In vitro antifungal efficacy of biguanides and quaternary ammonium compounds against cleanroom fungal isolates

Rajendran Vijayakumar, Velusamy Venkatesa Kannan, Tim Sandle, Chockaiya Manoharan

    Research output: Contribution to journalArticlepeer-review


    In vitro antifungal activities of three biocides including one biguanide (chlorhexidine) and two quaternary ammonium compounds (benzalkonium chloride and cetrimide) were studied against eight cleanroom fungal isolates by using a microbiological broth dilution technique as per Clinical and Laboratory Standards Institute (CLSI) M38-A guidelines. No data exists on the activity of biocides on pharmaceutical cleanroom fungal isolates. Minimum inhibitory concentrations (MICs) for all three biocides against species of Aspergillus and Penicillium species ranged between 4 and 16 μg/mL. MICs of Curvularia, Cladosporium, and Alternaria species also showed less than 16 μg/mL. To date, susceptibility breakpoints have not been established for biocides, and this is the first study using the CLSI broth microdilution antifungal susceptibility testing to determine the MIC value of biocides. This study clearly demonstrates that the most frequently isolated micro-organisms from an environmental monitoring program may be periodically subjected to microbroth dilution testing with cleanroom disinfectant agents used in the disinfection program to confirm their sensitivity profile. Further work is needed in this field to increase our understanding of biocides against different fungal isolates and to enable to the design of more efficient disinfection and contamination control programs. ©PDA, Inc. 2012.
    Original languageEnglish
    Pages (from-to)236-242
    Number of pages6
    JournalPDA Journal of Pharmaceutical Science and Technology
    Issue number3
    Publication statusPublished - May 2012


    • Biguanides
    • Biocides
    • Fungi
    • Microbroth dilution techniques
    • Quaternary ammonium compounds


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