Research Activated oxygen helps fight antibiotic-resistant bacteria

Experts are developing new form of treatment for MRSA

Antibiotic-resistant bacteria are becoming an ever greater threat to humanity. The life-threatening bacterium MRSA is no exception. It can spread quickly and is resistant to the previous treatment. Researchers are now developing a technique that uses light to activate oxygen so it can fight antibiotic-resistant bacteria.

Researchers at the University of Cincinnati have found in their current research that light-activated oxygen can be used to treat antibiotic-resistant bacteria. The physicians published the results of their study at this year's 256th National Meeting & Exposition of the American Chemical Society (ACS).

MRSA is a dangerous bacterium that has become resistant to antibiotics. So medics were looking for new ways to fight MRSA. (Image: royaltystockphoto / fotolia.com)

New form of treatment could also help with cancer

The newly developed method could help fight resistant MRSA bacteria without resorting to antibiotics. The method could also be used to treat other microbial infections and possibly even cancer, say the experts.

Disinfection in hospitals needs to be improved

Clinical facilities currently have few alternatives when attempting to cure MRSA (methicillin-resistant Staphylococcus aureus). One of these methods is improved disinfection. For example, a recent study has found that disinfecting all patients admitted to a so-called acute care unit halves the rate of circulatory infection. However, this procedure is not feasible in most hospitals, explain the doctors.

Dye molecules for the treatment of MRSA?

Instead of relying on antibiotics that are no longer effective against some bacteria such as MRSA, the scientists used in their study photosensitizers, mostly dye molecules, which is excited when illuminated with light, says study author Dr. Peng Zhang from the University of Cincinnati in a press release. Then the photosensitizers convert oxygen into so-called reactive oxygen species (oxygen radicals), which then attack the bacteria, adds the expert.

Why the use of photosensitizers is problematic

Although other research teams have already experimented with the use of these types of photocatalysts to kill bacteria, they did not destroy enough microorganisms to effectively prevent infection. Molecular form photosensitizers tend to be inadequately corralled to cause significant damage. In addition, many of them are hydrophobic. This makes them difficult to disperse in aqueous media where microorganisms typically exist, the researchers say.

New photosensitizer contains precious metal nanoparticles

Scientists developed a new, water-dispersible, hybrid photosensitizer containing noble metal nanoparticles coated with amphiphilic polymers to trap the molecular photosensitizers. These hybrid photosensitizers are much more effective in killing a variety of bacteria than equivalent compositions containing no metal particles, the experts explain.

According to the researchers, these new nanoparticles offer two advantages. The metal has a so-called plasmonic enhancement effect, which promotes the generation of a reactive oxygen species, while at the same time concentrating the photosensitizers at one site to achieve a more localized attack on the bacterial cells. A concentrated attack is always more effective, compared to many individual attacks, add the physicians.

How would a treatment go??

Photosensitizers can be made into a spray or gel. If the spray is approved for the market sometime in the future, it could be sprayed by doctors on any surface and then illuminated with blue or red light to remove any bacteria, including MRSA. This method could also be promising in direct wound applications to eradicate infections and aid healing.

Initial tests on human skin were promising

The scientists recently performed experiments on human skin laboratory samples and found that the photosensitizer does not kill the skin cells. In addition to eliminating MRSA, the nanoparticles are also ideal for destroying skin cancer cells. The nanoparticles work effectively with the illumination of red light, which has a long wavelength that penetrates deep into the skin. This is especially important for the treatment of skin cancer. In addition, the study found that the nanoparticles also eliminate nail fungus. (As)