Adding to the arsenal to fight oral bacteria

Gum disease and tooth decay are two of the most prevalent human diseases, affecting around three billion people worldwide. These oral diseases are caused by the build-up of bacterial biofilms, commonly known as plaque. Left untreated, they can lead to the destruction of tissues and leave those affected with significant oral pain, and even cause tooth loss.

Biofilms are a major problem today as they increase hospital stay times, as well as resistance in bacteria against antimicrobials.

Olivia Aherne

In her thesis, microbiologist and doctoral student Olivia Aherne has focussed on an antimicrobial agent, which could be used as a new active ingredient in mouthwash. This would add to the arsenal of what we use to treat such oral diseases which, in severe cases, have been suggested to a have links with secondary diseases, such as cardiovascular disease.

In medicine, biofilms are a major problem today as they increase hospital stay times, as well as resistance in bacteria against antimicrobials.

Olivia Aherne

Brushing and flossing can often be inadequate in removing dental plaque, meaning there is a demand for new anti-plaque agents, which work alongside our traditional methods. As stabilised hypochlorous acid (sHOCl) has emerged as a potential anti-biofilm agent in areas such as wound therapy, Aherne investigated its potential use in the oral cavity.

“When bacteria are in a community together, we call them biofilms. In a lab setting I’ve tried to create biofilms that model the oral diseases of dental caries and periodontitis. I’ve then treated these biofilms with this antimicrobial to see if it is effective in killing them,” she says.

In her thesis, Exploring the Effects of Stabilized Hypochlorous Acid on Multi-Species Oral Biofilms, Aherne and her colleagues found that at low concentrations, sHOCl was effective in killing biofilm bacteria.

“I think it is important that we are open to finding new treatments for bacterial diseases. In medicine, biofilms are a major problem today as they increase hospital stay times, as well as resistance in bacteria against antimicrobials. With this data, hopefully sHOCl can have a positive impact in the future.”

Another focus of the thesis was the creation of relevant disease models:

“When working with bacteria, we tend to create simple models of disease using bacteria growing as single cells, known as a planktonic state. But most diseases, especially in the mouth, are associated with mixed communities of bacteria that are much tougher than single cells.

“This difference is important as translating results from planktonic models to the clinic may not work. That’s because it is quite easy to kill single cells but when they are in a big cluster, as it would be in real life, it is a lot tougher. This is why I focussed on creating these mixed community biofilm models. For me that was an important aspect of this thesis; to better reflect the disease we’re interested in.”

Aherne says that while sHOCl is still meant to be used with brushing and going to the dentist, this research highlights the growing need to improve treatment strategies in our fight against diseases caused by bacteria.