Infection Control Today: Clinical Update

July 1, 2005

Waterborne Pathogens:
Whats Lurking in Your Facilitys Pipes?

By Jennifer
Schraag

The Centers for Disease Control (CDC) reports that nearly 2 million patients
contract infections during their stays in U.S. hospitals. Healthcare-acquired
infections (HAIs) in the U.S. resulted in 88,000 deaths in 1995 and their annual
cost is estimated to be as much as $5.7 billion, with per patient costs of up to
$50,000 per episode.

The numbers involving infection through waterborne pathogens aren't any more
heartwarming. The CDC notes that 23 percent of all cases of Legionnaires disease
reported in the U.S. during the 1980s was acquired in hospitals, and of these
cases, 40 percent died.

"The most common misconception in healthcare settings, and one that
education will eradicate, is that waterborne pathogens are not major
contributors to HAIs," says Joseph S. Cervia. MD, professor of clinical
medicine and pediatrics at the Albert Einstein College of Medicine in New York,
and medical director and senior vice president for Pall Medical of Pall
Corporation.

A review of waterborne-associated nosocomial infections found an estimated
1,400 deaths occur each year in the U.S. as a result of waterborne nosocomial
pneumonias caused by Pseudomonas aeruginosa alone.1
Medical conditions associated with these agents range from colonization of the
respiratory and urinary tracts to deep, disseminated infections that can result
in pneumonia and bloodstream bacteremia.2 With numbers such as
these, it is no doubt that members of the infection control and physical plant
departments are pulling out all the stops to contain this never-ending
prevalence of waterborne pathogens in healthcare facility water supplies.

Prevelant Waterborne Pathogens

A wide variety of bacteria and fungi are prevalent in water. Cervia says the
common waterborne pathogens of primary clinical significance include the
bacterias Legionella pneumophila, P. aeruginosa, Stenotrophomonas spp.,
Mycobacterium spp., Acinetobacter spp., Burkholderia spp., Enterbacter spp.,
Klebsiella spp., Serratia spp., Nocardia spp., Flavobacterium spp.,
and
Aeromaonas spp.

Fungi, such as Aspergillus fumigatus (nosocomial aspergillosis,
thought to be primarily airborne, can be airborne from a water source in the
hospital.3), Fusarium solani and Exophiala
jeanselmei
, are also prevalent.

Finally, protozoa such as Crytosporidium parvum, Giardia lamblia and
Acanthamoeba spp.
also are found in water.

"Amoebae are of particular interest because they are known to harbor
amoeba-resistant bacteria such as L. pneumophila, P. aeruinosa, B. cepacia,
B. pseudomallei, M. avium, M. fortuitum, M. simiae
and Flavobacterium
spp.
," Cervia says. "Amoebae containing amoeba-resistant bacteria
act like a 'Trojan horse' that protects the bacteria from systemic disinfection
technologies and transports them within the healthcare facility water
system."

French scientists conducted a study isolating amoeba-associated alpha
proteobacteria from water samples taken from intensive care unit (ICU) taps and
general hospital reservoir tanks at four university hospitals in
Marseilles.4 Eighty-five ICU patients with nosocomial
pneumonia also were tested. The scientists isolated 64 bacterial strains
identified as Afipia species or close relatives within the Rhizobiaceae subgroup
of alpha proteobacteria. Eleven patients were found to have elevated antibody
titer. No specific antibodies were found among the 100 controls.

Best Practices and Techniques

Transmission occurs via contact, ingestion, aspiration, or aerosolization of
potable water, or via the hands of healthcare workers (HCWs).5
Tap water used for drinking, showering, bathing, ice preparation and rinsing
medical devices presents a potential hazard -- especially to at-risk patients.

"It does depend on the chain of infection," says Stacy LC Coffman,
BS, MBA, CIC, M(ASCP)SM, RM(NRM), an infection control professional at the
University of Iowa Hospitals and Clinics. "You need to have a regular
reservoir and a susceptible host and some way for that susceptible host to be in
the way of vector (water is the vector) to get the bacteria to the
patient."

Dozens of reservoirs lurk in hospitals including hydrotherapy pools and spas,
eyewash stations and even flower vases. Waterbath-based blood/fluid warmers
using water that does not have an added disinfectant to prevent bacterial growth
is another hazard.

Other modes of transmission for waterborne infections may include direct
contact, ingestion of water, indirect-contact transmission (e.g., from an
improperly reprocessed medical device), inhalation of aerosols dispersed from
water sources; and aspiration of contaminated water.6 The
first three modes of transmission are commonly associated with infections caused
by gram-negative bacteria and nontuberculous mycobacteria (NTM). Aerosols
generated from water sources contaminated with Legionella spp. often
serve as the vehicle for introducing legionella to the respiratory tract.

