According to a recent College of Pharmacy study at Oregon State University, one over-the-counter product for minor wound care is substantially more effective than others in killing MRSA, including the virulent strain USA300. Scientists conducting the study compared three common OTC wound care treatments, typically purchased by families to prevent infection, for effectiveness against four strains of community acquired MRSA. Breaks in the skin, like cuts and scrapes, are the most common entry point for the highly aggressive staph bacteria.
The new laboratory study showed that standard OTC antibacterial products are helpful for preventing common infections but only one product, Staphaseptic, made by Tec Laboratories, was effective in killing MRSA and the USA300 strain. The ointment-like gel, made with Benzethonium chloride, tea tree oil and white thyme oil, killed MRSA quicker and more effectively than the other compounds tested and had a sustained killing effect for 24 hours.
“We wanted to try these common OTC wound-treating products to see if they would kill a wide range of MRSA strains since MRSA has mutated significantly into more than one strain,” said Oregon State’s Dr. J. Mark Christensen, one of the authors of the study.
According to information from OSU, scientists there found that the Staphaseptic product had a genuine “bactericidal” effect – meaning it reduced the number of bacteria by a factor of 1,000 – against all four of the tested MRSA strains. The four strains tested were USA300-1, USA300-2, USA300-3, and USA400.
Also included in the testing were products made with neomycin and polymyxin; and another made with polymyxin and gramicidin. All three of the compounds used in the tests are widely available over the counter at national drug store chains. Staphaseptic is relatively new, while the other two are commonly found, with slight variations, in “maximum strength” or “triple antibiotic” compounds routinely sold in drug stores.
The USA300 strain of MRSA was put in the spotlight recently in a study published online by The Annals of Internal Medicine. Results showed that at one Boston area health clinic monitored in the study, 97% of patients infected with MRSA had the USA300 strain. The AIM study was led by Dr. Binh Diep who stressed the urgent need for prevention of these potentially deadly infections.
"Once this reaches the general population, it will be truly unstoppable," said Diep. "That's why we're trying to spread the message of prevention."
Researchers conducting the Oregon State University study also focused on prevention by testing products that are commonly used by families to prevent various infections in cuts and scrapes, rather than testing more expensive prescription antibiotics that attempt to kill the superbug after a severe infection takes hold.
The study was recently presented at a meeting of the American Society of Health-System Pharmacists by Dr. David Bearden, a specialist in infectious diseases and an author of the study. Dr. George P. Allen joined Bearden and Christensen as the third author.
“Staphaseptic remained bactericidal for 24 hours, which surprised me,” said Christensen. “Usually you see an initial kill, which is followed by the bacteria growing again. But Staphaseptic blunted this regrowth and suppressed the bacteria, showing killing for up to 24 hours.”
According to Bearden, USA300 is being passionately studied for a reason. “USA300 has become the predominant strain in severe community-acquired skin infections. The strain is more virulent and infects individuals who are otherwise healthy, something that earlier hospital strains of MRSA did not.”