Super-bug Gene sasX Found

A gene that helps an antibiotic-resistant ‘super bug’ cling to the nasal passages of its host has now been identified, report scientists from National Institute of Health and their colleagues in China.

The gene called sasX found in the rapidly spreading Staphylococcus aureus, is now believed to be the reason that is enabling the super-bug MRSA or methicillin-resistant S. aureus to affect large populations in Asia.

The epidemics caused by these strains occur in waves. Healthy people tend to fight off these infections. People who are under intensive care units at hospitals are vulnerable to this super-bug.

“Like every good research paper, this raises many more additional questions,” says James Musser, head of the department of pathology and genomic medicine at Methodist Hospital in Houston, Texas. (Nature)

Although the gene sasX is extremely rare, scientists found that its prevalence has nearly doubled in the past few years.

From 2003 to 2011, the percentage of samples containing the gene sasX increased from 21 to 39 percent.

For the research the scientists analyzed 807 patient samples of S.aureus taken from three Chinese hospitals.

Scientists believe that the strains of bacteria with this gene have the ability to aggregate tightly

The researchers also found that the gene was not only passed through generations in the bacteria but also showed a tendency to jump from one strain to another.

PubMed Health says that, ’methillin resistant Staphylococcus aureus (MRSA) is a type of strain of staph bacteria that does not respond to some antibiotics that are commonly used to treat staph infections.

These infections occur in hospital settings. The symptoms range from mild (resulting in a pimple) to severe (affecting organs like heart or lungs)

Centers for Disease Control and Prevention (CDC) reports,’ in 2010, encouraging results from a CDC study published in the Journal of the American Medical Association showed that invasive MRSA infections in healthcare settings are declining. Invasive MRSA infections that began in hospitals declined 28% from 2005 through 2008.

According to Nature, in 2005, the estimated 18,650 deaths from MRSA in United States exceeded those from AIDS.

“The holy grail is to identify a gene that confers virulence and to develop a vaccine against it,” says Frank Lowy, an infectious- disease physician at Columbia University Medical College in New York.”So far they haven’t been successful in that approach, so now the idea is to combine different proteins associated with virulence with a single vaccine,” he says. “SasX presents another good target.” (Nature)

The scientists hope to find a way to prevent the gene sasX from expressing in the strains so that MRSA can be prevented from infecting people.

Michael Otto, molecular biologist at US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland and team studied a rare genetic element within a strain of MRSA.