While contaminated water systems have received more attention thanks to the lead-tainted drinking water in Flint, Mich., the healthcare costs of infections caused by waterborne bacteria have been increasing for years, according to a study published in the Journal of Public Health.

Authored by Elena Naumova, PhD, MS, and other researchers at Tufts University, the study examined Medicare records from 1991 to 2006 for bacterial pneumonia hospitalizations related to opportunistic premise plumbing pathogens (OPPPs), such as Legionella bacteria and Mycobacterium avium.

The study identified more than 617,000 cases for patients above the age of 65, with an average annual cost to Medicare of $600 million per year, increasing every year during the 15-year study period.

“Given these costs, recent outbreaks of Legionnaire’s disease, and the rising incidence of hospital-acquired OPPP illnesses, enhanced identification and reporting of these infections is warranted,” Naumova et al. wrote.

The study said despite the rise in OPPP-related illnesses, they’re rarely tested for in community settings, which may mean even the 617,000 cases they identified could be “substantially underestimated.”

Additionally, reporting of hospital-acquired infections and antibiotic-resistant infections was “imperfect” during the study period, but the researchers wrote that among the 1 to 2 percent of hospitalizations which showed signs of antibiotic resistance, costs to treat those patients rose between 10 and 40 percent.  

Naumova and her coauthors concluding by saying further study is needed to identify common signs of OPPP and help hospitals keep the bacteria out of their water systems.

“Implementing plumbing rules that eliminate or reduce OPPP organisms in water systems of healthcare facility buildings or in the homes of at-risk persons (such as those with cystic fibrosis or immunocompromised) may prove most effective,” the researchers wrote. “The long-term effectiveness, safety and cost associated with coatings that prevent biofilm formation either by chemical modification or micropatterned surfaces within the plumbing pipes could be further examined,” including whether they should be used in “high-risk surgical or hospital settings.”