Otomi Cho

Molecular characterization of the skin fungal microbiome in patients with psoriasis

The skin surface is colonized by a wide variety of fungi and bacteria. While many of these organisms, including Malassezia, Candida, Streptococcus and Staphylococcus species, are associated with provocation and/or exacerbation of psoriasis, a detailed analysis of the cutaneous fungal microbiome in psoriatic patients has yet to be performed. To identify the disease‐specific fungal microbiota on psoriatic scale samples, fungal rRNA gene sequences from 12 psoriatic patients and 12 healthy controls were analyzed by pyrosequencing. A total of 317 806 high‐quality sequences were obtained, representing 142 genera. Malassezia species were the most abundant sequences in both populations (46.9 ± 14.0% in psoriasis vs 76.0 ± 14.6% for healthy controls). Principal coordinate analysis revealed that the fungal microbiomes were independent. Although an association between the cutaneous fungal microbiome and psoriasis has yet to be established, our data indicate that the microbiome in patients with psoriasis is independent of that in healthy controls.

Molecular Characterization of the Skin Fungal Microbiota in Patients with Seborrheic Dermatitis

Background: Seborrheic dermatitis (SD) is an inflammatory disease associated with seborrhea that appears most often on the face, especially the nasolabial folds, scalp, and upper trunk, in sebaceous gland-rich areas of the skin. Although various factors are involved in the development of SD, Malassezia species of skin fungi play an important role in this skin disease. The aim of this study was to obtain basic information to elucidate the mycological involvement in the development of SD by performing a comprehensive analysis of the skin fungal microbiota of lesional and non-lesional sites in SD patients using a pyrosequencing approach. Methods: Scale samples were collected from lesional and non-lesional sites of 24 Japanese patients with seborrheic dermatitis and the skin fungal microbiome in the scale samples was analyzed using a pyrosequencing method. Results: Thirty taxa were detected from a total of 480,186 high-quality sequences. Malassezia species predominated at both lesional and non-lesional sites; however, the fungal microbiota at lesional sites was more diverse than at non-lesional sites. The fungal communities at lesional and non-lesional sites were clearly distinguished on principal coordinate analysis. Conclusion: Our data indicated that the skin fungal microbiota in lesional sites of SD patients was independent of that in non-lesional sites and will be utilized as basic information for understanding the association between skin fungi and development of SD.

Molecular evidence that the opportunistic fungal pathogen Trichosporon asahii is part of the normal fungal microbiota of the human gut based on rRNA genotyping

The fungus Trichosporon asahii is distributed widely in the environment and is frequently isolated from clinical specimens. It can cause life-threatening disseminated infections, including breakthrough infection after the administration of candin antifungal drugs. However, the definitive infection route is still unclear. In this study, 43 T. asahii genotypes were detected in 72 fecal samples from healthy subjects. The rRNA genotypes of the species were determined using a culture-independent method. The genotypes of T. asahii were almost identical to those of reported clinical isolates. Therefore, T. asahii colonizing the gastrointestinal tract might be associated with the development of trichosporonosis, and not environmental isolates.

Comprehensive pyrosequencing analysis of the bacterial microbiota of the skin of patients with seborrheic dermatitis

Seborrheic dermatitis (SD) is a chronic inflammatory dermatologic condition in which erythema and itching develop on areas of the body with sebaceous glands, such as the scalp, face and chest. The inflammation is evoked directly by oleic acid, which is hydrolyzed from sebum by lipases secreted by skin microorganisms. Although the skin fungal genus, Malassezia, is thought to be the causative agent of SD, analysis of the bacterial microbiota of skin samples of patients with SD is necessary to clarify any association with Malassezia because the skin microbiota comprises diverse bacterial and fungal genera. In the present study, bacterial microbiotas were analyzed at non‐lesional and lesional sites of 24 patients with SD by pyrosequencing and qPCR. Principal coordinate analysis revealed clear separation between the microbiota of non‐lesional and lesional sites. Acinetobacter, Corynebacterium, Staphylococcus, Streptococcus and Propionibacterium were abundant at both sites. Propionibacterium was abundant at non‐lesional sites, whereas Acinetobacter, Staphylococcus and Streptococcus predominated at lesional sites; however, the extent of Propionibacterium colonization did not differ significantly between lesional and non‐lesional sites according to qPCR. Given that these abundant bacteria hydrolyze sebum, they may also contribute to SD development. To the best of our knowledge, this is the first comprehensive analysis of the bacterial microbiotas of the skin of SD patients.

Three new basidiomycetous yeasts, Pseudozyma alboarmeniaca sp. nov., Pseudozyma crassa sp. nov. and Pseudozyma siamensis sp. nov. isolated from Thai patients.

We previously reported the first isolation of Pseudozyma species from the blood of Thai patients. In this study, three additional new Pseudozyma species were isolated from clinical specimens from Thai patients. The Pseudozyma species showed relatively low sensitivity to azole antifungal agents. The names proposed for these isolates are Pseudozyma alboarmeniaca (DMST 17135T = JCM 12454T = CBS 9961T), Pseudozyma crassa (DMST 17136T = JCM 12455T = CBS 9959T) and Pseudozyma siamensis (DMST 17137T = JCM 12456T CBS 9960T), where DMST is Department of Medical Sciences Culture Collection, JCM is Japan Collection of Microorganisms and CBS is Centraalbureau voor Schimmelcultures.