In several hospital outbreaks, patients have been infected through exposure
to contaminated aerosols generated by cooling towers, showers, faucets,
respiratory therapy equipment and room-air humidifiers.7 The
pathogens tend to colonize plumbing systems and point-of-use devices, and are
most commonly located in hot water systems.8

"They love warm temperature (not too hot, not too cold) and prefer
stagnant water in which they can multiply," says Elias Anaissie, MD,
professor of medicine and director of the Division of Supportive Care at the
Myeloma Institute for Research and Therapy at the University of Arkansas for
Medical Sciences.

Matthew J. Arduino, MS, DrPH, lead microbiologist with the Environmental and
Applied Microbiology Team at the Epidemiology and Laboratory Branch Division of
Healthcare Quality Promotion with theCDC, agrees and adds, "Stagnant water
and areas of the distribution system with low flow rates are opportune areas for
biofilms to develop. Most of the waterborne pathogens live in the distribution
system as community members of biofilms."

"When you get any kind of lime build-up or tuberculated surfaces on the
pipes, that is an area where the biofilm can take hold and harbor these harmful
bacteria," Coffman adds.

Is it Seasonal?

The changing of the seasons also brings increased factors to consider.
"Water quality and source of water may change throughout the year so it is
possible that one would see seasonal variations in the types of opportunistic
pathogens," says Arduino. Anaissie agrees, adding, it may be "more
likely in hot weather because of the increasing pressures on water
sources."

A French study examined the seasonal variation in nosocomial Aeromonas
hydrophila
infection. The high summer prevalence of A. hydrophila
infection coincided with periods when water counts from storage tanks were
highest. The scientists concluded monitoring A. hydrophila in hospital
water should particularly be done during the summer months.9

"There are a large variety of waterborne bacterial, fungal, and
protozoan pathogens, and each responds in its own unique way to the changing of
the seasons," explains Cervia. "Seasonal variation of water quality is
a widely recognized phenomenon that is characterized by changes in water
temperature, sediment level, chemical content and the concentration of available
nutrients for waterborne microbes. While waterborne pathogens pose a risk in the
healthcare setting throughout the year, seasonal variations in water quality
impact conditions for biofilm formation and proliferation."

"The key to successful management of waterborne pathogens is to be alert
to the threat that they pose throughout the year and to have the proper controls
in place at all times," Cervia says.

Testing

"Facilities must proactively and routinely test their water for
pathogenic microbes, and they must insure that proper water sampling and
culturing techniques are being employed," Cervia advises. "The use of
improper growth media and incubation conditions will not permit waterborne
microbes to be properly isolated and identified. Many facilities insist that
they do not have a problem with their water, when in fact they are not using the
correct sampling and culturing techniques."

The CDC recommends aggressive disinfection measures for cleaning and
maintaining devices known to transmit legionella, but does not recommend
regularly scheduled microbiologic assays for the bacteria. Arduino points out
the only routine testing recommended by the CDC deals with water and dialysate
for hemodialysis applications.

Scheduled microbiologic monitoring for legionella remains controversial
because the presence of legionella is not necessarily evidence of a potential
for causing disease.

"It is very difficult to do (water culture) surveillance on a regular
basis," Coffman adds. "HICPAC [CDC's Healthcare Infection Control
Practices Advisory Committee] does not have any recommendation on frequency of
culturing. We're lucky here to have a very large microbiology laboratory with a
lot of experience, so all of our tests are done internally with the help of our
university hygienic laboratory. So, we do on a routine basis, a culture of the
water, but we also have available tests for physicians to utilize. The
legionella urinary antigen, or for other organisms such as P. aeruginosa
culture, would be the quickest and most readily available way to determine those
infections.

"You can test water at any given time and it may have organisms in it.
It is never sterile, so it is very important to do a risk assessment of your
patient population and be vigilant about their health by doing targeted
surveillance. It's really important that the clinicians always keep purview of
the patients' health and be looking for these infections as well. It's really a
joint effort to be proactive in preventing an outbreak," she says.

To Report, or Not Report

The prevalence of waterborne HAIs is debated and point of origin makes it
difficult to decipher.

"The problem, I think, is because all of the waterborne organisms are
prevalent in the communities as well as in the hospitals," says Coffman.
"It is really a question of determining if the infection came to the
patient while they were hospitalized. Some of the confusion about the ability to
detect when the patient actually became infected due to incubation of the
disease [which is two to 10 days] -- whether they were at home or in another
care facility or in an acute care hospital -- is, I think, one of the more
difficult reasons why there seems to be a lack of knowledge."

Reporting of such incidences could be one aspect to blame. "A big fear
of lawsuits and bad publicity is the biggest obstacle to offering safer hospital
water," Anaissie points out.

