A universal vaccine for superbugs is possible

Researchers may have a way of fighting superbug infections , especially those that occur after bone and joint surgery.
Written by Boonsri Dickinson, Contributing Editor

Superbug infections can be life-threatening, and are a known problem in hospitals. I've written about a lot of ways researchers are working on fighting the war on superbugs, but the news announced last week seems unlike the other techniques: Scientists have discovered a route for developing a vaccine that would prevent superbug infections following bone and joint surgery.

Wow. This would mean a vaccine for superbugs is possible.

Scientists at the University of Rochester Medical Center figured out how to have an antibody slip past the surface of the bacteria and ultimately prevent the superbug from growing. At least in mice and cell cultures, the researchers have shown this to be true.

Edward Schwarz, professor of Orthopaedics at URMC, made the announcement last week at the Orthopaedic Research Society conference in Long Beach, California. Schwarz said in a statement:

A vaccine in humans would probably not be a foolproof approach to preventing infection 100 percent of the time. However, even if we could reduce the risk of MRSA by 35 percent, that would be an enormous improvement in the field.

Superbugs are a huge problem, including Methicillin-resistant Staphylococcus aureus, or MRSA. It is a group of bacteria that lives innocently on our skin and in our nose, but can become a problem in hospitals and in the community if it enters a person's body through cuts in the skin or through surgical operations.

The trouble arises when antibiotics can’t kill them. When the bacteria enters the blood stream, it begins to attack the body. This is when the infection can grow so large only surgery can get rid of the drug-resistant bug.

When a serious bacterial infection of the bone occurs after joint replacement surgeries, the condition is called osteomyelitis.

Not only are the infections life-threatening, a post-surgical infection can result in a six-month hospital stay, so doctors can take out the superbug-colonized item and have a chance to clean the site of infection on a regular basis.

I first read about how scientists discovered an antibody that can basically make the MRSA bacteria explode in New Scientist. By targeting a protein called glucosaminidase (GMD), the researchers made the MRSA bacterium unable to divide. Fortunately, the protein is the same in different strains of the bacteria, so it's not far-fetched to imagine creating a vaccine that could work against a number of superbug infections.

The researchers explained that the protein acts like a zipper on the bacteria. The MRSA needs the protein to replicate before it can launch its attack on the patient's body. So by taking out the protein, the bacterium loses its ability to divide and conquer. Electron microscopy images of the bacteria showed that the anti-Gmd antibodies actually made the MRSA bacteria explode.

When the antibody was put in a culture of MRSA, the Rochester researchers saw that the bacterial growth slowed down, according to New Scientist.

When scientists injected mice with the anti-Gmd antibody and then infected them with MRSA, half of the mice caught the superbug. As expected, the vaccine was only effective as the dose.

Regis O’Keefe, chief of Orthopaedics at URMC said in a statement:

It’s essential that we have mechanisms in place to prevent this awful infection. We are very excited about our vaccine research. It’ll have a phenomenal impact on individuals locally and across the country if we are successful.

The next step is to find anti-Gmd agents that might be used to make vaccines. The vaccine development company, Codevax, is working on that. Codevax was started by the University of Rochester, and played a role in the development of cancer drugs Herceptin and Rituxan.

Orthopedic infections occur two percent of the time for joint replacement surgery and even more at five percent for implanting fracture-fixation devices. The cost is $360 per year for joint replacement surgery and even more $1.5 billion per year for fracture repair.

A vaccine would not only save lives, it would help reduce health care costs. This is the plan for making the vaccine:

  • Use Schwarz's model of going after the bacterial antigen, which is the heart of the immune response.
  • Use monoclonal antibodies against MRSA and test them in mice.
  • Conduct an early clinical trial of the protective antibodies (and continue with a clinical efficacy trial in the future).

Right now, our best line of defense against MRSA is antibiotics. Sometimes, as a last line of defense, doctors prescribe vancomycin and linezolid. But even those drugs aren’t guaranteed to work.

The over-use of antibiotics spawned antibiotic resistance and suberbugs, a problem as lethal as the infection itself. Now, experts warn that we are at the end of the antibiotic era.

“It’s already happening,” University of California, Los Angeles professor Brad Spellberg told Newsweek — to the tune of roughly 100,000 deaths a year from antibiotic-resistant infections in the United States alone. “But it’s going to become much more common.”

As I've said before, scientists have been working on a number of ways to combat the spread of the potentially deadly pathogens. There’s anti-pathogenic drugs to treat superbugs and a coating that can kill MRSA upon contact. Scientists at the University of Strathclyde have shown that special light is enough to make the bacteria basically commit cell suicide.

Perhaps soon, we will have a jab for MRSA to add to our set of weapons against superbug infections.

via The University of Rochester news

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