New findings on infections caused by listeria

Professor Juan José Quereda Torres has collaborated with the Pasteur Institute of Paris to reveal new findings on how the listeria bacterium invades human and animal cells.Juan Jose Quereda

Researcher and professor at the Faculty of Veterinary Studies of the CEU Cardenal Herrera (CEU UCH) university of Valencia, Juan José Quereda Torres, has just published the results of his progress on the knowledge of the infectious process of the Listeria monocytogenes bacterium, together with researchers from the Pasteur Institute of Paris, where he used to work and who he continues collaborating with from the CEU UCH. His new findings, which have just been published in the high-impact Journal of Infectious Diseases, reveal how the bacterium invades cells to replicate and spread the infection in the organism of people and animals.

Listeria monocytogenes is a pathogenic bacterium of interest both to human and veterinary medicine: listeriosis is the zoonotic disease, which transmits from animals to humans, that causes the highest number of deaths, and the cases of infection have increased since 2008 in the EU, especially in Spain. As professor Quereda highlights, “Listeria monocytogenes can be found in a wide variety of foods, but cooking them at temperatures higher than 65ºC kills the bacterium. The risk is in consumer-ready foods, in other words, those that are not cooked before being consumed, including raw foods, processed foods and those made with non-pasteurised milk. This bacterium can also contaminate raw milk, which is in vogue in some areas.”

Findings on the infectious process

This new study has been developed together with the research team of doctors Pizarro-Cerdá and Cossart, from the Pasteur Institute of Paris, which he has been working together with for several years. His research work focuses on the infectious process through which the Listeria monocytogenes bacterium invades the cells of the host, breaks through their internalisation vacuole and reaches the cytosol in order to replicate. As Quereda notes, “in order to progress on the knowledge of this process, in this latest research with the Pasteur Institute, we inactivated the expression of the 165 most important genes of the host mammal for the infection by Listeria monocytogenes, and we have identified for the first time the factors of the host that modulate the rupture of the vacuole and the cytoplasmic access to epithelial cells.”

The CEU UCH professor also highlights that “these breakthroughs could make it possible to develop new therapies to treat listeriosis in humans and animals in the future. Listeriosis currently has a death rate between 10 and 30%, despite the implementation of antibiotic treatment.” The relevance of the findings obtained in this last study have enabled their publishing in the prestigious Journal of Infectious Diseases, one of the best international journals in the field of infectious diseases, with an impact factor of 5.

Spanish specialist

Veterinary medicine professor Juan José Quereda Torres is one of the most outstanding Spanish specialists in the study of listeriosis. Before arriving at the CEU UCH, he conducted his research work at the Genetics and Animal Health department of the University of Murcia (2006-2011), in the Laboratory of Intracellular Pathogenic Bacteria of the National Biotechnology Centre-CSIC of Madrid (2011-2014), and at the Bacteria-Cell Interactions Unit of the Pasteur Institute of Paris (2014-2017). As a professor of the CEU UCH, Quereda has been chosen as the beneficiary of a contract with the Ramón y Cajal programme of the Spanish Ministry of Science, Innovation and Universities in order to continue studying listeriosis.

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