Featured Research

from universities, journals, and other organizations

Listeria’s resistance to disinfectants

Date:
October 29, 2013
Source:
Veterinärmedizinische Universität Wien
Summary:
Listeria poses a significant risk to human health. The bacterium is frequently transmitted via dairy products, so it is important to disinfect dairies regularly. Unfortunately, listeria is developing resistance to the most frequently used compounds, including benzalkonium chloride.

Listeria (stained green) can acuire resistance through the transfer of foreign genes.
Credit: Monika Dzieciol / Vetmeduni Vienna

Listeria poses a significant risk to human health. The bacterium is frequently transmitted via dairy products, so it is important to disinfect dairies regularly. Unfortunately, listeria is developing resistance to the most frequently used compounds. Work in the group of Stephan Schmitz-Esser at the University of Veterinary Medicine, Vienna (Vetmeduni Vienna) has uncovered the mechanism for resistance to benzalkonium chloride. The findings have been published in the online journal Plos One.

Recent years have seen significant outbreaks of listeriosis on both sides of the Atlantic. Although the disease can usually be treated successfully, it is occasionally fatal, most frequently in pregnant women or immunocompromized people. And even when treatment is effective, the symptoms are anything but pleasant and include fever and muscle aches along with diarrhea and other gastrointestinal symptoms. The old adage is clearly true: prevention is better than cure.

Prevention of listeriosis relies on killing the causative agent, normally the bacterium Listeriamonocytogenes, in dairies and other food-processing facilities. A number of disinfectants are used for this purpose, most often quaternary ammonium compounds such as benzalkonium chloride (BC). Unfortunately, however, many strains of listeria seem to be developing resistance to these agents, although the underlying mechanisms have remained obscure. Together with colleagues in Ireland, the group of Stephan Schmitz-Esser of the Vetmeduni's Institute for Milk Hygiene has provided convincing evidence that a novel piece of DNA in the bacteria is involved.

The scientists used next-generation sequencing techniques to determine the DNA sequences of two strains of listeria known to be resistant to BC. When they examined the sequences they noticed a region of DNA of ca. 5 kb that was strikingly different in composition from the remainder of the genome. The bacteria seem to have acquired this novel element fairly recently and Schmitz-Esser termed it Tn6188 (so-called transposons are frequent in bacterial genomes, explaining the high number).

Of course, the presence of Tn6188 in two strains resistant to BC might merely be a coincidence. The researchers thus screened an additional 90 strains of listeria for the element, finding it in ten of them. The ten strains harbouring Tn6188 turned out to be far less sensitive to benzalkonium chloride. One of the five proteins that could be encoded by Tn6188, termed QacH by Schmitz-Esser and colleagues term because of its similarity to proteins of this name from other organisms, was activated by the presence of BC in culture medium. And in a final experiment, the scientists could show that deleting the QacH gene made listeria once again sensitive to the drug.

Although his group has not formally proved that the new transposon is responsible for BC resistance in listeria, Schmitz-Esser feels that he has "probably sufficient circumstantial evidence to obtain a conviction. In any case our results show that listeria can acquire new genetic material from other bacteria -- it is thus important to ensure thorough disinfecting of food-processing facilities to prevent reservoirs of resistant bacteria building up and transferring their resistance to listeria."


Story Source:

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


Journal Reference:

  1. Anneliese Müller, Kathrin Rychli, Meryem Muhterem-Uyar, Andreas Zaiser, Beatrix Stessl, Caitriona M. Guinane, Paul D. Cotter, Martin Wagner, Stephan Schmitz-Esser. Tn6188 - A Novel Transposon in Listeria monocytogenes Responsible for Tolerance to Benzalkonium Chloride. PLoS ONE, 2013; 8 (10): e76835 DOI: 10.1371/journal.pone.0076835

Cite This Page:

Veterinärmedizinische Universität Wien. "Listeria’s resistance to disinfectants." ScienceDaily. ScienceDaily, 29 October 2013. <www.sciencedaily.com/releases/2013/10/131029090514.htm>.
Veterinärmedizinische Universität Wien. (2013, October 29). Listeria’s resistance to disinfectants. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2013/10/131029090514.htm
Veterinärmedizinische Universität Wien. "Listeria’s resistance to disinfectants." ScienceDaily. www.sciencedaily.com/releases/2013/10/131029090514.htm (accessed October 22, 2014).

Share This



More Health & Medicine News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

CDC Revamps Ebola Guidelines After Criticism

CDC Revamps Ebola Guidelines After Criticism

Newsy (Oct. 21, 2014) — The Centers for Disease Control and Prevention have issued new protocols for healthcare workers interacting with Ebola patients. Video provided by Newsy
Powered by NewsLook.com
WHO: Ebola Vaccine Trials to Start a in January

WHO: Ebola Vaccine Trials to Start a in January

AP (Oct. 21, 2014) — Tens of thousands of doses of experimental Ebola vaccines could be available for "real-world" testing in West Africa as soon as January as long as they are deemed safe in soon to start trials, the World Health Organization said Tuesday. (Oct. 21) Video provided by AP
Powered by NewsLook.com
First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

First-Of-Its-Kind Treatment Gives Man Ability To Walk Again

Newsy (Oct. 21, 2014) — A medical team has for the first time given a man the ability to walk again after transplanting cells from his brain onto his severed spinal cord. Video provided by Newsy
Powered by NewsLook.com
CDC Issues New Ebola Guidelines for Health Workers

CDC Issues New Ebola Guidelines for Health Workers

Reuters - US Online Video (Oct. 21, 2014) — The U.S. Centers for Disease Control and Prevention has set up new guidelines for health workers taking care of patients infected with Ebola. Linda So 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