Breast cancer medication tamoxifen just might be key in fighting methicillin-resistant Staphylococcus aureus (MRSA), one of the worst superbugs to ever surface on the face of the earth.

Experts from the School of Medicine and Skaggs School of Pharmacy and Pharmaceutical Sciences of the University of California in San Diego found that tamoxifen boosts white blood cells and better arms them in killing bacteria in experiments. Treating mice with the drug also led to enhanced clearance of MRSA and reduced death.

Published Oct. 13 in Nature Communications, the study probed the benefits of tamoxifen – an estrogen receptor blocker used for treating advanced breast cancer patients – in combating the antibiotic-resistant bug implicated in 5,000 deaths in the United States in 2013.

“[W]e discovered that tamoxifen has pharmacological properties that could aid the immune system in cases where a patient is immunocompromised or where traditional antibiotics have otherwise failed,” reported pediatrics and pharmacy professor Dr. Victor Nizet, senior author of the study.

He warned against the growing threat of drug-resistant pathogens and called for using safe existing drugs with potential infection-fighting action.

More than targeting estrogen receptors, tamoxifen is shown to have other favorable effects, including influencing the production of sphingolipids, which are involved in regulating white blood cells known as neutrophils.

Tamoxifen-treated neutrophils exhibited a threefold increase of neutrophil extracellular traps (NETs), the known frontliners of the body's defense system against infection.

When tested on a mouse model, tamoxifen also protected MRSA-infected mice – about 35 percent of the drug-treated mice survived five days. Compared to control mice, about five times fewer MRSA were obtained from the drug-treated subjects.

The researchers warned that the effectiveness of tamoxifen against MRSA in their study may differ with other pathogens and that too many NETs could be harmful and have been linked to inflammatory disease such as bronchial asthma.

Other approaches to MRSA treatment are being investigated at present, including a 1,100-year-old home remedy that makes use of garlic, onion or leek, copper, wine and cow’s bile.

According to data analyzed by the U.S. Centers for Disease Control and Prevention, one in three individuals carry staph in the nose without any problem while two in 100 carry MRSA.

The infection is transmitted through contact with an infected wound or sharing contaminated things; at a higher risk, however, are those in crowded settings where skin-to-skin contact usually occurs such as hospitals or gym locker areas.

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