New generation of antibiotic-resistant “super-bug” bacteria on the horizon

From Maggie Koerth-Baker at Boing Boing blog:

Photo via Boing Boing blog

Maryn McKenna—my favorite “Scary Disease Girl” and author of Superbug—will be taking questions during a live chat today at Scientific American’s Facebook page. The chat starts at 2:00 Eastern and lasts for a half-hour.

The chat is connected to a new article that Maryn wrote for Scientific American, which centers around some disturbing new trends in antibiotic resistance. You may have heard about the recently announced discovery of a pneumonia-causing bacteria, called Klebsiella pneumoniae, that had developed a resistance to a class of antibiotics called carbapenems. This is more than just another bacteria resistant to another antibiotic.

Carbapenems are the antibiotics of last resort. The end of the line before we literally run out of ways to treat bacterial disease. The fact that bacteria are growing resistant even to them would, alone, be concerning. But the type of bacteria involved also matters. A lot.Klebsiella pneumoniae is a gram-negative bacteria….”

More on Boing Boing

Related — From the Scientific American story “The Enemy Within: A New Pattern of Anti-biotic Resistance”:

In early summer 2008 Timothy Walsh of Cardiff University in Wales got an e-mail from Christian Giske, an acquaintance who is a physician on the faculty of Sweden’s Karolinska Institute. Giske had been treating a 59-year-old man hospitalized that past January in Örebro, a small city about 100 miles from Stockholm. The man had lived with diabetes for many years, suffered several strokes and had lately developed deep bedsores. But those were not the subject of Giske’s message. Instead he was worried about a bacterium that a routine culture had unexpectedly revealed in the man’s urine. Would Walsh, who runs a lab that unravels the genetics of antibacterial resistance, be willing to take a look at the bug?

Walsh agreed and put the isolate through more than a dozen assays. It was Klebsiella pneumoniae, a bacterium that in hospitalized patients is one of the most frequent causes of pneumonia and bloodstream infection. This strain, though, contained something new, a gene that Walsh had never seen before. It rendered the Klebsiella, which was already resistant to many antibiotics used in critical care medicine, insensitive to the only remaining group that worked reliably and safely—the carbapenems, the so-called drugs of last resort. The one medication the investigators found that had any effect on the resistant strain was colistin, a drug that had been out of general use for years because of its toxic effects on the kidneys. Walsh named the enzyme that this gene produced New Delhi metallo-beta-lactamase, or NDM-1, for the city where the man acquired the infection just before he returned home to Sweden.

If there was one such case, Walsh thought, there were likely to be others—and he, Giske and a team of collaborators went in search of them. In August 2010 they published their results in Lancet Infectious Diseases: they had found 180 instances of patients carrying the gene. NDM-1 was widely distributed in Klebsiella in India and Pakistan and had already traveled to the U.K. via residents who had traveled to South Asia for medical care or to visit friends and family. Worse, it had spread in a few cases into a different bacterial genus—from Klebsiella into Escherichia coli, which lives in the gut of every warm-blooded being and is ubiquitous in our environment. That transfer raised the prospect that the gene would not stay confined to hospitals and hospital infections but would begin moving silently through the everyday world, carried in bacteria in the intestines of average people, advancing with­out detection via handshakes and kisses and doorknobs.

It raised another possibility as well: that the delicate, seesawing balance between bugs and drugs, set into motion in 1928 with the discovery of penicillin, was about to come down for good on the side of the bacteria. If so, many lethal infections that antibiotics have held at bay for decades might soon return with a vengeance….”

Read it all on Scientific American.

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