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Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung
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Use of Artificial Sputum Medium to Test Antibiotic Efficacy Against Pseudomonas aeruginosa in Conditions More Relevant to the Cystic Fibrosis Lung

Published on: June 5, 2012

Gentamicin-resistant Pseudomonas aeruginosa and Serratia marcescens in a general hospital

R D Meyer, R P Lewis, J Halter

    Lancet (London, England)
    |March 13, 1976
    PubMed

    Insights

    High rates of gentamicin resistance in Pseudomonas aeruginosa and Serratia marcescens are a significant hospital concern. Amikacin shows effectiveness against resistant strains, offering a viable treatment option.

    Area of Science:

    • Medical Microbiology
    • Infectious Diseases
    • Antimicrobial Resistance

    Background:

    • Gentamicin resistance in common hospital-acquired pathogens is a growing clinical challenge.
    • Pseudomonas aeruginosa and Serratia marcescens are significant causes of nosocomial infections.

    Purpose of the Study:

    • To assess the prevalence of gentamicin resistance in Pseudomonas aeruginosa and Serratia marcescens isolates.
    • To evaluate the in vitro susceptibility of resistant strains to alternative antibiotics, including amikacin, tobramycin, and sisomicin.

    Main Methods:

    • Standardized disc testing and agar-dilution methods were used to determine gentamicin resistance.
    • Minimum inhibitory concentrations (MICs) were determined for clinical isolates.
    • Susceptibility testing was performed for amikacin, tobramycin, and sisomicin.

    Main Results:

    • 19.1% of Pseudomonas aeruginosa and 50.0% of Serratia marcescens isolates were gentamicin-resistant.
    • 80% of resistant clinical isolates had gentamicin MICs ≥ 16 µg/ml.
    • Amikacin demonstrated high efficacy against gentamicin-resistant S. marcescens (100%) and Ps. aeruginosa (79%).
    • Tobramycin and sisomicin offered limited advantages over gentamicin.
    • Most isolates originated from the urinary tract, with some also found in blood cultures.
    • Resistant strains exhibited similar virulence to sensitive strains.
    • Clinical improvement was observed in 13 of 17 patients treated with amikacin.

    Conclusions:

    • A high frequency of gentamicin resistance in Ps. aeruginosa and S. marcescens poses a persistent problem.
    • Amikacin is an effective therapeutic option for infections caused by gentamicin-resistant strains.
    • The findings highlight the need for ongoing surveillance and management of antimicrobial resistance in hospital settings.

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