Scientists Find a New Toxin That May be Key to MRSA Severity

Jul 17, 2010

A research project to identify all the surface proteins of USA300—the most common community-associated strain of the methicillin-resistant form of the bacterium Staphylococcus aureus (MRSA)—has resulted in the identification and isolation of a plentiful new toxin that laboratory studies indicate is a potent killer of human immune cells.

Scientists at the National Institute of Allergy and , part of the National Institutes of Health, say the could be a key factor in the severity of MRSA infections in otherwise healthy people. The toxin, named LukGH, consists of two small proteins found on the surface of the and is secreted freely into the surrounding environment.

The scientists identified 113 proteins associated with the surface of USA300 and began to examine the role of the previously uncharacterized proteins. S. aureus surface proteins are key indicators of how the pathogen will respond to contact with , such as neutrophils, which the body produces in large numbers to kill invading microbes. Some proteins can aggressively attack these immune cells, and the demise of the neutrophils ultimately enables the bacteria to replicate and thrive. When the LukGH toxin was removed from USA300, studies showed that the strain caused little to no damage to human neutrophils. With the toxin present, the bacteria began forming pores in neutrophils which eventually led to their destruction.

The scientists say they do not know the full contribution of LukGH to the severity of MRSA infection. However, LukGH is the only MRSA toxin currently known to promote destruction of human neutrophils after the bacteria have been ingested by the immune cells designed to destroy them. Using animal models of MRSA infection, the NIH team is continuing to study the role of LukGH in disease.

Explore further: Researchers develop novel solutions to fight the obesity gene

More information: C Ventura et al. Identification of a novel Staphylococcus aureus two-component leukotoxin using cell surface proteomics. PLoS One DOI: 10.1371/journal.pone.0011634 (2010).

Provided by National Institutes of Health

5 /5 (4 votes)
add to favorites email to friend print save as pdf

Related Stories

Researchers find link to severe Staph infections

Dec 23, 2008

Researchers at The University of Texas School of Public Health recently described studies that support the link between the severity of community-acquired antibiotic-resistant Staphylococcus aureus (CA MRSA) infections and th ...

White blood cells are picky about sugar

Jul 11, 2007

Biology textbooks are blunt—neutrophils are mindless killers. These white blood cells patrol the body and guard against infection by bacteria and fungi, identifying and destroying any invaders that cross ...

Recommended for you

Head injury causes the immune system to attack the brain

8 hours ago

Scientists have uncovered a surprising way to reduce the brain damage caused by head injuries - stopping the body's immune system from killing brain cells. The study, published in the open access journal Acta Neuropathologica Co ...

User comments : 0