Evaluation of the Effectiveness of Nisin Combined with Amoxicillin and Metronidazole Against Oral Bacteria

• Grant number: 24/00739-0
• Support Opportunities: Scholarships in Brazil - Master
• Start date: December 01, 2024
• End date: February 28, 2026
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Karina Cogo Müller
• Grantee: Gabriela de Moraes Saqui
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Oral diseases, such as periodontitis, represent an inflammatory condition that can lead to tooth loss due to the reduction of supporting tissues. This condition is often associated with the formation of subgingival biofilms, caused by Gram-negative and Gram-positive bacteria. Although oral hygiene habits and mechanical procedures, such as scaling and root planing, can be effective in controlling these diseases, more serious cases may require prolonged use of antibiotics, such as amoxicillin and metronidazole. However, prolonged use of antibiotics can contribute to an increase in bacterial resistance, making it necessary to replace the antibacterial used or to combine it with other antibiotics. Given this scenario, recent studies have explored the potential of antimicrobial peptides, such as nisin. These peptides have not only been shown to reduce the induction of bacterial resistance, but have also exhibited synergy with effective antibiotics, making it possible to reduce possible doses. Therefore, the objective of this study is to evaluate the effect of the association of nisin with amoxicillin and metronidazole in vitro against oral bacteria, both those involved in the formation of biofilms and those associated with periodontal diseases. To this end, tests will be conducted to determine the minimum inhibitory and bactericidal concentration of each substance, association tests of the substances, morphological analyzes of the bacteria using transmission electron microscopy, in addition to investigating the impact of associations on the formation of Streptococcus oralis and Porphyromonas gingivalis biofilms. The bacteria tested will be Fusobacterium nucleatum, Porphyromonas gingivalis, Prevotella intermedia, Solobacterium moorei, Streptococcus oralis, Streptococcus mitis and Streptococcus sanguinis. Therefore, we expect that the combination of antibiotics with nisin is synergistic, enhancing the antimicrobial effect and allowing the reduction of concentrations to control or eradicate microorganisms.