10 Jul 2015
Germ warfare: why practices need to take hygiene seriously

Some members of the veterinary profession who will freely admit to only possessing superficial knowledge of practice hygiene.
And yet “progress”, in terms of treatment regimes and procedure techniques, has increased the (sick) patient throughput for veterinary practices, resulting in increased levels of microbiological challenges and potential cross contamination. Adding to this is the common practice of giving preoperative antibiotics, which has suppressed shortcomings in hygiene. Is this model sustainable? Not for very much longer.
Current position
Some vets do not take hygiene seriously, most define it as “cleaning” and are unaware what products are used, leaving it instead to someone else in the practice to deal with. Most staff who interface with disinfectant suppliers, for example, don’t have the knowledge to understand the technical pros and cons of different products when it comes to meeting the microbiological challenges faced in an environment that has a high transient population of sick animals.
Indeed, few vets or nurses possess a good understanding of the science behind cleaning and disinfection, for example.
Microorganisms
Microorganisms such as bacteria, fungi and viruses have different resistance to disinfectants. Gram-positive and Gram-negative bacteria can have a 10 to 20-fold difference in resistance to a disinfectant. Similarly, fungi in the early vegetative growth cycle are significantly less resistant than in the sporulating phase. Enveloped and non-enveloped viruses are likewise very different. Product selection must be made on the basis of the potential risks to patients and staff and include superbugs. How many staff receive regular health checks to identify carriers of communicable diseases such as MRSA?
Biofilms
Biofilms are simple to complex microbial ecosystems on surfaces. These surfaces can be inert and, therefore, indirectly linked to diseases in animal populations and patients, such as plastic water pipes in a reticulation system, air-conditioning humidification and filtration systems, intravenous catheters and prosthetic devices. They can also be biological and, therefore, more directly associated with animal health, such as granulomatous wound healing tissue, respiratory epithelium and epithelial to glandular mucosae in the udder.
The ecosystems can consist of bacteria, fungi and/or yeasts that “communicate” with each other in various ways. Several studies have indicated a 10 to 1,000-fold higher resistance to certain antimicrobials by bacteria in the biofilm growth phase, compared to the same isolate in the planktonic (free floating) form.
Some of these aspects have major practical implications regarding recurrent/reservoir infections, horizontal spread of resistance, nosocomial complications during long-term hospitalisation and intensive care situations to individual patients and populations.
Air-borne contamination
Air-borne microorganisms in the form of bacteria, fungi or viruses use air as a medium to travel within a given space, sometimes using dust particles as a carrier. Hard surface cleaning and disinfection, although essential, will not eliminate air-borne contamination. Cleaning and disinfecting the air space using special filtration equipment is ideal, but expensive for all areas. For most practical purposes, using atomised disinfectant droplets in aerosols or sprays to create a fog will significantly reduce the air-borne microorganism population in a room.
Layout and design
Potential cross-contamination issues can be addressed with a little forethought in practice design and layout, such as:
- careful consideration of patient flows
- provision of washable surfaces
- taking wall cabinets to ceiling height
- eliminating hard to clean internal corners
- not attaching notices to wall boards or leaving documents to gather dust
- using fans with suitable filters to create positive air pressure in patient sensitive areas
Regulation
The Chemical Regulation Directorate, part of the Health and Safety Executive, will revoke the Control of Pesticides Regulation approval to market a product in the UK by September 1, 2015 unless evidence is provided to prove the active ingredients supplier(s) is listed (approved) under Article 95 of the European Biocides Regulation, administered by the European Chemical Agency.
The aim is to eliminate hazardous biocide chemicals from EU markets. This EU initiative does not mean the product purchased by the end user is safe. Most antimicrobial products on the market today are chemical compounds made up of more than one active and non-active raw material, which can potentially change the efficacy and safety characteristics of a product. In fact, this is exactly what the formulator is seeking to achieve – more with less.
Product safety studies, although expensive, are the only way to provide reliable data. BS EN test standards based on harmonised test standards accepted by all EU states include disinfectant and antiseptic tests applicable to the veterinary area. The United Kingdom Accreditation Service (UKAS) audit microbiological laboratories to good laboratory practice (GLP) standards to carry out these tests, but not all labs are accredited. UKAS is part of a worldwide organisation to set GLP standards, which is an important indicator of test result reliability.
However, it remains the case in the UK the marketing of end-user finished veterinary disinfectant and antiseptic products is unregulated. Unfortunately, this can result in a free-for-all of exaggerated product claims made due to the absence of professional independent assessment and approval. This could also lead to products being put on the market that are not fit for purpose – for example, bacteria static rather than bactericidal, potentially adding to the growth of practice-specific microorganism mutations.
The “Defra disinfectant approval” for use in controlled disease outbreaks is taken by many as a general product endorsement which it certainly is not and is rather irrelevant to hygiene maintenance in a veterinary practice.
Defra approval is specific to:
- each designated controlled disease category (for example, general orders of poultry diseases)
- the unique Defra test protocol
- only for the (highest) concentration at which the specified product passes the test. Therefore, if a product has an approved dilution rate of 1:2 it will have failed the test at any greater dilution
Clearly, Defra approvals are for special, nominated circumstances and not everyday practice hygiene.
Professional oversight
The RCVS professional standards audits reflect the lack of importance and understanding of the factors impacting on practice hygiene and infection control. The Veterinary Medicines Directorate is very concerned about the excess use of preoperative antibiotics in place of good hygiene practice, which it considers is contributing to the increasing list of superbugs. Veterinary diagnostic labs are seeing an increasing incidence of complex microorganisms (40 per cent is not exceptional), making them significantly more resistant to disinfectants and antibiotics.
Future options
Professional bodies and associations, such as the RCVS and BSAVA, should consider becoming more involved with manufacturers to draw up acceptable product standards for efficacy and safety and best practice cleaning and disinfection routines.
Progressive practices should be adopting the view hygiene and infection control is a strategic business issue which will impact on its capacity to attract and retain clients.
As a start, a considered and encompassing practice hygiene operating policy drawn up by and signed off by the senior veterinarian(s) and the head nurse (at least), should be prominently displayed so clients understand the level of commitment in the practice. This policy must be supported by standard operating procedures and staff training.
The results from regular bacteriological surveys (relatively inexpensive and indicative of general hygiene) should form part of the internal practice performance reviews.