Hand Hygiene

Rigorous use of hand-hygiene procedures is one of the oldest recognized infection control measures, and it is perhaps the single most important infection control practice. Unfortunately, extremely poor compliance with best practices in human and veterinary hospitals as well as in the community negates much of the potential benefit.

Numerous indications for hand-hygiene procedures in health care settings have been identified as part of guidelines for human medicine. As shown in Box 46.2, hand hygiene is needed frequently in a clinical situation, something that may be problematic in typical settings where veterinary care is provided to large animals. Maintaining optimal hand hygiene can be especially important for ambulatory clinicians, yet can also be particularly difficult to achieve because of logistical difficulties. A variety of options exist for decontaminating hands., Ihe most common practices are handwashing and use of waterless hand-sanitizing solutions. Both are acceptable methods in most situations, and each has individual benefits and drawbacks. There are a variety of commercially available products that have documented efficacy for use as topical antiseptics and hand sanitizers; the most common ingredients of these products include ethanol, isopro­panol, povidone-iodine, benzalkonium chloride, benzethonium chloride, and chloroxylenol.^37,38 Recently, products containing triclosan and a variety of other active compounds used in hand washes and rubs have been deemed to be unsafe for repeated human exposure by the U.S.

Handwashing

Washing with antibacterial soap has been a standard method of decontaminating the hands of health care workers for more

A Recommended Technique for Handwashing

• Wet hands first with water and then apply an appropriate amount of disinfectant soap (as recommended by the manufacturer).

• Vigorously rub hands together for at least 15 seconds, covering all surfaces of the hands and fingers. Make sure to scrub fingertips and clean under fingernails.

• Rinse hands with water and dry thoroughly with a dispos­able paper towel. Multiple-use towels of any type are not recommended.

• Use towel to turn off the faucet (and open doors when exiting a restroom).

• Avoid using hot water because repeated exposure to hot water may increase the risk of dermatitis.

Adapted from Centers for Disease Control and Prevention: Guideline for hand hygiene in health-care settings: recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. MMWR 51(No. RR-16), 2002. http://www.cdc. gov/mmwr/PDF/rr/rr5116.pdf. (Accessed August 14, 2018.)

than a century. However, the potential benefits of this practice generally are not realized because of failure to use appropriate methods or failure to wash hands at all.^39,40 Common errors include inadequate duration of handwashing, inadequate thoroughness, failure to use soap, use of contaminated items to dry hands, and contamination of hands immediately following handwashing (e.g., through contact with contaminated faucets or door handles). An appropriate technique for handwashing is outlined in Box 46.3.

The importance of the type of soap used in handwashing is also often overlooked. Plain soaps, those without antibacterial agents, have minimal direct antibacterial activity.

Most soaps used in hospital settings contain biocides such as chlorhexidine, which produce greater decreases in skin contamination compared with plain soap.⁴⁰ Iodine and iodophors have been used as skin antiseptics and have a broader antibacte­rial spectrum. However, both (particularly iodine) can be irritating to skin and are less commonly used for routine handwashing and skin disinfection in medical personnel. In addition, some people become sensitized to skin contact with these products.

Compliance with handwashing protocols is often poor for a variety of reasons. The time required is a major factor, particularly in situations in which contact with many patients is likely. Although handwashing requires less than a minute to complete, if it is indicated 100 times in a day, this represents a significant amount of time cumulatively committed to this activity. Lack of convenient access to proper handwashing facilities is also frequently a problem. If access to sinks with running water, soap, and disposable towels is not convenient (i.e., not adjacent to where animal contacts occur), it is less likely that handwashing protocols will be rigorously followed. Regardless of the type of soap used, frequent handwashing leads to skin irritation and damage, which compounds compliance problems by making people reluctant to wash their hands; as well, skin damage associated with handwashing increases the potential for colonization or transient carriage of potential pathogens.^42-45

Nail care and jewelry can also be significant impediments to achieving optimal levels of hand hygiene.⁴⁶ Colonization with higher bacterial numbers, colonization with bacterial pathogens, and outbreaks of infectious disease have been reported in human hospitals in association with effects related to long fingernails and artificial nails.⁴⁷ Studies have shown that these hamper effective hand disinfection, and many health care facilities, particularly intensive care units, prohibit their staff from having long (% inch or longer) or artificial nails.

