A group of Western Australian scientists has made a promising start to developing a vaccine for mastitis.
One of the group, Dr Jully Gogoi-Tiwari, from Curtin University, presented results of the research at the Dairy Research Foundation's 2018 symposium at Camden, NSW, last week.
Dr Gogoi-Tiwari said mastitis was a major problem for the Australian dairy industry costing farmers about $130 million a year.
The only treatment option was antibiotics, but overuse of these had led to the development of antibiotic-resistant bacteria, resulting in reduced cure rates.
Previous attempts to develop a vaccine against the predominant mastitis-causing bacteria Staphylococcus aureus had failed because of the nature of the bacteria.
Dr Gogoi-Tiwari said Staphylococcus aureus could grow in two different forms: the free-living form and the biofilm form.
"The free-living form when it enters into the mammary gland of a cow starts forming a slimy layer all around it," she said.
"That slimy layer is known as biofilm; biofilm acts like a shield for the bacteria.
"It protects the bacteria from cow's own immune system, the protective mechanism and from antibiotics."
This led to antibiotic failure, allowing the infection to become chronic.
Dr Gogoi-Tiwari said previous unsuccessful attempts at creating the vaccine had used only the free-living form of the bacteria.
The WA researchers took a new approach, incorporating both the biofilm and live bacteria, to produce a vaccine called BOSA 51.
They had tested the vaccine on mice and it had been successful, producing an immune response in the mice and preventing mastitis.
Dr Gogoi-Tiwari and her team are processing a patent application for their research.
They are also applying for funding to then test the vaccine in a ruminant model, either goats or cows, and would then look to do field trials in dairy cows.
They are hopeful the vaccine would be effective in preventing both clinical and subclinical mastitis.
The early research also show the vaccine was safe and did not produce side effects.
“The vaccine is easy to produce, it doesn't cost much, and if we compare the cost involved in the repeated use of antibiotics, the vaccine is the solution,” she said.
Dr Gogoi-Tiwari said although the vaccine would only be effective against Staphylococcus aureus, the vaccine-development method might be successful with other mastitis-causing bacteria.
She said another group of scientists in the Netherlands was working on developing a vaccine using biofilm only.
Dr Gogoi-Tiwari won the Emerging Scientists prize at the symposium for her presentation.
Dairy Australia says mastitis is inflammation of the cow’s mammary gland usually caused by bacteria entering the teat canal and moving to the udder.
The main types are contagious mastitis and environmental mastitis.
The main bacteria causing contagious mastitis are Staphylococcus aureus and Strep agalactiae.
They mostly live inside udders or on teat skin and are spread either by splashes of infected milk or sprays during stripping, on milkers’ hands or teatcup liners, and by cross flow of milk between teatcups.
Staphylococcus aureus are a major cause of mastitis in Australia.
They are difficult to cure, especially during lactation, so prevention is essential.
