Editor's note: Rep. Louise M. Slaughter (D-NY) is the only microbiologist in Congress and has been a leader on public health issues, particularly on the overuse of antibiotics on the farm. Dr. Robert S. Lawrence is professor of Environmental Health Sciences, Health Policy, and International Health at the Johns Hopkins Bloomberg School of Public Health and the founding director of the Johns Hopkins Center for a Livable Future.
Strep throat should not kill you. Nor should a knee scratch that becomes infected.
For decades, the world has relied upon antibiotics to treat common infections. As bacteria develop resistance to antibiotics, these minor afflictions could soon become life-threatening.
Procedures that place patients at risk of infection, like hip replacements, dental work and open-heart surgery, could become far more dangerous.
The Centers for Disease Control and Prevention reported in October that antibiotic-resistant bacteria - known as "superbugs" - cause at least two million infections and 23,000 deaths in the United States yearly. The cost to the U.S. health care system has been pegged at $17 billion to $26 billion annually.
In 1977, the Food and Drug Administration found that feeding antibiotics to food animals at low doses, both to promote growth and to prevent disease, contributes to this public health crisis. The CDC concurred: "[M]uch of antibiotic use in animals is unnecessary and inappropriate and makes everyone less safe." The World Health Organization, the American Medical Association, the American Academy of Pediatrics, and many others have called for restrictions.
In the almost four decades since the FDA acknowledged this problem, Congressional opposition and intense industry lobbying has blocked meaningful action - even as hundreds of scientific studies have confirmed the link between antibiotic misuse in food animals and superbug infections in humans.
Read - How a cow could kill you: New antibiotic guidelines still fail to protect public
As one who is currently being treated for yet another severe MRSA infection with cellulitis, I can only underscore the need to eradicate unnecessary use of antibiotic AND antibacterial agents. The insanity surrounding the need for cleanliness in the US and Europe, with hand sanitizers, antibacterial soaps, antibacterial sprays, antibiotics given to animals in the food chain, antibiotic overuse in medical practices, etc., has made "superbugs" a reality and they are EVERYWHERE. For example, one-half of schoolkids are exposed to MRSA daily. We are so afraid to let kids get dirty that we have created an entire generation with horrendous allergies and record levels of asthma, then set them loose in a world in which we have created and unleashed the most vicious bacterial strains, resistant to treatment by any but the most potent and toxic of antibiotics.
Treatment for MRSA is not easy and has its own dangers. Twice I have had to be treated for Clostridium dificile colitis (known as "C. dif") caused by the antibiotics necessary to treat MRSA. C. dif. can kill, and even when it doesn't, it can make you wish you were dead. For the MRSA I am now taking large doses of clindamycin, three times a day, and the side effects are pretty awful - metallic taste in my mouth all the time, nausea, headache, etc. The scariest, though, is that it can cause C. dif. It has taken four days to see any effects AT ALL against the infection.
I do not eat meat, and I do not use antibacterial products. Nonetheless, I live in a society, and the practices of antibiotic usage by others have a very profound impact on me. The superbugs generated by the practices of the majority affect everyone. To deride action against use of antibiotics in food animals as ineffective because it ignores other antibiotic abuses is wrong. Although this one action may not solve the whole problem, it CAN solve a part of it, and a significant part at that. Animal antibiotic use causes $17 billion to $26 billion in human medical costs per year in the US, including MINE. That is a "REAL ISSUE". And while a prescription is not required for antibiotics in many countries, pharmacists DO review cases to determine whether they are appropriate for use before selling them over the counter. (Antibiotics are not sold like candy.) Since hundreds of scientific studies have confirmed the link between antibiotic misuse in food animals and superbug infections in humans, it seems eradicating such "growth promoters" (as the meat industry prefers to call antibiotic drugs) is a very good place to start.
This is a classical "pick the low hanging fruit" and "easy target" approach that will never work. Go to Tijuana and ask for some penicillin in a drug store. Go to India and get cosmetic surgery and ask for some "preventive" antibiotics. We are worrying about 10 g / ton of tetracycline while 2nd and 3rd world countries are doing curbside sales of the most essential drugs we have left. Eliminating growth promoters from animals will have zero impact on the battle against drug resistance. How about dealing with the real issues? World travel. Non-uniform policies for the sale and administration of abx to humans in different countries. Then you might get somewhere.
Aug. 13, 2013 — A strain of bacteria that causes skin and soft tissue infections in humans originally came from cattle, according to a study to be published in mBio®, the online open-access journal of the American Society for Microbiology. The researchers who conducted the genetic analysis of strains of Staphylococcus aureus known as CC97 say these strains developed resistance to methicillin after they crossed over into humans around forty years ago. Today, methicillin-resistant S. aureus (MRSA) strain CC97 is an emerging human pathogen in Europe, North and South America, Africa, and Asia. The findings highlight the potential for cows to serve as a reservoir for bacteria with the capacity for pandemic spread in humans.
The researchers sequenced the genomes of 43 different CC97 isolates from humans, cattle, and other animals, and plotted their genetic relationships in a phylogenetic tree. Corresponding author Ross Fitzgerald of the Roslin Institute and the University of Edinburgh in Scotland says strains of CC97 found in cows appear to be the ancestors of CC97 strains from humans.
"Bovine strains seemed to occupy deeper parts of the phylogenetic tree - they were closer to the root than the human strains. This led us to conclude that the strains infecting humans originated in cows and that they had evolved from bovine to human host jumps," says Fitzgerald.
Although the CC97 strains from animals were quite genetically diverse, the human isolates cluster together in two tight, distinct "clades," or relatedness groups, indicating that S. aureus CC97 in cattle crossed over into humans on two separate occasions. Using mutation rates as a molecular clock, the authors determined that the ancestor of clade A jumped from a bovine host to humans between 1894 and 1977 and clade B made the jump between 1938 and 1966.
After they made the jump, the human CC97 strains acquired some new capabilities, says Fitzgerald, thanks to genes encoded on portable pieces of DNA called mobile genetic elements.
"It seems like these elements, such as pathogenicity islands, phages, and plasmids, are important in order for the bacterium to adapt to different host species," says Fitzgerald. "The reverse is true as well: the bovine strains have their own mobile genetic elements."
Perhaps the most problematic new capability the human strains acquired is the ability to resist methicillin, an important antibiotic for fighting staphylococcal infections. Only human strains of CC97 were able to resist the drug, which indicates that the bacteria acquired resistance after they crossed over into humans, presumably through exposure to antibiotics prescribed for treating human infections.
This sequence of events contrasts with the case of a S. aureus strain from pigs, Fitzgerald points out, since a study in 2012 revealed that MRSA ST398 strains evolved the ability to resist methicillin before they crossed over into humans. Any number of factors could create these differences, making pigs - but not cattle - a source of a drug-resistant bacterium. At this point, though, there isn't enough information to say whether differences in the S. aureus strains, differences between pigs and cattle, or differences between swine and dairy farming practices might be responsible.
Moving forward, Fitzgerald says he and his colleagues plan to widen the investigation.
"We have a relatively small sample size, and the findings are robust, but we want to extend the study now to include a greater number of clones to get a bigger picture of what's going on across the S. aureus species," says Fitzgerald.
A wider variety of S. aureus strains, Fitzgerald says, from a wider variety of locations and hosts and a wider range of time, will allow them to better pinpoint the timing and circumstances of the host jump events. Understanding how and when MRSA has crossed over from other species in the past can help us to put the brakes on these crossovers in the future and hopefully prevent the birth of the next pandemic S. aureus strain.
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