Hamilton lab helps unravel strep mystery – "the flesh eater"

Jim Musser, of Rocky Mountain Laboratories in Hamilton, calls it "the flesh eater."

In 1995, that particularly vicious strain of strep bacteria, began a march through the Canadian province of Ontario. The deadly germ seemed to subside for a time, only to re-emerge five years later. By the time the two epidemics had passed, hundreds of Canadians had fallen ill and dozens were dead – their tissue literally eaten away inside them.

By JENNIFER McKEE of the Missoulian State Bureau

http://missoulian.com/articles/2004/07/26/news/mtregional/news06.txt

At the time, said Donald Low, chief of microbiology at Mount Sanai Hospital in Toronto and one of the doctors to treat the victims of the flesh-eating epidemic, physicians were at a loss to explain the suddenly savage turn of strep – an unwelcome, but by no means, deadly invader.

You’d be operating on someone with flesh-eating disease, Low said, "and you’d be removing (dead) tissue you think you’ve been able to identify, only to come back to that tissue 20 minutes later and it had advanced even further."

Their questions spanned the gambit, Low said: Was there something different about this strain of strep, or were the victims who were falling ill and dying just unlucky? What made this strep so bad? What should we be doing differently?

Scientists at Montana’s Rocky Mountain Labs helped unravel the mystery. In a study to be published in the online version of the Proceedings of the National Academy of Sciences this week, Musser and his colleagues describe how they mapped the genome of the killer bugs from all the Canadian patients. They showed the strep bugs weren’t ordinary at all, but infected with viruses which made the original bacteria more dangerous.

The cooperative, international study marks the first time scientists were able to pinpoint the genetic underpinnings of an emerging epidemic and to show, by mapping the bacteria’s entire genome, how genetic differences within the same species of pathogens can cause different kinds of disease. Marshall Bloom, associate director of Rocky Mountain Labs, said the discovery was a kind of watershed event.

"One hundred years ago, it was a big deal between telling the difference between a staph bacteria and a strep bacteria," he said. "Fifty years ago, it was a big deal to know if the bacteria was resistant to penicillin or not. Now with the genomic approach, we can actual scan the entire genomic sequence of the bacteria to reveal why they act the way they do."

The discovery also opens new doors for doctors, Low said. Before, physicians didn’t appreciate that the strep killing 45 percent of its victims in the Canadian outbreaks was actually genetically different from the more moderate kind of bacteria that causes strep throat. Now, he said, doctors know that a case or two of flesh-eating strep is not just happenstance or bad luck. It’s a vicious strain of strep that must be managed more aggressively.

Typically, doctors don’t put the family members of people with strep on antibiotics as a safeguard. But just one case of "the flesh-eater" now tips doctors off that they’re dealing with something different and people who have contact with the victim should be treated to prevent serious disease.

That viruses can infect strep bacteria and make them "flesh-eaters" is not entirely new. Musser and his team first published that discovery two years ago.

"This is an extension of that discovery," he said. "This was the utilization of that initial discovery to address a fundamental question: What at the molecular level creates the underpinning for a new epidemic?"