Decreasing exposure of equine patients and veterinary personnel to pathogens is an
important aspect of the infection control program. The ideal situation would be to
prevent entrance of pathogens into a veterinary hospital; however, the nature of medicine
is such that pathogen carriage by clinically affected animals as well as by subclinical
carriers is always present. Therefore, containment of pathogens is essential. Protocols
to contain pathogens and limit the risk of spread within a facility are variable and
depend on a variety of factors involving the facility and the animal caseload. Among
the factors that must be considered when attempting to limit the risk of transmission
of pathogens in a veterinary hospital are barrier precautions, isolation protocols,
and hygiene practices of veterinary personnel.
Barrier precautions
Barrier techniques, those used to prevent contamination of hospital personnel with
pathogens from animals or their environment, have been an important part of the infection
control program for decades. By preventing contamination of hospital personnel's skin,
regular clothing, personal items, and medical instruments, pathogen transmission from
equine patients to their caregivers can be reduced. Barrier techniques may also be
used to reduce the risk of infection of other hospitalized patients from hospital
personnel's regular clothing or equipment that might act as fomites and to reduce
the risk of infection of hospitalized animals with pathogens from the resident microflora
of hospital personnel.
In human medicine, prevention of transmission of bloodborne pathogens, such as HIV,
hepatitis B virus, and hepatitis C virus, from patients to health care workers (HCWs)
is a major concern [1], [2]. The epidemic of HIV in the general population and HCWs
led to the development of universal precautions. Based on universal precautions, infection
control practices are applied to all patients, regardless of known or suspected infectious
disease status, and emphasize the prevention of any contact with blood or certain
body fluids [2]. In veterinary medicine, there currently are not the same concerns
about transmission of bloodborne pathogens to veterinary personnel. Indeed, the attitude
toward blood contamination in veterinary medicine is somewhat cavalier. Nevertheless,
it is critical to remember that new diseases are emerging at all times and that many
of these new diseases are zoonotic. Just because there is minimal concern about bloodborne
pathogens of horses at this point in time does not mean that there is no risk posed
by exposure to equine blood now or in the future. It is prudent to ensure that adequate
precautions be taken now rather than waiting for the infection of large numbers of
veterinary personnel to stimulate change, as occurred in human medicine.
Although the initial focus of barrier precautions in human hospitals was prevention
of disease in HCWs, increasing attention has been paid to the role of HCWs in dissemination
of pathogens in human hospitals. The dissemination of multidrug-resistant (MDR) pathogens
and the severe impact of MDR infections in human hospitals have led to changes in
protocols to limit the spread of these organisms within hospitals. The use of barrier
precautions has been an important part of these protocols; however, the efficacy and
necessity of these protocols are unclear.
In the United States, the Occupational Safety and Health Administration (OSHA) has
mandated that HCWs have access to appropriate personal protective equipment. The type
of personal protective equipment required for each situation has been left to the
discretion of the employee and employer; however, potentially contaminated body fluids
are not to reach the employee's work clothes or street clothes, undergarments, skin,
eyes, mouth, or other mucous membranes [3]. The level of barrier protection required
would thus depend on the risk of contact with body fluids of concern, the potential
for splashing or aerosol exposure, the volume of fluid that might be produced, and
the duration of exposure [1]. These same points are relevant in the veterinary context.
Veterinary hospitals need to be aware of OSHA or equivalent rules to provide a safe
workplace and avoid potential liability. Thus, the development of appropriate infection
control protocols, including barrier precautions, is required. In general, consideration
must be given to the route of pathogen transmission: contact (direct or indirect),
droplet, airborne, common vehicle (eg, equipment, medical devices), and vector borne.
Standard protective outerwear
Standard protective outerwear includes clean coveralls, laboratory coats, scrubs,
or other dedicated clothing (eg, hospital uniforms). Protective outerwear should be
changed whenever it is visibly soiled or otherwise contaminated with body fluids perceived
or known to pose a risk (eg, feces, blood, nasal exudates, urine or uterine fluid).
Additionally, outerwear should be changed frequently (at least daily), because gross
contamination does not need to be present for pathogen contamination to have occurred.
