Antibiotics in Aquaculture Should We Be Concerned? A focus on Asian · PDF file ·...
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Antibiotics in Aquaculture – Should We Be Concerned? A focus on Asian aquaculture [email protected] Andreu Rico Alterra, Wageningen University and Research Centre
Transcript of Antibiotics in Aquaculture Should We Be Concerned? A focus on Asian · PDF file ·...
Antibiotics in Aquaculture – Should We Be Concerned?A focus on Asian aquaculture
Andreu Rico
Alterra, Wageningen University and Research Centre
Andreu Rico
Alterra, Wageningen University and
Research Centre (The Netherlands)
Background: Ecotoxicology and
Chemical Risk Assessment
PhD on Environmental Risk
Assessment of veterinary medicines
used in Asian aquaculture production
Focus on antibiotic exposure and
effects in China, Vietnam, Thailand
and Bangladesh
Outline
Current situation on the use of antibiotics
Fate of antibiotics after use in aquaculture
Antibiotic risks for the environment and human health
The State of World Fisheries and Aquaculture, FAO (2012)
Production Mtonnes in 2010 (FAO 2012)
90%
701
43.7
1.1 1.3
92.9
1.32
7.31
1.67
4.53
1.44
1
10
100
1000
Chile B. Columbia Scotland Norway Vietnam China Thailand China Thailand Vietnam Bangladesh
2013 2013 2013 2013 2011-2012 2011-2012 2011-2012 2011-2012 2011-2012 2011-2012 2011-2012
Salmon Pangasius Tilapia Shrimp
Antibiotic use
Varying among species and production practices
g a.i. / tonne harvested product
Data sources:
Bridson P. 2014. Four Region Summary Document: Salmon. MBA Seafood Watch
Rico et al. 2013 Aquaculture
701
43.7
1.1 1.3
92.9
1.32
7.31
1.67
4.53
1.44
122
368 346
144
1
10
100
1000
Chile B. Columbia Scotland Norway Vietnam China Thailand China Thailand Vietnam Bangladesh Netherlands Netherlands Netherlands EU/EEA
Salmon Pangasius Tilapia Shrimp Pig Veal Broiler Food-
producinganimals
Antibiotic use
On the range or below other food-producing commodities
g a.i. / tonne harvested product
Data sources:
Bridson P. 2014. Four Region Summary Document: Salmon. MBA Seafood Watch
Rico et al. 2013 Aquaculture; Dutch SDa Antibiotic Usage Report 2013; EFSA 2015
Netherlands 2013 EU/EEA 2012
Antibiotic use
Top-ranking occupied by the same compounds in almost all species/countries (OTC, FFC, SFM+TMP, AMX, ENR)
Efforts to exclude antibiotics listed as ‘critically important for human health’ such as quinolones (e.g. zero tolerance in US, recent ban in Vietnam)
Number of approved substances varies among countries e.g. US (4) vs Vietnam (26)
In many Asian countries there is no clear distinction between antibiotics used for human consumption and those used for aquaculture
Mostly in-feed medications
Differences between commercial medicated feeds and on-farm antibiotic mixing
Banned compounds not reported
Generally more than one antibiotic used per farm (cocktails are becoming popular)
Prophylaxis only in 5% of cases
Antibiotic use
Data source: Rico et al. 2013 Aquaculture
Fate of antibiotics
Options to manage environmental discharge of antibiotics in aquaculture are limited as compared to livestock production
Large differences between production systems
Fate of antibiotics
Cages ~ 75% ends-up in the surrounding environment
Ponds ~ 25% is discharged to the environment (mainly by effluents)
Data source: Rico et al. 2014 Science of
the Total Environment
Fate of antibiotics
2
4
1
Chemical application
1 2
3 4
3
The ERA-AQUA model predicts antibiotic exposure patterns
according to different scenarios and application regimes.
Main dissipation processes in ponds: sediment degradation,
drainage, degradation in water and biotransformation
www.era-aqua.wur.nl
2119
285
9567
4062
2339
OTC ENR ENROTC OTC ENR
0.1
1
10
100
0.25 1 15
Conc.
(µg/L)
Time after application (h)
37
0.4
Max MEC
Fate of antibiotics
Bangkok
Mun River
Tha Chin River
Monitoring: Oxytetracycline, Enrofloxacin
Thailand
OTC in Water
n.d.
Conc.
(µg/kg)
Tha Chin River
(dry) (wet)
Mun River
(dry)
Max MEC
OTC and ENR in Sediments
Data source: Rico et al. 2014
Environmental Pollution season
Antibiotic risks for aquatic organisms?
The toxic potential of antibiotics is lower to aquatic organisms than other veterinary medicines (disinfectants, parasiticides)
Environmental concentrations are not expected to result in direct short-term risks for fish, invertebrates and the majority of primary producers...
...but could affect some blue-green microalgae and other microorganisms
Antibiotic contamination affects the structure of microbial communities, and this is particularly seen in sediments
Microbial-mediated ecological processes have not been demonstrated to be affected at measurable levels
More research is needed to investigate this with prolonged exposure patterns and multiple stress conditions
Risks of antibiotics
Is there a contribution of aquaculture to antibiotic resistance?
Inherent relation between antibiotic contamination and the occurrence of resistant bacteria
Often difficult to elucidate what is the origin of resistance: fish gut, other stress factors...
Each of these resistance pathways should be investigated separately and in combination
The risk evaluation of antibiotic resistance would benefit from thresholds or breakpoint values that can be linked to exposure data to make predictions
Risks of antibiotics
Aprox. 25k deaths/year in EU, and
reports suggest about 30k in Asian
countries such as Thailand
Resistance mainly acquired due to
irrational antibiotic use and hospital
infestations
Contribution of aquaculture yet
unknown
Epidemiologic studies needed to
evaluate aquaculture risk factors
Risk factors are higher in developing
countries
Risks of antibiotics
Is antibiotic resistance a real problem for humans?
Risks of antibiotics
Sediment antibiotic concentrations 10 times higher than the concentrations that can cause resistance in human pathogens
YES: Aquaculture constitutes a major source of antibiotics to
the environment and the risks of resistance transfer to human
pathogens are high
Measures to reduce diseases and antibiotic use can still be
applied: reduce densities and need for water exchange, avoid
feed overuse, improved disease diagnosis...
Hopes of reduced use in important species e.g. Pangasius
(vaccines), shrimp (probiotics, immunostimulants)
Better information/training to workers in developing countries
Aquaculture expansion and intensification trends (Latin
America, Africa)
Should We Be Concerned?
Should We Be Concerned?
Antibiotic registration and evaluation systems should be
revised or implemented in many developing countries
Better tracking systems for antibiotic sales and use should be
established for future risk assessments
Multidrug resistance is likely to become an important issue for
the effective treatment of diseases
Quantitative risk assessments of resistance are complex
Research into the development of antibiotic standards for
resistance and their integration in the risk assessment
paradigm is needed!
Paul van den Brink, Andreas Focks, René van Wijngaarden, Rhaul Oliveira, Alfredo Tello, Mauricio Rocha, Tran Minh Phu, Jidapa Khatikarn, Kriengkrai Satapornvanit,
Arrienne Matser, Margot Andrieu, Mohammad Haque, Jiang Min, Phuong Nguyen, Trevor Telfer, A. Shahabuddin, Patrik Henriksson, Francis Murray, David Little, Anders Dalsgaard, Yue Geng, Sakchai McDonough, António Nogueira, Amadeu Soares, Inês
Domingues, Huong Do, Hauke Smidt
Thank you very much
