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 Pathogenic bacteria hitchhiking to North and Baltic Seas?
22.07.2016 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

nachricht Unconventional quasiparticles predicted in conventional crystals
22.07.2016 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

Im Focus: A Peek into the “Birthing Room” of Ribosomes

Scaffolding and specialised workers help with the delivery – Heidelberg biochemists gain new insights into biogenesis

A type of scaffolding on which specialised workers ply their trade helps in the manufacturing process of the two subunits from which the ribosome – the protein...

Im Focus: New protocol enables analysis of metabolic products from fixed tissues

Scientists at the Helmholtz Zentrum München have developed a new mass spectrometry imaging method which, for the first time, makes it possible to analyze hundreds of metabolites in fixed tissue samples. Their findings, published in the journal Nature Protocols, explain the new access to metabolic information, which will offer previously unexploited potential for tissue-based research and molecular diagnostics.

In biomedical research, working with tissue samples is indispensable because it permits insights into the biological reality of patients, for example, in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

Partner countries of FAIR accelerator meet in Darmstadt and approve developments

11.07.2016 | Event News

 
Latest News

The Exception and its Rules

25.07.2016 | Physics and Astronomy

Using Ultrashort Pulsed Laser Radiation to Process Fibre-Reinforced Components

25.07.2016 | Materials Sciences

Added bacterial film makes new mortar resistant to water uptake

25.07.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>