It is widely known that MRSA, or methicillin-resistant Staphylococcus aureus, is a major concern as a cause for dangerous infections. But what makes bacteria like MRSA dangerous? Research on phenol-soluble modulins may explain what helps these types of bacteria become so deadly.

So, what are phenol-soluble modulins? Called PSMs for short, they are toxins which are produced and secreted by staph bacteria. These toxins are a virulence factor of staph bacteria, meaning that they help the bacteria in becoming more deadly to the host by helping it to overcome the immune defenses. The bacteria then have a higher chance of multiplying and spreading.
PSMs help bacteria to survive and become more harmful to the body by killing red and white blood cells, as well as other types of cells. They also cause inflammation by attracting and activating white blood cells. How this is possible has not been determined by scientists yet. PSMs also aid in the formation of biofilms, helping them to survive. Biofilms are a group of bacteria that stick to each other to boost survival against the immune system.

In the lab, PSMs can be measured through a method called HPLC and mass spectrometry. HPLC stands for high performance liquid chromatography, which separates the different types of PSMs. The mass spectrometry machine separates the hydrophobic (water repelling) and hydrophilic (water attracting) substances, and measures the mass-to-charge ratio of the substances. Through the HPLC and mass spec machines, the specific PSM types can be determined.

Since PSMs were discovered quite recently, there is still more to be learned on their effects on infections. However, there should be more research conducted on this virulence factor. With more research on PSMs, there may be a way to cure bacterial infections by influencing bacterial PSM production. For example, if there is a way to lower the rate or stop productions of PSMs, the bacteria would be made more susceptible to the body’s immune system. This can already be done in the research lab by modifying the genes of the bacteria. However, being able to do that in a real life setting would be very useful, as bacteria like MRSA can easily develop a resistance to antibiotics and drugs. The new method would be a better alternative to curing infections and would also lower the number of antibiotics that the bacteria are resistant to.