Death by a thousand cuts: how antibacterial clays kill

OMT blue clay
A section of blue clay from the open pit mine at the Oregon Mineral Technologies clay deposit near Crater Lake. The antibacterial blue clay is surrounded by white clay which lacks antibacterial properties. (Credit: Keith Morrison)

By now most of you will have heard that more and more bacteria are becoming impervious to the many life-saving antibiotics on which we’ve come to rely. In November, scientists in China sampling bacteria from meat and hospitalized patients found a new gene called MCR-1 that confers resistance to colistin, a drug that is currently used as a last resort when all other antibiotics have failed. This report was the latest in a series of increasingly worrisome news that have spurred researchers to look for new ways to combat antimicrobial resistance. While some scientists are exploring futuristic ideas like light-activated nanoparticles, others are looking to nature and literally digging up dirt for inspiration.

In a paper published recently in Scientific Reports, researchers have revealed for the first time the mechanism behind the antibacterial properties of medicinal clay.

“People have been eating clays for thousands of years,” says Dr. Keith Morrison, the report’s lead author and now a postdoctoral fellow at the Lawrence Livermore National Laboratory. The purported benefits of eating clay relate to its ability to grab heavy metals and other “toxins” and expel them from your body. However, the scientific evidence supporting this idea (and the idea that our bodies need any detoxing at all) is lacking.

As a PhD student at Arizona State University, Morrison was interested in another curious property of some medicinal clays—their ability to kill bacteria. While the use of clay to treat wounds and skin infections can be traced back to the 19th century, the scientific study of these antibacterial clays is a fairly new field. Continue reading


Rethinking Salmonella: from food poisoning culprit to cancer-fighting agent

What would you look for in an ideal cancer treatment? You’d probably want something that would only kill cancer cells and leave healthy cells unharmed. It would also be nice if this drug could penetrate deep inside tumours, even if the tumours are dispersed across multiple sites in the body.

What if that anti-cancer treatment was a dose of Salmonella? Would you try it?

Scientists are developing ways to transform bacteria like Salmonella into lean, mean tumour-fighting machines. A new study published this week in Proceedings of the National Academy of Sciences describes a new and innovative way to turn Salmonella into highly specific vehicles that can deliver anti-cancer compounds into the heart of a tumour. Continue reading

More sex, more UTIs: how timing affects your risk of bladder infection

“Pee after sex” is perhaps one of the most memorable pieces of advice I’ve picked up in conversations with female friends over the years. The theory is that peeing right after sex will help to flush out any bacteria that may have entered your body during sex and prevent them from infecting your urinary tract.

Electron microscopy of UPEC binding to the surface of the bladder (Source)
Electron microscopy of UPEC binding to the surface of the bladder (Source)

Urinary tract infections, or UTIs, commonly refers to infection of the urethra or bladder and affects mostly women. It’s estimated that roughly half of all women will experience a UTI at least once in their lifetime. Of these women, 25-40% suffer from repeated UTIs and must take antibiotics continuously to prevent a recurrence. The most common cause of UTIs is uropathogenic E. coli, or UPEC. UPEC can enter the body through the urethra and then move into the bladder. Left untreated, the bacteria can spread from the bladder to the kidneys and cause serious health complications. Continue reading