Waterless Hand Sanitizers

Waterless hand sanitizers have proliferated in health care facilities and in the community because of their low cost, ease of use, and efficacy. The CDC has concluded that hand sanitizers are the preferred method for cleaning hands that are not visibly dirty in comparison to handwashing.³⁹ Most waterless hand sanitizers use varying concentrations of alcohol (isopropanol, ethanol, n-Propanol, or a combination), although a few products contain alcohol plus biocides or biocides (e.g., benzalkonium chloride) alone. Alcohol products are most commonly available, with concentrations ranging from 60% to 95%, although lower concentration products can sometimes be encountered and should be avoided. Concentrations greater than 95% should also be avoided because the presence of water is important for the bactericidal activity. They may be in liquid, gel, or foam preparations.

Alcohols have excellent effect against gram-positive and gram-negative bacteria but not bacterial spores or proto­zoal oocysts.^39,40 Antiviral effects are variable, with less reliable effects against nonenveloped viruses. Alcohol-based products have been shown to have good effect on reduction of hand contamination of health care workers and have been shown to be more effective than standard handwashing.⁴⁸ Frequent contact with alcohol can lead to significant drying of skin, so most commercial products contain emollients, humectants, or similar skin-conditioning agents. Alcohol-impregnated towelettes are also commercially available but contain a small volume of alcohol and are no more effective for hand decontamination than washing with plain soap.⁴⁹

In human health care, hand-hygiene efforts are focused on increased use of waterless hand sanitizers. One concern that is sometimes expressed in large animal practice about waterless hand sanitizers is their activity in the presence of organic debris.

While most available products contain only alcohol as a sanitizing agent (in addition to humectants or emollients), some commercial products contain alcohol plus other biocides such as chlorhexidine. These are sometimes present because of a purported residual effect; however, evidence of residual activity of chlorhexidine has been challenged.⁵¹

One of the main advantages of waterless hand sanitiz­ers is their portability. Although it is difficult to make the water source needed for handwashing portable or always accessible, these products can be easily placed in ambula­tory vehicles, carried by individual staff, and easily placed throughout hospitals. As such, there is a greater likelihood of obtaining compliance by facilitating access. Unfortunately, regardless of the types of products used, compliance with hand hygiene is often a major problem.^52,53 Infection control programs need to address hand-hygiene compliance through a variety of means to increase use of this critical infection control tool.

Surgical Hand Antisepsis

Scrubbing the hands and forearms with disinfectant solutions has been a standard practice prior to surgery, but there is increasing movement to the use of waterless products. Recom­mended techniques for presurgical scrubbing vary somewhat but typically involve a systematic 2- or 3-minute scrub of all hand and forearm surfaces.⁵⁴ One concern with repeated surgical scrubbing is the potential for skin irritation and subsequent increases in bacterial contamination. This has led to increasing use of brushless techniques, especially with the use of waterless hand sanitizers containing 1% chlorhexidine gluconate and 61% ethanol, which has been shown to be equal or superior to brush application of 4% chlorhexidine soap.⁵⁵ These can be directly applied to the hands and arms as the sole preoperative skin antisepsis method, or if there is concern about the degree of gross contamination, hands can be washed and dried, followed by application of the waterless product.

Barrier Protocols and Protective Attire

Barrier nursing techniques are an important infection control tool. The basic premise for their use is that placing some type of barrier between caregivers and patients prevents skin or clothing from being contaminated, whereas the contaminated outer barrier item can be discarded or left in the contaminated environment. Prevention of contamination of personnel’s skin, regular clothing, personal items, and medical instruments can substantially reduce the risk of transmission of pathogens between animals, contamination of the general environment, and zoonotic transmission.

