It only took 35 years for flesh-eating bacteria to become an infectious terror

[n2doc]

All it took for flesh-eating bacteria to go from harmless organisms to gruesome infectious pathogens was four mutations and about 35 years. That's what an international group of researchers announced today in a study that outside experts are calling the largest bacterial genome paper ever published.

Despite its name, flesh-eating bacteria — a type of streptococcus — doesn't consume flesh. What it does do is produce proteins that break down human skin, fat, and muscle — a process that causes flesh to die rather quickly. "One of the major proteins is an active ingredient in Adolph's meat tenderizer," says James Musser, an infectious disease expert at Houston Methodist Research Institute and co-author of the study published today in Proceedings of the National Academy of Sciences. The ensuing disease, called necrotizing fasciitis, is very difficult to treat; although antibiotics can do the trick, skin-grafting and amputations are not uncommon. Worse yet, the disease causes death in 70 percent of cases if left untreated. And the infection is actually human-specific, so other animals can't get the disease. These characteristics, Musser says, make it a particularly interesting beast with which to work.

To find out how the bacteria mutated, the researchers analyzed the genomes of over 3,615 population-based strains of streptococcus. For the most part, these organisms don't make humans sick, but some can result in pink eye, meningitis and pneumonia. The most notorious strep strain, however, is probably Group A streptococcus — the group that tends to cause the most epidemics of flesh-eating disease. "We needed this magnitude of data," Musser says, "to be clear about what transpired to create this thug pathogen."

Once the researchers had gathered all the historical genomic data, they set about building a molecular clock where each change in the bacterial genome brought them closer to finding out exactly what genetic changes allowed the pathogen to become this successful. "By working backward, we were able to determine that there were four key genetic changes," Musser says. The first two mutations — changes that took place prior to 1960 — arose after a single progenitor cell line became infected with two different types of viruses. "Bacteria can get viral infections too," Musser says, "and the viruses that they got infected with carried genes encoding novel toxins," which the bacteria were then able to integrate into their own DNA.

more

http://www.theverge.com/2014/4/14/5613642/only-thirty-five-years-flesh-eating-bacteria-infectious-terror

[longship]

1. Isn't nature wonderful?

It gives us food, a livable environment, the beauty of flora and fauna, the awesome universe, and necrotizing fasciitis, among other things.

R&K

[leftyohiolib]

2. cause nature is an uncontrollable lab

[Chemisse]

3. I love these little guys! (minus the necrosis, of course)