Page 500 - The Veterinary Laboratory and Field Manual 3rd Edition

Antimicrobial resistance: a threat to human and animal health 437

microbials and the appropriate selection, dosing, In situations where there is recurrence of
route of administration and duration of antimi- disease, or a failure of first line treatment,
crobial therapy. diagnostic tests should be utilized to deter-
Prudent use standards outlined by the OIE mine second-line treatment.
aim to maintain the efficacy of antimicrobi- • Narrow spectrum antimicrobial agents
als, ensure their rational use in animals, keep should be chosen before broad spectrum
animals in good health, prevent or reduce the products when appropriate.
transfer of resistant microorganisms within ani- • Aseptic techniques should be used to
mal populations and from animals to humans minimize the need of perioperative use of
and prevent antimicrobial residue in animal antimicrobials.
products for human consumption (OIE, 2015,
Teale and Moulin, 2012). A few guidelines are
provided below for the farm and for regional A note of the use of biocide
programmes. compounds

actIonS on tHE FarM Resistance to biocide compounds such as
1 Improving animal health disinfectants, antiseptics, preservatives and
sterilants can occur by similar mechanisms
• Decisions regarding treatment should be to antibiotic resistance. Products previously
made by professional veterinary services active against bacterial biofilms are becom-
or suitably trained individuals. Inaccurate ing less effective. These include chlorine,
diagnosis of a pathogenic bacteria can lead quaternary ammonium compounds and
to overtreatment with antimicrobials, and aldehydes. The combination of concen-
possibly delay the recognition of serious tration and contact time determines the
viral diseases. efficacy of the application. Environmental
• Where feasible, treatment should be at the factors such as temperature can also affect
individual animal level rather than treat- product efficacy. For example, repeated use
ment of a population. of low concentrations of a product may allow
• When antimicrobials are to be used to tolerance to the product to accumulate, ulti-
treat infection, accurate calculation of mately leading to biocide resistance. Usage
bodyweight is imperative to prevent over- guidelines for biocide products indicate the
or underdosing. Additionally, considering dilution of the product, storage, and contact
diseased animals may have a decreased time required for a specific application and
appetite; where medicated feeds containing these guidelines should be followed care-
a therapeutic dose of an antimicrobial are fully for all applications.
used, intake should be monitored to ensure
animals ingest an adequate quantity of the
product, and modifications made to the 2 Improved biosecurity
treatment protocol if necessary. Biosecurity refers to a set of measures or actions
• Clinical experience, the expected suscepti- taken to prevent and control the spread of infec-
bility of the target pathogen, administration tion and disease. Biosecurity protocols should be
route, expected activity at the infection in place on all livestock facilities. The following
site, and the history of the animals in ques- biosecurity guidelines should be implemented
tion will influence antimicrobial selection. where applicable (Figure 12.4).

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