Isolates of Exophiala jeanselmei have been classified into 15 types based on their mitochondrial DNA (mtDNA). Thirteen of the 15 types and E. spinifera, which has been classified as E. jeanselmei Type 14, were confirmed...Isolates of Exophiala jeanselmei have been classified into 15 types based on their mitochondrial DNA (mtDNA). Thirteen of the 15 types and E. spinifera, which has been classified as E. jeanselmei Type 14, were confirmed to be also clearly differentiated by restriction fragment length polymorphism (RFLP) in internal transcribed spacer (ITS) regions of ribosomal RNA genes in their nuclear DNA (nDNA). Twenty strains of E. jeanselmei, newly identified or isolated from patients in Japan, were examined for mtDNA-RFLP and ITS-RFLP. The twenty isolates were comprised of: 11 E. jeanselmei Type 5, 6 E. jeanselmei Type 6, 2 Type 10, and 1 Type 8. E. jeanselmei Type 6 was the second most common strain in Japan after Type 5. Type 5 was definitely identified as E. jeanselmei var. jeanselmei and Type 8 was identified as E. jeanselmei var. lecanii-corni based on the genotypes of type strains of these species. However, two other types were still designated as E. jeanselmei Type 6 and E. jeanselmei Type 10.
ABC (ATP binding cassette) transporters consist of transmembrane domains which confer specificity, and structurally conserved nucleotide binding domains that contain highly conserved amino acid motifs. They act not only...ABC (ATP binding cassette) transporters consist of transmembrane domains which confer specificity, and structurally conserved nucleotide binding domains that contain highly conserved amino acid motifs. They act not only as transporters but also as receptors or channels that use energy generated by ATP hydrolysis. ABC transporters are widely dispersed in nature. They are found in cells ranging from prokaryotes (bacteria) to eukaryotes (including humans) and several are considered to play crucial roles in cellular homeostasis. Defects in ABC transporters in humans are associated with severe diseases such as type 2 diabetes and cystic fibrosis. Some ABC transporters extrude xenobiotics and confer resistance to chemotherapeutics on microbial pathogens and cancer cells. Thus ABC transporters are of considerable medical importance. Structure-function analysis of ABC transporters has begun to elucidate their mechanisms of substrate recognition, the functional regulation of ATP-binding and hydrolysis and to identify intrinsic physiological functions. In pathogenic fungi, ABC transporters contribute to the clinical problem of drug resistance. The application of new technologies to the examination of fungal ABC transporter function is providing new insights into the use of antifungal drugs in medical mycology and contributing to a better understanding of these important membrane proteins.
Respiration-deficient (petite) mutation is caused by hereditary impairment in mitochondrial functions. Yeasts have been grouped into "petite-positive" and "petite-negative" yeasts. Candida albicans has been regarded as a...Respiration-deficient (petite) mutation is caused by hereditary impairment in mitochondrial functions. Yeasts have been grouped into "petite-positive" and "petite-negative" yeasts. Candida albicans has been regarded as a member of the petite-negative yeasts in which the respiration deficiency cannot be easily induced. We have succeeded in inducing the petite mutation in C. albicans by culturing in the presence of a chemical mutagen, acriflavine, at an elevated temperature. In the present review, we describe the cell biology of C. albicans petite mutants on the basis of experiments performed by our research group: namely, on respiratory activity and cytochrome composition, fine structures of cells and mitochondria, mitochondrial DNA structure, pathogenicity, oxidative stress sensitivity, generation of reactive oxygen species (ROS) and the roles of ROS in antifungal actions. We discuss also the usefulness of petite mutants in Candida research.
Candida albicans is the most common fungal opportunistic pathogen in humans. The AIDS epidemic, improved life-sustaining therapy, and aggressive anticancer therapy have contributed to a rise in the number of severely imm...Candida albicans is the most common fungal opportunistic pathogen in humans. The AIDS epidemic, improved life-sustaining therapy, and aggressive anticancer therapy have contributed to a rise in the number of severely immunocompromised patients. This has led to an increase in oral and systemic fungal infection. Several factors, such as adherence, persistence, dimorphism, germ tube formation, and/or contact sensing, phenotypic switching, interference with the host defense system, synergism with bacteria, and the production of hydrolases or other metabolites, have been proposed to be virulence factors of this fungus. Among these virulence factors, adherence and persistence are thought to be the most important, since the colonization and subsequent biofilm formation of oral surfaces may serve as a reservoir for disseminated infections, such as aspiration pneumonia and gastrointestinal infection. In the review, we summarized the factors involved in the Candida albicans biofilm formation.
