Stewardship of Antimicrobials and Hygiene Protocols in Practice. Are We There Yet?
Antimicrobial resistance (AMR) is a global public health concern and has been associated with antimicrobial usage in both human and veterinary medicine.1,2 The potential loss of efficacy of antimicrobials deemed as critically important for the treatment of severe infections in humans has led to a call from the World Health Organisation (WHO) for the prudent usage of antimicrobials in human and veterinary settings.1,3 There are currently guidelines for the prudent usage of antimicrobials and monitoring programmes in several EU countries; however, these are mainly focused on production animals due to the potential risk of transmission of antimicrobial residues, AMR determinants and resistant pathogens through the food chain to consumers. On the other hand, there is still scarce information on usage of antimicrobial drugs in companion animals and prescribing practices in veterinary settings. The role of small animals, particularly dogs and cats, in the epidemiology of antimicrobial resistance is still unknown, although there is growing evidence of antimicrobial resistance in pathogens with zoonotic potential in these species.4-7 Previous research has shown that pet animals can act as potential sources of infection of these pathogens to humans through social interactions and by sharing common areas.8,9 However, more data on disease prevalence, antimicrobial usage and national antimicrobial resistance patterns in these species would be necessary in order to be able to assess the potential risk to public health. Clinical data regarding animal patients collected in electronic practice management systems from veterinary practices could be a valuable source of surveillance data for the animal populations considered.
Although some countries possess guidelines for the prudent usage of antimicrobials in pet animals, veterinary surgeons must still use their professional skills and knowledge in the selection of adequate antimicrobials for their small animal patients as in evidence-based medicine. The decision-making involved in the selection of antimicrobials for the treatment of animals is a complex process that often has to be made during the limited time available for animal consultation. The veterinarian must take into account several requisites to choose the appropriate antimicrobial substance and dosage regimen; characteristics of the animal patient (species, age and immune status) and also of the potential pathogen(s) involved (pathogenicity, virulence) need to be taken into consideration. In clear-cut cases where the infecting organism and its antimicrobial sensitivity can be predicted with confidence, empirical selection of an appropriate drug can be made. Empirical choice may also be necessary in severe infections where treatment cannot be delayed to allow culture and antimicrobial sensitivity testing (AST) to be done or when there are limited logistic resources and financial constraints to be considered. In other cases further diagnostic procedures and AST will be required to aid in the selection of antimicrobial therapy.
Conventionally, dosage of antimicrobials has been based on assessment of the Minimum Inhibitory Concentration (MIC). However, there is currently discussion on the clinical value of the MIC as even if this is below the susceptibility breakpoint, it is not certain that the antimicrobial treatment will be effective and that clinical cure will occur. Consideration is now being given to new measurement units in conjunction with the MIC, such as the Mutant Prevention Concentration (MPC), that takes into account the variation in susceptibility within high density bacterial populations and the likelihood of occurrence of mutants in those same populations.10 It is also important to take into consideration the pharmacodynamics and the pharmacokinetics of the antimicrobial substance being considered as under-dosing of antimicrobials is associated with the selection of resistant strains (e.g., antimicrobial concentrations between MIC and MPC). As such, the correct dosage, frequency and duration of therapy are necessary to ensure clinical effectiveness of treatment. Interpretation of culture and AST results by veterinary surgeons in practice is often challenging and may lead to misinterpretation of findings. It is important that the practitioner interprets the laboratory data in the veterinary context, taking into account the clinical findings and animal patient to be treated.
The FECAVA Working Group on antimicrobial usage and hygiene in practice has as main aims to produce guidelines for hygiene that can be implemented efficiently at practice level and general recommendations for the stewardship of antimicrobials in everyday practice. For this purpose, surveys amongst the FECAVA members were conducted in 2009 to investigate the implementation of hygiene recommendations and antimicrobial guidelines in its country members. From the 36 members, only 8.3 per cent (n=3) and 11.1 per cent (n=4) possessed any guidelines for hygiene practices and stewardship of antimicrobials, respectively. Countries with guidelines for the usage of antimicrobials were Sweden, Norway, United Kingdom and the Netherlands. National hygiene guidelines for veterinary settings are only available in the United Kingdom, Sweden and Turkey, which has adopted the British recommendations.
A pilot study was then prepared in collaboration with the British Small Animal Veterinary Association (BSAVA). In the UK, there are approximately 4000 veterinary surgeons, from which over 95 per cent work with companion animals. The aim of the survey was to investigate antimicrobial usage and hygiene standards in everyday practice. For this purpose, a web-based questionnaire was created to assess the awareness of veterinarians of the importance of the stewardship of antimicrobials in everyday practice and the association between antimicrobial usage and the risk of antimicrobial resistance in companion animal's practice. In addition, veterinarians were requested to describe protocols and hygienic practices to control and prevent the spread of infectious diseases in their workplaces.
At the current moment, only a few countries possess guidelines for the stewardship of antimicrobials. There is still no research available on the feasibility of such guidelines and their impact on the attitudes and behaviour of veterinary surgeons when selecting antimicrobials for companion animal therapy. Recommendations for the stewardship of antimicrobials should be clear and concise, and should act as a reminder to the veterinary surgeon of the steps involved in the decision making process for the selection of antimicrobials based on anamnesis, clinical and/or laboratorial evidence and integrated knowledge of infectious diseases and pharmacology principles.
In terms of hygiene standards, there is still scarce information available on protocols to control disease transmission at practice level to prevent spreading of zoonotic diseases and resistant pathogens in the work environment. As health professionals, the veterinary profession should take into consideration the present situation in human health care settings, in which implemented hygiene protocols have shown to play an important role in the containment of infectious diseases.11,12
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