Contamination in veterinary hospitals.

Over recent years there has been much publicity directed towards human hospital hygiene and its potential implications for human health. A focus on some major infections with severe healthcare repercussions, such as meticillin resistant Staphylococcus aureus (MRSA) and Clostridium difficile, has resulted in hospital hygiene protocols being given increasing importance. Environmental contamination is known to be an important factor in the transmission of such infections. Surfaces with regular hand contact are most at risk of surface contamination (Gould 1991). While it is unrealistic that such infections will be eradicated completely from hospitals, ambitious targets have been set to reduce the morbidity and mortality associated with MRSA. Measures such as the ‘clean your hands’ campaign has taken hospital hygiene back to basics in the hope of ensuring appropriate hand washing by hospital staff and healthcare workers, as well as patients themselves and their visitors. Those of us who have visited human hospitals in recent years will undoubtedly be more aware of increasingly prominent hand washing facilities. Within hospitals, audits are carried out to ensure compliance with protocols and a person is given overall charge of the infection protocols for the different units. Such seemingly draconian measures as an individual watching healthcare workers wash their hands and questioning them if it does not meet the protocol standards may not always be popular but certainly seem to have been effective. While differences will always exist in the risk factors for different types of wards or units, use has been made of surveillance figures for infections such as MRSA-associated bacteraemias. Such measurements have allowed examination of time trends within individual units and comparison with other units and institutions. Overall, the success of this campaign has played a major role in the control of MRSA associated bacteraemias in England and Wales with a reported reduction of greater than 50% over several years (Health Protection Agency – healthcare associated infections, http://www.hpa.org.uk, accessed 8 October 2010). In veterinary hospitals, similar issues with surface contamination are likely. Staphylococcal infections, particular MRSA, have been increasingly reported from companion animals and more commonly associated with veterinary hospitals (Weese 2005). Studies of companion animals in the community suggest carriage rates are low (Loeffler and Lloyd 2010). However in some veterinary hospital situations especially where other risk factors are present the prevalence of carriage can be relatively high. Little data on surface or environmental contamination within veterinary practice is available. The paper in this issue by Aksoy and colleagues (2010) provides information on such a study in a large small animal referral hospital using quantification of staphylococcal load at various sites in the hospital taken over a five day period. Comparisons were made to the allowable limits of staphylococcal counts within human hospitals. It was found that over 50% of all samples taken would fail based on these criteria. Although the majority of these only failed by a small margin it remains worrying as such levels pose a potential risk to our patients. The study was able to identify areas of particular risk which included the ICU, surgery ward and laboratory when compared to the consultation rooms. In humans, risk factors for MRSA infection include high use of antibacterials and high numbers of invasive procedures including indwelling catheters and surgery (Graffunder and Venezia 2002). In addition, patients who are sicker are more at risk of also acquiring a nosocomial infection. This would help explain the findings for this veterinary hospital if risk factors for infection were similar for animals. Thus, if there is a higher number of animals infected or carrying the staphylococci then the level of surface contamination will be higher. It may not be realistic to aim to eradicate all infection from our hospitals but this study helps raise awareness of particular areas where levels of contamination may be high. In addition, these are also areas where our patients at the highest risk of infection may be housed. In effect this may represent a ‘catch 22’ situation but it highlights the need for increased levels of hygiene in such areas. The higher levels of contamination found in the laboratory in this study are more difficult to explain. It may suggest areas seen as lower risk may not have as intense a focus on cleaning. The study also found a higher level of surface contamination on floors rather than door handles. This may reflect contact of infected animals with the floor, but this finding has also been shown in human hospitals. Common hand contact sites, such as computer mice, were also found to have higher number of failed samples. Examination tables appeared to be at lower risk and it was suggested this may be due to regular cleaning of this surface between patients while routine cleaning of door handles and floors between each patient is unlikely. The day of sampling also had an effect on the staphylococcal quantification. Samples taken on a Monday were less likely to fail compared to samples taken later in the week. It was suggested this may be due to more time for cleaning at the weekend although a build up throughout the week as the throughput of animals increases may also play a role. If practices were kept free of human and animal traffic they would not become contaminated but this of course defeats their purpose. High turnover in human hospitals with less unoccupied bed days increases risk of infection (Clements and others 2008). It has been suggested by some that lower levels of bed occupancy in certain countries, such as the Netherlands, may explain in part their lower risk of MRSA infection. Although all situations may not be the same, lessons can be learnt from our colleagues in human healthcare. There is far greater emphasis on disposal or cleaning of any equipment or surfaces including hands which have had contact with a patient, prior to contact with a subsequent patient. Although each individual is responsible for their own hygiene standards there is also someone who oversees the hygiene and ensures protocols are adhered to. This can be done by studying staff working, auditing the use of hand gels and soaps or alternatively by surveillance strategies such as surveillance of surface contamination or surveillance of specific infections. In human hospitals all these measures are used routinely and an increase in a specific infection within a ward or unit triggers more detailed investigation. Although Contamination in veterinary hospitals