Liposomal amphotericin B (AmBisome) is a DDS (drug delivery system) formulation of amphotericin B (AMPH-B), and has been developed in an attempt to reduce the toxicity of AMPH-B while retaining its therapeutic efficacy....Liposomal amphotericin B (AmBisome) is a DDS (drug delivery system) formulation of amphotericin B (AMPH-B), and has been developed in an attempt to reduce the toxicity of AMPH-B while retaining its therapeutic efficacy. AMPH-B has been the "gold standard" of antifungal therapy over the past four decades. It has a broad spectrum of fungicidal activity against a number of clinically important pathogens including Aspergillus and Candida. The mechanism of action of AMPH-B involves binding to ergosterol, the principal sterol in fungal cell membranes. Binding to ergosterol causes an increase in fungal membrane permeability, electrolyte leakage, and cell death. AMPH-B has affinity for cholesterol in mammalian membranes, which leads to severe side-effects including kidney damage. AmBisome is a unilamellar vesicle composed of AMPH-B and phospholipid. Upon administration, AmBisome remains intact in the blood and distributes to the tissues where fungal infection may occur, and is disrupted after attachment to the outside of fungal cells, resulting in fungal cell death. AmBisome and AMPH-B show similar in vitro and in vivo antifungal activity and clinical efficacy. However, AmBisome has less infusion-related toxicity and nephrotoxicity than AMPH-B.
Voriconazole (VRCZ) is an azole-class antifungal agent with a broad spectrum. VRCZ shows high antifungal activity to Candida spp. including fluconazole less-susceptible species., Aspergillus spp. and Cryptococcus spp. VR...Voriconazole (VRCZ) is an azole-class antifungal agent with a broad spectrum. VRCZ shows high antifungal activity to Candida spp. including fluconazole less-susceptible species., Aspergillus spp. and Cryptococcus spp. VRCZ shows fungicidal activity to Aspergillus spp. In addition, voriconazole shows activity to rare pathogens like Fusarium spp. or Scedosporium spp. VRCZ is available in both IV and oral formulation. The oral formulation shows stable and almost 100% bioavailability. The protein binding ratio is approximately 58% and over 40% exists as unbound form. VRCZ shows a good tissue distribution including brain and CSF. Outside Japan, several RCTs were conducted for the treatment of deep seated mycosis. The results show a very good drug profile superior to the existing antifungal agents. VRCZ was approved by the FDA and EMEA in 2002. As of September 2004, it has been approved in over 50 countries worldwide.
Micafungin (MCFG) is a new lipopeptide antifungal agent of the echinocandin class. MCFG inhibits 1,3-beta-D-glucan synthesis in C. albicans and A. fumigatus in a non-competitive manner, and has antifungal activity agains...Micafungin (MCFG) is a new lipopeptide antifungal agent of the echinocandin class. MCFG inhibits 1,3-beta-D-glucan synthesis in C. albicans and A. fumigatus in a non-competitive manner, and has antifungal activity against both Aspergillus and Candida species. In neutropenic mouse models of disseminated candidiasis and pulmonary aspergillosis, the efficacy of MCFG was superior to that of fluconazole and itraconazole, but comparable to that of amphotericin B. The efficacy and safety of MCFG were investigated in 70 patients with deep-seated mycosis caused by Candida and Aspergillus species. The overall clinical response rates were 57.1% in aspergillosis and 78.6% in candidiasis. The incidence of adverse events related to micafungin was 17.9%, and there was no dose-related occurrence of any adverse events. The results from this study indicated that micafungin was effective in aspergillosis and candidiasis, with no tolerability problems.
The aim of this study was to investigate the susceptibility of the different phenotypes of Candida albicans strains isolated from clinical specimens to three antifungal agents, fluconazole, itraconazole and voriconazole....The aim of this study was to investigate the susceptibility of the different phenotypes of Candida albicans strains isolated from clinical specimens to three antifungal agents, fluconazole, itraconazole and voriconazole. Totally 215 specimens were collected from oropharyngeal, gastrointestinal and urogenital tracts of non-neutropenic patients who had received no previous prophylactic treatment. Each of the 215 C. albicans strains recovered was found to express one of the six phenotypes: smooth 73%, fuzzy 10.7%, irregular 2.3%, star 2.8%, ring 6% or stipple 5.1%. The mean MICs for the six phenotypes of C. albicans strains ranged between 0.25 microg/ml and 64 microg/ml for fluconazole, 0.03 microg/ml and 1 microg/ml for itraconazole and 0.03 microg/ml and 0.5 microg/ml for voriconazole. The mean minimum inhibitory concentration (MIC) of fluconazole was consistently higher for C. albicans strains expressing the stipple phenotype. The antifungal susceptibility of the phenotypic switching requires attention, especially in patients who are clinically unresponsive to fluconazole chemotherapy or in cases of serious C. albicans infections of immunocompromised hosts.
