Evidence-Based Hand Hygiene in Equine Practice Where "Clean Hands Save Lives" Becomes "Clean Hands Save Horses"

Guidelines for hand asepsis have changed. Well-formulated alcoholic rubs have several advantages and are more efficient than traditional medicated soaps. Hand hygiene protocols are crucial in our fight against hospital acquired infections, and acquired resistance to chlorhexidine is an increasing problem. Authors’ addresses: Department of Large Animal Sciences, University of Copenhagen, Denmark (Verwilghen, van Galen); Department of Pathobiology, (Weese); and Department of Clinical Studies (Singh), Ontario Veterinary College, Guelph, ON, Canada N1G 2W1; e-mail: denis@equinespecialists.eu.

1. Introduction

Over the past few decades, the World Health Organisation (WHO) has put increased focus on hand hygiene campaigns under the slogan “Clean Hands– Save Lives” following the global recognition of hand hygiene being a key factor in reducing surgical site infections (SSI) and other hospital associated infections (HAIs). These campaigns have tackled both hand hygiene as part of routine patient care as well as improved pre-surgical hand preparation protocols.

As equine medicine progresses, we must adapt our decision-making in light of new scientific evidence. As much as possible, recommended protocols should now be evidence-based,¹ recognizing that there are varying strengths of evidence and that equine-specific evidence may be limited. Regardless, increasing information from the human field and general understanding of infectious diseases indicate a need for changes in perceptions and practices in diagnostic methods and treatments in equine veterinary medicine,² as has occurred (and continues to occur) in human medicine. Despite this paradigm shift, in the field of hand hygiene, things have slowly evolved. Surely, the field has advanced since the 1800s, when Semmelweis and Lister were making seminal (yet controversial) discoveries of the benefits of hand hygiene. They laid the foundations for the concepts of asepsis and vigorously fought the disbelief they were facing, yet while basic concepts of hand hygiene are now widely recognized, parallel actions in veterinary medicine are often lacking. Are we open-heartedly embracing the evidence today? 

According to a survey performed in 2009 amongst ECVS and ACVS diplomates, only 6.7% of respondents indicated that they were following WHO guidelines for pre-surgical hand asepsis.³ A subsequent survey in 2013 showed that, while practices had improved, 66% of the 218 respondents⁴ still did not follow the current WHO guidelines. So what do current guidelines and evidence say? Additionally, what is right: current guidelines or current practices?

2. Hand Preparation Today

The goal of surgical hand hygiene is not to sterilize the skin. Rather, it is to reduce or eliminate the burden of potentially pathogenic transient skin organisms and to reduce resident microbiota for the duration of a surgical procedure in order to reduce the risk of an SSI. These goals should be achieved while minimizing damage to the skin that might promote rebound bacterial overgrowth or compromise future hand asepsis attempts. The transient microbiota is acquired by contact with people, animals, and contaminated surfaces. It colonizes the superficial layers of the skin and is the most common cause of SSIs. The resident microbiota is a more established deeper component of the microbiota that is regarded as less pathogenic. Elimination of this component may be undesirable because its presence is a means of defense against the growth of opportunistic transient pathogens. Techniques involving aggressive cleaning of the skin with alkaline medicated soaps, like chlorhexidine gluconate (CHX) scrubs will have deleterious effects on the skin’s local defense mechanisms.⁵ Moreover, while brushing and scrubbing does not necessarily have any beneficial impact on bacterial reduction,⁶ they can cause small excoriations and, therefore, damage to the skin, further increasing the risk of skin colonization by pathogenic species.⁷ Despite the suboptimal features of the surgical scrub, 44% of the respondents to a survey of veterinary surgeons stated that they always use brushes. Current recommendations are to use soft sponges, if any, for hands and forearms, only if visibly soiled and brushes for fingertips.⁸

Ideally, the chosen method must balance antimicrobial activity, skin compatibility and ease of use to be optimally effective and used. A variety of methods and products for surgical hand preparation are available. Aqueous solutions containing either povidone-iodine (PVP) or CHX have been widely used for many decades. Alcohol-based hand rubs (AHRs) have been described for surgical hand preparation for more than a century,⁹ although only recently have they become widely recommended for surgical hand preparation. Although no randomized controlled trials have been conducted showing any significant differences in SSI rates between the aforementioned methods, the AHR method is considered superior for a number of reasons.^10,11 The antibacterial efficacy of products containing high concentrations of alcohol was shown to significantly surpass that of any medicated soap currently available.¹² The initial reduction of the resident skin flora (microbiota) is so rapid and effective with AHRs that bacterial regrowth to baseline values on the gloved hand takes more than 6 hours.¹³ These observations were also confirmed in a veterinary trial that compared the activity of an AHR solution to CHX and PVP soap.¹⁴ In that study, a 1.5 min application of an AHR solution was performed with the 3 h residual effect on colony forming units (CFU) reduction of AHRs significantly better than for traditional hand scrubbing with PVP and CHX. Another potential benefit of AHRs is the lack of any known (or plausible) mechanism of alcohol resistance in bacteria. Therefore, there is no concern that repeated alcohol application could select for alcohol-resistance or co-select for resistance to antimicrobials. It should be noted that when choosing an AHR solution, the product should meet the EN12791 or equivalent standard required for pre-surgical hand-rub formulations.¹⁵ Many available gel products will not meet these surgical standards and are therefore not recommended.

About 17% of respondents of one survey⁴ used a medicated scrub technique combined with an AHR, in clear contradiction to published evidence and recommendations that do not advocate the use of both methods together. Medicated soaps are either less effective or have a similar efficacy to the hand rub. An initial scrub with medicated soaps will not result in ultimately increased reduction of microbiota after AHR application.¹⁴ On the contrary, long-term use of medicated soaps increases the risk of dermatitis, making the skin more difficult to decontaminate and the combination of medicated soaps and AHR likely to increase the risk of skin damage, while providing no demonstrable positive effect. Furthermore, prior hand washing can alter the effectiveness of AHR solutions,¹⁶ particularly if hands are not completely dried before AHR application. Hand washing also increases preparation time, cost, carbon footprint, and water usage.^17,18 It is estimated that 20 L of water is used per hand when preparing with medicated soaps. Faucets and basins can also be sources of Pseudomonas spp. and other Gram-negative bacteria, creating a potential for recontamination of the hands prior to gloving.⁸ Considering the aforementioned concerns, it has been suggested in human medicine there is no reason to include a hand wash before AHR solutions are applied^16,19 and that hands should only be washed if they are visibly soiled. However, compared with human hospitals, the bacterial burden in veterinary settings may be higher, especially for equine surgeons. Until further objective data are available, it is reasonable to recommend a short hand-wash with a gentle soap (pH neutral) prior to the AHR application when the surgeon has handled animals or their environments. In this way, bacterial spores and organic material that might interfere with alcohol antisepsis can be eliminated. [...]