Researchers work to develop a vaccine against salmonid bacterium

  • By means of a Regular Fondecyt Project, researchers at the Faculty of Chemistry and Biology, led by Dr. Brenda Modak, are studying a treatment to protect the national salmon farming industry from the dangerous bacterium Piscirickettsia Salmonis, by using wild plants from the Atacama Desert.
  • “Synthetic products have proved to be a problem where they have been used as they accumulate at the bottom of the sea. This is the reason why we refer to this as a sanitary challenge that national aquaculture has to face. Working with a natural compound will not only lead to a less invasive cure: there will also be less pollution in waters where it is used,” Dr. Modak stressed.

In the last decades, aquaculture in Chile has been constantly growing, placing Chile in the first place of producers in America, according to the Food and Agriculture Organization of the United Nations (FAO). Also, salmon production accounts for 76% of the national fish farming industry, according to the National Service of Fishing. For these reasons, infections affecting salmon farming at a national level can become a serious problem for the country.

“We are the world’s second leading country in salmon farming, after Norway. So, everything related to infectious diseases becomes important, even more, when it comes to Piscirickettsia salmonis, a bacterium that has killed about 50% of the salmon population in the country,” affecting an industry that generates more than 60 thousand jobs in the south of the country,” Dr. Brenda Modak stressed.

In order to find effective solutions to this problem, Dr. Modak, together with a multidisciplinary research team from Universidad de Santiago’s Faculty of Chemistry and Biology, are working on the Regular Fondecyt Project “Evaluation of natural products with potential antibacterial activity against P. Salmonis.”

“We are trying to test the activity of natural products isolated from plants against this bacterium (P. Salmonis), which has been difficult to combat with common synthetic antibiotics. However, our compounds have proved to be effective as antiviral drugs and immunostimulants for salmons, so this is where the idea of testing them in salmons already infected came from,” she said.

To develop the treatment, researchers will work with plants that grow wildly in the Atacama Desert, which produce a resin that covers the plants to protect themselves against the unfavorable environment in which they grow.

“We will extract the resin from the plant and then we will separate its different components. We have seen that the resin is made of two groups of compounds, from which we will take some samples and test them against the bacterium,” she said.

Three Universidad de Santiago’s laboratories are taking part in this study: the Laboratory of Chemistry of Natural Products, the Laboratory of Immunology and the Laboratory of Virology. First, the study of the extracted resin will be started until the pure compounds are obtained. This will be followed by the bacterial cell growth. Then, the in vitro work will be done, observing how the bacterium is affected by the compounds. Finally, in the in vivo work, salmons will be infected and then they will be given an injection with the elaborated product.

“Synthetic products have proved to be a problem where they have been used as they accumulate at the bottom of the sea. This is the reason why we refer to this as a sanitary challenge that national aquaculture has to face. Working with a natural compound will not only lead to a less invasive cure: there will also be less pollution in waters where it is used,” Dr. Modak stressed.
 

Translated by Marcela Contreras