Featured Research

from universities, journals, and other organizations

Treatment for S. aureus skin infection works in mouse model

Date:
August 31, 2010
Source:
NIH/National Institute of Allergy and Infectious Diseases
Summary:
Scientists have found a promising treatment method that in laboratory mice reduces the severity of skin and soft-tissue damage caused by USA300, the leading cause of community-associated Staphylococcus aureus infections in the United States.

The USA300 strain of Staphylococcus aureus bacteria, colorized in gold, shown outside a white blood cell.
Credit: RML/NIAID

Scientists from the National Institutes of Health and University of Chicago have found a promising treatment method that in laboratory mice reduces the severity of skin and soft-tissue damage caused by USA300, the leading cause of community-associated Staphylococcus aureus infections in the United States.

By neutralizing a key toxin associated with the bacteria, they found they could greatly reduce the damaging effects of the infection on skin and soft tissue. Community strains of S. aureus cause infection in otherwise healthy people and are considered extremely virulent, as opposed to hospital strains that infect people who already are weakened by illness or surgery.

While much recent attention has been focused on deaths caused by S. aureus infection in the bloodstream -- and those caused by methicillin-resistant S. aureus in particular -- the Centers for Disease Control and Prevention estimates that in 2005, physicians treated 14 million non-lethal S. aureus skin and soft-tissue cases in the United States.

In their study, now online in The Journal of Infectious Diseases, scientists from NIH's National Institute of Allergy and Infectious Diseases (NIAID) examined the effects of the bacterial toxin alpha-hemolysin, or Hla, on S. aureus skin infections in laboratory mice. In all aspects of the study where the Hla toxin was either removed from S. aureus bacteria or neutralized through immunization, skin abscesses were significantly smaller, mice recovered faster and there was little or no skin destruction.

When S. aureus secretes Hla during infection in humans, the toxin pokes holes in a variety of different host cells, killing them. Scientists who have studied Hla for years have mainly focused on neutralizing the toxin in cases of pneumonia-related S. aureus infection. Until now, no one had tested how the absence of Hla would affect the severity of USA300 skin infections and whether immunization against the toxin could neutralize Hla and its contribution to the severity of skin disease.

"For cases of skin and soft-tissue infection caused by Staph aureus, this study highlights the potential for antitoxin treatment to become an effective alternative to traditional antibiotics, which we know have limitations because of drug resistance," says NIAID Director Anthony S. Fauci, M.D. Antitoxins prevent harm caused by a specific part of a pathogen -- such as Hla in S. aureus -- rather than trying to kill the entire pathogen, as antibiotics do.

The study, led by Frank DeLeo, Ph.D., of NIAID's Rocky Mountain Laboratories in Hamilton, Mont., documented physical differences in mice infected with different strains of S. aureus, including USA300 with or without Hla. The second portion of the study tested what is known as active and passive immunity, with mice being immunized with a non-lethal version of the toxin or injected with Hla-specific antibodies, respectively. Both types of immunization protected mice from skin lesions that typically destroy skin and surrounding tissue.

The group noted that multiple S. aureus molecules must contribute to skin infection because simply removing or neutralizing Hla did not completely prevent the formation of skin abscesses, although the abscesses were smaller in size.

Study collaborators from the University of Chicago, Olaf Schneewind, M.D., Ph.D., and Juliane Bubeck Wardenburg, M.D., Ph.D.,contributed the Hla treatment concept, which they developed through their recent work on S. aureus pneumonia. Dr. DeLeo's group adapted that work to their mouse model of skin infection, which is a good indicator of how abscess size and skin destruction could affect humans, according to the study investigators.

"This toxin is probably one of the most promising targets we currently have in our efforts to develop therapeutics that protect against severe Staph aureus skin infections," says Dr. DeLeo. His group is continuing its collaboration with Drs. Schneewind and Bubeck Wardenburg on the project.


Story Source:

The above story is based on materials provided by NIH/National Institute of Allergy and Infectious Diseases. Note: Materials may be edited for content and length.


Journal References:

  1. AdamD. Kennedy, JulianeBubeck Wardenburg, DonaldJ. Gardner, Daniel Long, AdelineR. Whitney, KevinR. Braughton, Olaf Schneewind, FrankR. DeLeo. Targeting of Alpha‐Hemolysin by Active or Passive Immunization Decreases Severity of USA300 Skin Infection in a Mouse Model. The Journal of Infectious Diseases, 2010; 202 (7): 1050 DOI: 10.1086/656043
  2. J. B. Wardenburg, O. Schneewind. Vaccine protection against Staphylococcus aureus pneumonia. Journal of Experimental Medicine, 2008; 205 (2): 287 DOI: 10.1084/jem.20072208
  3. Juliane Bubeck Wardenburg, Taeok Bae, Michael Otto, Frank R DeLeo, Olaf Schneewind. Poring over pores: α-hemolysin and Panton-Valentine leukocidin in Staphylococcus aureus pneumonia. Nature Medicine, 2007; 13 (12): 1405 DOI: 10.1038/nm1207-1405

Cite This Page:

NIH/National Institute of Allergy and Infectious Diseases. "Treatment for S. aureus skin infection works in mouse model." ScienceDaily. ScienceDaily, 31 August 2010. <www.sciencedaily.com/releases/2010/08/100831121435.htm>.
NIH/National Institute of Allergy and Infectious Diseases. (2010, August 31). Treatment for S. aureus skin infection works in mouse model. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2010/08/100831121435.htm
NIH/National Institute of Allergy and Infectious Diseases. "Treatment for S. aureus skin infection works in mouse model." ScienceDaily. www.sciencedaily.com/releases/2010/08/100831121435.htm (accessed August 22, 2014).

Share This




More Health & Medicine News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins