Viet Nam, with the favorable geography and climate conditions for aquaculture, reaching a total seafood export turnover of US$ 6.8 billion in 2011. Shrimp export value only was estimated at US$ 3.1 billion for the same year. Rapid development of shrimp farms in both Mekong River and Red River reaches nowadays more than 640 million hectares.
In practice, most farmers have access to and make use of a wide variety of antibiotics (ABs) and other chemicals to treat animals or prevent disease outbreak in their farms. According to our knowledge, a high proportion of farmers use high amounts of antibiotics based upon their own practical experience rather than seeking professional advice in the use of these chemicals. As stated by the World Health Organization (2014), resistance to antimicrobial substances is a growing public health threat of broad concern to countries and multiple sectors. The risks identified in relation to uncontrolled or indiscriminate AB use in aquaculture are namely the development and the transfer of a reservoir of AB-multi-resistant bacteria in the aquatic environment. Antibiotic resistance genes (ARGs) disseminated by horizontal gene transfer to other bacteria ultimately reach human bacterial pathogens. Among the dispersing routes, fresh water is an important vehicle for the spread and emergence of antibiotic resistance. Moreover, fresh water – using as irrigation of plants, and drinking water for human and animals – was known as major route for the transmission of pathogenic bacteria to people.
In our research activities, we aim first to study quantitatively the levels of ARGs in the aquatic environment of shrimp farms. These data are required so as to assess the AB-multi-resistant bacterial reservoir, the precise identity of the AB resistant bacterial strains as well as the composition of the ARGs. Second, we aim at revealing the routes of the spreading of these resistances in the adjacent river receiving the effluents of the culture basins, as well as the geographical extend. These data constitute a strong base for the evaluation of the risk and policy decision making, improving awareness to proper antibiotic usage in the aquaculture industry sector. Finally, we aim at developing water cleaning systems for aquaculture so as to keep water quality and prevent diseases outbreak. Constructed wetlands are artificial wetlands, which are designed to harness natural process occurring in natural wetland to treat wastewater. Various biotic and abiotic processes regulate the removal of pollutants. They also function as recirculation filters, reducing the impact of the effluent on local water bodies, conserving large amounts of water. Constructed wetlands are characterized by the advantage of moderate capital costs, low energy consumption and low maintenance capacity, as well as a beneficial increase in wildlife habitat.
Research partners:
Thi Thu Hang Pham: Environmental Biotechnology Laboratory, Vietnam National University HCM City, Viet Nam
Quoc Tuc Dinh : Asian Center for the Research of Water, Ho Chi Minh City University of Technology, HCM City, Viet Nam
Nicolas Gratiot : CARE Laboratory, Ho Chi Minh University of Technology, HCM City, Vietnam