Staph germ causes deadly pneumonia
Drug-resistant infection can kill in 72 hours, researchers say
http://www.msnbc.msn.com/id/16691062
Reuters
Updated: 4:33 p.m. ET Jan 18, 2007
WASHINGTON - A nasty staph germ circulating in the community and some hospitals produces a poison that can kill pneumonia patients within 72 hours, researchers said Thursday.

Staphylococcus aureus bacteria — Staph for short — can pass one another the gene for the toxin and are apparently swapping it more often, the researchers report in Friday’s issue of the journal Science.

The toxin, called Panton Valentine leukocidin or PVL, can itself cause pneumonia and can kill healthy tissue.

Luckily, people infected with the bacteria quickly develop a high fever and astute doctors can identify it, said Gabriela Bowden of the Texas A&M Health Science Center in Houston, who led the study.

“This is a scary situation. We are trying to put the word out and to educate people about it,” Bowden said in a telephone interview.

S. aureus is the most common cause of hospital-acquired infections, and can cause inflammation of the heart, toxic-shock syndrome and meningitis.

A new strain resists the antibiotic methicillin, but it can be treated with other antibiotics like doxycycline and vancomycin.

Methicillin-resistant Staph broke out in a British hospital in December and killed two patients with a new type of pneumonia called necrotizing pneumonia. This infection destroys lung tissue and also kills some of the immune system cells sent to battle it.

“The pneumonia itself is very severe,” Bowden said. “There is massive inflammation and there is fluid in the lungs and there is damage to the tissue. It can progress very quickly and in 72 hours the patient can be in a severe condition, or it can even be lethal in 72 hours.”

The bacteria, which commonly live on the skin anyway and cause pimples, boils and other minor infections, can cause a serious wound if the toxin-producing strains get into a cut.

Wash your hands
Old-fashioned hygiene is the best line of defense, Bowden said.

“This is a community-associated strain, which means that in schools, the kids can carry it. Anybody can be colonized with it,” she said.

“I tell my kids if you scrape your knee, go to the bathroom immediately and wash it with soap.” Hospitals must impose strict hygiene to control it.

Any skin infection that appears to become serious quickly requires immediate attention, Bowden said. The strain is common in Houston, where she works, and researchers in Europe are also concerned about its spread.

Bowden’s team tested the PVL-producing Staph on mice and found that two days after infection, their lungs were filled with immune cells and lung tissue was starting to bleed and die.

A stretch of DNA known as a cassette carries the code for the PVL toxin. Such a little segment is easily passed from one strain of bacteria to another, said Bowden, and viruses called bacteriophages can also carry them.

Understanding how this happens could provide a way to develop new drugs or vaccines and shed light on how bacteria acquire new and dangerous qualities.

Because bacteria swap genetic material so easily, the risk that this toxin could spread is real, Bowden said.

Penicillin once cured Staph infection but the bacteria quickly developed resistance. The U.S. Centers for Disease Control and Prevention says that in 1972, only 2 percent of Staphylococcus aureus bacteria infections were drug-resistant, but by 2004, 63 percent were.

Some companies are working on staph vaccines but none is on the market.

Copyright 2007 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content is expressly prohibited without the prior written consent of Reuters.