Washington, Sept 10 : The sticky glue secreted by the bacterium Staphylococcus aureus may hold the key for making an effective vaccine against MRSA (Methicillin-resistant Staphylococcus aureus), according to a new study.
While Staphylococcus aureus stay as a biofilm fairly harmlessly on most of the people who carry the bacteria, it may rarely cause severe and life threatening infections that are significant medical problems.
Many of these infections are made worse by the biofilm component of the overall disease, which helps to protect the bacteria from antibiotics.
"If individuals get infections many times, even after they have been cured by antibiotics, it indicates that their bodies have not become immune to Staph bacteria," said Professor Gerald Pier from Harvard Medical School in Boston, USA.
Staph bacteria tend to grow in cellular communities, particularly on medical devices commonly used on patients, like catheters, artificial heart valves, knees and hips, producing what are called biofilm type infections. All patients with these types of devices in them have an increased risk for Staph infections. Living in biofilms protects the bacteria from antibiotics, making treatment more difficult.
"To grow as a biofilm the bacteria must produce sticky factors, one of which is a type of complex sugar called PNAG. We are targeting this material as a possible vaccine, but natural exposure to the sugar compound does not result in most people and animals making an immune response that would protect them from attack by the bacteria or recurring infections," said Pier.
The scientists have manipulated the sugar chemically to discover that they can produce variant forms, which can be used as vaccines by causing the right type of immune response.
This approach has already been shown to work successfully in animal studies.
"We now have a way to tip the balance for resistance to infection back towards humans by vaccination. It is most likely that one or more forms of the vaccine will be prepared to test in humans to see which form is best to get the most desirable antibodies made," said Pier.
Besides, the scientists have also created an antibody with the desired properties to give to people if they have a high risk of getting a Staph infection, thus preventing infection.
"This antibody is being manufactured to start tests in humans in about 12 to 18 months. An effective antibody treatment for Staph infections could have a major benefit for anyone who enters a hospital or works in the community and is at risk of Staph infections," said Pier.
The study was presented at the Society for General Microbiology's Autumn meeting being held this week at Trinity College, Dublin.