Bacteria are all around us, we are told. However, according to the National Institutes of Health, less than 1% of them cause disease in people. Well, that list may have just gotten a little bigger. A 47-year-old French man sustained a nasty foot infection from a bacterium never before known to cause disease in people, according to a recently published report in the journal Emerging Infectious Diseases.  

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The man, while vacationing in Comoros – an island nation located at the northern end of the Mozambique Channel, between the African mainland and Madagascar – decided to go for a jog barefoot. Later his foot became swollen, red, hot, and painful. The wound had gotten so bad that by the time he returned home to Marseille in the south of France, he needed to be admitted to the hospital. At the Hospital Nord-Marseille, he underwent surgical cleaning of the wound, implantation of a tube for drainage, and a 7-week course of antibiotics.   

The identity of the bacterium cultured from the patient’s wound surprised his doctors. It was a bacterium called Sporolactobacillus laevolacticus, and it was originally discovered from the roots and associated soil (what scientists call the plant’s “rhizosphere”) of a yellow lily from Japan in 1967. The bacterium had never before been isolated from humans. Because of the unusual nature of this bacterium, conventional laboratory identification methods could not identify the organism.

Fortunately, a few years ago, the laboratory at the Hospital Nord-Marseille installed a new state-of-the-art instrument called a MALDI-TOF mass spectrometer that was able to correctly identify the bug.

According to the report, “This case confirms that S. laevolaticus can be responsible for human infections and suggests that this bacterial species could be an emerging opportunistic pathogen responsible for human infections.”

 Next time you decide to go for a jog, make sure to grab your tennis shoes!

Chris A. Whitehouse is a microbiologist and science writer who lives in Maryland.  He writes extensively on emerging infectious diseases of humans and animals.