Targeted approach to kill specific disease-causing bacteria in the mouth

Research to develop a narrow-spectrum antibiotic that can target a particular species of bacteria without harming the other "good" bacteria present was described at the Society for General Microbiology meeting at Harrogate today (Thursday April 2).

Professor Kim Brogden from the University of Iowa attached a broad-spectrum antibiotic to a protein that targets a receptor on a particular bacterium's surface. When this newly-formed narrow-spectrum antibiotic was tested on a mix of bacteria that included the target organism, Porphyromonas gingivalis, a cause of gum disease, low concentrations of the antibiotic killed the P. gingivalis bacteria but left the other two bacterial species in the mix untouched.

Antibiotics have clear clinical benefits in treating oral infections like gum (periodontal) disease. This therapy reduces the number of harmful bacteria in patients who have received non-surgical and surgical treatments. Hard and soft tissue damage is much less in patients who have received antibiotics than in patients who have not received these drugs. Unfortunately, complications are associated with antibiotic use. Side effects such as nausea, vomiting, abdominal discomfort, diarrhoea, allergic skin rashes and fever can be caused by penicillin and related drugs. Overuse of antibiotics leads to the development of drug-resistant bacteria. And antibiotics can kill the normal bacterial population of the mouth, urogenital tract, and gastrointestinal tract. This can lead to infections by opportunistic Candida albicans yeast in the mouth and urogenital tract or the bacterium Clostridium difficile in the gastrointestinal tract.

A targeted approach is needed to kill specific disease-causing bacteria in complex environments, said Professor Brogden. "We are developing an antibiotic that can target and kill a particular pathogen without harming or altering the composition of the normal, more beneficial bacteria in the body. Such a product would provide a variety of new treatments for oral diseases as well as a means of prevention".

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