New, deadly bacteria may be lurking in US; CDC warns of three puzzling cases

Enlarge / Burkholderia pseudomallei grown on sheep blood agar for 24 hours. Burkholderia pseudomallei is a Gram-negative aerobic bacteria, and it's the causative agent of melioidosis. (credit: Getty | CDC/Courtesy of Larry Stauffer, Oregon State Public Health Laboratory)

A deadly soil bacterium common in tropical and subtropical climates has mysteriously infected three people in three different US states, killing at least one, according to a health alert from the Centers for Disease Control and Prevention.

While US cases of the infection periodically pop up in travelers, none of the three infected people have recent travel history that could easily explain how they picked up the dangerous germ. The bacteria, Burkholderia pseudomallei, usually infects by direct contact with an environmental source, i.e. contaminated soil or water. It most often attacks through breaks in the skin and it very rarely jumps from human to human. Yet genetic analyses of the bacterial strains in the latest US cases indicate that the three, geographically-separated infections are related.

The curious cluster of cases suggests there was a common source of the bacteria. Investigators speculate that a yet-unidentified imported product or animal could be a common source. For instance, iguanas and monkeys imported with infections have been linked to cases in the past. But the cluster also resurfaces concern that B. pseudomallei is no longer a mere interloper in the US, rather it may have become a permanent, low-key resident.

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