(ANSA) - Rome, October 16 - Italian researchers at Rome's Catholic University have discovered the 'Achilles heel' of one of the most antibiotic-resistant and aggressive bacteria plaguing hospital wards world over. Together with French and Dutch scientists, the team identified a weak point in Enterococcus faecium, the second-leading cause of dangerous and sometimes fatal gastrointestinal infections in hospitals and clinics. The weak-link gene identified by the researchers governs a molecular switch that protects the bacteria from antibiotic treatments, leaving it immune to therapy. The finding was published in the journal PLoS Pathogens by Maurizio Sanguinetti, director of the Institute of Microbiology at the Catholic University of Rome and associate professor Brunella Posteraro, along with researchers from Caen University Hospital in France and Utrecht University in the Netherlands. "Enterococcus faecium is the second leading cause of catheter-related and urinary-tract infections and can have serious consequences, such as sepsis and endocarditis, with fatal outcomes," Sanguinetti said. "Moreover, since the 1980s it has developed a strong resistance to available treatments, specifically the antibiotic vancomycin," Sanguinetti said. In the US, more than 80% of Enterococcus faecium strains are vancomycin-resistant. "The discovery is important because today Enterococcus faecium is not only among the most feared bacteria in hospitals, it is also a frequent cause of urinary tract infection for hospital patients," Posteraro said.