Indian government declared victory over leprosy in 2005, but the disease is making a comeback in some parts of the country, with more than a hundred thousand lepers still living in colonies, shunned from society. Duration: 02:41 Video provided by AFP
Powered by NewsLook.com
7-Year-Old Girl Gets 3-D Printed 'robohand'

7-Year-Old Girl Gets 3-D Printed 'robohand'

AP (Mar. 31, 2015) — Although she never had much interest in prosthetic limbs before, Faith Lennox couldn&apos;t wait to slip on her new robohand. The 7-year-old, who lost part of her left arm when she was a baby, grabbed it as soon as it came off a 3-D printer. (March 31) Video provided by AP
Powered by NewsLook.com
Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
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:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

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