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Enterococci bacteria are the bane of hospitals, causing thousands of multidrug-resistant infections in patients each year. Now, researchers have traced evidence of the bacteria’s evolutionary history back 425 million years and theorize that the same traits that allow the bacteria to thrive in hospitals likely emerged when they were carried onto land in the guts of the world’s first terrestrial animals. The study was funded in part by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health.

Researchers at the Massachusetts Eye and Ear Infirmary, Harvard Medical School, and the Broad Institute of MIT and Harvard examined DNA from 24 species of enterococci, taken from the guts of a wide variety of animal and human hosts. The team calculated the average rate of genetic change within enterococcal species and compared genes of existing enterococci to those of related, non-enterococci bacteria. The analysis allowed the researchers to build an evolutionary timeline to estimate when key enterococci traits emerged. They then checked this timeline against the fossil record of terrestrial animal evolution.

All enterococci sampled were resistant to a common set of stresses–including antibiotics, disinfectants, drying and starvation–suggesting that the ancestors of all enterococci also shared these abilities. Enterococci appear to have developed these traits at around the same time that terrestrial animal life evolved. The researchers theorize that the ancestors of all enterococci lived in the guts of prehistoric aquatic animals, and as their hosts left the sea around 425 million years ago, the bacteria were carried along. Simultaneously, they evolved the traits needed to survive introduction into the harsher environment of dry land.

The researchers note that while their model is difficult to prove, it does partially explain the ability of enterococci to survive in hospital environments: they have long been equipped to thrive in a wide range of challenging environments. Having a better sense of what prompted the bacteria to evolve these abilities, the researchers say, could help control enterococci as the bacteria continue to circumvent hospital infection control methods.

Article

F Lebreton, et al. Tracing the enterococci from Paleozoic origins to the hospital (link is external). Cell. DOI: 10.1016/j.cell.2017.04.027 (2017)

According to Prof. dr hab. Zuzanna Drulis-Kawa from the Department of Pathogen Biology and Immunology Institute of Genetics and Microbiology at University of Wroclaw, Poland: “Most phages target bacterial surface molecules, especially those of carbohydrate nature, which are the dominant phage receptors. Surface glycans and glycoconjugates (polysaccharides PS) such as capsules and lipopolysaccharides (LPS) serve as molecular patterns for recognition by the innate immune system, and also provide shields to antibiotic entry and host defence mechanisms (e.g. complement system and phagocytosis). Loss or alteration of these molecules by gene mutation, which leads to phage resistance, could result in less virulent bacteria. This presentation shows a multidisciplinary approach to characterize bacterial population treated with phages and phage-based products and evaluate its consequences in terms of bacterial pathogenicity, interactions with the innate immune system, antibiotic resistance, and biofilm formation. “

If you are interested to know more about Phage and phage-based products, don’t hesitate to participate to Targeting Antibiotic Resistance Congress which will be held in Florence on October 2-3, 2017. More information on www.tid-site.com/

 

Lille researchers (Inserm, University of Lille, Pasteur Institute of Lille, CNRS) * invented a prototype drug (SMARt-420 **) capable of suppressing resistance to ethionamide, an antibiotic used to treat tuberculosis. This work is published in the journal Science *** dated March 17, 2017 and opens a new way in the fight against resistance to antibiotics.

Antibiotic resistance, a major global health issue Antibiotics are universally regarded as one of the greatest medical advances of the twentieth century. They have transformed human health by allowing the cure of previously severe or life-threatening infections. They are also essential for patients particularly vulnerable to infections such as those with certain cancers or diabetes, persons receiving organ transplants, or undergoing surgical procedures.

Tuberculosis is a bacterial disease caused by Mycobacterium tuberculosis (Mtb), which is transmitted by air and mainly affects the lungs. The treatment of tuberculosis combines several antibiotics over a period of six months. The continuing increase in the number of strains of antibiotic-resistant Mtb is particularly worrying. In 2016, of the 10 million new cases of tuberculosis reported worldwide, 500,000 were considered multiresistant to antibiotics, causing the death toll of one in every two patients.