A new analysis of 100 million Medicare records from U.S. adults aged 65 and older reveals rising healthcare costs for infections associated with opportunistic premise plumbing pathogens–disease-causing bacteria, such as Legionella–which can live inside drinking water distribution systems, including household and hospital water pipes.A team led by researchers from the Friedman School of Nutrition Science and Policy at Tufts University and Tufts University School of Medicine found that between 1991 and 2006, more than 617,000 hospitalizations related to three common plumbing pathogens resulted in around $9 billion in Medicare payments–an average of $600 million a year. The costs may now exceed $2 billion for 80,000 cases per year, write the study authors. Antibiotic resistance, which can be exacerbated by aging public water infrastructure, was present in between one and two percent of hospitalizations and increased the cost per case by between 10 to 40 percent.