Use of Barrier Precautions

Basic barrier techniques should be used in all veterinary hospitals. Standardized, clean, protective outwear should be worn over hospital-dedicated attire for any patient contact, regardless of the anticipated nature of contact or the assumed infectious disease status of the patient. The need for other barrier items varies with circumstances and is often dictated by the type of disease syndrome being managed (e.g., diarrhea or GI disease, respiratory disease, wound infection, fever of unknown origin) as opposed to documentation of specific infections or diseases. Other factors that might indicate a need for additional barriers include farm of origin (e.g., farms with endemic S. equi or rotavirus infections) or a patient that is considered to have an increased risk of infection (e.g., com­promised neonates). Gloves, gowns, and overboots are the most commonly used items for additional barrier protection, but masks, caps, and eye protection may also be required at times. In some facilities, overboots are not used in all areas, but personnel are required to wear footwear that can be readily disinfected. Disinfection of this footwear is required after exiting potentially contaminated areas.

Limitations to Barrier Precautions

The greatest limiting factors associated with use of barrier precautions in infection control are poor compliance and improper use. Written protocols that document practical use of barrier precautions should be developed. They should specifically state when additional barriers are required; it is not possible to achieve consistent results if protocols are ambiguous or suggest too much discretionary interpretation. In addition, it is critical to educate personnel on the need for barrier nursing precautions and on proper application. Many human hospitals require physicians and nursing staff to undergo practical training in the proper use of barrier precautions to avoid inadvertent spread of contaminants, and this type of active training may help to ensure uniform understanding and application of protocols. It is also important to regularly monitor compliance with protocols.

Protective Outerwear

Standard protective outerwear for large animal veterinary personnel should include clean coveralls, lab coats, scrubs, or other dedicated clothing (hospital uniforms), in addition to easily cleanable footwear. Protective outerwear should be worn for every animal contact and should be changed regularly. This includes any time outerwear becomes visibly soiled or otherwise contaminated with body fluids perceived or known to be contaminated with potential pathogens (e.g., feces, blood, nasal exudates, urine, or uterine fluid). In addition, 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 to decrease the risk of transfer of infectious agents from the hospital to the community. To facilitate this control measure, it is optimal from an infection control perspective for veterinary practices to provide laundry services or laundry facilities. Clothing that is potentially contaminated with biohazardous material should be handled appropriately so that personnel handling laundry are aware of the hazards and how to reduce risks for exposure.

Gloves

Gloves are an important component of barrier precautions if used properly. The CDC recommends glove use by health care workers to reduce the risk of transmission of infections from patients to personnel, to prevent health care workers' skin flora from being transmitted to patients, and to reduce transient contamination of the skin on the hands of personnel by microorganisms that can be transmitted from one patient to another.⁵⁶ The same concepts apply to veterinary medicine. In certain situations, glove use has been shown to be an effective means of reducing pathogen transmission in human medicine.⁵⁷ However, incorrect use can negate these effects or even be harmful. Common errors with glove use include failing to wear gloves when needed, not changing gloves after contact with infectious items, touching items (e.g., cell phones, computers, pens, medical supplies) while wearing contaminated gloves, contamination of hands or clothing while removing gloves, and failing to wash hands after glove removal.⁵⁸ Although gloves are used to prevent contamination of hands, the potential for inadvertent contamination through microbreaks in the glove surface or contamination during glove removal necessitates use of handwashing or application of hand-sanitizing solutions in conjunction with glove use.⁵⁶

There are no widely accepted standards in veterinary medicine for when gloves must be used, apart from the use of sterile gloves during surgical procedures. Examination gloves that are clean but not sterile are often used when handling wounds or infected body sites and for contact with animals known or suspected to be shedding contagious pathogens. Despite relatively widespread use of examination gloves in a variety of circumstances in veterinary medicine, it is quite unusual for practices to have formal protocols regarding how and when they should be used.

Gowns

Although protective gowns have traditionally been used during surgery, their use as a barrier garment when contacting high-risk patients is increasing in both human and veterinary medicine. The CDC has produced guidelines for human medicine stating that “gowns should be 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.”⁵⁶ In general, gowns should be worn whenever direct or indirect contact with patients or their environment may result in contamination of caregivers' clothing or skin that facilitates transmission of pathogens.

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 easy to put on and remove without contamination of regular attire, be nonabrasive to skin, be unlikely to startle patients, and be of acceptable cost. Unfortunately, a product with all of these characteristics does not currently exist, and facilities must prioritize the relative importance of different gown properties. This is often difficult because neither the overall effectiveness of gowning nor the effectiveness of different gowns in veterinary situations has been adequately evaluated. The problem most likely to be encountered with barrier gowns in veterinary practice is poor resistance to liquids, especially under direct contact or pressure. In large animal practice, there is a greater likelihood of contact with relatively large volumes of fluids (e.g., with diarrheic animals) or direct contact with patient surfaces that have moist secretions or excretions (e.g., animals with nasal discharge or large infected wounds). The types of anticipated activities may also have an impact on the required size of gown. Gowns that do not completely cover the legs and feet may be useful in some circumstances but ineffective in situations with prolonged direct contact, such as assisted neonatal nursing.

In human medicine, there are conflicting data regarding the efficacy of gowning for prevention of HAIs.^57,58 Gowns may be more effective for reducing infection of personnel. It is possible that the most significant advantage in some situations is not the protective effect of gowns or other protective out­erwear, but rather the raised awareness of the potentially infectious nature of the patient, which may in turn encourage concurrent application of other important infection control practices.

Footwear, Footbaths, and Footmats

Contaminated footwear has been shown to be an important factor in transmission of contagious pathogens in intensive agriculture settings,^59-62 but the role of footwear contamination in spread of contagious diseases in veterinary hospitals or human health care facilities is less clear.⁶³ A few investigations have noted the dissemination of Salmonella on floors in veterinary hospitals, indicating a potential for transmission via this route, but these have not directly linked disease transmission to environmental contamination.^1-4,64 Regardless, use of disposable shoe covers or footwear that is dedicated for use in isolation areas is a commonly implemented control strategy in veterinary hospitals, as is the use of footbaths or footmats containing disinfectants. Use of disinfectant footbaths or footmats does not affect total numbers of bacteria found on floor surfaces,^32,65 nor do these products completely sterilize footwear. It must be remembered that disinfection is a chemical process affected by time, temperature, and the presence of organic debris, whereas footbaths are frequently used with an unreasonable expectation of immediate sterilization. However, broad­spectrum, rapidly acting disinfectants such as peroxygens and accelerated hydrogen peroxide products have been shown to decrease bacterial counts on footwear surfaces if adequate time is allowed for action and if surface contamination such as manure is routinely removed from footwear.^66-71 Implementation of requirements for change of footwear or use of footbaths or footmats should not be undertaken lightly, as enforcing uniform compliance with these policies can be difficult and the cost for implementing can be significant. Further, a substantial effort is required to ensure that reusable footwear is kept clean and that disinfectant solutions are frequently changed (at least daily, but typically more frequent changes are warranted when solutions become dirty, as this significantly decreases the activity of disinfectant solutions). Still, it is our impression that rigorous use of disposable or dedicated footwear in isolation areas, in addition to the best-practice use of disinfectant footbaths or footmats, provides a useful adjunct in the control of diarrheal agents such as Salmonella. It is less clear that they provide substantive benefit in control of highly resistant agents such as rotavirus, respiratory agents, or contact-transmitted agents such as MRSA. Regardless, easily cleanable, closed-toe footwear should be mandatory for working in large animal health care environments.

