Narifumi Akaza

Malassezia folliculitis is caused by cutaneous resident Malassezia species

Malassezia folliculitis [MF] is caused by the invasion of hair follicles by large numbers of Malassezia cells, but it remains unclear which Malassezia species are involved in the disease. To clarify this situation, Malassezia species isolated from lesions of MF patients were analyzed by both culture and non-culture methods. In addition, Malassezia species recovered from the non-lesion areas of the skin of MF patients and skin samples of healthy subjects were included in this study. The test population consisted of 32 MF patients and 40 healthy individuals. The lesions were obtained using a comedone extractor, while swabs were employed to obtain skin samples from non-lesion areas of the patients and healthy subjects. Malassezia DNA was analyzed using a real-time PCR technique. The detection limit of the culture method was 5 CFU/cm(2) as opposes 50 cells/cm(2) with non-culture procedures. The predominant species recovered from MF lesions were M. globosa and M. sympodialis by culture method analysis, and M. restricta, M. globosa, and M. sympodialis with non-culture methods. These results were in agreement with those found with samples from non-lesion skin areas of MF patients and healthy subjects. This study clarified that MF is caused by Malassezia species that are part of the cutaneous microflora and not by exogenous species.

Effects of Propionibacterium acnes on various mRNA expression levels in normal human epidermal keratinocytes in vitro.

Propionibacterium acnes is one of the most significant pathogenic factors of acne vulgaris. This bacteria relates to acne by various pathways. It has also been reported that P. acnes influences pro‐inflammatory cytokine production in keratinocytes in vitro. However, the influence on the differentiation of keratinocytes by P. acnes has not been studied extensively. We analyzed the expression of keratinocyte differentiation‐specific markers, keratins, and pro‐inflammatory cytokines in normal human epidermal keratinocytes (NHEK) exposed to P. acnes in vitro. All P. acnes strains used in this study increased transglutaminase (TGase), keratin 17 (K17) and interleukin (IL) mRNA expression levels in NHEK, and decreased K1 and K10 expression levels. Some P. acnes strains increased involucrin and K6 mRNA expression levels in NHEK and decreased filaggrin, K6 and K16 expression levels in vitro. This experiment clarified that P. acnes influences the differentiation of NHEK in vitro. As a result, P. acnes influenced the expression of not only pro‐inflammatory cytokines but also some keratinocyte differentiation‐specific markers and keratins in NHEK. Our results suggest that P. acnes relates to acne pathogenesis by not only the induction of inflammation but also in the differentiation of keratinocytes. Moreover, it was considered that the reaction of NHEK to P. acnes may be different depending on the type of bacteria.

Cutaneous Malassezia microbiota of healthy subjects differ by sex, body part and season.

Malassezia is a component of normal cutaneous resident microbiota. The aim of this study was to quantitatively clarify the differences in cutaneous Malassezia microbiota in healthy subjects by sex, body part and season. Samples were collected from the forehead, cheek, upper chest and upper back of 20 healthy men and 20 healthy women (average age 32 years) in summer and winter by the swab method. Malassezia DNA was analyzed using a real‐time PCR system. As a result, in sex, body parts and season, men, the upper trunk and summer showed the highest total numbers of cutaneous Malassezia species on average. There were also differences depending on the analytical method. The predominant species were M. restricta on the face of men, M. globosa and M. dermatis on the upper trunk of men, and M. globosa and M. sympodialis on the upper trunk of women. This study clarified that the cutaneous Malassezia microbiota of healthy subjects differed by sex, body part and season.

Analysis of Facial Skin-Resident Microbiota in Japanese Acne Patients

Objectives: We investigated the facial skin microbiota of Japanese acne patients. Methods: Skin swab samples were obtained from 100 acne patients and 28 healthy controls to evaluate Propionibacterium and Staphylococcus spp. using a culture method. Malassezia spp. were evaluated using a nonculture method. Antibiotic resistance of Propionibacterium spp. was also examined. Results: Acne patients and controls did not show significant differences in Propionibacterium and Staphylococcus spp. populations. However, the number of Malassezia globosa from patients was greater than that from controls. Moreover, the number of Propionibacterium spp. from patients carrying antibiotic-resistant strains was significantly greater than that from patients not carrying them. Conclusions: The present study characterized the facial skin microbiota of Japanese acne patients, suggesting a correlation between acne and quantitative differences in Malassezia microbiota. It was also found that the antibiotic resistance of Propionibacterium spp. may affect its abundance in the skin.

