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Transfer of plasmid-mediated antibiotic resistance from streptococci to lactobacilli
Abstract:
The transmissible plasmid pAMbeta1, which codes for erythromycin and lincomycin resistance, was conjugally transferred from a Lancefield group F Streptococcus to a strain of Streptococcus avium. Both organisms served as pAMbeta1 donors for three strains of Lactobacillus casei. Introduction of pAMbeta1 into one of the L. casei strains caused the organism to lose its native 6.7 X 10(6)-dalton plasmid. Loss of the native plasmid produced no alterations in the organism's growth characteristics or fermentation pattern.
Insights
The transmissible plasmid pAMbeta1 was successfully transferred between Streptococcus and Lactobacillus species. Introducing this plasmid into Lactobacillus casei did not affect its growth or fermentation, despite native plasmid loss.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- The transmissible plasmid pAMbeta1 confers resistance to erythromycin and lincomycin.
- Plasmid transfer is a key mechanism for antibiotic resistance dissemination in bacteria.
Purpose of the Study:
- To investigate the conjugal transfer of plasmid pAMbeta1 between different bacterial species.
- To determine the effect of pAMbeta1 introduction on the recipient Lactobacillus casei strain.
Main Methods:
- Conjugal transfer of pAMbeta1 from Lancefield group F Streptococcus to Streptococcus avium.
- Subsequent transfer of pAMbeta1 from both donor strains to three strains of Lactobacillus casei.
- Analysis of plasmid content and phenotypic characteristics (growth, fermentation) of recipient L. casei.
Main Results:
- Successful transfer of pAMbeta1 to Streptococcus avium and subsequently to Lactobacillus casei.
- Introduction of pAMbeta1 into one L. casei strain resulted in the loss of its native 6.7 x 10(6)-dalton plasmid.
- The loss of the native plasmid in L. casei did not alter its growth characteristics or fermentation patterns.
Conclusions:
- Plasmid pAMbeta1 can be conjugally transferred between Gram-positive bacteria, including species from different genera.
- Lactobacillus casei can accommodate the transmissible plasmid pAMbeta1, even if it leads to the loss of endogenous plasmids.
- Acquisition of pAMbeta1 and subsequent loss of a native plasmid do not necessarily impair the basic physiological functions of Lactobacillus casei.