Every year in the United States, staph infections result in more than 11 million outpatient and emergency room visits, plus more than 460,000 hospital admissions. The bacteria Staphylococcus aureus also frequently infects patients while they're in the hospital for other reasons; if the bacteria reach the bloodstream, heart, lungs or urinary tract, the infections can be fatal.
And drug-resistant strains of staph are on the rise. According to the Centers for Disease Control and Prevention, approximately 94,000 of these cases occur each year, killing 19,000 people.
"We've seen drug-resistant strains of staph in hospitals for decades, but now it's increasing in the community, where it once was rare. In some places, 50 percent or more of community-acquired staph infections are resistant to first-line antibiotics. Thus, there's an urgent need for new medications," said Joshua D. Nosanchuk, associate professor in the departments of medicine and microbiology & immunology at Albert Einstein College of Medicine of Yeshiva University.
Nosanhcuk is one of the senior authors of a new study, published this month in the online version of the Journal of Investigative Dermatology, that unveils a novel new way to attack drug-resistant staph infections.
The Einstein scientists developed a drug-delivery system consisting of biocompatible nanoparticles-each tinier than a grain of pollen - that can carry drugs and release them in a measured and sustained manner. In the experiment, the nanoparticles transported and slowly released nitric oxide gas, which is produced by many cells throughout the body and helps kill bacteria, heal wounds and increase blood flow.
"The problem is that nitric oxide is very short-lived and, until now, methods to deliver it to targeted tissues in the proper dosages have proven elusive," said Joel Friedman, another lead author of the study, in a press release. "As the particles take on water, they loosen up and the nitric oxide slowly trickles out, releasing specific amounts of the gas, which is exactly what happens in your body."
In the study, mice whose skin was infected with staph were treated topically with nitric oxide-containing nanoparticles or with nanoparticles bereft of the gas. A third group received no treatment at all.
After seven days, the group treated with the nitric oxide-containing nanoparticles had significantly improved wounds and smaller lesions than the other two groups. The nitric oxide-treated group also had much lower bacterial counts, along with accelerated wound healing.
After further refining their nanoparticles, the Einstein team — which has already filed patent applications covering the nanoparticles and their pharmacological applications — plans to test them in clinical trials. The researchers are also confident that the therapy will ultimately prove safe for human use.
"To have a topical medication for staph that you don't have to take orally and systemically would revolutionize the way we take care of our patients," said Nosanchuk.
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