Eye and Face Protection

The use of protective eyewear, including goggles and face shields, is common in human medicine during procedures that generate aerosols or airborne droplets of blood, body fluids, and secretions⁷² but often overlooked in veterinary medicine.⁷³ Face shields have the advantage that they decrease the potential for facial mucous membrane exposures in addition to ocular exposures. Inexpensive disposable face shields are commonly available and are generally quite comfortable for people with varying face shapes and sizes, and thus would seem to have great potential for use in all large animal practices. Despite the current low prevalence of bloodborne zoonotic pathogens in large animal species, it would be prudent to consider the use of some type of eye protection whenever generation of small particulates or aerosols of liquids or secretions is likely to occur, including when motorized equipment is being used for dental procedures, foot trimming, or orthopedic surgery. Situations in which eye protection should be seriously con­sidered include examination of animals with suspected viral encephalitides or draining abscesses and working with a struggling animal with a respiratory or skin/soft tissue infection where infectious agents might be aerosolized during movement. Although not studied, face protection may also help protect against zoonotic disease involving fecal-oral transmission, such as C. parvum, which has an extremely small infectious dose, most likely through prevention of inadvertent hand-mouth contact.

Respiratory Protection

Masks and respirators are often used to reduce the risk of respiratory and oral exposures to infectious agents, to reduce the risk of contamination of patient sites with organisms from personnel, and in some situations to prevent contamination of hands with nasal or oral microflora. Standard 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 feet) from infected patients.⁷⁴ However, the overall effectiveness of surgical masks in hospital situations has recently been questioned.⁷⁵

Airborne transmission of zoonotic pathogens is of minimal concern in most veterinary settings, and mask use is uncommon in veterinary hospitals apart from during surgical procedures. One exception that has been frequently overlooked is the risk of zoonotic Coxiella burnetii transmission when handling periparturient ruminants, especially during obstetrical proce­dures in small ruminants.²⁸ The actual reduction in zoonotic disease risk that might be associated with the use of surgical masks during routine patient contact is unclear. However, increased awareness of risks of specific zoonotic diseases and infections in immunocompromised personnel and others with special disease risks has prompted reconsideration of recom­mendations regarding personal protective equipment in some circumstances. For example, although clinical Q fever is considered relatively rare, it has become abundantly clear that people working with small ruminants are very commonly infected with C. burnetii, and the significant health consequences of these rare clinical infections may warrant mandatory use of respiratory protection when handling high-risk patients, especially if people have a higher risk for serious infection sequellae (e.g., pregnant women). In addition, although airborne transmission is not considered an important route of exposure for MRSA, the hospital personnel primarily become colonized in the nasal passages, and hand-to-nose contact is frequent. Thus mask use may prevent direct contact of hand and nose, thereby decreasing hand contamination or decreasing the risk of inoculation of the nose following contamination of the hands during animal contact. Mask use may be particularly important for prevention of MRSA exposure when working in barns containing many MRSA-positive animals and high dust burdens. This is most relevant for swine veterinarians but could include clinicians entering veal calf units in some regions. Masks capable of filtering non-oily particulate aerosols with 95% capability (N95 masks) are recommended in human medicine for dealing with airborne contagions such as the severe acute respiratory syndrome (SARS) coronavirus. Although there is currently little indication for routine use of these masks, except in regard to periparturient small ruminants,²⁸ it is reasonable to expect facilities to at least have a plan in place to implement N95 masks if required. A critical aspect of the use of N95 masks is fit testing and training in their use, since improperly fitted or used masks may confer little or no benefit over surgical masks. Use of powered air-purifying respirators (PAPRs) has become increasingly common in large veterinary teaching hospitals in situations where risks for small-particle transmission of zoonotic agents are recognized.^28,36 PAPRs require a larger initial invest­ment, but they do not require fit testing, and minimal training is required for effective use in controlling airborne hazards.