Antibiotic-Resistant Bugs Go Wild

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One of the most notorious and hard-to-treat bacteria in humans has been found in wildlife, according to a new study in the Journal of Wildlife Diseases. The researchers isolated methicillin-resistantStaphylococcus aureus (MRSA) in two rabbits and a shorebird. Wild animals may act as an environmental reservoir for the disease from which humans could get infected.


S. aureus can cause skin infections or, if it gets into the bloodstream, life-threatening illness. Most infections are easy to manage with penicillin and related antibiotics, but MRSA, the resistant variety, is on the rise; also known as a “superbug,” it kills an estimated 18,000 Americans a year. In most cases, people contract the bacterium from a hospital stay. Hospitals are breeding grounds for antibiotic-resistant organisms, because patients are treated with a wide variety of antimicrobial drugs, prompting pathogens to develop defenses.

It’s been clear for more than a decade, however, that people can catch MRSA strains outside of the hospital as well; researchers call these “community-associated” strains. For instance, pigs on livestock farms have been found harboring the bug, likely because farmers give antibiotics to food animals as they grow, another way of encouraging resistance to evolve. Other studies have found MRSA in pets and zoo animals; they may have been infected by human caretakers.

Now it appears that even animals in the wild can be infected with MRSA. Researchers led by epidemiologist Tara Smith of the University of Iowa’s College of Public Health in Iowa City took samples from 114 animals that came into the Wildlife Care Clinic, which rehabilitates injured or orphaned animals, at Iowa State University in Ames. Seven of the animals, or 6.1%, carried S. aureus that was sensitive to methicillin; these included owls, pigeons, a beaver, a heron, and a squirrel. Three animals, or 2.6%, carried MRSA: two Eastern cottontail rabbits and a lesser yellowlegs, a migratory shorebird. (For comparison’s sake: An estimated 1.5% of Americans carry MRSA in their noses.)

 

Written By: Jill U. Adams
continue to source article at news.sciencemag.org

7 COMMENTS

  1. @OP -  Most infections are easy to manage with penicillin and related
    antibiotics, but MRSA, the resistant variety, is on the rise; also known
    as a “superbug,” it kills an estimated 18,000 Americans a year. In most
    cases, people contract the bacterium from a hospital stay.

    It’s been clear for more than a decade, however, that people can catch
    MRSA strains outside of the hospital as well; researchers call these
    “community-associated” strains. For instance, pigs on livestock farms have
    been found harboring the bug, likely because farmers give antibiotics
    to food animals as they grow, another way of encouraging resistance to
    evolve.

    It was only a matter of time for these to evolve, because of under-dosing by people taking antibiotics, careless disposal of residual medicines, and the gratuitous use of antibiotics in animal feed to boost growth rates.

    I can remember discussing the potential problems of antibiotic resistance arising from medicated animal feed, at a university college of agriculture experimental farm in the 1960s.  Warnings from academics were available at that time – 45 years ago!

    My father-in-law died of Cdiff 2 years ago after making a full recovery in hospital from 2 injuries and having a pacemaker fitted.

    As with tobacco & cancer, vaccines, toxic pesticides, AGW, and more recently GM issues, scientific warnings have been met all too frequently, with denial, disinformation, and the hiding or suppression of the science by vested interests pursuing short term reckless profits, regardless of damage to others or the environment!

  2. I have HIV. My personal set of microbes, which no one else in the world has, have evolved immunity to about 10 anti-HIV drugs.  They developed this immunity with ordinary natural selection, despite heroic efforts to thwart them with multi-drug cocktails, and suppression to unmeasurable levels to reduce the emergence of variants. HIV is particularly good at creating variants.  MRSA, working in millions of individuals should thus too be expected to evolve rapidly, though not as fast as HIV.  Using human-antibiotics in animal feed is of course speeds the resistance process many times.

    This means you really have to run to stay ahead of them.  This means you can’t wait until there is an economic need for a new antibiotic before developing it. You must have several new drugs in the pipeline at all times.  You also have to have some reserved for a few very serious cases so the bugs don’t get to see them often and develop immunity. Our current economic system does not encourage this sort of behaviour.

    I think we need some sort of agency funded by the world’s goverments to provide new antibiotics, whether they are profitable or not, and to rigidly control how they are used to prevent early resistance. The actual work could be done by ordinary for-profit companies, paid in cash, patents, or rights.

    The essential economic problem is you can’t sell a new patented drug, if it has to compete with an end of life generic drug.  HIV is a special case. It evolves so fast that generic drugs are almost useless.

  3. I was surprised to read that MRSA is “on the rise.”Life threatening MRSA infections in both healthcare and community environments are actually declining in the US http://www.cdc.gov/mrsa/statis… by 28% and 17% respectively (2005-2008). Furthermore, bloodstream MRSA infections have fallen 50% (1997-2007)

    Taken together and with other reports such as the March 2011 CDC Vital Signs article, these studies provide evidence that rates of invasive MRSA infections in the United States are falling. While MRSA remains an important public health problem and more remains to be done to further decrease risks of developing these infections, this decrease in healthcare-associated MRSA infections is encouraging.

    The study in the Journal of Wildlife Diseases is important and interesting in its own right, but it really shouldn’t have been jumbled together with community and hospital acquired MRSA data in such a manner, imho.

    Mike

  4.  Sample -  I was surprised to read that MRSA is “on the rise.”Life threatening MRSA infections in both healthcare and community environments are actually declining in the US

    I don’t know about the US hospitals or care-homes, but in the UK in recent years , alcohol gel disinfectant dispensers in corridors, and notices in wash rooms, have sprung up all over the place.
    Could this be the reason for the reduction?

  5. I don’t know why MRSA is on the decline. I’m not sure anyone does (exactly). It’s also declining in the military, btw. If I recall, European hospitals were swabbing/culturing the nasal passages of all hospital patients upon admission while the US chose not to do this (at least on such a broad scale). The reasoning being (at least according to my personal physician) was that even if one was positive (but asymptomatic) there would be no treatment required anyway.

    Interestingly, about 14% of equine vets test positive for MRSA (nasally) while being without symptoms whereas the general public, I think, is around 2% (I’m recalling these stats from memory from about 2 years ago so they may have changed).

    The North American go-to person for zoonotic MRSA data is veterinarian Scott Weese of Ontario (University of Guelph). I’m sure he’s on the road to an answer, or as close to one as any. 

    Mike

  6. “Hospital … patients are treated with a wide variety of anti-microbial drugs,
    prompting pathogens to develop defences.”

    Pathogens have their own labs. now?

    Surely:
    “Hospital … patients are treated with a wide variety of anti-microbial drugs,
    prompting pathogens to evolve defences.”  No?

    If we can’t get journalists to use the right word for even the basic, most commonly observed and frequent examples of evolution what chance do we stand of getting the message across that SCIENCE WORKS.

    Peace.

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