Draft Genome Sequence of the Causative Antigen of Summer-Type Hypersensitivity Pneumonitis, Trichosporon domesticum JCM 9580

ABSTRACT Here, we report the draft genome sequence of Trichosporon domesticum JCM 9580, isolated from the house of a patient with summer-type hypersensitivity pneumonitis (SHP) in Japan. This genomic information will help elucidate the mechanisms of the development of SHP.

Relationships among the Genotypes of Malassezia Globosa Colonizing Patients with Atopic Dermatitis, the Clinical Severity of the Disease, and the Level of Specific IgE Antibodies

Background: Various types of microorganisms colonize the skin surface, and some such as the bacterium Staphylococcus aureus and fungus Malassezia, exacerbate the symptoms of atopic dermatitis. Malassezia-specific IgE antibodies are present in the sera of patients with atopic dermatitis and the level thereof correlates with the severity of the condition. Malassezia has many genotypes. In the present study, we explored the relationships among the genotypes of Malassezia species colonizing patients with atopic dermatitis, the clinical severity of the disease, and the level of specific IgE antibody. Methods: Scale samples were obtained from head or neck lesions of 74 patients with atopic dermatitis and 40 healthy subjects. The intergenic spacer (IGS) 1 region of the rRNA genes of M. globosa (the major flora of patients with atopic dermatitis) were amplified by PCR and directly sequenced. M. globosa-specific IgE antibody levels were determined using the AlaSTAT™ microplate system. Results: Eighteen M. globosa IGS1 genotypes were detected in scale samples from patients with atopic dermatitis and healthy individuals. Of these, the proportion of the (GT)10:(CT)8 genotype increased with the clinical severity of disease and increasing levels of M. globosa-specific IgE antibodies, whereas this genotype was not found on the skin of healthy subjects. Conclusion: A specific genotype of Malassezia selectively colonized the skin of patients with atopic dermatitis, contributing to the clinical severity of disease. Thus, a “bad Malassezia” may be present on the skin of patients with atopic dermatitis.

Comparative Analysis of Extracellular Polymeric Substances from Cryptococcus gattii VGIIa Strain Isolated for the First Time in Japan

Cryptococcus gattii and C. neoformans are pathogenic yeasts that cause meningoencephalitis. C. gattii has four molecular types: VGI, VGII, VGIII, and VGIV. Furthermore, three genotypes have been reported for VGII, and a high pathogenicity of the VGIIa genotype has been proposed. The VGIIa strain has been isolated from a patient in Japan, but little is known about the characteristics of the polysaccharides in this strain. In this study we examined the induction of interleukin-8（IL-8）transcriptional activation and compared the nuclear magnetic resonance（NMR）spectra of extracellular polymeric substances（EPSs）, mainly polysaccharides, from the VGIIa, VGIIb, and VGIIc genotypes. The induction of IL-8 by C. gattii EPSs was weaker than that by C. neoformans EPSs. The anomeric proton signals in the NMR spectra of EPSs obtained from VGII isolates were similar, and the polysaccharides were mainly mannose, xylose, galactose, and glucuronic acid. These results suggest that the extracellular polysaccharides from the VGIIa strain isolated in Japan are almost the same as those from other VGII strains.

Culture Supernatants of Lactobacillus gasseri and L. crispatus Inhibit Candida albicans Biofilm Formation and Adhesion to HeLa Cells

PurposeVulvovaginal candidiasis (VVC) is a common superficial infection of the vaginal mucous membranes caused by the fungus Candida albicans. The aim of this study was to assess the mechanisms underlying the inhibitory effects of the culture supernatants of Lactobacillus gasseri and L. crispatus, the predominant microbiota in Asian healthy women, on C. albicans biofilm formation. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was also investigated.MethodsCandida albicans biofilm was formed on polystyrene flat-bottomed 96-well plates, and the inhibitory effects on the initial colonization and maturation phases were determined using the XTT reduction assay. The expression levels of biofilm formation-associated genes (HWP1, ECE1, ALS3, BCR1, EFG1, TEC1, and CPH1) were determined by reverse transcription quantitative polymerase chain reaction. The inhibition of C. albicans adhesion to HeLa cells by Lactobacillus culture supernatant was evaluated by enumerating viable C. albicans cells.ResultsThe culture supernatants of both Lactobacillus species inhibited the initial colonization and maturation of C. albicans biofilm. The expression levels of all biofilm formation-related genes were downregulated in the presence of Lactobacillus culture supernatant. The culture supernatant also inhibited C. albicans adhesion to HeLa cells.ConclusionThe culture supernatants of L. gasseri and L. crispatus inhibited C. albicans biofilm formation by downregulating biofilm formation-related genes and C. albicans adhesion to HeLa cells. These findings support the notion that Lactobacillus metabolites may be useful alternatives to antifungal drugs for the management of VVC.

Loop-mediated isothermal amplification for the rapid detection of Gardnerella vaginalis : LAMP for rapid detection of G. vaginalis

The aim of this study was to develop a method for the rapid detection of Gardnerella vaginalis, which is proposed to play a key role in the pathogenesis of bacterial vaginosis. Specific loop‐mediated isothermal amplification (LAMP) primers were designed and used to detect target DNA within 45 min under isothermal conditions. Comparative screening indicated that the LAMP assay is superior to PCR in terms of rapidity, and is equivalent in sensitivity and specificity. This LAMP assay can be used for rapid screening and detection of G. vaginalis in vaginal samples; the limit of detection is 10 fg DNA.