What are biofilm pathogens, and why are they a problem?

Biofilm Pathogens are structured communities of microorganisms that adhere to surfaces and produce a sticky, protective layer. In water systems, biofilms grow on the inner surfaces of pipes, fixtures, and tanks primarily due to stagnant water and inconsistent flow. Low disinfectant levels, fluctuating water temperatures, and dead-end piping create an ideal environment for biofilm clusters to form. Buildings with complex plumbing systems or aging infrastructure are particularly vulnerable to biofilm growth.

Biofilms often harbor waterborne pathogens such as Legionella, Pseudomonas, Nontuberculous mycobacteria (NTM), and E.coli. Due to their protective matrix, biofilms can resist standard disinfection methods, increasing the risk of Hospital-Associated-Infections (HAIs) for immunocompromised patients in healthcare settings.

Surveillance of Waterborne Disease Outbreaks Associated with Drinking Water - United States, 2015-2020

Overview

The report summarizes U.S. waterborne disease outbreaks from 2015 to 2020, highlighting Legionella as the leading cause of outbreaks, hospitalizations, and deaths in both public and private water systems. It emphasizes the need for better water management and biofilm control. Enteric illness outbreaks were often linked to well water contamination, stressing the importance of proper well construction and maintenance. The report underscores the complexity of preventing waterborne diseases and calls for comprehensive prevention strategies and enhanced surveillance.

CDC MMWR Report

Key Findings

From 2015 to 2020, 214 waterborne disease outbreaks across 28 states resulted in 2,140 illnesses, 563 hospitalizations, and 88 deaths. Legionella caused 86% of outbreaks, followed by Nontuberculous mycobacteria (NTM) and Pseudomonas. Public water systems were linked to 80% of outbreaks, while private systems were implicated in 43%. Biofilm-associated outbreaks were often due to premise plumbing issues, and enteric illness outbreaks were frequently linked to well water contamination. Improved water management and biofilm control are needed, along with proper well construction and maintenance.

Public Health Implications

Legionella was the leading cause of drinking water-related outbreaks, hospitalizations, and deaths, with an increasing number of outbreaks over the study period. Health care settings saw two-thirds of hospitalizations and three-fourths of deaths, often linked to premise plumbing issues, highlighting the need for effective water management programs. Enteric illness outbreaks were frequently associated with well water contamination due to improperly constructed or maintained wells and lack of proper disinfection. The complexity of drinking water-related disease prevention is illustrated by the range of biofilm and enteric pathogen contributing factors. The report emphasizes the need for comprehensive water source-to-tap prevention strategies to address both biofilm and enteric pathogens. Future directions include enhanced surveillance and improved reporting and data collection to better understand and prevent waterborne diseases, along with a focus on water management programs and regulations to control pathogens in drinking water.

Waterborne Disease Outbreaks: Patient Safety, Biofilm Pathogens, and Compliance

Phigenics CEO Mark Crockett, MD, was joined by Healthcare Epidemiologist Angela Tonozzi, MD, MS, CIC, and Product R&D Supervisor Leah Wickenberg, MS, for an engaging discussion on the CDC’s MMWR article, Surveillance of Waterborne Disease Outbreaks Associated with Drinking Water — United States, 2015–2020. Together, they explained the role of biofilm pathogens, their impact on patient safety, changes in the regulatory landscape, and why Water Management Programs are more critical than ever.

Learning Objectives:

Identify waterborne disease outbreaks, their impact on healthcare settings, and key biofilm pathogens involved
Understand how biofilms promote pathogen growth in premise plumbing and at point of use, contributing to health care-associated infections
Explain why public health agencies, accreditation bodies, and standards organizations recommend water management programs

Watch the video clip below to learn more about controlling biofilm pathogens in plumbing systems and at point of use.

Presenters

Angela Tonozzi

Healthcare Epidemiologist

Mark Crockett

Phigenics CEO

Leah Wickenberg

Product R&D Supervisor

Questions from the Field

What are the most striking findings from the CDC’s March 2024 MMWR report on waterborne disease outbreaks?

Patients undergoing surgeries, transplants, and CHF treatments are at risk of infections from contaminated water in healthcare facilities. Continuous water management is crucial to prevent these infections and ensure patient safety. Biofilm-associated pathogens in water systems can cause significant morbidity and mortality. The article also reports on waterborne disease outbreaks from 2015-2020 using data from the National Outbreak Reporting System (NORS), similar to the National Healthcare Safety Network (NHSN).

What are some specific examples of how patients might be exposed to biofilm pathogens in a healthcare setting?

Patients can be exposed to Legionella from water aerosols produced by showerheads and cooling towers. Multidrug-resistant Pseudomonas often spreads from handwashing sinks and faucet aerators, infecting through direct contact, airborne droplets, aspiration, or contaminated hands. Nontuberculous mycobacteria (NTM) are commonly linked to heater-cooler units used in cardiac surgery. Understanding these sources enables healthcare professionals to implement targeted water system controls and reduce the risk of infection.

How do biofilm pathogens affect patient safety and hospital operations by causing costly hospital-acquired infections?

Waterborne infections pose serious risks to patient safety and hospital operations. For instance, a diabetic patient’s successful knee replacement resulted in a longer hospital stay and increased costs after contracting Legionella. Research shows that drinking water is the source of 40% of hospitalizations and half of all deaths from waterborne infections in the U.S., costing $1.39 billion annually. Preventing these infections is essential to protect patients and healthcare resources.

How have regulatory standards, like those from CMS, helped healthcare systems address biofilm-related risks?

Effective control of biofilm pathogens in healthcare starts with a comprehensive water management program. Following CMS, ANSI/ASHRAE Standard 188 regulations, VHA Directive 1061, and TJC EC 02.05.02 helps reduce risks from Legionella and other waterborne threats. The CDC Toolkit offers step-by-step support for building these programs. Staying compliant ensures patient safety and reliable operation of complex plumbing systems.

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