Malassezia spp. which normally colonize on the skin surface, are known as being either the cause or an exacerbating factor in a variety of skin conditions, including pityriasis versicolor, folliculitis, seborrheic dermat...Malassezia spp. which normally colonize on the skin surface, are known as being either the cause or an exacerbating factor in a variety of skin conditions, including pityriasis versicolor, folliculitis, seborrheic dermatitis and atopic dermatitis. We report here three cases of Akatsuki disease (pomade crust). Scales and crusts were collected from the lesional skin and analyzed using a PCR-based non-culture method. Malassezia microflora in Akatsuki disease was compared to that of healthy subjects and atopic dermatitis patients. Samples were collected from upper and lower eyelids (Case 1), an operation scar (Case 2) and parietal scalp (Case 3). DNA was extracted from the scales and nested PCR was performed using specific primers for each species. Our analysis detected only M. obtusa and M. slooffiae in Cases 1 and 3 and only M. slooffiae in Case 2. Our previous data indicated that while M. globosa, M. restricta and M. sympodialis were common in healthy subjects, the two aforementioned species were rare, suggesting that the presence of M. obtusa and M. slooffiae in the subjects in the present study is correlated to the pathogenesis of Akatsuki disease.
A safe method is described for observing ultrastructure of highly infectious fungi by ultrathin sectioning electron microscopy. The fungal cells were first chemically fixed by glutaraldehyde to kill them. They were then...A safe method is described for observing ultrastructure of highly infectious fungi by ultrathin sectioning electron microscopy. The fungal cells were first chemically fixed by glutaraldehyde to kill them. They were then rapidly frozen by propane slush in liquid nitrogen and freeze-substituted in acetone containing 2% osmium tetroxide. This method gave clear cell images with high resolution in a natural state, close to the image obtained by rapidly frozen freeze-substituted specimen of living cells. Although we have demonstrated the utility of this method using Exophiala dermatitidis and Cryptococcus neoformans, it could also be used for observing highly infectious fungi such as Coccidioides immitis.
Alternaria is a saprophytic fungus that naturally subsists on decaying plant materials, but may be an opportunistic pathogen in immunocompromised hosts. We describe a case of dermal cutaneous alternariosis in a 70-year-o...Alternaria is a saprophytic fungus that naturally subsists on decaying plant materials, but may be an opportunistic pathogen in immunocompromised hosts. We describe a case of dermal cutaneous alternariosis in a 70-year-old patient, who was on systemic steroid administration for autoimmune hemolytic anemia. The patient also had chronic heart failure, liver dysfunction, and diabetes mellitus. Infection was confirmed by histological examination, and multiple positive culture results. Treatment with oral terbinafine and itraconazole was ineffective. We review the literature of dermal cutaneous alternariosis reported in Japan; including our case, 15 cases have been reported. Recognition of Alternaria as a potential opportunistic pathogen is important for the differential diagnosis of dermatologic lesion, such as granulomatous lesion or ulcer, in immunocompromised hosts.
UNLABELLED: We report the efficacy of miconazole nitrate shampoo (Furfur Shampoo) to prevent T. tonsurans infection. METHOD: Experimental models were made from stratum corneum of healthy human heel or guinea pig skin. Be...UNLABELLED: We report the efficacy of miconazole nitrate shampoo (Furfur Shampoo) to prevent T. tonsurans infection. METHOD: Experimental models were made from stratum corneum of healthy human heel or guinea pig skin. Before and/or after T. tonsurans was applied, samples were washed with miconazole nitrate shampoo, then inoculated on a Sabouraud culture plate. RESULT: Though miconazole nitrate shampoo did not eliminate T. tonsurans on the sample completely, the time required to develop the colony (9.9 days) was obviously extended (7.7 days by control). DISCUSSION: We concluded that miconazole nitrate shampoo is a useful method of preventing T. tonsurans infection, and should be used every day (before/after the chance to infect).
In terms of both diagnosis and treatment, onychomycosis remains a problem in Indonesia. To examine this situation, we performed a retrospective study of the incidence of onychomycosis involving 10 state university hospit...In terms of both diagnosis and treatment, onychomycosis remains a problem in Indonesia. To examine this situation, we performed a retrospective study of the incidence of onychomycosis involving 10 state university hospitals across the country. We collected data from medical records of patients treated at these hospitals in 1997-1998 (study 1) and from a 1998-1999 multi-center Indonesian study on pulse-dose itraconazole therapy (study 2), both of which were part of onychomycosis campaigns with the objective of increasing the awareness of physicians of onychomycotic problems. Further, we analyzed data from year 2003 medical records of patients from 4 hospitals in Java (study 3). The average incidence of onychomycosis among fungal diseases increased to 4.7% in large cities that, from an average incidence within Indonesia of 3.5% in 1997-1998. At only 0.5%, the incidence of onychomycosis among all skin diseases was low in both study 1 and 3. Female patients outnumbered male patients with a ratio of 1.5:1 to 2:1. In study 2, the fingernail was the site most frequently affected. KOH examinations and fungal culture in study 1 (n=557) showed causative organisms to be Candida (50.1%), dermatophytes (26.2%), moulds (3.1%) and mixed infections (1.8%), with the remainder (18.7%) unidentified. Similar frequency of causative organisms was reported in study 2 (n=113) and in study 3 (n=183). People's low awareness of nail disease and consequent lack of concern as well as the limited diagnostic ability of KOH examination and fungal culture might influence the low incidence of the disease and the frequency of detection of the causative organisms.
