The Influence of the CRISPR-Cas System on the Antimicrobial Susceptibility of P. gingivalis

PI: Frank C. Gibson III
UF College of Dentistry, Oral Biology Department

In bacteria, the CRISPR-Cas system is a genetic feature traditionally known for its role in bacterial defense against phages. Intriguingly, it is increasingly recognized for its involvement in immune evasion, virulence, and antimicrobial resistance. Preliminary in silico analyses from our research group indicate a potential connection between CRISPR-Cas activity and antimicrobial susceptibility in P. gingivalis.

I have been working on this semester from Spring 2025. To evaluate the impact of the CRISPR-Cas system on antimicrobial resistance, both wild-type and CRISPR-Cas mutant P. gingivalis strains (including P. gingivalis Acas3, Acas6, Acas7, and a total CRISPR region mutant (ATCR)) will be exposed to antimicrobial agents commonly used in periodontal therapy, including Amoxicillin, Doxycycline, and Metronidazole. Antimicrobial susceptibility patterns will be evaluated using both planktonic and biofilm assays, with comparisons made between wild-type and mutant strains. Controls will include cultures with no antibiotic treatment, as well as vehicle control groups, as needed. Where appropriate, we will determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), which establish the lowest antibiotic concentrations required to inhibit bacterial growth and achieve complete kill, respectively. For biofilm assays, biomass quantification will measure bacterial growth and survival in the presence of antimicrobial agents. All data will be imported and analyzed using PRISM statistical analysis software.

The findings from this study have the potential to significantly advance our understanding of P. gingivalis mechanisms of antibiotic resistance. If a link between the CRISPR-Cas system and antimicrobial susceptibility is established it could pave the way for novel therapeutic approaches that target CRISPR-associated pathways to enhance periodontal treatment efficacy.