Malassezia globosa tends to grow actively in summer conditions more than other cutaneous Malassezia species

Malassezia globosa is a major pathogen of Malassezia folliculitis (MF) and the predominant species on human skin. The aim of this study was to clarify the differences between M. globosa and other cutaneous Malassezia species, M. restricta, M. dermatis, M. sympodialis and M. furfur. The optimum growth temperature, effects of compounds of sweat and free fatty acids on growth, and lipase activities of five cutaneous Malassezia species were determined. The growth of M. globosa was promoted strongly by the compounds of sweat and high temperature unlike that of other cutaneous Malassezia species. This result clarified that M. globosa tended to grow actively in summer conditions more than other cutaneous Malassezia species. Furthermore, M. globosa showed high lipase activity. We consider these characteristics of M. globosa to relate to the pathogenesis of MF.

Increased hydrophobicity in Malassezia species correlates with increased proinflammatory cytokine expression in human keratinocytes

Malassezia cells stimulate cytokine production by keratinocytes, although this ability differs among Malassezia species for unknown reasons. The aim of this study was to clarify the factors determining the ability to induce cytokine production by human keratinocytes in response to Malassezia species. M. furfur NBRC 0656, M. sympodialis CBS 7222, M. dermatis JCM 11348, M. globosa CBS 7966, M. restricta CBS 7877, and three strains each of M. globosa, M. restricta, M. dermatis, M. sympodialis, and M. furfur maintained under various culture conditions were used. Normal human epidermal keratinocytes (NHEKs) (1 × 10(5) cells) and the Malassezia species (1 × 10(6) cells) were co-cultured, and IL-1α, IL-6, and IL-8 mRNA levels were determined. Moreover, the hydrophobicity and β-1,3-glucan expression at the surface of Malassezia cells were analyzed. The ability of Malassezia cells to trigger the mRNA expression of proinflammatory cytokines in NHEKs differed with the species and conditions and was dependent upon the hydrophobicity of Malassezia cells not β-1,3-glucan expression.

Cutaneous Malassezia microbiota in atopic dermatitis patients differ by gender and body part.

Background:Malassezia is a particularly important factor in the occurrence of atopic dermatitis (AD).Aim: The aim of this study was to quantitatively clarify the Malassezia species isolated from AD patients by gender, body part and analytical method in detail. Methods: The subjects were 20 AD males and 47 AD females. Samples were collected from lesion and nonlesion areas on the face and upper trunk of AD patients. Malassezia DNA was analyzed using a real-time PCR system. Results: The cutaneous Malassezia microbiota in AD patients differed by gender, body part and analytical method. Conclusions: The present results indicate the possibility that the influence of Malassezia antigens is different according to gender and body part.

Microorganisms inhabiting follicular contents of facial acne are not only Propionibacterium but also Malassezia spp.

To clarify the relationship between major cutaneous microorganisms (Propionibacterium, Staphylococcus and Malassezia spp.) and acne vulgaris (acne), we examined the microbiota quantitatively in the follicular contents of inflammatory acne and on the facial skin of patients with acne. Fifteen Japanese untreated acne outpatients were studied. The follicular contents from inflammatory acne lesions of the face were collected using a comedo extractor. The skin surface samples were obtained by the swab method from 10 cm2 of facial skin. The microbiota was analyzed using polymerase chain reaction. The microbiota in follicular contents was similar to that on the skin surface, namely, there were large populations of Propionibacterium spp., Staphylococcus spp. and Malassezia spp. Moreover, the number of Malassezia spp. on the skin surface was correlated with that of inflammatory acne and that in follicular contents. This study clarified that there are large populations of Propionibacterium spp., Staphylococcus spp. and Malassezia spp. in follicular contents. These results suggest the possibility that not only Propionibacterium acnes but also other cutaneous resident microorganisms are related to acne. Particularly, we considered that Malassezia spp. is closely related.

