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Antibiotic use in farm and equine practice - Coggle Diagram
Antibiotic use in farm and equine practice
AM use drives AMR
responsible use helps maintain a healthy microbiome
many infections involve commensal or environmental opportunist bacteria
single infections= inappropriate sites (bacteria in the wrong place)
recurrent or chronic infections= dysbiosis of local microbiome
patients with recurrent infections do not have antibiotic deficiencies
don't use abx to mask clinical problems from poor medical treatment, surgical technique, patient care +/- animal husbandry
e.g. E. coli in lambs, improving husbandry and management will:
promote healthy gut biome in newborn lambs
improve health + growth rates
reduce antibiotic use
decrease the likelihood of AMR
Targeted treatments
are abx really needed?
viral + fungal infections won't respond
is infection trivial or life threatening?
are there other ways to manage the problem?
stop group prophylactic abx
AM stewardship!!!
Responsibility
Reduction
Refinement
Replacement
Review
Prescribing cascade
pharmacologically active substances contained in the medicine must have a Maximum Residue Limit (MRL)
must keep specific records
must specify withdrawal period
Withdrawal periods (WDP)= period of time, after the last dose of the vet medicine that must elapse before an animal (meat) or foodstuffs from an animal (e.g. eggs, milk) can enter food chain
Residues= substances which remain in foodstuffs obtained from animals that have been treated with a veterinary medicinal product
Maximum Residue Limit (MRL)= max conc. of residue in a food product from an animal that has received a veterinary medicine that can safely be consumed
Pharmacokinetics
Systemic cephalosporins (injectables)
poor penetration into udder due to poor plasma to milk transfer
not effective for clinical or subclinical mastitis
zero milk withdrawal, 19d meat withdrawal
Intramammary cephalosporin tubes
low lipid solubility which means mammary preparation remains in the udder
localised treatment of udder
4d meat withdrawal, 132hr milk withdrawal
no MRL can be established in metronidazole or chloramphenicol, so both are prohibited substances and it is illegal to use them in food producing species
Essential substance list for horses= list of substances considered essential for the treatment of Equidae that may be used in food horses legally
can only be used with a WDP of 6 months
all medications must be recorded in horses unless the horse has been declared as non-food producing
Adverse reactions to antibacterial drugs
Adverse event= any observation in animals (product-related or not), that is unfavourable and unintended that occurs after any use of a veterinary medicine (off-label and on-label use)
must report adverse reactions or treatment failures
adverse physical reactions in farm species are rare
tetracyclines can discolour teeth + affect bone development of foetus in pregnant animals
DO NOT give oral abx to adult ruminants + only use oral abx in camelids with care
DO NOT give Tilmicosin Macrolide to pigs, goats, alpacas, horses or humans (vet use only)
horses
anaphylactic reactions
immune mediated reactions to penicillin + cephalosporins
procaine toxicity
nephrotoxicity
DO NOT give oral erythromycin (macrolide) to adult horses (over 1 year)
DO NOT give IV doxycycline (tetracycline)
Suggested approach to responsible prescribing: PLERRS
Pathogen
classification, behaviour, virulecne
bacterial, viral, fungal, parasitic
do we NEED abx?
Licensed
licensed in FA: beta-lactams, aminoglycoside, tetracycline, TMPS, macrolides, lincosamides, amphenicols, fluoroquinolones
licensed in horses: natural penicillins, tetracycline, TMPS, cephalosporins (3rd generation), aminoglycoside, amphenicol
Efficacy
spectrum of actvity
bacteriocidal or bacteriostatic
penetration into tissues
activity in pus
Resistance
Responsible use
use first line abx whenever possible
avoid using CIA--> only use as second line treatment and after C+S has been perfomred
use focused selection process to choose correct antibiotic for correct patient
correct dose, correct route, correct length of time
Safety
patient, client, vet, public, environment, wider population