Abstract
A comparative study of fluconazole and amphotericin B susceptibility testing was performed with 68 clinical Candida species isolates and three test methods. The methods used were an agar diffusion method (E-test) and two broth dilution methods, the National Committee for Clinical Laboratory Standards (NCCLS) reference broth macrodilution method and an in-house-prepared semiautomated broth microdilution method based on the Bioscreen turbidometer. In the microdilution method, growth of the yeasts was measured continuously by the automatic turbidometer (Bioscreen), which permitted precise and objective determination of endpoints. MIC endpoints were read after 24 h for the microdilution method and the E-test. Amphotericin B susceptibility testing with the NCCLS method and the E-test yielded comparable results in 89% of the tests, meaning that the endpoints obtained were identical or differed by no more than 2 twofold dilutions. The NCCLS and broth microdilution tests scored 97% comparable results, and the E-test and the broth microdilution test yielded 90% comparable results. Fluconazole susceptibility testing produced 96% comparable results with the NCCLS test and the E-test, 100% comparable results with the NCCLS and the microdilution methods, and 98.5% comparable results with the microdilution method and the E-test. We conclude that the E-test and the Bioscreen microdilution method are valuable alternatives to the NCCLS reference method for routine susceptibility testing of Candida species with fluconazole and amphotericin B.
Full Text
The Full Text of this article is available as a PDF (209.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Anaissie E. J., Bodey G. P., Rinaldi M. G. Emerging fungal pathogens. Eur J Clin Microbiol Infect Dis. 1989 Apr;8(4):323–330. doi: 10.1007/BF01963467. [DOI] [PubMed] [Google Scholar]
- Banerjee S. N., Emori T. G., Culver D. H., Gaynes R. P., Jarvis W. R., Horan T., Edwards J. R., Tolson J., Henderson T., Martone W. J. Secular trends in nosocomial primary bloodstream infections in the United States, 1980-1989. National Nosocomial Infections Surveillance System. Am J Med. 1991 Sep 16;91(3B):86S–89S. doi: 10.1016/0002-9343(91)90349-3. [DOI] [PubMed] [Google Scholar]
- Barchiesi F., Colombo A. L., McGough D. A., Rinaldi M. G. Comparative study of broth macrodilution and microdilution techniques for in vitro antifungal susceptibility testing of yeasts by using the National Committee for Clinical Laboratory Standards' proposed standard. J Clin Microbiol. 1994 Oct;32(10):2494–2500. doi: 10.1128/jcm.32.10.2494-2500.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brass C., Shainhouse J. Z., Stevens D. A. Variability of agar dilution-replicator method of yeast susceptibility testing. Antimicrob Agents Chemother. 1979 Jun;15(6):763–768. doi: 10.1128/aac.15.6.763. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Galgiani J. N. Susceptibility testing of fungi: current status of the standardization process. Antimicrob Agents Chemother. 1993 Dec;37(12):2517–2521. doi: 10.1128/aac.37.12.2517. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ghannoum M. A., Ibrahim A. S., Fu Y., Shafiq M. C., Edwards J. E., Jr, Criddle R. S. Susceptibility testing of Cryptococcus neoformans: a microdilution technique. J Clin Microbiol. 1992 Nov;30(11):2881–2886. doi: 10.1128/jcm.30.11.2881-2886.1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Odds F. C. Laboratory evaluation of antifungal agents: a comparative study of five imidazole derivatives of clinical importance. J Antimicrob Chemother. 1980 Nov;6(6):749–761. doi: 10.1093/jac/6.6.749. [DOI] [PubMed] [Google Scholar]
- Odds F. C. Resistance of yeasts to azole-derivative antifungals. J Antimicrob Chemother. 1993 Apr;31(4):463–471. doi: 10.1093/jac/31.4.463. [DOI] [PubMed] [Google Scholar]
- Pfaller M. A., Bale M., Buschelman B., Lancaster M., Espinel-Ingroff A., Rex J. H., Rinaldi M. G., Cooper C. R., McGinnis M. R. Quality control guidelines for National Committee for Clinical Laboratory Standards recommended broth macrodilution testing of amphotericin B, fluconazole, and flucytosine. J Clin Microbiol. 1995 May;33(5):1104–1107. doi: 10.1128/jcm.33.5.1104-1107.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pfaller M. A., Grant C., Morthland V., Rhine-Chalberg J. Comparative evaluation of alternative methods for broth dilution susceptibility testing of fluconazole against Candida albicans. J Clin Microbiol. 1994 Feb;32(2):506–509. doi: 10.1128/jcm.32.2.506-509.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rex J. H., Cooper C. R., Jr, Merz W. G., Galgiani J. N., Anaissie E. J. Detection of amphotericin B-resistant Candida isolates in a broth-based system. Antimicrob Agents Chemother. 1995 Apr;39(4):906–909. doi: 10.1128/aac.39.4.906. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rex J. H., Pfaller M. A., Rinaldi M. G., Polak A., Galgiani J. N. Antifungal susceptibility testing. Clin Microbiol Rev. 1993 Oct;6(4):367–381. doi: 10.1128/cmr.6.4.367. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rodriguez-Tudela J. L., Martinez-Suarez J. V. Improved medium for fluconazole susceptibility testing of Candida albicans. Antimicrob Agents Chemother. 1994 Jan;38(1):45–48. doi: 10.1128/aac.38.1.45. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sewell D. L., Pfaller M. A., Barry A. L. Comparison of broth macrodilution, broth microdilution, and E test antifungal susceptibility tests for fluconazole. J Clin Microbiol. 1994 Sep;32(9):2099–2102. doi: 10.1128/jcm.32.9.2099-2102.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]