Chink discovered in staph’s armor

TAIWANESE CONTRIBUTION A three-person team from the Academia Sinica has been instrumental in finding a vulnerability in ‘Staphylococcus aureus’ bacteria

By Meggie Lu / STAFF REPORTER

Bacteria get harder to treat as they build resistance to antibiotics, but while some scientists have tried to combat this by developing stronger antibiotics, a group of scientists — including US experts and Academia Sinica Vice President Andrew Wang (王惠均) and two other Academia Sinica researchers — have taken a different approach by attempting to weaken bacteria’s defenses.

The team touted its preliminary success when it published a paper in Science last year about an experimental cholesterol-lowering drug can also weaken the defense system of Staphylococcus aureus (staph) in mice.

Staph is the second-most common cause of infection in Taiwan, next to Escherichia coli bacteria (E. coli).

The paper was recently named by the US National Institute of Health (NIH) as one of 24 research highlights of last year, Academia Sinica said yesterday.

“A strain of antibiotic resistant staph, called methicillion-resistant Staphylococcus aureus [MRSA], is spreading in epidemic proportions in both hospitals and communities,” said Liu Chia-I (劉佳宜), a researcher at the Institute of Biological Chemistry.

Though staph is commonly found on human skin or in open wounds, MRSAs can cause difficult to treat infections or even bacteremia and sepsis.

“Our team decided to fight staph using a new approach — by preventing the formation of its exterior golden pigment,” Liu said.

The research was based on a 2005 discovery — made by one of the members of the team — that staph’s golden pigments were anti-oxidants that shield the bacteria from attacks by the human immune system, Liu said.

“The immune system releases super oxides to fight the bacteria. Without the golden armor, staph would be much more vulnerable to attack,” Liu said.

The researchers found that the metabolic pathway of the production of staph’s golden pigments was very similar to that of cholesterol in humans, and that the structure of a bacterial enzyme needed to create the pigment in staph was similar to a human enzyme needed to create cholesterol, Liu said.

“We found that cholesterol-fighting drugs will also bind tightly to this bacterial enzyme,” she said.

Academia Sinica researchers contributed to the research by solving the structure of the enzyme by X-ray crystallography, which helps prevent the formation of the golden pigments at the first step, Liu said.

With lab success on mice, the team’s next step will be to investigate whether this new approach of fighting staph works on humans, she said.