According to the CDC, 43 outbreaks of waterborne nosocomial infections had
been reported in the U.S. in a 2002 study. However, the CDC reports this number
is far from accurate "due to both under-diagnosing and
under-reporting."

"It's kind of controversial in one sense," says Coffman, "many
states do not require reporting of these infections so places do not necessarily
report it. For instance, not all states have a requirement that legionella
pneumonias be reported. Water quality in general being an environmental issue, I
think that's what makes it touchy in many ways. I really don't think it's a
reticence to report per se, rather a lack of understanding of the ecology of the
organisms."

Effective Measures/Case Studies

Waterborne pathogens are present in hot, cold, circulating and stagnant water
and clean-up is challenging, at best. A prominent misconception, according to
Cervia, is that systemic disinfection technologies alone can totally eradicate
waterborne pathogens.

Coffman agrees, "I think one of the common misconceptions in healthcare
settings concerning waterborne pathogens are that it's possible water can even
be sterile. It just isn't possible. Water is a very active, living thing. So the
best thing we can do as healthcare professionals is to consider the fact that
we'll always have these organisms with us."

Approaches of long-term <I>Legionella spp. eradication from
the plumbing system are rarely successful,10 and a recent
survey found that five out of six hospitals in one geographic region of the U.S.
had Legionella bacteria in their water supplies.11 In a
13-year study conducted by one of Coffman's associates at the University of
Iowa, a clone that was present in the 1980s persisted in a particular building
for the duration of the study. "The point is," Coffman explains,
"once it is in your supply, the best you can do is suppress it to its
lowest levels. You will probably never get rid of it."
A similar study examined an outbreak of infections caused by L. pneumophila
serogroup 5.12 The water distribution system had been
sanitized using superheat and flush sanitation, but the epidemic strain was
shown to be persisting in the hospital water outlets several years after its
initial discovery. Finnish scientists also found the diversity of legionella
strains in a hospital water system remains stable over the years, regardless of
the use of recommended disinfection procedures.13

"Facility personnel should develop realistic expectations regarding the
capabilities of these technologies," Cervia says. "Namely that they
cannot totally eradicate resident biofilm in water delivery systems and they
cannot respond effectively to sudden microbial challenges derived from seasonal
water quality variations, new facility construction and facility renovation
activities."

To decrease the prevalence of waterborne pathogens to a controllable level,
combinations of several methods are imperative. Such methods may include
treating water with chlorine dioxide, heavy metal ions such as copper/silver
ions and ultraviolet (UV) light -- all of which have limited the growth of
legionella under laboratory and operating conditions.14

"Any facility contemplating disinfection of its water supply system
without special equipment (e.g., hot water flush), initial installation of a
systemic water disinfection system, or the conversion from one type of system to
another, must perform the appropriate research to evaluate the initial purchase
and installation costs, running costs to maintain the system and expected
efficacy of the technology," Cervia says. "Keeping abreast of the
latest literature on these systems is also essential in order to obtain a
thorough understanding of their strengths and weaknesses with respect to
short-term and long-term efficacy."

After years of clinical studies, sampling and internal testing, Coffman and
her coworkers have come up with a full line of defensive mechanisms to fight
against waterborne pathogens.

"We have had many controls in place for many years, and a variety of
methods have been used here [University of Iowa Hospitals and Clinics],"
she says. "We use a combination of copper/silver and chlorine dioxide, we
have some filters, we are aware of the technology for UV light disinfection.
There are other methods to attempt to clean out the pipes -- should the biofilm
get so large that it is well-entrenched -- and to reduce it to levels until it
is undetectable; that includes superheating and flushing the water. Also
hyperchlorination, if that's possible within the infrastructure."

Another concern for clean-up measures is if the method will be effective for
both hot and cold water. A heat-shock unit was used to decrease legionella and
NTM in the water systems of a tertiary care hospital where nosocomial infections
due to the two genera had been verified.15 Though the unit
decreased the levels found in the hot water system, mycobacteria were constantly
present in the incoming cold water and were never isolated from the circulating
hot water.

"Much attention is focused, and rightfully so, upon L. pneumophila
in the recirculating hot water systems of healthcare facilities," Cervia
says. "However, many microbial pathogens are also present in cold water,
and failure to take the appropriate measures to pay attention to cold water is
to ignore a potentially significant problem. Furthermore, an effort must be made
to understand the physical layout of the water delivery system and not only
correct existing design flaws that lead to water stagnation, but also prevent
the formation of new foci that can promote biofilm formation through water
stagnation."
Taps, faucets, etc., should be factored into regular maintenance needs,
according to Coffman. Others may disagree, citing cost is too exorbitant,
however, "whenever you consider what an outbreak may cost, it is often much
more cost effective to prevent the infection," she points out.

