New research using nearly a dozen different genomic testing procedures has revealed unprecedented detail about the molecular characteristics and virulence of group A streptococcus (GAS), the “flesh-eating” bacteria, according to scientists at the Rocky Mountain Laboratories, part of the National Institute of Allergy and Infectious Diseases.
The study, conducted by an international team led by RML scientist James M. Musser, M.D., Ph.D., will appear in the Proceedings of the National Academy of Sciences online sometime this week.
“This work indicates that using extensive genome-wide molecular analyses is an important new strategy for understanding how and why pathogens emerge,” notes NIAID Director Anthony S. Fauci, M.D. “What’s more, the method can be applied to other bacterial and viral pathogens by adjusting the techniques and strategies.”
Previous studies, Dr. Musser says, substantially underestimated genetic diversity in bacteria because these studies neither employed the array of molecular techniques they did nor analyzed a comprehensive database of patient samples.
“Before the advent of genome sequencing and genome-wide analysis methods, our knowledge of molecular characteristics of pathogenic bacterial infections in distinct populations was extremely limited,” says Dr. Musser.
In the new study, the RML team identified previously unknown genetic distinctions in M3 strains of GAS, revealing why only some strains rapidly expand to cause epidemics. All GAS strains can cause serious infections, Dr. Musser says, but the M3 strains are unusually virulent.
Dr. Musser explains that shortly after 2002, when he and his colleague Stephen Beres, Ph.D., at RML completed a genome sequence of the serotype M3 GAS, they turned their attention to using the new information to molecularly dissect two epidemics of life-threatening GAS infections, or necrotizing fasciitis—the “flesh-eating” syndrome. The study involved analyzing hundreds of patient cultures obtained over 11 years from Ontario, Canada, in epidemiologic studies conducted by Donald Low, M.D., and Allison McGeer, M.D., of the Mount Sinai Hospital in Toronto.