Hospital personnel should change their hospital outerwear before leaving the building;
coveralls, laboratory coats, surgical scrubs, and related items should not be worn
out of the hospital setting. Wearing protective outerwear home increases the risk
of transmission of pathogens from the hospital to the household and from animals at
home to hospitalized animals. All veterinary hospitals should provide laundry services
so that outerwear does not leave the building.
Gloves
Gloves are an important component of most, if not all, barrier protocols. The Centers
for Disease Control and Prevention (CDC) recommend glove use by HCWs to reduce the
risk of transmission of infections from patients to personnel, to prevent HCW skin
flora from being transmitted to patients, and to reduce transient contamination of
the skin on hands of personnel by microorganisms that can be transmitted from one
patient to another [2].
Glove use has been shown to be an effective means of reducing pathogen transmission
in human medicine. The use of gloves during peripheral venous catheter placement has
been demonstrated to reduce the frequency of complications in human patients compared
with regular handwashing [4]. Glove use has been an important part of successful infection
control programs in human hospitals [5], [6], [7], although the relative effect of
glove use versus concurrently applied measures is sometimes difficult to interpret.
It has been suggested that universal glove use in human hospitals might be preferable
for prevention of transmission of MDR bacteria, because as many as 5 to 10 patients
may be colonized for every patient known to be infected [8].
To the author's knowledge, there are no published standards for glove use in veterinary
hospitals apart from the use of sterile gloves during surgery. Examination gloves
that are clean but not sterile are often used when handling wounds, infected body
sites, and animals known or likely to be shedding pathogens in body fluids from orifices
or on their skin; however, widespread use of examination gloves and protocols regarding
glove use are not common. At the Ontario Veterinary College Veterinary Teaching Hospital
(OVC-VTH), a policy requiring glove use for any contact with equine patients was instituted
in response to nosocomial and zoonotic transmission of methicillin-resistant Staphylococcus
aureus (MRSA). Whether this has reduced the transmission of MRSA or other MDR bacteria
at the OVC-VTH is under investigation. Objective data are not available to help develop
glove use protocols for veterinary hospitals; however, it is reasonable to recommend
that gloves be worn whenever there might be contact with nasal secretions; feces;
or discharge from surgical incisions, draining abscesses, or wounds.
Education of hospital personnel is important so that glove use does not result in
less emphasis on hand hygiene. Gloves may have small inapparent defects or be torn
during use, and hands may be contaminated while removing gloves. Hand hygiene measures
should be performed immediately after glove removal. If gloves are used to handle
potentially contaminated items and not immediately discarded, they are not acting
as an effective barrier in preventing the spread of nosocomial pathogens to surfaces
or other patients, although they may still be protecting the wearer. Care should be
taken to remove gloves before handling items like pens, stethoscopes, thermometers,
stall surfaces, medical records, pagers, telephones, and cabinet or door handles.
Gloves should be changed between all patient contacts.
Gowns
For more than a century, gowns have been used to prevent transmission of disease to
HCWs and patients [1]. Gowns have most commonly been used in surgery; however, their
use in hospital wards is increasing. The CDC has produced guidelines stating that
“gowns are worn by personnel during the care of patients infected with epidemiologically
important microorganisms to reduce the opportunity for transmission of pathogens from
patients or items in their environment to other patients or environments” [2]. Gowns
should be worn whenever direct contact with the patient or indirect contact with the
environment or patient care items may result in transmission of pathogens.
A variety of types of gowns are available in terms of the degree of body coverage
and the material the gown is made of. The ideal barrier gown would cover all areas
of the body that might become contaminated, prevent penetration of liquids, be of
adequate strength to resist tearing and puncture under normal activities, be comfortable
to wear for long periods, be available in appropriate sizes for all personnel, be
nonabrasive to skin, and be of acceptable cost [1].
