ABSTRACT
A comparative study of Etest and broth macrodilution methods for susceptibility testing to fluconazole, ketoconazole, itraconazole and amphotericin B was conducted for sixty strains of C. neoformans isolated form Aids patients. The MICs obtained by these two methods were read after 72 hours of incubation for broth macrodilution and 48 hours for Etest. The rate agreement was obtained between the broth macrodilution and Etest methods using differences with 2 doubling dilutions. Our data showed that there was a good correlation between the MICs obtained by broth methods. The correlation between these two methods tested was 96.6 percent (58/60), 90.0 percent (54/60), 93.3 percent (56/60) and 100 percent (60/60) for fluconazole, ketoconazole, itraconazole, and amphotericin B, respectively. These results indicate that Etest could be considered useful for antifungal sensitivity evaluation of yeasts in clinical laboratories.
Subject(s)
Cryptococcus neoformans , Antifungal Agents , In Vitro Techniques , Acquired Immunodeficiency SyndromeABSTRACT
Sixty clinical isolates of Cryptococcus neoformans from AIDS from Goiânia, state of Goiás, Brazil, were characterized according to varieties, serotypes and tested for antifungal susceptibility. To differentiate the two varieties was used L-canavanine-glycine-bromothymol blue medium and to separate the serotypes was used slide agglutination test with Crypto Check Iatron. The Minimal Inhibitory Concentration (MIC) of fluconazole, itraconazole, and amphotericin B were determined by the National Committee for Clinical Laboratory Standards macrodilution method. Our results identified 56 isolates as C. neoformans var. neoformans serotype A and 4 isolates as C. neoformans var. gattii serotype B. MIC values for C. neoformans var. gattii were higher than C. neoformans var. neoformans. We verified that none isolate was resistant to itraconazole and to amphotericin B, but one C. neoformans var. neoformans and three C. neoformans var. gattii isolates were resistant to fluconazole. The presence of C. neoformans var. gattii fluconazole resistant indicates the importance of determining not only the variety of C. neoformans infecting the patients but also measuring the MIC of the isolate in order to properly orient treatment.
Subject(s)
Amphotericin B/pharmacology , Antifungal Agents/pharmacology , Cryptococcus neoformans/drug effects , Fluconazole/pharmacology , Itraconazole/pharmacology , AIDS-Related Opportunistic Infections/microbiology , Adolescent , Adult , Agglutination Tests , Cryptococcus neoformans/classification , Cryptococcus neoformans/isolation & purification , Female , Humans , Male , Microbial Sensitivity Tests , Middle Aged , SerotypingABSTRACT
Sixty clinical isolates of Cryptococcus neoformans from AIDS from Goi⮩a, state of Goiᳬ Brazil, were characterized according to varieties, serotypes and tested for antifungal susceptibility. To differentiate the two varieties was used L-canavanine-glycine-bromothymol blue medium and to separate the serotypes was used slide agglutination test with Crypto Check Iatron. The Minimal Inhibitory Concentration (MIC) of fluconazole, itraconazole, and amphotericin B were determined by the National Committee for Clinical Laboratory Standards macrodilution method. Our results identified 56 isolates as C. neoformans var. neoformans serotype A and 4 isolates as C. neoformans var. gattii serotype B. MIC values for C. neoformans var. gattii were higher than C. neoformans var. neoformans. We verified that none isolate was resistant to itraconazole and to amphotericin B, but one C. neoformans var. neoformans and three C. neoformans var. gattii isolates were resistant to fluconazole. The presence of C. neoformans var. gattii fluconazole resistant indicates the importance of determining not only the variety of C. neoformans infecting the patients but also measuring the MIC of the isolate in order to properly orient treatment
