Fish slime crock of gold at end of rainbow

The slippery mucus on the skin of rainbow trout is being studied by scientists as a possible source of new medicines to fight infectious diseases, according to research presented Monday, 06 September 2004 at the Society for General Microbiology’s 155th Meeting at Trinity College Dublin.

“Anglers, cooks and anyone cleaning up mess in their kitchen know how difficult it is to hold onto fresh slippery fish like rainbow trout,” says Dr Vyv Salisbury from the University of the West of England in Bristol. “Trout are tricky to grasp because of the thick mucus they secrete from their skin. This slime helps them in many ways, and contains important chemicals which let them fight off bacteria living in the river.”

The scientists are looking at the possibility that the same chemicals might be used to help people fight off infectious disease-causing bacteria including food poisoning culprits E. coli O157and Salmonella, and Pseudomonas aeruginosa which affects the lungs of vulnerable cystic fibrosis patients. To see if the fish slime has an effect, the team at UWE are using genetically modified disease-causing bacteria, which glow in the dark when they are active and stop glowing when they are killed. The drop in the light given off by these bioluminescent reporter bacteria when they are put on the fish slime is a very effective way of seeing how successful the slime action is, but it does mean that the researchers have to spend hours in a totally darkened lab, peering at the fish.

Extracts from the trout mucus have already been shown to prevent growth and slow down the metabolic activity of some of these types of infectious bacteria. “If we can purify and produce these chemicals commercially, they may give us a new type of antibiotic, badly needed with the growing menace of antibiotic-resistant bacteria,” says Dr Salisbury.