IADR Abstract Archives

The Impact of Ampicillin on the Oral Microbiome and Resistome

Objectives: Antibiotic exposure can lead to major perturbations in the human microbiome. In addition to promote dysbiosis, antibiotics can select for antimicrobial-resistance. In the oral cavity, penicillin-type antibiotics are detected at low concentrations in saliva following systemic administration, and in vivo studies have reported changes in oral microbiome composition. Due to challenges in quantifying in vivo effects of antibiotics in complex microbial communities and the presence of confounding factors, reproducible laboratory models are widely used. Here, we aim to investigate the effect of low concentrations of a broad-spectrum antibiotic, ampicillin, on oral microbiome ecology.
Methods: We utilized an ex vivo oral microbiome model with a highly complex microbial diversity. Pre-formed oral biofilms from three donors were exposed to ampicillin at three concentrations: 0.025, 0.05, and 0.1 µg/ml, with three replicates each, including a control without antibiotic exposure. We used whole metagenomics sequencing to characterize the microbiome taxonomic and resistance profiles.
Results: 284 million paired reads were generated. Samples from the three donors showed significant inter-individual differences. Clustering analysis using multi-dimensional-scaling revealed a pattern in which antibiotic exposure resulted in higher dissimilarity in microbial composition across replicates, compared to the non-exposure controls. Low concentrations of ampicillin showed decrease in microbiome diversity, as revealed by comparisons at the genus and species levels. Shifts in specific bacterial species varied in an individual basis. For oral resistome, 28 different antibiotic resistance genes (ARGs) were found in the three donors. In all cases, oral resistome diversity showed no major changes following ampicillin treatment, although some ARGs were only detected in the ampicillin exposed samples.
Conclusions: In conclusion, our results using a model-system for oral microbiomes show that short-term exposure of low concentrations of ampicillin can lead to ecological disturbances in microbial composition and resistance patterns, and support in vivo studies showing that ampicillin at low concentrations can promote dysbiosis.

2022 Pan European Region Oral Health Congress (Marseille, France)
Marseille, France
  • Brar, Navdeep Kaur  ( Oral Biology , Oslo , Norway )
  • Dhariwal, Achal  ( Oral Biology , Oslo , Norway )
  • Åmdal, Heidi Aarø  ( Oral biology , Oslo , Norway )
  • Junges, Roger  ( Oral biology , Oslo , Norway )
  • Salvadori, Gabriela  ( Oral biology , Oslo , Norway )
  • Petersen, Fernanda  ( Oral biology , Oslo , Norway )
  • None
    Olav Thon Stiftelsen 001, Norges forskningsråd 273833, Norges forskningsråd 274867
    Oral Session
    Periodontology and Pharmacology
    Thursday, 09/15/2022 , 10:30AM - 12:30PM