Neither the overall effectiveness of gowning nor the effectiveness of different gowns
in veterinary situations has been adequately evaluated. All these factors must be
considered when choosing a gown for use in a hospital (nonsurgical) situation. In
particular, the ability to resist contamination during anticipated animal contacts,
ease of use, and cost are important. The most likely problem in veterinary practice
is poor resistance to liquids, especially under direct contact or pressure. In equine
medicine, there is a greater likelihood of high-volume contact with fluids (ie, diarrheic
horse) or direct contact with patient surfaces that would have moist secretions or
excretions (ie, horse with nasal discharge rubbing against personnel). These types
of high-risk situations must be considered when choosing an appropriate gown. Additionally,
prolonged contact with potentially infectious patients, such as with 24-hour nursing
care of neonatal intensive care unit foals, creates additional problems. If gowns
do not cover the entire body (eg, gowns that do not cover the lower extremities) and
hospital personnel are in prolonged contact situations with foals, the likelihood
of contamination is high. Full body gowns may be more appropriate in these situations.
There is more evidence supporting the effectiveness of gowns in preventing disease
transmission to HCWs compared with the prevention of spread of nosocomial disease
[1]. Some studies have failed to show any benefit of gowning in specific situations,
such as newborn units and neonatal intensive care units [9], [10], [11], whereas others
have reported significant beneficial effects on nosocomial disease [12], [13], [14].
In particular, the use of gowns that offer little resistance to liquid penetration
and those that leave the lower extremities exposed have been questioned. Perhaps the
main advantage of gowns in these situations is raising awareness of the potential
infectious nature of the patient and encouraging the concurrent use of other appropriate
infection control protocols.
Eye protection
Protective eyewear, including goggles and face shields, is used in human medicine
during procedures in which sprays of blood, body fluids, and secretions may occur
[2], and the use of these items is mandated in some instances by the OSHA bloodborne
pathogens final rule [3]. The use of eye protection in equine hospitals is extremely
uncommon, perhaps justifiably so, considering the low prevalence of bloodborne zoonotic
pathogens in horses. Nevertheless, it would be prudent to consider the use of these
items when spraying of potentially infected secretions may occur.
Masks
Normal surgical masks may be effective against the spread of large particle droplets
that are transmitted by close contact and travel only short distances (up to 3 ft)
from infected patients [2]. Transmission of severe acute respiratory syndrome to HCWs
prompted re-evaluation of the effectiveness of normal surgical masks in the prevention
of disease transmission. One study reported that wearing of surgical or N95 masks
(but not paper masks) by staff was associated with protection [15]. Other authors
have questioned the overall effectiveness of surgical masks in hospital situations
[16].
Airborne transmission of zoonotic pathogens from horse to veterinary personnel is
thought to be of minimal concern in most hospital settings, and mask use is uncommon
in veterinary hospitals apart from surgical procedures. Surgical masks might be useful
for reducing transmission of MRSA. Although MRSA is not considered to be spread via
the airborne route, the main location of colonization of MRSA in hospital personnel
is in the nasal passages, and hand-to-nose contact is frequent. Thus, mask use prevents
direct contact between the hand and nose, thereby decreasing hand contamination or
decreasing the risk of inoculation of the nose after contamination of the hands during
contact with a horse. The actual benefit of masks during short-term patient contact
situations is unclear.
Use of barrier precautions in equine hospitals
Basic barrier techniques must be used in all veterinary hospitals. Clean protective
outerwear must be worn by all hospital personnel. The use of other barrier techniques
is much more variable and should be directed at control of specific diseases or syndromes.
It is important that written protocols outlining the required level of barrier protection
be available. Gowns and overboots are the most commonly used items for additional
barrier protection, but masks, caps, and eye protection may be required at times.
In some facilities, overboots are not used but personnel are required to wear rubber
boots that are easy to disinfect, and disinfection of boots is required after exiting
potentially contaminated areas.
Determination of the required level of barrier precautions may be based on clinical
findings (ie, diarrhea, fever of unknown origin, nasal discharge), farm history (eg,
endemic disease, recent infectious diseases on farms), or the nature of the disease.
At some hospitals, mainly those in regions where salmonellosis is of particular concern,
all horses with colic are treated as if they may be shedding Salmonella. Common protocols
for these equine patients include the use of gloves, gowns, and overboots; restriction
of movement in the hospital; and provision of dedicated medical equipment (eg, thermometers,
nasogastric tubes, buckets). An understanding of the incidence of pathogen shedding
by certain groups within the equine population is required to define appropriate protocols.
Thus, ongoing active and passive surveillance of nosocomial infection rates plays
a key role in determination of the appropriate barrier protocols.
