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Veterinary products and aquatic animals Peter Smith Chair OIE ad hoc Group on the responsible use of antimicrobials in aquatic animals.

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Presentation on theme: "Veterinary products and aquatic animals Peter Smith Chair OIE ad hoc Group on the responsible use of antimicrobials in aquatic animals."— Presentation transcript:

1 Veterinary products and aquatic animals Peter Smith Chair OIE ad hoc Group on the responsible use of antimicrobials in aquatic animals

2 Veterinary products Vaccines Disinfectants Anti-parasitics Antibiotics

3 FAO Definition ‘a drug of natural or synthetic origin, with the capacity to inhibit the growth of or to kill microorganisms. Antibiotics that are sufficiently non-toxic to the host are used as chemotherapeutic agents in the treatment of infectious diseases of man, animals and plants.’

4 Reasons for antibiotic use in aquaculture Prevention (good husbandry and correct use of vaccines) is the best way of reducing disease risks but When bacterial infections occurs in farmed animals antibiotics are the only therapy that will reduce loses

5 Reasons why antibiotic use must be prudent Antibiotics are powerful chemicals - biologically active at low concentrations Aquacultural use involves the deliberate introduction of these chemicals into the food chain and the environment Use of antibiotics lead to the emergence of resistant bacteria and resistance compromises their value as therapeutic agents Presence of residues may affect consumers of aquaculture products Public perception of a “drug-based” industry and results in reduced market acceptability of aquaculture products

6 Resistance to antibiotics Resistance and aquatic animal health There is clear evidence that resistance to antibiotics has emerged when these agents are used in aquaculture The more we use (and misuse) these agents the smaller is the chance that antibiotics will be effective therapeutically We run the risk of entering the ‘pre-antibiotic’ era

7 Resistance to antibiotics Resistance and human health Resistance to antibiotics is global There is a risk that antibiotic resistance selected by aquacultural use will compromise therapy of human infections Pressure from human medicine (WHO) may reduce availability of antibiotics to aquaculture

8 Presence of unacceptable residues Presence of any residues of banned antibiotics or Presence of levels of other antibiotics above maximum allowed limit Will have major trade implications

9 Overall strategy to ensure prudent use Regulation Monitoring Education

10 A new draft chapter of the OIE Aquatic Animal Code is being prepared It will primarily address issues of the regulation and the monitoring/surveillance of the use of antibiotics in aquaculture This talk is an introduction to some of these issues

11 Current global status There is huge variety in the extent and the style of regulation and monitoring/surveillance of antibiotic use in aquaculture Some authorities have very sophisticated procedures but the majority, including many responsible for large production volumes, have not

12 Current global status Regulation Central to regulation is the licensing of antibiotic containing products by the granting of Marketing Authorizations

13 Current global status Regulation Very few antibiotics are licensed for aquaculture Many countries have licensed no antibiotics Some have only licensed a few (2-4) Some large industries (shrimp) have no licensed antibiotics

14 Current global status Monitoring We have little (quality) information on the consequence (target bacteria resistance) of antibiotic use in aquaculture We have no accurate estimates of the amount of antibiotics used in aquaculture

15 The way forward

16 The way forward - Regulation Aims To ensure that antibiotics used in aquaculture are safe to the animals treated and to the consumers To ensure that antibiotics are used in a way that is likely to be efficacious (cost/effective) To ensure all stakeholders are informed of their duties and responsibilities

17 The way forward - Regulation Regulations based on Marketing Authorization Only products for which MA have been granted should be used in aquaculture MA will facilitate correct product labeling and definition of the responsibilities and duties of all stakeholders

18 The way forward - Regulation Marketing authorizations Safety (treated animals, users and to consumers) and Efficacy

19 The way forward - Regulation Safety to consumers Maximum residue level (MRL) independent of species and rearing conditions - internationally set Withdrawal time time after therapy when residue is below MRL dependent on species and rearing conditions – locally set

20 The way forward - Regulation Efficacy Establish that a specified dose regimen delivered using a specified antibiotic containing product will control loses resulting from a specified bacterial infection of a specified species under specified environmental conditions

21 The way forward - Regulation Problems with basing regulation on MA MA are expensive and time-consuming to produce (who pays?) MA are specific but disease conditions encountered in aquaculture are diverse

22 The way forward - Regulation Problems with basing regulation on MA There will always be a need for extra/off label use of antibiotics in aquaculture

23 The way forward – Monitoring resistance Information on resistance in target bacteria is essential: to ensure individual therapies are rational and prudent to understand emerging patterns of resistance nationally, regionally and globally to inform risk assessment

24 The way forward – Monitoring resistance We are in the process of standardizing and harmonizing laboratory methods for measuring susceptibility in aquatic bacteria We possess no quality information on resistance in bacteria that infect fish

25 Embarrasing fact After 50 years of research we have no clear procedures for establishing if a bacterium isolated from an aquatic animal will be resistant or sensitive to an antibiotic therapy

26 The way forward – Monitoring resistance Determining resistance involves 2 stages Development of appropriate standardized laboratory protocols Developing interpretive criteria that allow meaning (sensitive/resistant) to be given to the results of these laboratory tests

27 The way forward – Monitoring resistance Test protocols There is general agreement that the test protocols outlined in the CLSI documents M42-A and M49 -A should be adopted

28 Current status of CLSI resistance methods Test protocolInterpretive criteria Aeromonas salmonicida++ Aeromonas spp+ Edwardsiella spp+ Flavobacterium spp+ Photobacterium spp.+ Streptococcus spp.? Photobacterium spp+ Vibrio spp+ Piscirickettsia salmonis Vibrio salmonicida? Tenacibaculum maritimum? Francisella spp?

29 We know how to do the tests but We don’t know what the results mean

30 Current status of CLSI methods Interpretive criteria There is an urgent need for progress Progress can be made on a species by species basis Not all species are relevant to all industries or all regulatory authorities The work required to set criteria for one species is not expensive or time-consuming

31 The way forward – Monitoring use Data on how much antibiotics are being used is essential: to understand emerging patterns of resistance to inform and monitor strategic planning to perform risk analysis

32 The way forward – Monitoring use Use data requirements Essential Absolute amount (kg active drug) used Animals treated (species, number, weight) Rationale for use (diagnosis, therapy/prophylaxis) Additional Mode of administration, type of husbandry system, environmental conditions etc

33 Risk analysis What are the risks that use of antibiotics in aquaculture will select for resistances that will have a negative impact on human therapies? A very difficult question to answer

34 Risk analysis Risks associated with aquacultural use much less than those associated with use in land-based agriculture Risk primarily associated with selection of transferable resistance factors in environmental bacteria Risks associated with resistant bacteria in aquaculture products less important

35 Antimicrobial Resistance (AMR) Risk Analysis in Aquaculture Discussion on the applicability of risk analysis principles for AMR in aquaculture Thursday, 30 June 2011 8:30 am Speakers Room/Salon Republicco To receive a copy of a white paper describing the topic drafted by the OIE ad hoc Group on antimicrobial resistance in aquatic animals send a message to

36 Prudent use of antibiotics Farmers buy and use antibiotics because they think/hope that it will increase their profits Much use by farmers is inappropriate and imprudent The greatest gain in prudent use and economic efficiency will be achieved by providing farmers with quality advice

37 Prudent use of antibiotics - education Education programmes to train farmers and their on-farm advisors in the correct use of antibiotics and the provision of adequate and local diagnostic and antibiotic susceptibility testing services Will greatly reduce imprudent use

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