Dartmouth Researchers Take Aim At A Deadly Infection

May 28, 2015

MRSA, short for Methicillin Resistant Staphylococcus Aureus, is one of the most dangerous infections you can get. It’s usually a skin disease, it's often transmitted in hospitals and it resists many antibiotics.

But researchers at Dartmouth’s Thayer School of Engineering believe they have discovered a novel kind of treatment for the MRSA bacteria.

That could save a lot of lives. There are about 75,000 cases of MRSA in the United States each year. It can be fatal if untreated, and it’s challenging to treat.

MRSA strains carry an extra gene that resists many widely used antibiotics. There is an alternative to antibiotics — a protein that helps protect humans from invasion by dangerous microbes.

It’s called lysostaphin. But there’s a big problem with it.

Dartmouth researcher Karl Griswold says the body sees lysostaphin as a foreign invader and attacks it. So he and his Dartmouth colleague, Chris Bailey-Kellogg, have redesigned the protein so that the body will allow it to fight MRSA.

“We’re changing the attacker,” Griswold explained in his office at the Thayer School. “So we’re changing the molecule, lysostaphin, so that the red flags that it waves to the human immune system are suppressed, so the human immune system lets the molecule work in the body. We want to make a stealth version of lysostaphin.”

Which explains, in part, why they call their own bio-tech company Stealth Biologics. Their research is sponsored by the National Institutes of Health. Chris Bailey-Kellogg says redesigned lysostathin has not yet been tried on humans, but it’s worked well on rodents.

“In fact, that’s the subject of the study we just published. We showed that in humanized mice – that is, mice with some human immune system genes within them – we could treat MRSA when those mice were infected with MRSA," says Bailey-Kellogg. "We could effectively treat them with our drug multiple times and the drug was still effective.”

That suggests that human bodies will not build up a resistance to it, as they have to some antibiotics.

But that has yet to be proven. In fact, it could take as long as a decade to get this new drug through clinical trials and onto drugstore shelves.

Other researchers are conducting some similar experiments, but Karl Griswold says even though he and Bailey-Kellogg have formed their own company they are not in a race to the market.

As academics, he says they have the luxury to see what other breakthroughs could come from this concept of redesigning proteins to be more acceptable to the body. Griswold hopes the same principles behind this MRSA research might some day be applied to cancer.

“These are broadly applicable platforms to help advance discover and development of next generation drugs,” Griswold said.

Although effective remedies for life-threatening MRSA are many years away, hospitals are already having some success preventing it and other invasive infections by practicing better hygiene. Vermont does not track individual MRSA cases except in an outbreak, but data from the Centers for Disease Control show Vermont health care providers have lowered their rates of MRSA cases much faster than the national average.