Limitations to barrier precautions
Barrier precautions, as a whole, have been successful in controlling some outbreaks
of nosocomial disease [17], [18] but not others [19]. The reasons why barrier precautions
are variably effective is difficult to determine; however, nosocomial infection is
a complex multifactorial process, and the individual effects of certain factors are
difficult to discern. Like most other infection control methods, barrier precautions
are only effective if used appropriately, and poor compliance is an ever-present concern
that can have a negative impact on the entire infection control program. Failure of
barrier techniques may involve inherent weaknesses in the items used, inappropriate
selection of items, inappropriate use of items, inadequate training of personnel,
or the inherent inability of barrier precautions to prevent pathogen transmission
completely in all cases. It is important that barrier items do not create a false
sense of security. Barrier items are useful but by no means 100% effective at preventing
transmission of pathogens. It is critical that veterinary personnel use all adjunctive
infection control techniques (ie, hand hygiene) and not rely solely on barriers. The
reported variability in the benefits of barrier precautions should not dissuade hospitals
from implementing these protocols.
Isolation units and isolation protocols
Isolation units
The use of quarantine to prevent transmission of human or animal disease dates back
to biblical times and was widespread in the Middle Ages [20], predating understanding
and acceptance of the “germ theory.” Published recommendations for isolation protocols
appeared as early as 1877 [21]. The early emphasis was on segregating certain patients
in “infectious disease hospitals,” which continued to have high levels of nosocomial
disease because of a lack of barrier precautions, asepsis, and separation of patients
according to their disease [2]. These hospitals were closed over time as better infection
control practices and hospital designs were developed [2].
Isolation protocols are designed with two basic goals in mind: prevention of transmission
of pathogens from infected animals to other animals, people, or the hospital environment
and prevention of nosocomial infection to high-risk individuals.
Guidelines published by the CDC in 1970 and 1975 recommended that hospitals divide
isolation precautions into a variety of categories: strict isolation, respiratory
isolation, protective isolation, enteric precautions, wound and skin precautions,
discharge precautions, and blood precautions [22], [23]. The protocols for each category
were based on epidemiologic features of diseases in the given category. In 1983, guidelines
were revised to allow for more decision making on the part of the users [24]. Hospital
infection control committees were given broader powers to develop their own protocols
considering the circumstances and environment specific to the hospital. Category-specific
guidelines were modified and consisted of strict isolation, contact isolation, respiratory
isolation, tuberculosis isolation, enteric precautions, drainage/secretion procedures,
and blood and body fluid precautions [24]. Further changes occurred later, largely
in response to the HIV epidemic, and these earlier categories may be most relevant
to veterinary hospitals at this point.
In veterinary hospitals, there has been less attention paid to the development of
standardized protocols for different diseases or categories. It is logical, however,
that veterinary hospitals design appropriate guidelines to deal with diseases of concern
in their area and hospital. Most isolation protocols have been developed to limit
transmission of Salmonella. Whether all these protocols are necessary for other pathogens,
such as viral respiratory pathogens and MDR bacteria, needs consideration, as does
whether extra precautions are required in some instances. At a minimum, strict isolation,
respiratory isolation, contact isolation, enteric precautions, and drainage/secretion
isolation protocols based on CDC recommendations should be considered, and veterinary-specific
guidelines for working with those classes should be developed.
Identification of the isolation status of patients is critical. This is particularly
important when horses may be housed under isolation protocols implemented in the main
hospital. Appropriate signage should be used to make it clear to all personnel that
the animal may be infectious and that additional protocols must be used. At the Colorado
State University Veterinary Teaching Hospital, a color-coding system is used to indicate
the infectious disease status of each patient (P. Morley, DVM, PhD, personal communication,
2003). Under this system, adhesive dots are placed on the stall cards of all animals.
Red dots indicate animals with a known highly contagious disease. Yellow dots indicate
that the animal is suspected of having an infectious disease or is at increased risk
of acquiring an infectious disease. Green dots indicate that the animal is not suspected
of carrying a relevant infectious agent and that it is not at an increased risk of
acquiring an infectious agent compared with the general hospital population. This
type of system is easy to apply and easy to understand and should be considered in
all hospitals. Additionally, more prominent signs can be used to indicate certain
concerns (ie, Salmonella, MRSA, rabies suspect) more clearly to all personnel.
