Surgical facilities have become more vigilant in hand washing practices to prevent the transmission of potentially harmful organisms to patients. It's time to become just as focused on the use of tap water in your ORs and on your instrument-reprocessing protocol because water entering your facility through an unfiltered faucet can infect patients. But don't take my word for it - plenty of clinical evidence shows that tap water is a potential agent for transferring harmful microbes on staff or contaminated instruments.

Pipe streams
What dangers are really lurking in tap water? Plenty. Many microorganisms are found in the water systems of hospitals; they include bacteria (Legionella pneumophila, Stenotrophomonas maltophilia, Pseudomonas aeruginosa), fungi (Aspergillus species, Fusarium species) and amoebae (Hartmanella, Naegleria, Acanthamoeba). Microorganisms in water improve their chances of survival by attaching to and multiplying in the biofilm that lines pipes and fixtures, as well as living inside other microbes. Those living inside amoebae can survive contact with chemical disinfectants and other harsh environmental conditions. Such amoeba-resisting microorganisms include Legionella pneumophila (the causative agent of Legionnaires' disease), Mycobacterium avium and Pseudomonas aeruginosa.

Lawrence F. Muscarella, PhD, director of research and development and chief of infection control for medical manufacturer Custom Ultrasonics, Inc., in Ivyland, Pa., reviewed existing literature to examine the contribution of tap water on the nosocomial transmission of Pseudomonas aeruginosa.1 He discovered one outbreak that began in the endoscopy suite of a hospital when a colonoscope, a gastroscope, the faucets of wash basins and water taps were each contaminated with P. aeruginosa.

It was determined that the contamination of the faucets and water taps possibly occurred when drinking glasses were poured into the wash basins, splashing contaminated water up onto the taps. This study reports that the endoscopes may have become contaminated when they were removed wet from the facility's automated endoscope re-processors by staff who carried the bacteria from the sinks and washbasins on their hands. The outbreak was controlled when staff focused on hand hygiene and glove use, concentrated on the proper drying of the endoscopes and periodic cleaning and disinfecting of the water taps, according to Dr. Muscarella's report.

Legionnaires' disease acquired in the healthcare setting is a serious condition, but one that can be prevented through the disinfection of water systems. In a study conducted with Victor L. Yu, MD, from the Department of Medicine at the University of Pittsburgh, I surveyed 16 hospitals that had installed copper-silver ionization systems for Legionella disinfection.2

The first surveys were conducted in 1995, followed by a second round of surveys in 2000. Half the hospitals questioned in 1995 reported that Legionella contamination dropped to 0 percent. In 2000, 43 percent of the hospitals reported 0 percent Legionella contamination. More importantly, none of the hospitals surveyed reported a single case of hospital-acquired Legionnaires' disease after 1995.

Our study proved the long-term efficacy of copper-silver ionization in reducing Legionella in hospital water systems, and while other means of disinfection may be equally effective, the results demonstrate that water disinfection plays a key role in reducing or eliminating cases of hospital-acquired Legionnaires' disease.

Preventative measures
In another study, I helped examine the efficacy of point-of-use filters in eliminating Legionella and other pathogens from water.3 We collected 594 hot water samples over 12 weeks from seven faucets in a hospital setting. Filters were affixed to four of the seven faucets, and samples were taken immediately after opening the faucet, and again after a one-minute flush.

We found no traces of Legionella or M. gordonae in the samples taken from the filtered faucets and determined that the filters achieved a greater than 99 percent reduction in HPC bacteria in both the immediate and post-flush samples. Based on these findings, we concluded that point-of-use filters completely eliminated L. pneumophila and M. gordonae from hot water samples and the filter units could prevent exposure of high-risk patients to waterborne pathogens.

In 2003, the CDC published guidelines that detailed practices for controlling the spread of waterborne microorganisms.4 The guidelines note that tap water used during gastrointestinal procedures or during the final step of instrument reprocessing can lead to pseudo-outbreaks of Mycobacterium chelonae, M. gordonae and M. xenopi, specifically when tap water is used to irrigate the surgical site or rinse the viewing tip of the endoscope.

The guidelines suggest that staff practice hand hygiene and use barrier protection to prevent the transfer of water pathogens. The report also says that sinks and washbasins should be cleaned and disinfected regularly with EPA-registered products.

Waterborne microbial contamination can be prevented within water distribution systems by maintaining hot water at the highest temperature allowable by state regulations, preferably 51'C or higher, says the CDC. Cold water should be maintained at less than 20'C, according to the guidelines.

When state regulations do not allow for hot water temperatures to reach above 40.6'C to 49'C, the CDC recommends facilities periodically increase the hot water temperature to 66'C or higher at the point of use or chlorinate the water to flush through the system. Finally, the guidelines state that constant recirculation should be maintained in hot-water distribution systems.

Researchers at Grady Memorial Hospital in Atlanta examined the facility's water system as a potential source of Mycobacterium avium complex (MAC) isolates.5 The study's authors compared 161 respiratory isolate samples from 131 patients to 13 MAC isolates taken from the hospital's hot water system. They discovered that the 25 percent of MAC isolates causing disease and the 65 percent of isolates that did not cause disease were "closely related to or indistinguishable from isolates from the hospital's hot water system."

The researchers note that because MAC obtained from institutional water leads to substantial MAC disease, the elimination of the isolates from hospital water supplies might help prevent the spread of MAC infection. They warn, however, that MAC isolates may regenerate in water supplies to take the place of isolates that have been removed, necessitating "the continuous decontamination of circulating hot water systems to eliminate this reservoir as a source of MAC."

Just a start
While research is key to understanding the role of decontaminated water in causing surgical site infections, much is left to do. As a 2003 study states: "Despite progress in understanding the pathogenesis of nosocomial waterborne infections, outbreaks, pseudo-outbreaks and sporadic infections still occur. Targeted quality control of hospital water, updated procedures for the appropriate use of sterile and non-sterile water, coupled with surveillance constitute the cornerstones of prevention of these infections."6

References:
1. Muscarella, L.F. "Contribution of tap water and environmental surfaces to nosocomial transmission of antibiotic-resistant Pseudomonas aeruginosa." Infection Control and Hospital Epidemiology. April 2004; 25(4): 342-345.
2. Stout JE and Yu VL. "Experiences of the first 16 hospitals using copper-silver ionization for Legionella control: implications for the evaluation of other disinfection modalities." Infect Control and Hosp Epidemiology. August 2003: 24: 563-568.
3. Sheffer P, Stout JE. "Efficacy of new point-of-use water filters to prevent exposure to Legionella and waterborne bacteria." 31st Annual Meeting of the Association for Professionals in Infection Control. 87. 2004. Ref Type: Abstract
4. "Guidelines for Environmental Infection Control in Healthcare Facilities." Centers of Disease Control and Prevention and the Healthcare Infection Control Practices Advisory Committee: 2003.
5. Melissa J. Tobin-D'Angelo, et al. "Hospital Water as a Source of Mycobacterium avium Complex Isolates in Respiratory Specimens." The Journal of Infectious Diseases. 2004: 189: 98-104.
6. Merlani GM, Francioli P. "Established and emerging waterborne nosocomial infections." Current Opinion in Infectious Diseases. 2003; 16: 343-347.