Scientists desperate to find a cure for a fast-spreading "superbug" that attacks the lungs of healthy young people with a deadly toxin that kills within 72 hours believe they've unlocked its secrets, according to a report published Friday in the journal "Science."

The news comes just two days after a British biologist reported a possible breakthrough in the search for a cure for PVL-MRSA, a virulent and highly resistant strain of the relatively common Staphylococcus aureus bacteria — the staph infection commonly found in hospitals and locker rooms — that produces the toxin Panton Valentine leukocidin (PVL).

Already responsible for two recent deaths in Britain, experts there and in the United States fear they are seeing the early stages in both countries of what already is the largest bacterial epidemic in the world.

The superbug generally attacks the body through open wounds and can cause necrotising pneumonia, a disease that rapidly destroys lung tissue and kills in 75 percent of cases, scientists said.

This "community-acquired MRSA", or CA-MRSA, produces and releases PVL toxin, which destroys white blood cells. While the bacteria is relatively harmless on the skin, this new toxified CA-MRSA can be deadly if it gets into the bloodstream through a cut.

British health officials reported this week that one victim, an 18-year-old Royal Marine, died after the bacteria entered a scratch on his leg received during a training exercise. An outbreak last month at Norfolk and Norwich University Hospital in England killed a baby and infected five others.

College and school sports programs in the U.S. have reported more than 5,000 cases of CA-MRSA in the last two years. British health officials, meanwhile, say more than 7,000 cases were reported in the U.K last year alone, but at least 100 of those cases turned into the potentially fatal PVL-MRSA, according to the Web site MRSA Watch.

"The virulence of CA-MRSA strains that produce the PVL toxin presents a nightmare scenario," according to Gabriela Bowden of the Texas A&M Health Science Center in Houston, who led a breakthrough study of the deadly bacteria published in "Science."

"If the community-acquired strain establishes itself in the hospital setting, it will be difficult to contain," Bowden warned.

One positive aspect of the disease is that its victims quickly develop a high fever allowing for fast diagnosis and treatment, Bowden said.

Bowden's researchers found that a gene passed between the CA-MRSA bacteria causes it to produce the deadly PVL toxin.

"This is a scary situation," Bowden told NewsMax.com. "We are trying to put the word out and to educate people about it."

Bowden also said that their new understanding of how the bug works gives them hope of heading it off before it finds a home and spreads through hospitals.

Staphylococcus aureus bacteria — also known as S. aureus — is the most common cause of hospital-acquired infections, and can cause inflammation of the heart, toxic-shock syndrome and meningitis.

The S. aureus bacterium is found on the skin or in the nose of about 25 percent to 30 percent of people. It also can cause minor skin infections such as pimples.

"We've shown that not only is PVL responsible for causing necrotising pneumonia, but it somehow also causes over-production of these other proteins which cause damage and help the infection spread," Bowden told The Guardian newspaper in London.

"We now have targets to go for."

On Wednesday the Guardian newspaper reported that mathematical biologist Malcolm Young of Newcastle University claimed to have discovered that the commonly used antiobiotic ETS 1153 was effective in fighting the MRSA bacteria.

Neither U.S. or British health officials commented on Young's claim.

The Guardian and Express newspapers, and the journal Science contributed to this report