Probiotics gain favor for woundcare

Key Points

London, Ontario - Probiotics, or live micro-organisms that enhance host defenses through replenishing the supply of "good" bacteria, will likely play a role in woundcare one day, but that role remains to be determined, according to the director of the Canadian Research and Development Centre for Probiotics.

Speaking here at the annual meeting of the Canadian Association for Wound Care, Gregor Reid, Ph.D., professor of microbiology, immunology, and surgery at the University of Western Ontario, London, Ontario, says that modulation of immunity via the gut following oral ingestion of probiotics could reduce the risk of infection of a wound.

Studies in Berlin, for example, have shown that Lactobacillus plantarum 299v, a probiotic administered with oat fiber after abdominal surgery, significantly reduced hospital-acquired infections.

"The administration of live organisms on a wound might cause bacteremia, even if the probiotics are non-pathogenic and easily eradicated with antibiotics," he says.

The plus of probiotics

If the topical administration of probiotics works, as Dr. Reid's rat studies have shown in preventing Staphylococcus aureus infection, it could contribute greatly to the well-being of many people, Dr. Reid tells Dermatology Times.

In those studies, published in the Journal of Infectious Diseases in 2002, there was reduced swelling, dehiscence and wound discharge, plus increased activity and body weight in the rats whose wounds were inoculated with live probiotic organisms or their byproducts.

The mechanism appeared to involve signaling molecules that modulated immunity and infection.

One problem with applying living probiotic bacteria to a wound is that the viability of the organisms would be difficult to maintain in an ointment or cream formulation, Dr. Reid says. This would limit shelf life.

An alternative might be to first isolate by-products or specific molecules from the probiotic organisms, such as ones with anti-infective or anti-inflammatory properties, and deliver them to the wound.

"The key is to use the host and probiotic in tandem," Dr. Reid says.

When pathogenic bacteria invade a wound, they form dense layers called biofilms. These are very difficult to eradicate, as antibiotics are designed to kill single organisms, not clumps of organisms.

Dr. Reid has shown that some probiotic organisms can penetrate these biofilms and potentially pave the way for easier eradication.

"Rather than trying to stop the biofilm from occurring, it might be more useful to manipulate it," he says.

Dr. Reid predicts the same phenomenon will happen with silver, the latest antimicrobial against infection.

Research

Dr. Reid has used specific lactobacilli strains to reduce the risk of urinary tract, vaginal and bowel infections.

In one study, the lactobacilli GR-1 and RC-14 strains proved more effective than antibiotic metronidazole gel in curing bacterial vaginosis.

His research has recently shown that lactobacilli can decrease inflammation markers in patients with inflammatory bowel disease.

Addition of the lactobacilli to yogurt taken daily led to an increase in anti-inflammatory environment.

It is fitting that clinicians look for alternative approaches to woundcare and minimizing infection when there is a global rise in the incidence of multi-drug resistant bacteria, particularly clinical isolates of S. aureus. This is not helped by the vast use of antibiotics in both human and agricultural settings.

Dr. Reid admits that the addition of live bacteria, either orally through diet or topically through an ointment or cream, would be controversial in clinical settings.

But, he says, currently hospitals are filled with drug-resistant bacteria, so he suggests it's not unreasonable to bring beneficial ones into the picture.

In Europe, one food manufacturer, Danone, has introduced a new yogurt called Essensis, which claims to improve the health of the skin after 30 days. In addition to yogurt bacteria, the product contains borage oil, vitamin E and antioxidants from green tea, and is claimed to act at the basal layer of the skin.

If probiotic foods could also deliver factors that reach skin cells and improve healing and infection-fighting defenses, it would represent a new paradigm in wound management, Dr. Reid says.