In vitro susceptibility of dermatomycoses agents to six antifungal drugs and evaluation by fractional inhibitory concentration index of combined effects of amorolfine and itraconazole in dermatophytes.

To investigate the antifungal drug susceptibility of fungi responsible for dermatomycoses, minimum inhibition concentration (MIC) tests were performed in 44 strains of dermatophytes, including Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton verrucosum, Trichophyton tonsurans, Microsporum canis, Microsporum gypseum and Epidermophyton floccosum, with six antifungal drugs (amorolfine, terbinafine, butenafine, ketoconazole, itraconazole and bifonazole) by broth microdilution assay according to Clinical Laboratory Standard Institute protocols. Six possible dermatomycosis-causing non-dermatophytic fungi were also tested. The two major causes of tinea, T. rubrum and T. mentagrophytes, showed significantly different sensitivities to ketoconazole and bifonazole. Clinically derived dermatophytes were sensitive to the six antifungal drugs tested. However, non-dermatophytes, especially Fusarium spp., tended to be resistant to these antifungal drugs. In Trichophyton spp., the MICs of non-azole drugs had narrower distributions than those of azoles. To evaluate the effects of antifungal drug combinations, the fractional inhibitory concentration index was calculated for the combination of amorolfine and itraconazole as representative external and internal drugs for dermatophytes. It was found that this combination had synergistic or additive effects on most dermatophytes, and had no antagonistic effects. The variation in susceptibility of clinically derived fungal isolates indicates that identification of causative fungi is indispensable for appropriately choosing effective antifungal drugs in the early stages of infection. The results of combination assay suggest that multiple drugs with different antifungal mechanisms against growth of dermatophytes should be used to treat refractory dermatomycoses, especially onychomycosis.

Specific detection of Bjerkandera adusta by polymerase chain reaction and its incidence in fungus-associated chronic cough.

Chronic cough is a common symptom at outpatient care. An uncontrollable cough with difficulty in treatment is called chronic idiopathic cough. Recent reports have demonstrated that the presence of basidiomycetous fungi in sputum is an important clinical finding that assists in clarifying the cause of chronic cough in some cases. Research has suggested that Bjerkandera adusta is related to fungus-associated chronic cough (FACC). FACC is defined as a chronic cough associated with basidiomycetous fungi found in induced sputum and can be treated with antifungal medication. B. adusta is one of the basidiomycetous fungi that exist in cosmopolitan environments. The aim of this study was to develop a B. adusta detection method using polymerase chain reaction (PCR) with a specific primer set and to research the incidence of B. adusta in FACC. The new method successfully detected B. adusta from FACC patients. The incidence of B. adusta in FACC was 42.86 %. Antifungal drugs were effective in most cases. Significant differences in treatment duration between B. adusta patients and non-B. adusta patients were observed. It is therefore suggested that the presence of B. adusta may be one of the allergic intractable factors of chronic cough. This finding may provide identifiable differences in clinical manifestations between B. adusta and non-B. adusta in FACC and lead to possible differing remedies to treat the two forms. PCR can specifically detect B. adusta from patients suffering from chronic cough and provides a new diagnosis for FACC associated with B. adusta.

Utilization of matrix-assisted laser desorption and ionization time-of-flight mass spectrometry for identification of infantile seborrheic dermatitis-causing Malassezia and incidence of culture-based cutaneous Malassezia microbiota of 1-month-old infants.

Matrix-assisted laser desorption and ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has been utilized for identification of various microorganisms. Malassezia species, including Malassezia restricta, which is associated with seborrheic dermatitis, has been difficult to identify by traditional means. This study was performed to develop a system for identification of Malassezia species with MALDI-TOF-MS and to investigate the incidence and variety of cutaneous Malassezia microbiota of 1-month-old infants using this technique. A Malassezia species-specific MALDI-TOF-MS database was developed from eight standard strains, and the availability of this system was assessed using 54 clinical strains isolated from the skin of 1-month-old infants. Clinical isolates were cultured initially on CHROMagar Malassezia growth medium, and the 28S ribosomal DNA (D1/D2) sequence was analyzed for confirmatory identification. Using this database, we detected and analyzed Malassezia species in 68% and 44% of infants with and without infantile seborrheic dermatitis, respectively. The results of MALDI-TOF-MS analysis were consistent with those of rDNA sequencing identification (100% accuracy rate). To our knowledge, this is the first report of a MALDI-TOF-MS database for major skin pathogenic Malassezia species. This system is an easy, rapid and reliable method for identification of Malassezia.