Navigation Links
Passing the Gac
Date:10/29/2013

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 diarrhoea 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 Listeria monocytogenes, 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."


'/>"/>

Contact: Susanna Kautschitsch
susanna.kautschitsch@vetmeduni.ac.at
43-125-077-1153
University of Veterinary Medicine -- Vienna
Source:Eurekalert  

Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Passing the Gac
(Date:6/21/2016)... , June 21, 2016 NuData ... the new role of principal product architect and ... the director of customer development. Both will report ... technical officer. The moves reflect NuData,s strategic growth ... response to high customer demand and customer focus ...
(Date:6/9/2016)... 2016 Paris Police Prefecture ... security solution to ensure the safety of people and operations ... the major tournament Teleste, an international technology group ... announced today that its video security solution will be utilised ... up public safety across the country. The system roll-out is ...
(Date:6/2/2016)... 2016 Perimeter Surveillance & Detection ... Physical Infrastructure, Support & Other Service  The ... offers comprehensive analysis of the global Border Security ... revenues of $17.98 billion in 2016. Now: ... leader in software and hardware technologies for advanced video ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... -- Liquid Biotech USA , Inc. ... Research Agreement with The University of Pennsylvania ("PENN") ... patients.  The funding will be used to assess ... outcomes in cancer patients undergoing a variety of ... to support the design of a therapeutic, decision-making ...
(Date:6/24/2016)... ... , ... While the majority of commercial spectrophotometers and fluorometers use the z-dimension ... are higher end machines that use the more unconventional z-dimension of 20mm. Z-dimension ... bottom of the cuvette holder. , FireflySci has developed several Agilent flow cell ...
(Date:6/23/2016)... , June 23, 2016   Boston ... of novel compounds designed to target cancer stemness ... has been granted Orphan Drug Designation from the ... treatment of gastric cancer, including gastroesophageal junction (GEJ) ... inhibitor designed to inhibit cancer stemness pathways by ...
(Date:6/23/2016)... Lawrence, MA (PRWEB) , ... June 23, 2016 ... ... the Peel Plate® YM (Yeast and Mold) microbial test has received AOAC Research ... test platform of microbial tests introduced last year,” stated Bob Salter, Vice President ...
Breaking Biology Technology: