A team at University of British Columbia claims that a type of clay found northwest of Vancouver is effective against a dangerous class of drug-resistant bacteria. These germs are called ESKAPE bacteria because they don’t seem to respond to any anti-microbial medication, escaping any agent we throw at them and causing extensive morbidity and mortality in infected patients. Once patients get infected with ESKAPE bacteria, there is no available treatment and most die, ironically in a hospital where the drug-resistant germs congregate. The clay investigated by the Canadian researchers destroyed the ESKAPE germs, in some instances in less than 5 hours. Furthermore, the clay is completely natural and no toxic side-effects have been reported thus far.
“More than 50 years of misuse and overuse of antibiotics has led to a plague of antibiotic resistance that threatens to reduce the efficacy of antimicrobial agents available for the treatment of infections due to resistant organisms,” reads the paper.
“The main threat is nosocomial infections in which certain pathogens, notably the ESKAPE organisms, are essentially untreatable and contribute to increasing mortality and morbidity in surgical wards.”
The Kisameet clay (KC), a natural clay mineral from British Columbia, has been widely known for its therapeutic qualities for many years. Anecdotal evidence suggests that it was used by the local First Nations (Heiltsuk) people for several centuries for a variety of ailments, including ulcerative colitis, duodenal ulcer, arthritis, neuritis, phlebitis, skin irritation, and burns. Such is the case with other clay minerals, not just KC, however no such therapy has been approved by regulatory agencies in Canada.
The researchers at University of British Columbia are among the first to perform an extensive study of the therapeutic effects of KC.They collected 16 ESKAPE pathogen strains from a number of sources in Vancouver, including Vancouver General Hospital (VGH), St. Paul’s Hospital (SPH), and the University of British Columbia (UBC) wastewater treatment pilot plant (WWTP). Each strain was grown in-vivo in Luria-Bertani (LB) broth or on LB agar.
When all else fails, this clay shines
Tests were performed using a panel of 36 antibiotics. These showed that the pathogens were resistant to the antibiotics, though with variability in their resistance. The presence of KC dramatically reduced the viability of all strains tested, though.
“For example, after a 5-h exposure to KC, no viable cells of A. baumannii AB-1270, Enterobacter sp. strain MI1, or Enterobacter sp. strain MI16 could be recovered, indicating potent activity against these strains. S. aureus, K. pneumoniae, P. aeruginosa, A. baumannii AB-1264, and Enterobacter cloacae 1172 lost viability completely after 24 h, and the same killing took 48 h for E. faecium strains. In contrast, in water-only controls without KC, the decline in CFU during the same period of incubation was ≤1 log10 for all Gram-negative strains and ~1 to 3 log10 for E. faecium and S. aureus strains, respectively.”
The researchers were extremely surprised to find out the clay had killed at 16 strains! “They wanted microbial testing on clay, so I was a bit skeptical at first,” said UBC microbiologist Julian Davies. “Well, there are all sorts of claims out there, all kinds of folklore medicine and witchcraft.”
We’re beginning to run out of weapons against bacteria, which have caught on to our tricks. It may be only a matter of time until our anti-microbial arsenal is exhausted. Fatalities from ESKAPE pathogens will only increase in time, but there is progress. For one, there’s KC which definitely warrants more attention from the medical community (it works against fungal infections as well). Previously last week, I wrote about how nanoparticles activated by light selectively kill drug-resistant bacteria. The future isn’t as gloom as it seems, but such efforts require support, as Dr. Mark Blaskovich urged in a ZME Science guest post.
The clay is a complex mixture made up of about 24% by weight clay minerals, which are aluminum silicates, with various exchangeable metal ions and elemental sulfur. So, we don’t know for sure what makes KC so good at killing germs — even the toughest ones. “So far, we are sure that the mechanism of action is multifactorial,” says graduate student Shekooh Behroozian. “And we know the antimicrobial activity is pH-dependent, with the clay showing the best activity at acidic pH.”
“It’s a dream that there could be isolates [in the clay] that make new antibiotics,” says Davies. But the clay must be tested for toxicity and its activity defined well enough to satisfy drug regulators, he added.