Isolation units should be designed so that, apart from surgical procedures, horses
rarely, if ever, have to leave the unit. Stocks, examination areas, and weight scales
should be available if possible. The isolation unit should be designed so that there
is minimal movement of personnel and items between it and the main hospital. Changing
rooms with showers are ideally present in the unit. Preferably, the isolation unit
should be physically separated from the main hospital. In cold snowy climates, this
may be problematic because of the difficulty in moving personnel, animals, and supplies.
If the isolation unit is properly designed and largely self-sufficient in terms of
supplies and staffing, these difficulties may be largely overcome, although there
may be resistance from clinicians because of the additional effort required to evaluate
animals in the isolation unit.
Much consideration should be given to the design of stalls in isolation units. In
particular, the area of entry and means of manure disposal should be considered. Anterooms
containing routine supplies and medical records are commonly used. These rooms allow
for containment of routine items used on the animal but can be a highly contaminated
environment depending on the barrier methods used when in the stall, the method of
removal of barrier items, and cleaning protocols for the stall and anteroom. If anterooms
are stocked with routine items (ie, syringes, bottles of soap and disinfectant, medical
records), consideration should be given to preventing contamination of these items
and what to do with all items in the stall after an infectious animal is discharged.
Ideally, anterooms should be minimally stocked and all items disposed of when the
animal leaves the hospital. Any items returned to the hospital from an isolation stall
should be cleaned and disinfected in the stall if possible, placed in a leak-proof
bag, labeled as potentially infectious, and returned to the hospital to a designated
area for further disinfection. Contamination of the anteroom with manure should be
avoided.
Ideally, there should be minimal contact of personnel with infectious animals and
their stall environment. Minimization of contact should not interfere with the delivery
of appropriate veterinary care, however. Sealed windows used as viewing sites allow
for general inspection of patients without having to enter the stall or anteroom.
Closed-circuit televisions or Web-cameras can be placed in stalls and projected to
a central area for frequent remote monitoring. An added advantage of Web-cameras is
that remote password-controlled access from any computer can be established so that
clinicians can evaluate the general appearance of the patient without even entering
the isolation unit, let alone the stall.
Isolation of animals in the main hospital
In some situations, a degree of increased barrier precautions or some physical distance
from other patients when transferring a horse to the isolation unit is not indicated,
practical, or desirable. Examples of this would be when animals cannot be safely or
effectively treated in isolation (eg, neonatal intensive care unit foals, horses with
severe neurologic disease) or when the isolation unit is full. In these situations,
some clinics use in-hospital isolation or “semi-isolation.” In-hospital isolation
protocols allow for an increased level of protection but are not a replacement for
a proper isolation unit and should not be used solely for clinician convenience.
It is critical that animals isolated within the main hospital be prominently identified,
as discussed previously. Protocols should be developed regarding the handling of animals,
the stall, and the area around the stall. Animals that are isolated in the hospital
should not be walked outside their stall unless they are being moved for a required
procedure. If they are moved, their feet should be picked out and scrubbed with an
appropriate disinfectant (ie, 0.5% chlorhexidine) at the time they leave the stall.
One person should follow behind the horse to collect and appropriately dispose of
any feces, and any areas potentially contaminated by the horse or its body fluids
should be sprayed with disinfectant. People handling these horses should wear protective
barrier clothing, such as full waterproof coveralls or a full-length waterproof gown,
gloves, and dedicated footwear or boot covers. Care should be taken to avoid clutter
of potentially contaminated items (ie, barrier items, buckets, nasogastric tubes)
outside the stall. The area around the stall entrance should be considered potentially
infectious and disinfected routinely (at least three to four times per day). Attention
should be paid to the pattern of water drainage from the stall and in the area. If
water runs from the stall to the breezeway or runs down the breezeway past the stall,
housing of potentially or known infectious animals in the stall may be inappropriate.
