Water: Is It a Breeding Ground for Bacteria in Your Facility?
By Susan Burns, BSMT, CIC
In March, this publication ran an article on the hidden bacteria and fungi in whirlpool baths, but what other sources of pathogens are found hiding in hospitals? It is known that bacterium thrive in water, yet water is ever-present in healthcare facilities. Water enters the hospital through water distribution systems. There is water in ice machines, showerheads, toilets and taps. Water is even contained in many of the devices used in the operating room. Outbreaks of infection have been traced back to all of these sources.
Where is the Water?
Water distribution systems are a common source of outbreaks of all types, some common and others more obscure. Emmerson reported that, while more than 40 Legionella ssp. are known, most outbreaks of Legionnaires' disease are caused by Legionella pneumophila serotypes 1 and 6. Six hundred to 1,300 cases are reported each year in the United States, although these figures may be underreported. Legionellae are naturally distributed in aquatic environments, growing best at temperatures of 25 degrees Centigrade to 42 degrees C. Colonization is enhanced by water stagnation and sediment build-up as a result of alterations in the plumbing of the complex distribution systems often found in hospital hot water systems.1
Other contaminates include fusariosis, an opportunistic mold infection that was recovered from 162 (57 percent) of 283 water systems sampled in a recent study of infections in hospital water systems. The study was conducted in a hospital with cases of known fusarial infections. Fusarium species was found in 72 (88 percent) of the 92 sink drains tested; 12 (16 percent) of 71 sink faucet aerators and 2 (8 percent) of 26 showerheads. Fusarium solani was isolated from the hospital water tank and aerosolization of Fusarium species was documented after running the showers.2
Nosocomial aspergillosis is primarily a disease caused by Aspergillus sp. organisms in the air, but also has been found in hospital water systems. In March 2002, research was published on a three-year prospective study of the air, environmental surfaces and water distribution system of a hospital. The study found Aspergillus sp. in the hospital's water system and correlated the rank orders of Aspergillus sp. recovered from the water and air. Higher concentrations of airborne Aspergillus were found in the bathrooms, where water use was highest. Water from tanks yielded higher counts of colony-forming units than did municiple water.3 Additionally, Chryseobacterium (Flavobacterium) meningosepticum has been found in sink taps.4
Given this background, it is easy to understand the transfer of these pathogens to environmental reservoirs, such as showerheads, toilets or tap water. Fourteen cases of urinary tract infection by Pseudomonas aeruginosa occurred in three months in a pediatric surgical unit in Paris. A study of the incidence indicates a possible direct contamination to tap water. It is thought that handwashing in this tap water contaminated the patients.5 Who knows? It may be that washing hands using waterless hand products, rather than soap and water, will prevent future outbreaks from potentially contaminated tap water. Use of waterless hand products is now recommended under federal guidelines.6
The importance of maintaining a higher water temperature was emphasized in a yearlong study done by Sniadack, et al. A pseudo-outbreak of Mycobacterium xenopi was attributed to exposure of clinical specimens to tap water, including rinsing of bronchoscopes with tap water after disinfection, irrigation with tap water during colonoscopy, gargling with tap water before sputum collection and collecting urine in recently-rinsed bedpans. Mycobacterium xenopi was isolated from tap water in 20 of 24 patient rooms tested, the endoscopy suite and the central hot water mixing tank. The pseudo-outbreak occurred following a decrease in the hot water temperature from 130 degrees Fahrenheit to 120 degrees F.7
Devices used in hospital settings may contain water or water may be used in conjunction with the device. Waterbath-based blood/fluid warmers contain warm water that can be a source of gram-negative bacilli in the operating room. Endocarditis, bacteremia and peritonitis with Pseudomonas sp. or Acinetobacter sp. have been traced to contaminated 37 degree C waterbaths.8-9 Sitting just inches from the sterile field in the OR, these waterbaths may leak and indirectly transmit pathogens to patients.
As an infection prevention specialist at Henry Ford Health System in Detroit, I reported a possible link between surgical infections and a waterbath fluid warmer. During a two-week period, four patients developed a bloodstream infection within 2 to 10 days of neurosurgical procedures.
As part of the investigation, I cultured the water from the Hotline/Level 1 fluid warmers used to administer IV fluids during these procedures. Microbiology cultures of the water were found to have high levels of bacterial contamination (greater than 100,000 colonies of multiple gram negative organisms). I observed that each time the disposable IV connector was connected or disconnected to the warming unit, the open ports on the side of the unit allowed the water to spray out and potentially contaminate the clinician's hands and/or the OR.10
Waterbath-based blood/fluid warmers utilizing water that does not have an added disinfectant to prevent bacterial growth is a hazard that jeopardizes patient safety. This potential source of contamination can be avoided by replacing waterbath-based technology with dry heat fluid warming systems, thereby avoiding continual surveillance of cleaning and disinfection methods necessary for water-based technology.
Excessive levels of gram-negative bacteria in the dialysate of hemodialyzers have been shown to be responsible for pyrogenic reactions or bacteremia. This hazard is caused either by the organism gaining entrance to the blood from the dialysate or by endotoxins from gram-negative bacteria associated with the water and dialysate passing intact through membranes and causing pyrogenic reactions.
