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The Case of MRSA
Methicillin is an antibiotic that was developed to treat infections by the bacterium Staphylococcus aureus, which had begun to develop resistance to many other antibiotics. At a Boston hospital in 1968, there was an outbreak of Staphylococcus infections that couldn't be cured by methicillin or several other antibiotics the first outbreak of MRSA in the U.S. MRSA has since proven to be an extremely troubling source of infections, first in hospital patients and later in communities.
There are only a limited number of antibiotics that can be given to humans to treat infections. And with disease organisms becoming resistant to multiple antibiotics, this number was rapidly dwindling. Antibiotic resistance was no longer a theoretical topic for scientists to discuss. It was now an extremely serious health problem.
A 2007 study published by the CDC found that 20 percent of all human MRSA in the Netherlands is of animal origin, from pigs and likely from cows. And the researchers strongly doubt that this problem is confined to the Netherlands. In other words, antibiotic-resistant bacteria from farm animals have been linked to antibiotic-resistant infections in humans. (5)
The issue of whether antibiotic-resistant bacteria from farm animals have already caused infections in humans is really moot. The ease with which resistance spreads from one species of bacteria to another means that the pool of drug-resistant bacteria created on animal farms is bound to spread to humans sooner or later. Unless of course, these resistant bacteria can be reduced or eliminated.
This was the idea behind the Maryland School of Public Health study. Could drug-resistant bacteria be discouraged by a reduced reliance on antibiotics?
Short-Circuiting Antibiotic Resistance
Bacteria don't choose to become antibiotic resistant. When they are growing in the presence of an antibiotic that would normally kill them, those that are able to resist the antibiotic survive and breed, while those that don't die. It's a survival trait, pure and simple.