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In vivo transfer of pAM beta 1 from Lactobacillus reuteri to Enterococcus faecalis
L Morelli1, P G Sarra, V Bottazzi
1Istituto di Microbiologia, Università Cattolica del Sacro Cuore, Piacenza, Italy.
Abstract:
Trials were conducted to determine the in vivo transferability of plasmid-mediated antibiotic resistance between two strains of enteric Gram-positive bacteria. Germ-free mice were associated with the donor Lactobacillus reuteri DSM 20016 strain, carrying the broad host range pAM beta 1 plasmid, and with the Enterococcus faecalis JH2SS recipient strain. Analysis of faecal content of associated mice demonstrated that the in vivo transfer of this plasmid did occur and that frequencies of conjugation were affected by the presence of subtherapeutic levels of antibiotic in the diet.
Insights
Antibiotic resistance genes can transfer between gut bacteria in vivo. This study shows plasmid transfer occurred in mice, with antibiotic levels influencing the rate of gene transfer.
Area of Science:
- Microbiology
- Genetics
- Molecular Biology
Background:
- Antibiotic resistance is a growing global health concern.
- Plasmid-mediated gene transfer is a key mechanism for the spread of antibiotic resistance.
- Understanding in vivo transfer is crucial for predicting resistance dynamics.
Purpose of the Study:
- To investigate the in vivo transferability of plasmid-mediated antibiotic resistance.
- To examine the influence of diet and antibiotics on this transfer process.
Main Methods:
- Germ-free mice were colonized with donor (Lactobacillus reuteri) and recipient (Enterococcus faecalis) strains.
- The donor strain carried the pAM beta 1 plasmid conferring antibiotic resistance.
- Faecal samples were analyzed to confirm plasmid transfer and quantify conjugation frequencies.
Main Results:
- Plasmid transfer from Lactobacillus reuteri to Enterococcus faecalis was confirmed in vivo.
- The frequency of conjugation was significantly affected by the presence of subtherapeutic antibiotic levels in the diet.
- This suggests environmental factors can modulate antibiotic resistance gene spread.
Conclusions:
- Plasmid-mediated antibiotic resistance transfer occurs between enteric Gram-positive bacteria in a host environment.
- Dietary subtherapeutic antibiotic levels can impact the rate of in vivo plasmid transfer.
- These findings highlight the complex interplay between host, bacteria, and environment in the dissemination of antibiotic resistance.