It also has been demonstrated that certain types of waterborne bacteria have the capability to survive and multiply in distilled, deionized, reverse-osmosis and softened water, all of which have been used to supply water for hemodialysis. Based on this data, it has been suggested by the Centers for Disease Control and Prevention (CDC) that water used to prepare dialysis fluid should be sampled monthly and that the supply water should have less than 200 bacteria/mL. The dialysate should be sampled monthly and should contain less than 2,000 bacteria/mL.11
In a 1984 study, sterile irrigation solution was tested for bacterial contamination. At the end of 13 of 21 operations, the solution tested displayed growth of Staphylococcus epidermidis, diphtheroid rods and/or other species. The study concluded that irrigation solutions kept in open bowls during an operation, are a potential source of contamination.12 In a similar study, Baird, et al cultured samples of splash basin fluids at the end of 78 randomly-selected orthopedic operations. Fifty-eight (74 percent) of the specimens were positive on culture. This study demonstrated that splash basin fluid is frequently contaminated and may be a source of wound contamination.13
In addition to devices, many factors related to hospital facilities, equipment, supplies, procedures and patient-care practices may be responsible for the transmission of infections to patients. For example, a recent study looked at seven in-use cotton samples and three cotton balls soaked in sterile, distilled water in canisters seven days after they were prepared in hospitals. All samples were contaminated with bacteria including 10 log 6 to 10 log 7 colony-forming units/mL of Pseudomonas aeruginosa. The study concluded that when using cotton gauze and cotton balls containing water, contamination should be expected.14
Contaminated ice and ice machines may occasionally be a source for nosocomial infections. Several reports have linked nosocomial epidemics or pseudoepidemics to contaminated ice or ice machines.8,15
Finally, water has been implicated in causing infection through such innocuous objects as a child's water toy.16 Rutala and Weber listed dozens of other reservoirs in hospitals, including eyewash stations, dialysis water, ice baths, tub immersion and flower vases.8
Why is Water Bad?
When water is used in the healthcare setting, the chance of transmitting infections exists. A century ago, a patient entering the hospital for surgery had a better-than-ever chance of picking up an infection. Now, only 5 percent of surgery patients get a new infection as part of their stay. Still, the CDC estimates that such infections cost $4.5 billion in 1995 and contributed to more than 88,000 deaths. Measured by patient days in the hospital, infections increased more than one-third from 1975-1995.17 More recent data on hospital-wide infection rates is difficult to assess. The hospital-wide component of the National Nosocomial Infections Surveillance System (NNIS) report has been eliminated, according to the most recent report from this organization, as it required considerable time and resources and did not yield rates that were meaningful for national comparison purposes.18
Several non-coliform bacteria can replicate in relatively pure water, including Pseudomonas aeruginosa, Burkholderia cepacia, Serratia marcescens, Acinetobacter calcoaceticus, Flavobacterium meningosepticum, Aeromonas hydrophila and certain nontuberculous mycobacteria. Reports that gram-negative bacilli may be isolated in large numbers from water-related sources raises concerns that these pathogens may, on occasion, be sources of nosocomial infection.8
In addition, nosocomial blood stream infections (BSIs) have been traced back to water in the OR. Jarvis, et al write, "In nearly all of these situations, water sources or healthcare workers (HCWs)' hands play a critical role in the contaminating event." Jarvis outlines reports that demonstrate common methods by which water inadvertently contaminate a device. A study by Rudnick, et al outlines nosocomial polymicrobal BSIs in open-heart surgery patients that were traced to intravascular devices and pressure transducers that were set up (prefilled and left without line endcaps) the night before a surgical procedure. These devices were presumably contaminated by maintenance personnel spraying water from a hose connected to a malfunctioning disinfectant proportioning device during routine operating room cleaning at the end of the day.19
Jarvis points out that by following current guidelines, which stipulate that setup of equipment should happen as near as possible to time of employment (not the night before), these types of infections can be easily avoided.16
What Else Can be Done?
Aside from suggestions made above, Stout and Yu argue that controlling some types of outbreaks related to water (e.g. Legionella sp.) could be greatly decreased through routine environmental cultures of water sources. The authors argue that Legionnaires' disease remains underdiagnosed largely because of failure to adopt in-house laboratory testing for Legionella. They argue that evidence-based medicine is a rational, cost-effective approach to controlling outbreaks.20
Water system design plays a big part is stemming the outbreaks. Water systems should be designed to minimize colonization and multiplication of bacteria. Water should not be allowed to stagnate and should be circulated at temperatures below 20 degrees C or above 60 degrees C. Storage tanks and calorifiers should be regularly inspected, cleaned and disinfected. Infections can be minimized by good engineering practices supplemented by heat, disinfectants, and biocides.1
The best advice is to eliminate water where possible. This will greatly decrease chances of contamination. Replace all water-containing devices with those that do not require water to work, keep potentially contaminated water away from the patient, and include waterless hand products in your hand hygiene program. Disinfect, either chemically or by heating, and monitor water when it cannot be eliminated. Prevent infection from potentially contaminated water.
Susan M. Burns, BSMT, CIC, is the infection prevention specialist for Henry Ford Health System in Detroit. She serves as the 2002 president of the Greater Detroit chapter of the Association for Professionals in Infection Control and Epidemiology (APIC).