Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pathogens in Cheese – Researchers Follow the Traces of Deadly Bacteria

21.03.2014

If food products are not produced in a hygienic environment, consumers can face the threat of dangerous pathogens. This is exactly what happened in 2009 and 2010 when two different strains of Listeria monocytogenes were found in the traditional Austrian curd cheese known as “Quargel”.

34 people were infected, and a total of 8 patients died. Experts from the University of Veterinary Medicine, Vienna analysed the genomes of the outbreak strains and were able to show that the strains displayed distinct properties and entered the food chain independently. The results were published in the journal PLOS ONE and will increase the understanding of outbreaks and their prevention.


Contaminated Quargel cheese caused several deaths in 2009 and 2010.

Photo: Kathrin Rychli/Vetmeduni Vienna

Listeria is a rod-shaped bacterium highly prevalent in the environment and generally not a threat to human health. One species however, Listeria monocytogenes, can cause listeriosis, a very dangerous disease. This pathogen can be present in raw milk and soft cheeses, smoked fish, raw meat and ready-to-eat products.

In Austria, health care providers are required to report all cases of listeriosis, which can be fatal particularly for patients with weakened immune systems. In 2009 and 2010, a dairy in Hartberg (Styria, Austria) produced Quargel cheese contaminated with Listeria monocytogenes leading to a multinational listeriosis outbreak in Austria, Germany and the Czech Republic, ultimately forcing the dairy to shut down. 

Detective work: finding the source

“I’m happy to report that we see relatively few cases of listeriosis here in Austria. When an outbreak occurs though, the disease has among the highest mortality rate of all food-borne illnesses”, explains lead author Kathrin Rychli from the Institute for Milk Hygiene, Milk Technology and Food Science at the University of Veterinary Medicine, Vienna. The Institute was involved in investigating the causes of the outbreaks back in 2009 and 2010. The culprits: two distinct bacterial strains which had not recently evolved from a common ancestor, and therefore entered the food chain independently. 

Genetics reveal the pathway

In their current study, the scientists sequenced and analysed the genomes of both strains, and assessed their virulence, the ability to infect cells. The samples were taken from listeriosis patients from the outbreak.

The first contamination event from June 2009 to January 2010 was attributed to one L. monocytogenes strain very effective at infecting epithelial cells of the intestine and liver cells. It contained additional four virulence genes, making it extremely invasive, and ultimately caused 14 cases resulting in 5 deaths.

A few months later in December 2009, the second L. monocytogenes strain emerged. It was particularly successful at infecting macrophages, important immune system cells. Over time, this highly infectious second strain replaced the first and by February 2010 had infected a total of 20 people, 3 of whom died. The average age of those taken ill was 70. 

Highest level of operational hygiene essential

Listeria expert and co-author Stephan Schmitz-Esser emphasizes the importance of cleanliness in production: “It is absolutely essential that appropriate disinfectants are used properly, lots of salt, and that possible food for the bacteria be limited. Any products listeria is found in must be recalled immediately. Recalls are very expensive for producers, and we need to do everything we can to prevent them.” Austria-wide the Institute for Milk Hygiene, Milk Technology and Food Science at the University of Veterinary Medicine, Vienna offers effective Listeria monitoring and a range of molecular and microbiological examination methods for the food industry. 

What are the symptoms of listeriosis?

Listeriosis generally manifests in healthy people with diarrhoea and stomach cramps, whereas the elderly, newborns and people with weakened immune systems are more susceptible. Listeriosis can result in septicaemia and meningitis. In pregnant women it can lead to miscarriage or stillbirth. Therefore, experts recommend pregnant women to avoid raw milk, raw meat and raw fish products. 

The article „Genome sequencing of Listeria monocytogenes “Quargel” listeriosis outbreak strains reveals two different strains with distinct in vitro virulence potential“, by Kathrin Rychli, Anneliese Müller, Andreas Zaiser, Dagmar Schoder, Franz Allerberger, Martin Wagner and Stephan Schmitz-Esser was published in the Journal PLOS ONE. DOI: 10.1371/journal.pone.0089964
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0089964

About the University of Veterinary Medicine, Vienna

The University of Veterinary Medicine, Vienna is the only academic and research institution in Austria that focuses on the veterinary sciences. About 1,200 employees and 2,300 students work on the campus in the north of Vienna which also houses five university clinics and various research sites. Outside of Vienna the university operates Teaching and Research Farms. http://www.vetmeduni.ac.at

Scientific Contact:
Dr. Stephan Schmitz-Esser
Institute of Milk Hygiene, Milk Technology and Food Science
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-3510
stephan.schmitz-esser@vetmeduni.ac.at

Released by:
Susanna Kautschitsch
Science Communication / Public Relations
University of Veterinary Medicine Vienna (Vetmeduni Vienna)
T +43 1 25077-1153
susanna.kautschitsch@vetmeduni.ac.at

Weitere Informationen:

http://www.vetmeduni.ac.at/en/infoservice/presseinformation/press-releases-2014/...

Dr. Susanna Kautschitsch | idw - Informationsdienst Wissenschaft

Further reports about: Food Hygiene Listeria Medicine Technology Veterinary immune monocytogenes strain strains virulence

More articles from Life Sciences:

nachricht How algae and carbon fibers could sustainably reduce the athmospheric carbon dioxide concentration
14.11.2018 | Technische Universität München

nachricht NIH scientists illuminate causes of hepatitis b virus-associated acute liver failure
14.11.2018 | NIH/National Institute of Allergy and Infectious Diseases

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

NIH scientists illuminate causes of hepatitis b virus-associated acute liver failure

14.11.2018 | Life Sciences

The unintended consequences of dams and reservoirs

14.11.2018 | Earth Sciences

NIH scientists combine technologies to view the retina in unprecedented detail

14.11.2018 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>