Horses should not be able to come into direct contact with neighboring animals. Barriers
may be required if solid walls are not present on all sides. Horses potentially carrying
respiratory pathogens that can be spread via the aerosol route should not be housed
in general ward areas. Specific protocols should be developed for cleaning in-hospital
isolation stalls. These stalls should be cleaned last, personnel cleaning stalls must
wear protective gear, and items used to clean the stall must be disinfected immediately
after use.
Compliance with barrier and isolation protocols
One of the major problems with barrier precautions is obtaining compliance by hospital
personnel. “Time factors” and “too cumbersome” were the most commonly reported reasons
for noncompliance with barrier precaution protocols by trauma professionals in a human
hospital [25]. A similar study evaluated the use of barrier precautions during trauma
resuscitations and reported that none of 104 HCWs in the study were in complete compliance
with protocols for the use of barrier precautions; however, 98% wore gloves [26].
The authors concluded that HCWs are cavalier with respect to bloodborne diseases and
that measures to encourage or force compliance are required.
Compliance is also of concern in isolation units in terms of admission of potentially
infectious horses and the correct use of appropriate protocols. Depending on the facility,
there may be reluctance to admit certain moderate-risk patients to the isolation unit
because of difficulties in case management, such as distance to the unit from the
main hospital, time required to comply with all the isolation protocols, and the associated
increased cost to the client.
Cost is another factor that may limit the use of barrier precautions. Barrier precautions
almost always involve the use of disposable items, and the cost of these items is
not insignificant. At the OVC-VTH, approximately US $42,000 is spent annually on disposable
isolation gowns ($14,000), gloves ($18,000), and overboots ($10,000). Although these
figures are for the entire teaching hospital, most barrier items are used in caring
for hospitalized equine patients. It is also important to note that glove use is required
for any contact with horses in this institution, thereby explaining the use of more
than 4200 boxes of examination gloves. In times of fiscal constraint, especially at
veterinary teaching institutions, there may be reluctance to spend this amount of
money without clearly demonstrated benefits. Concerns about cost should be tempered
with the consideration of the costs of nosocomial and zoonotic infections and costs
of hospital closure and decontamination should major outbreaks occur.
Cost is also a concern with isolation facilities because they are expensive to build,
maintain, and staff. Isolation units should be designed so that enough stalls are
present to allow contaminated stalls to be cleaned and disinfected, followed by a
specific period when the stall remains empty between patients. Ideally, isolation
facilities should have dedicated personnel so that there is no cross-contact with
the main hospital. This is not feasible in all situations, particularly in small hospitals,
where the caseload does not justify full-time technical staffing.
Effect of barrier protocols and isolation on patient care
Another area of concern that is difficult to quantify is the potential adverse effect
of barrier precautions on patient care. If cumbersome protocols are required, particularly
in busy hospitals, there may be a tendency to spend less time in direct contact with
animals. In human medicine, it has been reported that certain infection control protocols
may be a disincentive to enter patient rooms [27]. In some aspects, this might be
desirable, because infection control protocols should reduce personnel traffic and
limit the potential for spread of pathogens. Although limiting unnecessary contact
is desirable, the concern is that medically required contacts may be limited and that
patient care may be compromised. A recent study in a human hospital confirmed this
suspicion, reporting significantly lower contact times with isolated patients, despite
the isolated patients being more severely ill [28]. Results of this study clearly
demonstrate that proper consideration be given to which patients to isolate and how
to manage these patients to ensure proper care.
Personal hygiene and its impact on the infection control program
Hand hygiene
Of all the possible measures that can be taken to reduce nosocomial and zoonotic infection,
hand hygiene is perhaps the most important, easiest to use, most cost-effective, and
most underused measure [29], [30], [31]. An understanding of the beneficial effects
of hand hygiene dates back to the middle 1800s and the astute observations of Ignaz
Semmelweis [32]. His institution of a mandatory hand disinfection program for clinicians
and students resulted in a tremendous decrease in puerperal fever, which was a common
cause of postpartum disease in women during that period. Independently, Oliver Wendell
Holmes concluded that the hands of HCWs spread puerperal fever, and he described methods
for limiting the spread of disease [33]. Formal implementation of hand hygiene policies
lagged tremendously, however, and it was well into the twentieth century before an
emphasis began to be placed on hand hygiene. Hands of HCWs are thought to be the most
common source of nosocomial infection; despite convincing data regarding the benefits
of hand hygiene, particularly when compared with the overall dearth of other objective
data regarding infection control measures, hand hygiene is still underused in the
medical field.
