Wednesday, August 17, 2011

Ringing the Warning Bell: Colistin-Resistant Klebsiella

In all the latest bad news about bacteria becoming highly resistant — through carbapenem resistance, or the “Indian supergene” NDM-1 — there has been one hopeful thread: All of the organisms have remained susceptible to one very old, little-used drug called colistin.

That might be about to change. Which would be very, very bad news.

Writing in a recent issue of Clinical Infectious Diseases, faculty from the University of Pittsburgh say they saw five patients last year with colistin-resistant Klebsiella pneumoniae, a Gram-negative bacterium that is a frequent cause of very serious hospital infections and that has already become resistant to multiple classes of drugs.

The patients were seen over four months at University of Pittsburgh Medical Center. Four of them were cared for by the transplant team and the fifth was in a medical ward in a separate building. One of the patients died.

The cluster unfolded like this:

The first patient was a 63-year-old man who was hospitalized in January 2010, initially on a surgical ward, and then scheduled for a liver transplant. Ten days after being admitted, he was diagnosed with carbapenem-resistant Klebsiella or CRKP, an increasingly common drug-resistant organism (subject of my Scientific American piece last April) for which the drugs colistin and tigecycline are the only remaining treatments. He was transferred to the transplant intensive care unit, and on March 10, his Klebsiella infection was discovered to have become colistin-resistant. (more)