Cervia agrees and says such measures should be undertaken on an ongoing
basis, rather than merely as a reaction to a recognized outbreak. "There is
a misconception that point-of-use filtration as an adjunct to systemic
disinfection technologies is unnecessary and too expensive to maintain. The
value propositions associated with point-of-use filtration, such as cost savings
when compared to the use of bottled water and sterile water, fewer HAIs,
decreased lengths-of-stay and decreased antimicrobial costs, all must be more
effectively communicated."

He adds the use of 0.2 micron filters at the point-of-use (e.g., faucets,
showers, ice machines, drinking fountains, hydrotherapy equipment, etc.) to
complement systemic disinfection technologies by trapping those waterborne
microbes that inevitably survive systemic disinfection, also is imperative.

"The best approach for faucets is to remove aerators completely and
replace them with 0.2 micron point-of-use filters," Cervia says.
"Similarly, conventional shower heads should also be removed and replaced
entirely with point-of-use filters. Finally, in-line filters can be placed
slightly upstream of drinking fountains and ice machines to control waterborne
pathogens. Thorough draining, cleaning, disinfection and drying of such
equipment after each use also are essential in preventing patient-to-patient
microbial transmission via these devices. The use of water filtered to trap
waterborne pathogens can also effectively decrease the inoculum density to which
at-risk patients are exposed."

Preventive Measures

"The issue is not more or less how did it get there, but is it in a
situation where it may be causing disease in a patient," Coffman offers.

Measures must be taken to prevent the spread of these organisms. Measures may
include hand hygiene, glove use, barrier precautions and eliminating potentially
contaminated environmental reservoirs. Water system design may play a big part
in stemming outbreaks, and water should not be allowed to stagnate and should be
circulated at proper temperatures. Storage tanks and calorifiers should be
regularly inspected, cleaned and disinfected as well.

Restricting the use of tap water in high-risk populations interrupts
transmission of waterborne pathogens.16 Anaissie also advises
strict infection control policies which include no water treatment for high-risk
patients during the high-risk periods.

"The expanding base of knowledge concerning the potential pathogenicity
of many waterborne microbes, as well as our knowledge of biofilm formation and
shedding in complex water delivery systems mandates the restriction of tap water
for high-risk patients," Cervia adds.

Coffman says one of her facility's infection control measures is no tap water
use on fresh or open wounds. In addition, "when we isolate legionella from
our water, we will send out water restrictions to prevent transmission to
patients. That includes using bottled water, no showering, brushing teeth only
with bottled water, using sterile water regularly in patient care, cleaning of
their items and that sort of thing. Making sure humidifiers are using clean
water. Restrictions may also include shower restrictions after surgery,"
she says.

Arduino offers further advice. A few key points include, "clean and
disinfect sinks and wash basins on a regular basis; avoid placing decorative
fountains and fish tanks in patient-care areas; and maintain constant
recirculation in hot water distribution systems serving patient-care
areas."

Anaissie adds he'd also like to see the CDC mandate education of HCWs about
the risks of tap water for high-risk patients.

Teamwork is Key

"It's really the only way," according to Coffman. IC teams must
initiate teamwork throughout the facility and keep it at the forefront of
thought in order to win the battle against waterborne pathogens.
Communication between clinicians, IC practitioners and facilities management
personnel is critical to the success of any team-oriented program designed to
control waterborne pathogens," says Cervia. "Effective communication
between clinicians and IC practitioners is essential to identify HAI trends and
to locate geographical "hot spots" within the facility. Facilities
management personnel must in turn properly maintain the systemic disinfection
system. Finally, IC practitioners and facilities management personnel must work
in tandem to develop and implement strategy."
Infection control teams also must work closely with hospital engineering and
technical services departments -- and hospital management -- as well as ensure
physicians and others have a heightened awareness of these types of
HAIs.17

"We work very closely with housekeeping and facilities
maintenance," Coffman says. "Facilities maintenance, for example,
understands the ins and outs of the plumbing system. Knowing the ins and outs of
the plumbing system is very important in controlling waterborne organisms, and
it's usually those people that have worked on those pipes for years that
generally know exactly where the kinks in the pipes are.

"Our facility's housekeeping has been flushing the water in patient
rooms while they are in cleaning," Coffman continues. "So, they will
enter a patient's room and turn on the water in the sink, and the water in the
shower, and let them run for the five or ten minutes it takes them to do the
daily cleaning of the patient's room."


References

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8;162(13):1483-92.
2. Centers for Disease Control and Prevention. "Guideline for Environmental
Infection Control in Health-Care Facilities, 2003." Recommendations of CDC
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3. Anaissie EJ, Costa SF. "Nosocomial aspergillosis is waterborne."
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