Quantitative effect of face washing on cutaneous resident microbiota in female subjects who wear make-up.

include staphylococcal furunculosis, pyoderma, leishmaniasis, dracunculiasis, actinomycosis, tungiasis and herpes zoster. The diagnostic clinical feature is a nodule with a small central punctum. The larvae’s 1–3-mm thread-like posterior respiratory spiracle protrudes to maintain contact with the air and may withdraw when touched. Recent travel history should be elicited with emphasis on endemic areas. Goals of therapy are removal of larvae and treatment of any associated infection. After removal of the larvae, the lesions typically heal quickly as seen with our patient. Rare complications resulting from incomplete extraction of the larvae include cellulitis, abscess formation, osteomyelitis and tetanus. Rarely, deeper myiasis infections of the striated muscles and even bone may cause tissue destruction. Removal of larvae with hemostat, forceps or by manual pressure is often curative. Injection into the furuncle with lidocaine or pilocarpine to paralyze the worm may ease larval extraction. Larvae may also be suffocated by obstructing the cutaneous orifice with substances such as oil, petroleum jelly and liquid paraffin. Limiting the oxygen supply induces the larvae to migrate to the surface through the central punctum. Larvae in deeper tissues can also be induced to migrate by applying turpentinesoaked gauze over the lesions and by use of systemic antihelminthics. All patients should receive tetanus prophylaxis, and antibiotics are appropriate if bacterial infection is suspected. Physicians may aid patient awareness of ectoparasitic infestations associated with international travel to endemic regions by teaching patients simple preventive strategies. Patient education about C. anthropophaga myiasis should emphasize thorough washing of clothes, drying garments on a clothesline located in the bright sunshine or in a house with closed windows, and ironing of clothes on both sides.

Normal human epidermal keratinocytes react differently than HaCaT keratinocyte cell line on exposure to Propionibacterium acnes

1 Samuelsson B. Leukotrienes: mediators of immediate hypersensitivity reactions and inflammation. Science (New York, NY) 1983; 220: 568–575. 2 Lynch KR, O’Neill GP, Liu Q et al. Characterization of the human cysteinyl leukotriene CysLT1 receptor. Nature 1999; 399: 789–793. 3 Sansom JE, Taylor GW, Dollery CT, Archer CB. Urinary leukotriene E4 levels in patients with atopic dermatitis. Br J Dermatol 1997; 136: 790–791. 4 James JM, Kagey-Sobotka A, Sampson HA. Patients with severe atopic dermatitis have activated circulating basophils.J Allergy Clin Immunol 1993; 91: 1155–1162. 5 Pillai SG, Cousens DJ, Barnes AA et al. A coding polymorphism in the CYSLT2 receptor with reduced affinity to LTD4 is associated with asthma. Pharmacogenetics 2004; 14: 627–633. 6 Thompson MD, Storm van’s Gravesande K, Galczenski H et al. A cysteinyl leukotriene 2 receptor variant is associated with atopy in the population of Tristan da Cunha. Pharmacogenetics 2003; 13: 641–649. 7 Fukai H, Ogasawara Y, Migita O et al. Association between a polymorphism in cysteinyl leukotriene receptor 2 on chromosome 13q14 and atopic asthma. Pharmacogenetics 2004; 14: 683–690. 8 Fauler J, Neumann C, Tsikas D, Frolich J. Enhanced synthesis of cysteinyl leukotrienes in psoriasis. J Invest Dermatol 1992; 99: 8–11. 9 Hussain I, Kitagaki K, Businga TR, Kline JN. Expression of cysteinyl leukotriene receptor-1 in skin. J Am Acad Dermatol 2004; 51: 1032–1033. 10 Yanase DJ, David-Bajar K. The leukotriene antagonist montelukast as a therapeutic agent for atopic dermatitis. J Am Acad Dermatol 2001; 44: 89– 93.