Science  10 Jun 2011:
Vol. 332, Issue 6035, pp. 1248

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  1. New Superbug Found in Cows and People

    A novel form of deadly drug-resistant bacteria has turned up in dairy cows and humans in the United Kingdom. But don't toss that milk just yet: The superbug isn't a concern in pasteurized dairy products.

    The bug is methicillin-resistant Staphylococcus aureus (MRSA), a drug-resistant form of the normally harmless S. aureus bacterium. It preys on people with weakened immune systems, causing about 19,000 hospital deaths a year in the United States.

    Mark Holmes of the University of Cambridge in the United Kingdom and colleagues stumbled upon a new MRSA strain while studying mastitis, or infected udders, in U.K. dairy cows. While clearly resistant to antibiotics, the strain came back negative on a standard PCR test for mecA, a gene found in all MRSA strains. Only by sequencing the bacterium's entire genome did the team find the gene in an altered form.

    About two-thirds of 74 human samples of drug-resistant S. aureus from the United Kingdom and Denmark, despite also failing the usual PCR test, carried the new mecA, the team reported online 3 June in The Lancet Infectious Diseases. A nearly identical mecA gene has also been reported in human MRSA samples from Germany and Ireland.

    The strain probably makes up less than 1% of all detected MRSA cases, the team says. And infected cows probably don't pass the bug to humans through milk, which is almost always pasteurized, but via contact with diary workers who may become carriers.

  2. Antiatoms, Ready for Work

    ALPHA catches an antihydrogen atom.


    Six months ago, physicists trapped atoms made of antimatter for a fraction of a second. Now, the same team, which works with the ALPHA experiment at the European particle physics lab, CERN, near Geneva, Switzerland, has held individual atoms of antihydrogen, each consisting of an antiproton bound to a positron, for up to 15 minutes. That's long enough for an atom to radiate all of its internal energy and settle into its “ground state,” a prerequisite for probing its inner workings.

    The result, reported online 5 June in Nature Physics, brings physicists closer to their decades-old goal of precisely comparing the spectrum of light absorbed by antihydrogen to that of hydrogen. Any difference in the spectra would spoil a key symmetry thought to exist between matter and antimatter and, hence, a symmetry of space and time that undergirds Einstein's theory of special relativity.

    Measuring antihydrogen's spectrum with sufficient precision may take years, however, and ALPHA faces competition from two other experiments, also at CERN. “This is clearly a very, very important experimental step forward,” says University of Tokyo physicist Ryugo Hayano, who leads the rival ASACUSA team. “But that doesn't mean the next step is going to be easy.”