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Decreased conjugation efficiency by Fla-mutants of Escherichia coli K-12 bearing F-like plasmids

W J Kennedy, A M Reynard

    Microbios
    |January 1, 1978
    PubMed

    Insights

    Escherichia coli mutants lacking flagella or pili showed reduced transfer of resistance plasmids. This suggests pili are crucial for plasmid transfer and antibiotic resistance, potentially linked to cell envelope integrity.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Genetics

    Background:

    • Escherichia coli (E. coli) is a key model organism for studying bacterial conjugation and plasmid transfer.
    • F-like plasmids mediate their own transfer through conjugation, a process dependent on specific surface structures like pili.
    • Antibiotic resistance genes are often carried on plasmids, contributing to the spread of antimicrobial resistance.

    Purpose of the Study:

    • To investigate the role of flagella (Fla) and pili in the transfer efficiency of F-like resistance plasmids in E. coli K-12.
    • To determine if mutations affecting pili production impact antibiotic resistance levels conferred by these plasmids.
    • To explore the host-mediated influence on pilus production and its potential connection to cell envelope integrity.

    Main Methods:

    • Comparison of F-like resistance plasmid transfer efficiency between wild-type E. coli K-12 and Fla-, Pil- mutants.
    • Assessment of conjugation pilus production in the different E. coli strains.
    • Determination of antibiotic resistance levels conferred by the plasmids in wild-type and mutant strains.
    • Evaluation of plasmid transfer efficiency and pilus production using the F'gal plasmid as a control.

    Main Results:

    • Fla-, Pil- mutants exhibited significantly decreased transfer efficiency of F-like resistance plasmids compared to parent strains.
    • These mutants also showed reduced production of conjugation pili and diminished resistance to certain antibiotics.
    • No reduction in pilus production or transfer efficiency was observed when using the F'gal plasmid, indicating a host-mediated effect.

    Conclusions:

    • Conjugation pili are essential for efficient transfer of F-like resistance plasmids in E. coli.
    • Mutations affecting pili production can influence both plasmid transfer and the expression of antibiotic resistance.
    • The findings suggest a potential link between cell envelope integrity and the production of all cellular appendages, including pili.

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