Research to illuminate resistance of oral flora to antiseptics
FREIBURG/REGENSBURG, Germany: Over the last two decades, antibiotic resistance has been investigated many times and has been the subject of public debate. However, resistance to antiseptics, locally acting disinfectants, has received less attention. Now, researchers from the Medical Center—University of Freiburg and the University Hospital Regensburg are investigating how such resistance develops for the caries pathogen Streptococcus mutans and how this might also lead to antibiotic resistance.
For the next three years, the researchers will receive joint funding of €664,000 from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation). Using selected bacterial species and patient samples, the researchers will investigate how microorganisms of the oral flora change when treated with chlorhexidine.
“Our goal is to understand the development of resistance of oral bacteria to chlorhexidine, both on the genome level as well as with regard to changes in the bacteria metabolism,” said Prof. Ali al-Ahmad, head of the research group at the Department of Operative Dentistry and Periodontology at the Medical Center—University of Freiburg. He will lead the project in collaboration with Dr Fabian Cieplik, senior physician at the Department of Operative Dentistry and Periodontology at the University Hospital Regensburg. “One of the project’s questions is whether freely available chlorhexidine-based mouthwashes can also contribute to the development of resistances,” said Cieplik.
Whether resistance to chlorhexidine is associated with resistance to antibiotics—a cross-resistance—will be investigated by both research groups with the help of different methods. “In the future, we might be able to specifically decide when a broad-spectrum antiseptic should be used and when alternative drugs are sufficient,” explained al-Ahmad.
In addition, a special genetic test, the shotgun metagenomic analysis, will be used. With this method, it will be examined whether the composition of the entire bacterial oral flora of patients, who have to use chlorhexidine over a longer period of time owing to an oral surgical procedure, will change under the influence of the antiseptic.