Featured Research

from universities, journals, and other organizations

Genes Key To Staph Disease Severity, Drug Resistance Found Hitchhiking Together

Date:
August 2, 2009
Source:
NIH/National Institute of Allergy and Infectious Diseases
Summary:
Scientists studying Staphylococcus bacteria, including methicillin-resistant S. aureus, have discovered a potent staph toxin responsible for disease severity. They also found the gene for the toxin traveling with a genetic component of Staphylococcus that controls resistance to antibiotics.

Scientists studying Staphylococcus bacteria, including methicillin-resistant S. aureus (MRSA), have discovered a potent staph toxin responsible for disease severity. They also found the gene for the toxin traveling with a genetic component of Staphylococcus that controls resistance to antibiotics. The study, now online in PLoS Pathogens, shows for the first time that genetic factors that affect Staphylococcus virulence and drug resistance can be transferred from one strain to another in one exchange event.

One of the ways Staphylococcus bacteria become drug-resistant is through horizontal gene transfer, whereby resistance genes move from one bacterium to another. Staph bacteria also can exchange virulence genes using the same mechanism, but this was previously assumed to occur separately from the transfer of antibiotic resistance.

Scientists from the National Institute of Allergy and Infectious Diseases (NIAID), a component of the National Institutes of Health, led the study. They collaborated with researchers at the University of Tubingen in Germany and the University of Medicine and Dentistry of New Jersey.

"The discovery that bundled genes determine virulence and antimicrobial resistance suggests a new research focus for scientists trying to better prevent and treat serious staph infections," says Anthony S. Fauci, M.D., NIAID director.

The research involved more than 100 strains of S. aureus and S. epidermidis, both bacteria found on the skin of most people. In recent decades, these bacteria have become increasingly virulent, often causing severe disease that can be resistant to traditional antibiotics such as methicillin.

The studies were directed by NIAID senior investigator Michael Otto, Ph.D. In 2007, he and his colleagues found that staphylococci secrete toxins of the phenol-soluble modulin (PSM) family that are primarily responsible for attracting and killing human white blood cells called neutrophils. This process is critical for the ability of S. aureus—including community-acquired MRSA—to cause disease.

While screening S. aureus and S. epidermidis strains, Dr. Otto's group noticed that some strains produced one additional, previously unknown, PSM toxin. The researchers hypothesized that the toxin was somehow connected to drug resistance. This idea surfaced because the toxin appeared in 10 percent of all MRSA strains and 68 percent of all methicillin-resistant S. epidermidis strains analyzed—whereas the researchers did not find it in strains of S. aureus or S. epidermidis that are sensitive to methicillin.

The research group confirmed its theory by identifying the specific location that encodes the toxin, which was in gene clusters that control drug resistance, known as SCCmec. The group named the new toxin PSM-mec.

"This work represents a previously unknown example of a toxin hitchhiking on staphylococcal mobile genetic elements that are primarily in charge of transferring antibiotic resistance," says Dr. Otto. He adds that the finding "should alert the research community that aggressive, drug-resistant staph can evolve more quickly than we assumed."

The research group is continuing its study of PSM-mec in S. epidermidis, where the toxin is more prevalent. Ultimately, being able to neutralize PSM-mec and other toxins that attack human defenses could lead to new treatments for S. aureus and S. epidermidis disease.


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. Queck et al. Mobile Genetic Element-Encoded Cytolysin Connects Virulence to Methicillin Resistance in MRSA. PLoS Pathogens, 2009; 5 (7): e1000533 DOI: 10.1371/journal.ppat.1000533
  2. Wang et al. Identification of novel cytolytic peptides as key virulence determinants for community-associated MRSA. Nature Medicine, 2007; 13 (12): 1510 DOI: 10.1038/nm1656

Cite This Page:

NIH/National Institute of Allergy and Infectious Diseases. "Genes Key To Staph Disease Severity, Drug Resistance Found Hitchhiking Together." ScienceDaily. ScienceDaily, 2 August 2009. <www.sciencedaily.com/releases/2009/07/090731132921.htm>.
NIH/National Institute of Allergy and Infectious Diseases. (2009, August 2). Genes Key To Staph Disease Severity, Drug Resistance Found Hitchhiking Together. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/07/090731132921.htm
NIH/National Institute of Allergy and Infectious Diseases. "Genes Key To Staph Disease Severity, Drug Resistance Found Hitchhiking Together." ScienceDaily. www.sciencedaily.com/releases/2009/07/090731132921.htm (accessed July 29, 2014).

Share This




More Health & Medicine News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
$15B Deal on Vets' Health Care Reached

$15B Deal on Vets' Health Care Reached

AP (July 28, 2014) A bipartisan deal to improve veterans health care would authorize at least $15 billion in emergency spending to fix a veterans program scandalized by long patient wait times and falsified records. (July 28) Video provided by AP
Powered by NewsLook.com
Two Americans Contract Ebola in Liberia

Two Americans Contract Ebola in Liberia

Reuters - US Online Video (July 28, 2014) Two American aid workers in Liberia test positive for Ebola while working to combat the deadliest outbreak of the virus ever. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
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