Traditionally, handwashing with water and soap has been the standard for hand hygiene.
The cleaning activity of soaps is from their detergent properties, which results in
removal of debris from the hands [33]. Plain soaps have little if any effect on pathogens
residing on the hands, however. It has been demonstrated that handwashing with plain
soap fails to remove pathogens from the hands of hospital personnel [34]. Paradoxically,
some studies have shown that handwashing with plain soap may increase bacterial counts
on the skin [35], [36]. Handwashing with plain soap before intravenous catheter placement
was reported to be no more effective than no hand hygiene at reducing the incidence
of catheter complications in human patients [4].
Antimicrobial soaps are widely available in hospitals and have been demonstrated to
be effective at reducing bacterial hand contamination. These may contain a variety
of antimicrobial substances, including triclosan, hexachlorophene, povidone-iodine,
and chlorhexidine [33]. Unfortunately, compliance with handwashing is typically poor.
Studies evaluating handwashing frequency in HCWs have yielded disappointing results,
with handwashing only occurring after 12.9% to 75% of situations in which it was indicated
[30], [37]. In particular, physicians tend to have poor compliance with hand hygiene
protocols [27]. Compliance with hand hygiene protocols is a major challenge for infection
control programs. Reasons given for poor compliance with hand hygiene include lack
of time, poor access to proper handwashing facilities, and skin damage from repeated
washing [33], [38]. Skin damage from repeated handwashing is a definite concern in
hospital situations. The frequency of dermatitis can be high in personnel who wash
their hands frequently. One study reported that 25% of nurses evaluated had clinical
signs of dermatitis and 85% had a history of skin problems [38]. Damaged skin is of
particular concern from an infectious control standpoint because it can harbor greater
numbers of bacteria than normal skin.
More recently, alcohol-based hand sanitizers have become popular. These products have
many advantages over antimicrobial soaps, including their spectrum of antimicrobial
activity, speed of activity, dermal tolerance, and ease of use. They also eliminate
the chance for cross-contamination from water taps and paper towel dispensers [39].
Increasingly, hand hygiene guidelines are recommending the use of these products when
gross contamination of hands is not present [33]. Most alcohol-based hand sanitizers
contain 60% to 70% alcohol and may be in a gel or liquid form. Recently, it has been
suggested that an alcohol concentration of 80% or higher is desirable, and a product
containing 85% alcohol is now available [40]. Although there are potential advantages
of alcohol-based products in terms of effectiveness against microorganisms, the main
advantage is ease of use. Additionally, alcohol-based hand sanitizers can easily be
placed throughout the hospital at minimal cost. As well, individual use bottles can
be dispensed to health care providers to keep on their person for ease of use even
when wall dispensers are not in the immediate area. Sinks, on the other hand, are
difficult and costly to add in an established facility.
The use and effectiveness of hand hygiene in veterinary situations have not been adequately
explored. Although much of the information obtained in human medicine can be applied
to veterinary hospitals, care must be taken with direct extrapolation of human studies.
It is logical to assume that horses would have a higher endogenous bacterial load
on their skin because of their haired coat and typical housing methods. This would
translate into the potential for greater contamination of the skin on hands of veterinary
personnel who handle horses compared with human health care providers. Veterinarians
typically wear gloves less commonly than their counterparts in the medical field,
and there is a somewhat cavalier attitude taken toward hand contamination in veterinary
medicine as compared with human medicine. Gross contamination of hands with feces,
discharge, and pus is likely more common, and access to handwashing facilities may
be limited.
Effectiveness of hand hygiene in veterinary situations has not been thoroughly evaluated.
A recent study reported that use of an alcohol-based hand sanitizer was more effective
at reducing hand contamination after physical examination of horses than a 15-second
handwash with antibacterial soap (J.L. Traub-Dargatz, DVM, MS, personal communication,
2004). This finding is important because it countered concerns that debris on the
hands from animal contact might inhibit the efficacy of alcohol-based products.
Many facilities are now placing alcohol-based hand disinfectant dispensers widely
throughout the hospital. At the OVC-VTH, approximately 80 dispensers have been placed.
At some hospitals, individuals have been given small personal containers of hand disinfectant
to carry around while on clinical duty. All hospitals should consider widespread placement
of alcohol-based hand dispensers as part of the infection control program.
Fingernails
The area under the fingernails tends to harbor large numbers of bacteria. Hospital
personnel with false fingernails have been shown to harbor more gram-negative bacterial
pathogens under their fingernails before and after handwashing [41], [42]. Naturally
long (>0.25 in) fingernails may also affect the effectiveness of hand hygiene and
harbor excessive bacteria [43]. Additionally, chipped nail polish may support the
growth of larger numbers of bacteria on the fingernails [33]. At the OVC-VTH, people
in animal contact positions are not allowed to wear false fingernails or nail polish
and must keep their nails cut short.
Personal items
Studies have indicated, not surprisingly, that skin underneath rings is more heavily
colonized with bacteria compared with other areas on the fingers [44], [45]. This
may relate to a more hospitable environment for bacterial growth (eg, warm, moist,
protected) and decreased exposure during handwashing. Whether the wearing of rings
is linked to transmission of disease is unknown and requires further study [33]. In
the interim, some facilities, including our institution, have restricted jewelry to
wedding rings and wedding bands, although there has been little effort to evaluate
and enforce compliance at this point. Long neck chains and bracelets that could come
into contact with animals are also of concern for safety (entanglement) and infection
control reasons. Although the risk of these items is unclear, it is reasonable to
prohibit wearing of any jewelry items that could come into contact with animals.
Hospital personnel commonly carry cellular and wireless telephones, and these items
have a high likelihood of becoming contaminated. Frequently, personnel handle telephones
if they are ringing regardless of the cleanliness of their hands or examination gloves.
Further, disinfection of telephones and pagers is rarely performed because of the
possibility for damage to the telephone or pager. MRSA has been isolated from a wireless
telephone in a veterinary clinic [46]. Pagers have a similar potential to become contaminated
[47]. The role of contaminated surfaces of telephones and pagers in pathogen transmission
is unclear at this point but should be considered. Unlike barrier materials, an additional
concern about these items is that they frequently accompany personnel home and, if
contaminated, could expose other individuals or animals at home. Personnel training
should emphasize that telephones and pagers should only be handled with clean hands.
Telephone covers that protect the telephone from contamination and can be routinely
disinfected should be considered.
Personal medical items, particularly stethoscopes, have come under scrutiny as reservoirs
of potential pathogens. Stethoscopes have close and frequent contact with patient
skin surfaces and can easily become contaminated. One study reported that 69% of doctors'
stethoscopes had microorganisms on them, with most organisms being potential nosocomial
pathogens [48]. Regular cleaning of the stethoscope bell and diaphragm with alcohol
has been shown to reduce bacterial contamination significantly [49]. Stethoscopes
should be cleaned at least once daily and after every contact with a potentially infectious
horse. Consideration should be given to providing dedicated stethoscopes for infectious
cases and animals at greater risk of acquiring a nosocomial infection (ie, compromised
neonatal foals).
Summary
Because nosocomial and zoonotic diseases are inherent and ever-present risks in veterinary
hospitals, proactive policies should be in place to reduce the risk of sporadic cases
and outbreaks. Policies should ideally be put in place before disease issues arise,
and policies should be effectively conveyed to all relevant personnel. Written policies
are required for practical and liability reasons and should be reviewed regularly.
Although no infection control program can eliminate disease concerns, proper implementation
of barrier precautions and isolation can reduce the exposure of hospitalized animals
and hospital personnel to infectious agents. Appropriate personal hygiene, particularly
hand hygiene, can assist in the prevention of disease transmission when pathogens
bypass barriers and are able to contact personnel.
Veterinary hospitals have moral, professional, and legal requirements to provide a
safe workplace and to reduce the risks to hospitalized patients. Based on experience
in the human medical field and on the continual emergence of new infectious diseases,
infection control challenges can only be expected to increase in the future. Regular
reassessment of protocols based on ongoing research and clinical experiences is required.