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While considering how to write about this topic for an informed layperson, I happened upon the term mobile genetic elements. For the more technically-focused people, in today's post I am lumping bacteriophages, transposons, group II introns, and plasmids under this heading, and I refer you to this review.
My other impetus was a court order yesterday ordering the FDA to re-issue notices to drug companies of proposed withdrawals of penicillins and tetracyclines used to promote growth of livestock. These FDA notices will also have to be updated because the FDA took no action after issuing them decades ago.
I am confident most readers will have heard and read of overprescription of antibiotics by physicians as a cause of the increase in antibiotic-resistant bacteria, but 28.8 million pounds of antibiotics were used in domestic livestock in 2009. (See Table 1 of this FDA report.) Humans used 7.2 million pounds that same year. The concerns the FDA expressed in the sixties and seventies were valid, but science was unaware of how fast antibiotic-resistant bacteria would arise because of their ability to genetically engineer themselves via mobile genetic elements. What the bacteria were doing became more apparent as humans genetically engineered various organisms beginning in the seventies. This quote from the review article below refers only to one type of MGE, but the others are implicated in the following paragraphs on p. 726.
The Antibiotic Trial of the Century by Kevin Outterson at The Incidental Economist
Mobile Genetic Elements: The Agents of Open Source Evolution by Laura S. Frost, et al., Nat Rev Microbiol 3(9):722-732, 2005.
My other impetus was a court order yesterday ordering the FDA to re-issue notices to drug companies of proposed withdrawals of penicillins and tetracyclines used to promote growth of livestock. These FDA notices will also have to be updated because the FDA took no action after issuing them decades ago.
I am confident most readers will have heard and read of overprescription of antibiotics by physicians as a cause of the increase in antibiotic-resistant bacteria, but 28.8 million pounds of antibiotics were used in domestic livestock in 2009. (See Table 1 of this FDA report.) Humans used 7.2 million pounds that same year. The concerns the FDA expressed in the sixties and seventies were valid, but science was unaware of how fast antibiotic-resistant bacteria would arise because of their ability to genetically engineer themselves via mobile genetic elements. What the bacteria were doing became more apparent as humans genetically engineered various organisms beginning in the seventies. This quote from the review article below refers only to one type of MGE, but the others are implicated in the following paragraphs on p. 726.
"The earliest described accessory function of plasmids was antibiotic multi-resistance. Now recognized as an inevitable result of the widespread use of antibiotics, this phenomenon threatens to return certain areas of medical practice (notably critical and end-of-life care) to a pre-antibiotic era in which there are no drugs to treat infected people."Many of the genes carried by MGEs are associated with antibiotic resistance, and others insure that the antibiotic-resistance genes are rapidly mobilized among bacteria.
The Antibiotic Trial of the Century by Kevin Outterson at The Incidental Economist
Mobile Genetic Elements: The Agents of Open Source Evolution by Laura S. Frost, et al., Nat Rev Microbiol 3(9):722-732, 2005.
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