Bacteria Sneaks and Hides in Cells

(Ivanhoe Newswire) -- Researchers have found Staphylococcus aureus bacteria may elude the immune system by sneaking into cells and hiding out to avoid detection.

Researchers from University Hospital of Geneva in Switzerland and the Institute of Food Research in Norwich, UK, embarked on a study to find out just what S. aureus does in human lung epithelial cells. S. aureus is a major cause of human and animal infections.

Just like a villainous shape-shifter, shortly after S. aureus entered the lung cells, researchers found the bacteria's gene expression profile changed dramatically. They found the gene expression for bacterial metabolic functions and transport actually shut down, leaving the infectious bug in a dormant state. At the same time, researchers discovered the production of toxins that can kill epithelial cells became strictly controlled to limit cell damage. Then, the mechanisms that help the bacteria survive resumed.

Results of the study could pave the way to a better understanding of these types of infections as well as help researchers come up with better antibacterial drugs to fight them. It could also help them better understand what goes on at the molecular level that makes S. aureus so persistent. Researchers say the bacteria can re-surface and cause another infection years after the initial episode was "cured."

Patrice Francois, from University Hospital in Geneva, was quoted as saying, "S. aureus intracellular survival appears related to its capability to adopt a discrete behavior instead of actively duplicating. S. aureus then benefits from natural or programmed cell death to re-emerge and trigger another episode of infection, leading to chronicity."

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SOURCE: BMC Genomics, June 14, 2007