A recent study by American scientists revealed the bullying mechanism of "super bacteria". They found that this most drug-resistant and fierce Staphylococcus aureus can destroy the human immune system by releasing a deadly "molecular bomb". Related papers 1 1.9 were published online in Nature-Medicine.

Drug-resistant Staphylococcus aureus (MRSA) can resist the most powerful antibiotics and drugs, and can cause various infections, so it is also called "superbug". The number of deaths caused by "superbugs" in the United States can reach10.8 million each year, which is more than10.6 million people who died of AIDS in the United States in 2005. At the same time, the number of people infected with "superbugs" is also increasing. In 1974, only 2% of people infected with staphylococcus were MRSA, but in 2003, this figure reached 64%. Symptoms after infection with "superbugs" include papules and pneumonia.

In the latest research, michael otto, a microbiologist at the National Institute of Allergy and Infectious Diseases (NIAID), and his colleagues found that MRSA can produce a kind of phenol-soluble protein (PSMs), which gave them great power. It is worth noting that this is probably one of the many "tricks" of MRSA.

Otto's team cultivated some PSM molecules in the laboratory and applied them to human neutrophils (a human immune cell, the first line of defense against staphylococcus). It was found that after a few minutes, these immune cells began to flatten, and after an hour, many immune cells were destroyed. Otto said, "We think this is the way for Staphylococcus aureus to get rid of its main' enemy'."

The researchers also compared MRSA strains obtained from hospitals and communities. Although the drug resistance of the latter is slightly lower than that of the former, it is more vicious and often causes death within a few days. The results showed that several community-acquired MRSA strains could produce more PSM, but most hospital strains did not produce this protein. Researchers believe that this may be the reason why community-acquired MRSA is stronger.

Further research confirmed this view. When the researchers removed the gene encoding PSM, the threat of community-acquired MRSA to mice was reduced, and there were fewer abscesses left on the skin of mice.

Henry Chambers, a microbiologist and physician at the University of California, San Francisco, said that although PSM is very important for understanding community-acquired MRSA, it is only the tip of the iceberg. Chambers said: "It is naive to think that staphylococcus has a mechanism suitable for everyone, because there are many kinds of staphylococcus."

Otto's team is working to create PSM antiserum and test it on mice.