TBO.com - TBO is Tampa Bay Online

Study: Aggressive Staph Germ Attacks Immune Cells

ADVERTISEMENT

By RANDOLPH E. SCHMID, The Associated Press

Published: November 12, 2007

WASHINGTON - The aggressive antibiotic-resistant staph infection responsible for thousands of recent illnesses undermines the body's defenses by causing germ-fighting cells to explode, researchers reported Sunday.

Experts say that the findings may help lead to better treatments.

An estimated 90,000 people in the United States fall ill each year from methicillin-resistant Staphylococcus aureus, or MRSA.

It is unclear how many die from the infection. One estimate put it at more than 18,000, which would be slightly higher than U.S. deaths from AIDS.

The infection long has been associated with health care facilities, where it attacks patients who have reduced immune systems.

Many recent cases, however, involve an aggressive strain, community-associated MRSA, or CA-MRSA.

This strain can cause severe infections and even death in otherwise healthy people outside of health care settings.

The CA-MRSA strain secretes a kind of peptide - a compound formed by amino acids - that causes immune cells called neutrophils to burst, eliminating a main defense against infection, researchers said.

The study, done by a U.S. and German research team led by Michael Otto of the National Institute of Allergy and Infectious Diseases, appeared in Sunday's online edition of the journal Nature Medicine.

While only 14 percent of the serious MRSA infections are the community-associated variety, they have drawn attention in recent months with a spate of reports in schools, including the death of a 17-year-old Virginia high school student.

Hospital-associated and community-associated MRSA contained genes for the peptides.

But their production was much higher in the CA-MRSA, the researchers said.

The compounds first cause inflammation, drawing immune cells to the site of the infection, and then they destroy those cells.

The research was conducted in mice and with human blood in laboratory tests.

Lindsey N. Shaw of the division of cell biology, microbiology and molecular biology at the University of South Florida, also was enthusiastic about the research.

"Specifically identifying a factor which seemingly makes CA-MRSA more pathogenic than HA-MRSA is a real find," Shaw, who was not part of the research group, said by e-mail.

The "molecules identified in the study are indeed novel," he said.

Share this:

Loading Comments...

Email Print

ADVERTISEMENT