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In vitro studies of the killing of clinical isolates by povidone-iodine solutions

D J Gocke, S Ponticas, W Pollack

    The Journal of Hospital Infection
    |March 1, 1985
    PubMed

    Insights

    Most staphylococcal isolates showed resistance to povidone-iodine (PVP-I) initially. However, increasing contact time or using a new formulation (SP-Betadine) ensured complete bacterial killing.

    Area of Science:

    • Microbiology
    • Antimicrobial Susceptibility Testing

    Background:

    • Povidone-iodine (PVP-I) is a widely used antiseptic.
    • Understanding its efficacy against various clinical isolates is crucial for infection control.

    Purpose of the Study:

    • To evaluate the susceptibility of clinical bacterial isolates to povidone-iodine.
    • To assess the impact of contact time and formulation on PVP-I efficacy.

    Main Methods:

    • Surveyed 230 clinical isolates for susceptibility to 10% povidone-iodine (PVP-I).
    • Varied contact times (15s, 30s, 120s) and tested a new PVP-I formulation (SP-Betadine).
    • Included staphylococcal, Gram-positive, and Gram-negative isolates (e.g., Pseudomonas aeruginosa, Escherichia coli).

    Main Results:

    • 19% of staphylococcal isolates were killed by 10% PVP-I in 15s; 81% showed apparent resistance.
    • Prolonging contact time to 30s or 120s eliminated resistance in most isolates.
    • Lower PVP-I concentrations (around 0.1%) showed paradoxical increased killing.
    • The new SP-Betadine formulation was cidal for all isolates within 15s.

    Conclusions:

    • Short contact times with standard PVP-I may lead to apparent resistance in staphylococci.
    • Contact time is a critical factor in achieving complete bacterial kill with PVP-I.
    • A novel PVP-I formulation demonstrates enhanced rapid-acting antimicrobial properties.

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