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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria
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Biosensor for Detection of Antibiotic Resistant Staphylococcus Bacteria

Published on: May 8, 2013

Phenotypic suppression of methicillin resistance in Staphylococcus aureus by mutant noninducible penicillinase

S Cohen, C J Gibson, H M Sweeney

    Journal of Bacteriology
    |November 1, 1972
    PubMed

    Insights

    Regulatory gene mutations in Staphylococcus aureus penicillinase plasmids suppressed methicillin resistance by making penicillinase production noninducible. Resistance was restored by secondary mutations or plasmid complementation, suggesting trans-acting repression.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Genetics

    Background:

    • Methicillin resistance in Staphylococcus aureus (MRSA) is a significant public health concern.
    • Penicillinase plasmids play a role in bacterial resistance mechanisms.
    • Understanding the genetic regulation of antibiotic resistance is crucial for developing new therapeutic strategies.

    Purpose of the Study:

    • To investigate the role of regulatory gene mutations in penicillinase plasmids on methicillin resistance in Staphylococcus aureus.
    • To elucidate the mechanism by which these mutations affect methicillin resistance.
    • To explore the genetic relationship between penicillinase plasmids and methicillin resistance genes.

    Main Methods:

    • Introduction of regulatory gene (penI(1)) mutations into penicillinase plasmids.
    • Assessment of penicillinase production inducibility and methicillin resistance levels.
    • Complementation studies using compatible plasmids to analyze the mechanism of resistance restoration.

    Main Results:

    • Penicillinase plasmid regulatory gene mutations rendered penicillinase production noninducible, almost completely suppressing methicillin resistance.
    • Secondary mutations altering the noninducible phenotype or complementation with compatible plasmids restored methicillin resistance.
    • No evidence of genetic linkage was found between penicillinase plasmids and the methicillin resistance gene.

    Conclusions:

    • Mutant noninducible repressors likely act in trans by binding to the methicillin resistance determinant.
    • This mechanism suggests potential homology between penicillinase plasmids and methicillin resistance genes.
    • The findings provide insights into the complex genetic regulation of antibiotic resistance in Staphylococcus aureus.

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