Does MRSA ring a bell? Yeah, Methicillin-Resistant Staphylococcus Aureus, known for causing nasty infections in hospitals around the country. Well, If you ever wanted to know where MRSA may have developed it's methicillin resistance, read the following:
Bacteria Subsisting on Antibiotics (The full article is no longer freely available. This link will take you to the free abstract.)
So, an "antibiotic resistome" eh? My favorite line, "We cultured clonal bacterial isolates from 11 diverse soils (table S2) that were capable of using one of 18 different antibiotics as their sole carbon source." Wow! Not only were bacteria found to be merely resistant to antibiotics, they were found to be using them as their SOLE energy source! That's what I call specialization!
The relatively recent development of antibiotic resistance in strains of Staph might lead one to wonder, considering the relatively little time humans have been using antibiotics in medicine, how have bacteria been able to adapt so quickly to our treatments to become so resistant in only a matter of decades? Though bacteria do reproduce quickly allowing for accelerated evolution, random mutations seem like an unlikely culprit for how fast Staph has been able to adapt to our treatments. Then how did it happen? One possible answer is in this paper. The problem is thinking in such a human centric manner. Ultimately, resistance mechanisms did have to evolve at some point in time, but these resistance genes did not likely evolve in the past hundred years.
Think about where we got our first antibiotics - from fungi, molds, plants! Bacteria have been evolving alongside all of these hosts for far more than thousands of years. So, how did Staph, a human pathogen, manage to get the resistance gene from a bacteria that colonizes on fungi? Horizontal Gene Transfer (HGT). Hence, the concept of the "antibiotic resistome," an environmental reservoir of antibiotic resistance. From this reservoir, bacteria can essentially share genes that they have evolved through co-evolution with another species of bacteria.
Put simply, bacteria can share certain defenses. Staph can pick up what it needs to survive our "advanced" treatments by just picking up the defenses another species of bacteria has used to survive these antibiotics for thousands of years.
Anyhow... I thought that was interesting.
April 24, 2008
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2 comments:
Here is a first---A comment on your new blog! My god do you sound educated and smart. Cool explantion..I feel I understood it. Many students At the high schools using our gyms are in a panic due to MRSRA. Don't know if you knew but Uncle Adam picked the MRSRA problem in Hawaii. Later Mom.
Ha! Yeah it's a pretty serious problem. Let me know if there is anything you'd like me to explain in more detail. It's a great way to help me learn about the material I'm studying in lecture.
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