London, November 13: Methicillin-resistant Staphylococcus aureus (MRSA) develops drug resistance by producing deadly proteins called phenol-soluble modulins (PSMs), which kills cells of the immune system.

In an experiment, microbiologists Michael Otto and his colleagues at the National Institute for Allergy and Infectious Disease in Hamilton, Montana, rained several of these proteins onto a type of human immune cell called neutrophil, which are key to battling Staphylococcus infections.

This caused the cells to flatten, and many of the cells were destroyed after an hour.

“This is how we think S. aureus gets rid of its main enemies, ” Nature Medicine quoted Otto as saying.

An examination of the hospital and community strains of MRSA isolated from patients showed researchers that several of the community strains produce lots of PSMs, while most hospital varieties produced none.

The researcher said that it was an indication that the community-based MRSA might be more infectious.

A second experiment conducted by them confirmed this idea by showing that removing the genes encoding for PSMs lessened the the community-based bacteria’s ability to kill lab mice, and left smaller abscesses on the skin of infected mice than usual.

The researchers are developing PSM antisera to test in mice infected with community-associated MSRA. (ANI)