Protein from Staph Infection Causes Lung Injury in Pneumonia

Staphlococcus aureus, a bacterium frequently found on the skin, is one of the four most common causes of hospital-acquired infections. S. aureus infections range from mild skin infections such as pimples to life-threatening diseases such as pneumonia and meningitis.

Pneumonia caused by Staphlococcus aureus is characterized by severe inflammation that results in lung injury. Hayashida et al found that mice infected with S. aureus deficient in the protein beta-toxin had lower levels of lung injury compared with mice infected with wild-type S. aureus.

In addition, S. aureus beta-toxin caused lung injury in normal mice, although not in mice that lacked a specific type of white blood cells, neutrophils.

Dr. Park and colleagues "have uncovered a previously unknown in vivo function of beta-toxin in enhancing lung injury during S. aureus pneumonia. …[Their] data suggest that beta-toxin exaggerates lung injury not through its cytotoxic activity, but through its capacity to enhance neutrophil infiltration."

Hayashida A, Bartlett AH, Foster TJ, Park PW: Staphylococcus aureus beta-toxin Induces Lung Injury through Syndecan-1. Am J Pathol 2009, 174: 509-518

By American Journal of Pathology