November 16, 2012
Accidental Injury Leads To Discovery Of Medically Important Bacteria
Brett Smith for redOrbit.com - Your Universe Online
History is filled with stories of groundbreaking scientific discoveries that happen by chance--the most famous being Sir Alexander Fleming´s discovery of penicillin on a Petri dish, which had been accidentally left open for several days.
The discovery began on Oct. 15, 2010 when retired inventor and medical technician Thomas Fritz impaled the fleshy part of his hand between his thumb and index finger on a crabapple tree he had just cut down outside of his home in Evansville, Indiana.
After dressing the wound, Fritz called his doctor to schedule an appointment. By the time the retiree made it in to see his physician, a cyst had formed around the wound. The doctor put Fritz on an antibiotic, but the pain and swelling continued as the wound became abscessed.
Eventually, an orthopedic surgeon would remove several pieces of tree bark from the wound, allowing it to finally heal.
Initial lab tests of a tissue sample taken from Fritz´s wound were not able to properly identify the bacteria that had caused the infection. So, the mystery organism was shipped to ARUP Laboratories, a national pathology reference library operated by the University of Utah, for further analysis.
The tests at ARUP showed the organism was common E. coli bacteria. However, the scientists had doubted that finding and conducted further testing.
"We had close matches for it, but none were validly described species," said study co-author Mark Fisher of the ARUP Institute for Clinical and Experimental Pathology. "It caught my eye because I knew Colin Dale worked on Sodalis."
Dale, a biologist from University of Utah, is the researcher who, in 1999, discovered and named Sodalis, a genus of bacteria that lives symbiotically inside different types of insects.
Through genetic sequencing, Dale and researchers had realized they had a new bacterium called human Sodalis, or HS, that is related to the Sodalis bacteria that live symbiotically inside 17 insect species.
According to Dale, the findings of the study offer "a missing link in our understanding of how beneficial insect-bacteria relationships originate.”
"They show that these relationships arise independently in each insect,” he said in a statement. “The insect picks up a pathogen that is widespread in the environment and then domesticates it. This happens independently in each insect."
Dale added that these symbiotic bacteria are then passed from mother to offspring.
The researchers hypothesized there are many other undiscovered bacteria that form symbiotic relationships with insects and understanding them could help to prevent diseases spread by the insects that host them.
"We have identified very few of the bacteria that exist in nature," says Dale, "and new species and strains like HS are often only discovered when they infect humans."
"If we can genetically modify a bacterium that could be put back into insects, it could be used as a way to combat diseases transmitted by those insects," said lead author Adam Clayton, a University of Utah biologist.