In vitro antifungal activity of topical and systemic antifungal drugs against Malassezia species

Abstract

The strict nutritional requirements of Malassezia species make it difficult to test the antifungal susceptibility. Treatments of the chronic and recurrent infections associated with Malassezia spp. are usually ineffective. The objective of this study was to obtain in vitro susceptibility profile of 76 clinical isolates of Malassezia species against 16 antifungal drugs used for topical or systemic treatment. Isolates were identified by restriction fragment length polymorphism. Minimal inhibitory concentrations (MIC) were obtained by a modified microdilution method based on the Clinical Laboratory Standards Institute reference document M27-A3. The modifications allowed a good growth of all tested species. High in vitro antifungal activity of most tested drugs was observed, especially triazole derivatives, except for fluconazole which presented the highest MICs and widest range of concentrations. Ketoconazole and itraconazole demonstrated a great activity. Higher MICs values were obtained with Malassezia furfur indicating a low susceptibility to most of the antifungal agents tested. Malassezia sympodialis and Malassezia pachydermatis were found to be more-susceptible species than M. furfur, Malassezia globosa, Malassezia slooffiae and Malassezia restricta. Topical substances were also active but provide higher MICs than the compounds for systemic use. The differences observed in the antifungals activity and interspecies variability demonstrated the importance to studying the susceptibility profile of each species to obtain reliable information for defining an effective treatment regimen.

Antifungal Susceptibility of Malassezia Species Isolated From Pityriasis Versicolor Cases

“…In agreement with other reports, this study also found higher in vitro antifungal activity against all the tested clinical isolates of Malassezia spp, with itraconazole. [8,14,16] In this study fluconazole MICs were significantly higher than those observed for other azole drugs and ranged from ≤ 0.125 µg/mL -16µg/mL for all the isolates in PV cases. This is similar to or lower than those documented in various other studies.…”

“…The ketoconazole MICs range from ≤ 0.03 -8 μg/mL with all the species tested, These values are similar to or higher than those documented in other studies. [14,15,8,17] Garau M et al [8] registered MICs of ≤0.03µg/mL against 70 isolates of Malassezia. Gupta AK et al [15] demonstrated that out of 55 of strains of Malassezia the MIC ranges as ≤ 0.03µg/mL -0.125μg/mL with 95% of them having an MIC of ≤ 0.03μg/mL.…”

“…The overall MICs range for fluconazole, itraconazole and ketoconazole were ≤ 0.125-16μg/mL, ≤ 0.03-1µg/mL and ≤ 0.03-8µg/mL respectively. When all the strains were considered together, this [14,15] Hence, studying Malassezia susceptibility might provide better information about the susceptibility pattern of different species. The ketoconazole MICs range from ≤ 0.03 -8 μg/mL with all the species tested, These values are similar to or higher than those documented in other studies.…”

“…This is similar to or lower than those documented in various other studies. [15,16,18] The various MIC ranges against fluconazole shown in various studies are ≤ 0.125 -> 64 µg/mL, [16] 0.06 µg/mL -1.0 µg/mL, [18] ≤ 0.5 µg/mL -32 µg/mL, [6] 0.25µg/mL -4 µg/mL, [8] 0.25µg/mL -256 µg/mlL [14] and ≤ 0.125 -> 64µg/mL. Remya et al…”

A study on malassezia micro flora in the skin of healthy individuals in North Kerala, India

“…5 Since the new descriptions, several recent studies have been carried out worldwide to study the distribution of the newly defined species of Malassezia on healthy adult human skin in which variable results have been reported among studies from different geographical regions. 6 An enhanced understanding of the distribution of Malassezia spp in healthy individuals is necessary to gain insight to the involvement of these species in human skin disorders particularly in pityriasis versicolor.…”