New Technology Lights Chronic Bacterial Infection Inside Bone

New research demonstrates how a sensitive imaging technique gives scientists an advantage in looking for bacteria in chronic infections.

Listeria monocytogenes is a type of pathogenic bacteria that can cause severe illness and death. Listeria outbreaks recently killed 20 people in Canada. Moreover, Listeria infection is the third most common cause of bacterial meningitis in newborns, and can cause abortion and stillbirth. When the infection is caught in time, treatment can be difficult and take weeks to work with intravenous administration of antibiotics.

Therefore, to determine how this pathogen can be so sneaky and difficult to treat, a research team from Stanford University School of Medicine (CA, USA) examined laboratory mice infected with Listeria. Their study describes how they used a technique called in vivo bioluminescence to light up bacteria and allow them to see extremely tiny amounts of bacterial cells in living animals. Using this method, they found that small persistent patches of Listeria took up residence inside bone marrow in the mice. This is significant because it is thought that the bone marrow can act as a reservoir to the brain and spinal cord, potentially causing life-threatening infections, such as in bacterial meningitis in newborns.

Another interesting feature of this study is the use of specially designed Listeria stains in treating cancer. Clinical trials are ongoing in which non-disease-causing strains of Listeria are administered to cancer patients to generate immune responses against tumors. The researchers thus also looked at these attenuated strains, and discovered that they too could be harbored in bone marrow. It is still unclear, however, if such bacterial persistence will increase or decrease therapeutic effects.

The Stanford researchers, Drs. Jonathan Hardy, Pauline Chu, and Christopher H. Contag, published their study in the January/February 2009 issue of a new research journal, Disease Models & Mechanisms (DMM).

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Stanford University School of Medicine