Resistance of Asian Cryptococcus neoformans Serotype A Is Confined to Few Microsatellite Genotypes

Contains fulltext : 109375.pdf (publisher's version ) (Open Access)BACKGROUND: Cryptococcus neoformans is a pathogenic yeast that causes cryptococcosis, a life threatening disease. The prevalence of cryptococcosis in Asia has been rising after the onset of the AIDS epidemic and estimates indicate more than 120 cases per 1,000 HIV-infected individuals per year. Almost all cryptococcal disease cases in both immunocompromised and immunocompetent patients in Asia are caused by C. neoformans var. grubii. Epidemiological studies on C. neoformans in pan-Asia have not been reported. The present work studies the genetic diversity of the fungus by microsatellite typing and susceptibility analysis of approximately 500 isolates from seven Asian countries. METHODOLOGY/PRINCIPAL FINDINGS: Genetic diversity of Asian isolates of C. neoformans was determined using microsatellite analysis with nine microsatellite markers. The analysis revealed eight microsatellite complexes (MCs) which showed different distributions among geographically defined populations. A correlation between MCs and HIV-status was observed. Microsatellite complex 2 was mainly associated with isolates from HIV-negative patients, whereas MC8 was associated with those from HIV-positive patients. Most isolates were susceptible to amphotericin B, itraconazole, voriconazole, posaconazole, and isavuconazole, but 17 (3.4%) and 10 (2%) were found to be resistant to 5-flucytosine and fluconazole, respectively. Importantly, five Indonesian isolates (approximately 12.5% from all Indonesian isolates investigated and 1% from the total studied isolates) were resistant to both antifungals. The majority of 5-flucytosine resistant isolates belonged to MC17. CONCLUSIONS: The findings showed a different distribution of genotypes of C. neoformans var. grubii isolates from various countries in Asia, as well as a correlation of the microsatellite genotypes with the original source of the strains and resistance to 5-flucytosine

Chemical composition and antifungal activity of essential oil from Eucalyptus smithii against dermatophytes

ABSTRACT INTRODUCTION: In this study, we evaluated the chemical composition of a commercial sample of essential oil from Eucalyptus smithii R.T. Baker and its antifungal activity against Microsporum canis ATCC 32903, Microsporum gypseum ATCC 14683, Trichophyton mentagrophytes ATCC 9533, T. mentagrophytes ATCC 11480, T. mentagrophytes ATCC 11481, and Trichophyton rubrum CCT 5507. METHODS: Morphological changes in these fungi after treatment with the oil were determined by scanning electron microscopy (SEM). The antifungal activity of the oil was determined on the basis of minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values. RESULTS: The compound 1,8-cineole was found to be the predominant component (72.2%) of the essential oil. The MIC values of the oil ranged from 62.5μg·mL−1 to >1,000μg·mL−1, and the MFC values of the oil ranged from 125μg·mL−1 to >1,000μg·mL−1. SEM analysis showed physical damage and morphological alterations in the fungi exposed to this oil. CONCLUSIONS: We demonstrated the potential of Eucalyptus smithii essential oil as a natural therapeutic agent for the treatment of dermatophytosis