Navigation Links
Genes key to staph disease severity, drug resistance found hitchhiking together

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. aureusincluding community-acquired MRSAto 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 analyzedwhereas 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.


Contact: Ken Pekoc
NIH/National Institute of Allergy and Infectious Diseases

Related medicine news :

1. Suicide Genes Help Slow Ovarian Tumor Growth in Mice
2. Nanoparticle-delivered 'Suicide' Genes Slowed Ovarian Tumor Growth
3. Five Hypertension Genes Found in Black Americans
4. Anti-angiogenesis treatment improves hearing in some NF2 patients
5. Genes Linked to Cholesterol in Cells Are Identified
6. Australian researchers identify genes that cause melanoma
7. News from the Latest Issue of Molecular Medicine Kicking The Habit - It's In The Genes
8. Five Genesis HealthCare Centers To Be Awarded Prestigious National Award
9. Hundreds of Genes Could Be Linked to ADHD
10. Cardiogenesis Corporation Names Paul J. McCormick Executive Chairman
11. Genes May Raise Risk of Neuroblastoma in Kids
Post Your Comments:
(Date:11/27/2015)... ... November 27, 2015 , ... A simply groundbreaking television series, "Voices ... show that delves into an array of issues that are presently affecting Americans. Dedicated ... open dialogue, this show is changing the subjects consumers focus on, one episode at ...
(Date:11/27/2015)... ... 2015 , ... Dr. Thomas Dunlap and Dr. Patrick Coleman ... with Emergency Medicine at St., Joseph Health System’s Santa Rosa Memorial Hospital , ... in similar ways and require time-critical intervention to avoid large area heart damage and ...
(Date:11/26/2015)... ... November 26, 2015 , ... CognisantMD ... for diagnostic imaging in the Waterloo region. Using the Ocean Platform, family physicians ... directly from their electronic medical record (EMR) without the need for redundant patient ...
(Date:11/26/2015)... ... November 26, 2015 , ... WorldCare International, Inc., ... the 61st annual Employee Benefits Conference. The Employee Benefits Conference was hosted by ... through Wednesday, November 11th, 2015. The conference was held at the Hawaii Convention ...
(Date:11/25/2015)... IN (PRWEB) , ... November 25, 2015 , ... ... water accessible for all, Water For Empowerment ™ attracts volunteers together who ... clean water by empowering women as key stakeholders in the process. The non-profit ...
Breaking Medicine News(10 mins):
(Date:11/25/2015)...  Linden Care, LLC, a retail specialty pharmacy focused ... suffering from chronic pain, said today that it is ... (TRO) enjoining Express Scripts from unilaterally terminating the Pharmacy ... --> --> The company said that ... --> --> In ...
(Date:11/25/2015)... USA , Inc., a leader in ... accuracy of its blood glucose meter systems. Last week ... Cardiovascular Disease in Los Angeles , ... 01 meter and the Assure ® Prism multi-user ... measure glucose levels in blood is essential for people ...
(Date:11/25/2015)... DUBLIN , Nov. 25, 2015 Allergan plc ... an agreement with the New York State ... 2 of the Sherman Act, and other statutes with the ... in February 2014, to cease marketing and selling the now ... of settlement, Allergan admits no liability, has released its counterclaims ...
Breaking Medicine Technology: