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By Susan Burns, BSMT, CIC
In March, this publication ran an article on the hidden bacteria and fungi inwhirlpool baths, but what other sources of pathogens are found hiding inhospitals? It is known that bacterium thrive in water, yet water is ever-presentin healthcare facilities. Water enters the hospital through water distributionsystems. There is water in ice machines, showerheads, toilets and taps. Water iseven contained in many of the devices used in the operating room. Outbreaks ofinfection 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 40Legionella ssp. are known, most outbreaks of Legionnaires' disease are caused byLegionella pneumophila serotypes 1 and 6. Six hundred to 1,300 cases arereported each year in the United States, although these figures may beunderreported. 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 resultof alterations in the plumbing of the complex distribution systems often foundin hospital hot water systems.1
Other contaminates include fusariosis, an opportunistic mold infection thatwas recovered from 162 (57 percent) of 283 water systems sampled in a recentstudy of infections in hospital water systems. The study was conducted in ahospital with cases of known fusarial infections. Fusarium species was found in72 (88 percent) of the 92 sink drains tested; 12 (16 percent) of 71 sink faucetaerators and 2 (8 percent) of 26 showerheads. Fusarium solani was isolated fromthe hospital water tank and aerosolization of Fusarium species was documentedafter 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. InMarch 2002, research was published on a three-year prospective study of the air,environmental surfaces and water distribution system of a hospital. The studyfound Aspergillus sp. in the hospital's water system and correlated the rankorders of Aspergillus sp. recovered from the water and air. Higherconcentrations of airborne Aspergillus were found in the bathrooms, where wateruse was highest. Water from tanks yielded higher counts of colony-forming unitsthan 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 thesepathogens to environmental reservoirs, such as showerheads, toilets or tapwater. Fourteen cases of urinary tract infection by Pseudomonas aeruginosaoccurred in three months in a pediatric surgical unit in Paris. A study of theincidence indicates a possible direct contamination to tap water. It is thoughtthat handwashing in this tap water contaminated the patients.5 Whoknows? It may be that washing hands using waterless hand products, rather thansoap and water, will prevent future outbreaks from potentially contaminated tapwater. Use of waterless hand products is now recommended under federalguidelines.6
The importance of maintaining a higher water temperature was emphasized in ayearlong study done by Sniadack, et al. A pseudo-outbreak of Mycobacteriumxenopi was attributed to exposure of clinical specimens to tap water, includingrinsing of bronchoscopes with tap water after disinfection, irrigation with tapwater during colonoscopy, gargling with tap water before sputum collection andcollecting urine in recently-rinsed bedpans. Mycobacterium xenopi was isolatedfrom tap water in 20 of 24 patient rooms tested, the endoscopy suite and thecentral hot water mixing tank. The pseudo-outbreak occurred following a decreasein 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 inconjunction with the device. Waterbath-based blood/fluid warmers contain warmwater that can be a source of gram-negative bacilli in the operating room.Endocarditis, bacteremia and peritonitis with Pseudomonas sp. or Acinetobactersp. have been traced to contaminated 37 degree C waterbaths.8-9Sitting just inches from the sterile field in the OR, these waterbaths may leakand 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 fluidwarmer. During a two-week period, four patients developed a bloodstreaminfection within 2 to 10 days of neurosurgical procedures.
As part of the investigation, I cultured the water from the Hotline/Level 1fluid warmers used to administer IV fluids during these procedures. Microbiologycultures of the water were found to have high levels of bacterial contamination(greater than 100,000 colonies of multiple gram negative organisms). I observedthat each time the disposable IV connector was connected or disconnected to thewarming unit, the open ports on the side of the unit allowed the water to sprayout and potentially contaminate the clinician's hands and/or the OR.10
Waterbath-based blood/fluid warmers utilizing water that does not have anadded disinfectant to prevent bacterial growth is a hazard that jeopardizespatient safety. This potential source of contamination can be avoided byreplacing waterbath-based technology with dry heat fluid warming systems,thereby avoiding continual surveillance of cleaning and disinfection methodsnecessary for water-based technology.
Excessive levels of gram-negative bacteria in the dialysate of hemodialyzershave been shown to be responsible for pyrogenic reactions or bacteremia. Thishazard is caused either by the organism gaining entrance to the blood from thedialysate or by endotoxins from gram-negative bacteria associated with the waterand dialysate passing intact through membranes and causing pyrogenic reactions.
It also has been demonstrated that certain types of waterborne bacteria havethe capability to survive and multiply in distilled, deionized, reverse-osmosisand 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 andPrevention (CDC) that water used to prepare dialysis fluid should be sampledmonthly and that the supply water should have less than 200 bacteria/mL. Thedialysate should be sampled monthly and should contain less than 2,000bacteria/mL.11
In a 1984 study, sterile irrigation solution was tested for bacterialcontamination. At the end of 13 of 21 operations, the solution tested displayedgrowth of Staphylococcus epidermidis, diphtheroid rods and/or other species. Thestudy concluded that irrigation solutions kept in open bowls during anoperation, are a potential source of contamination.12 In a similarstudy, Baird, et al cultured samples of splash basin fluids at the end of 78randomly-selected orthopedic operations. Fifty-eight (74 percent) of thespecimens were positive on culture. This study demonstrated that splash basinfluid 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 responsiblefor the transmission of infections to patients. For example, a recent studylooked 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 7colony-forming units/mL of Pseudomonas aeruginosa. The study concluded that whenusing cotton gauze and cotton balls containing water, contamination should beexpected.14
Contaminated ice and ice machines may occasionally be a source for nosocomialinfections. Several reports have linked nosocomial epidemics or pseudoepidemicsto contaminated ice or ice machines.8,15
Finally, water has been implicated in causing infection through suchinnocuous objects as a child's water toy.16 Rutala and Weber listeddozens of other reservoirs in hospitals, including eyewash stations, dialysiswater, ice baths, tub immersion and flower vases.8
Why is Water Bad?
When water is used in the healthcare setting, the chance of transmittinginfections exists. A century ago, a patient entering the hospital for surgeryhad a better-than-ever chance of picking up an infection. Now, only 5 percent ofsurgery patients get a new infection as part of their stay. Still, the CDCestimates that such infections cost $4.5 billion in 1995 and contributed to morethan 88,000 deaths. Measured by patient days in the hospital, infectionsincreased more than one-third from 1975-1995.17 More recent data onhospital-wide infection rates is difficult to assess. The hospital-widecomponent of the National Nosocomial Infections Surveillance System (NNIS)report has been eliminated, according to the most recent report from thisorganization, as it required considerable time and resources and did not yieldrates 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, Aeromonashydrophila and certain nontuberculous mycobacteria. Reports that gram-negativebacilli may be isolated in large numbers from water-related sources raisesconcerns that these pathogens may, on occasion, be sources of nosocomialinfection.8
In addition, nosocomial blood stream infections (BSIs) have been traced backto water in the OR. Jarvis, et al write, "In nearly all of thesesituations, water sources or healthcare workers (HCWs)' hands play a criticalrole in the contaminating event." Jarvis outlines reports that demonstratecommon methods by which water inadvertently contaminate a device. A study byRudnick, et al outlines nosocomial polymicrobal BSIs in open-heart surgerypatients that were traced to intravascular devices and pressure transducers thatwere set up (prefilled and left without line endcaps) the night before asurgical procedure. These devices were presumably contaminated by maintenancepersonnel spraying water from a hose connected to a malfunctioning disinfectantproportioning device during routine operating room cleaning at the end of theday.19
Jarvis points out that by following current guidelines, which stipulate thatsetup of equipment should happen as near as possible to time of employment (notthe 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 sometypes of outbreaks related to water (e.g. Legionella sp.) could be greatlydecreased through routine environmental cultures of water sources. The authorsargue that Legionnaires' disease remains underdiagnosed largely because offailure to adopt in-house laboratory testing for Legionella. They argue thatevidence-based medicine is a rational, cost-effective approach to controllingoutbreaks.20
Water system design plays a big part is stemming the outbreaks. Water systemsshould be designed to minimize colonization and multiplication of bacteria.Water should not be allowed to stagnate and should be circulated at temperaturesbelow 20 degrees C or above 60 degrees C. Storage tanks and calorifiers shouldbe regularly inspected, cleaned and disinfected. Infections can be minimized bygood engineering practices supplemented by heat, disinfectants, and biocides.1
The best advice is to eliminate water where possible. This will greatlydecrease chances of contamination. Replace all water-containing devices withthose that do not require water to work, keep potentially contaminated wateraway from the patient, and include waterless hand products in your hand hygieneprogram. Disinfect, either chemically or by heating, and monitor water when itcannot be eliminated. Prevent infection from potentially contaminated water.
Susan M. Burns, BSMT, CIC, is the infection prevention specialist forHenry Ford Health System in Detroit. She serves as the 2002 president of theGreater Detroit chapter of the Association for Professionals in InfectionControl and Epidemiology (APIC).