|
One Tough Bacterium Can 'Teach' Others to Resist Antibiotics The average person might be unaware of the fact that millions of bacteria thrive within the human body. They are supposed to be there. One such bacterium, Enterococcus faecalis, resides within the gastrointestinal
tracts of most of us, nearly 95% of the population, says Helmut Hirt,
K-State assistant professor of biology.
Its negative effects include meningitis, urinary tract infections, heart infections, and central nervous system infections, he said. Dr. Hirt has spent the last 10 years studying this bacterium not only because of the specific problems it can create but also because of what it can "teach" to other bacteria. He said that E. faecalis is an extremely antibiotic-resistant bacterium. It has a unique surface structure that enables it to hook to other bacteria and transfer its plasmids to them. Plasmids are small circular molecules of extra chromosomal-DNA that carry additional genes. Very little is known about the surface structure of E. faecalis and how it is able to transfer its plasmids to other bacteria, he said. Hirt said that he has dedicated his studies to uncovering the mysteries of E. faecalis. For one thing, E. faecalis is a very "tough" bacterium, he said. It resists general antibiotic treatment very well, and 20 percent of E. faecalis strains isolated today are vancomycin-resistant. Vancomycin is the "antibiotic of last resort," used only when all other antibiotic treatments have failed, he said. For example, when an antibiotic like penicillin is ineffective in treating a Staph infection, doctors will turn to vancomycin then and only then, as a sure fix. Because E. faecalis is able to transfer its plasmids to other bacteria, then, in theory, the bacteria is enabling those other bacteria to resist antibiotic treatment, too, Dr. Hirt said. He said that certain Staph infections, for example, could become untreatable by all known antibiotics, from penicillin to vancomycin, due to the resistance genes. "Our fear is that E. faecalis will spread its vancomycin-resistant genes to these other bacteria," he said. Dr. Hirt said his ultimate goal is to uncover the surface structures of E. faecalis and learn specifically how it is able to transfer resistance genes. If he's successful, new avenues of bacterial treatment could become available for patients in the future.
Story prepared by Natasha Johnson
Fore more information contact Helmut Hirt
|