Pityriasis versicolor (PV) is a superficial infection of the stratum corneum caused by Malassezia. Eleven species have been recognized within this genus, namely M. globosa, M. restricta, M. sympodiasis, M. furfur, M. obt...Pityriasis versicolor (PV) is a superficial infection of the stratum corneum caused by Malassezia. Eleven species have been recognized within this genus, namely M. globosa, M. restricta, M. sympodiasis, M. furfur, M. obtusa, M. slooffiae, M. pachydermatis, M. dermatis, M. japonica, M. yamatoensis, M. nana. To examine the distribution of the microorganism in the skin of patients with PV, we detected Malassezia species without M. pachydermatis and M. nana using a non-culture-based method that consisted of nested PCR with specific primers. The most frequently isolated species were M. globosa and M. restricta (both 93.9%). M. globosa was detected in scales in which only the mycelial form (yeast cells, < 10/sample) were observed microscopically; M. restricta was not found. We suggest that M. globosa is the causative agent of PV.
Malassezia species, organisms normally colonizing the skin surface, are thought to play a role as either the cause or an exacerbating factor in a number of skin conditions, including pityriasis versicolor, Malassezia fol...Malassezia species, organisms normally colonizing the skin surface, are thought to play a role as either the cause or an exacerbating factor in a number of skin conditions, including pityriasis versicolor, Malassezia folliculitis, seborrheic dermatitis (SD) and atopic dermatitis (AD). Using a non-cultural PCR method, we analyzed Malassezia spp. extracted from the skin surface of SD and AD patients. The species most commonly detected in both patient groups were M. globosa and M. restricta, and the number of Malassezia spp. In these patients was higher than in healthy subjects. After a topical application of 2% ketoconazole cream, changes in the population of Malassezia spp. in 20 intractable cases of AD were recorded. The addition of the 2% ketoconazole cream to the standard topical treatments was found to have reduced the Malassezia spp. population by 90%, and showed a clinical efficacy rate of 70%. Furthermore, a combination of azole agents and tacrolimus produced a synergistic anti-fungal effect against Malassezia spp. in vitro. A clinical trial using this drug combination conducted on the face and neck of patients with intractable AD showed a 66.6% efficacy rate in both the reduction of the flora and in clinical improvement. From these results it was evident that Malassezia is one of the factors exacerbating AD, and that removal of the organism results in an improvement in the clinical condition of the patient.
Malassezia species have been recognized as members of the microbiological flora of human and animal skin; they are also considered to play an important role in the pathogenesis of folliculitis, atopic dermatitis and otit...Malassezia species have been recognized as members of the microbiological flora of human and animal skin; they are also considered to play an important role in the pathogenesis of folliculitis, atopic dermatitis and otitis externa. Therefore, the molecular characteristics were investigated to clarify the epidemiology and the pathogenesis of diseases associated with Malassezia species in human and animals. Molecular investigation was made of 105 clinical isolates of M. pachydermatis from dogs and cats by random amplification of polymorphic DNA (RAPD) and chitin synthase 2 (CHS2) gene sequence analyses. The RAPD analysis and CHS2 gene analysis indicated that clinical isolates of M. pachydermatis were divided into four distinct genetic types (A, B, C and D). Type A was isolated from lesions of atopic dermatitis, flea allergic dermatitis, otitis externa, pyoderma and seborrheic (dermatitidis) in dogs and cats, and might be predominant on this. The phylogenetic analysis of the nucleotide sequences of CHS2 gene fragments of standard strains of 11 Malassezia species showed 11 distinct clusters of this species.
Mitochondrial cytochrome b genes of pathogenic yeasts and fungi were analyzed for identification and phylogenetic relationship. The species of genus Malassezia also were analyzed and each sequence was specific in the sam...Mitochondrial cytochrome b genes of pathogenic yeasts and fungi were analyzed for identification and phylogenetic relationship. The species of genus Malassezia also were analyzed and each sequence was specific in the same domain of cytochrome b gene. Some species represented intraspecies variation. The structure and function of cytochrome b protein was retained and its substitution rates may be in proportion to the evolutionary period. The deduced amino acid sequence was encoded by each nucleotide sequence of cytochrome b gene, and the phylogenetic tree of eukaryote and basidiomycetous yeast was obtained using this sequence. The species of genus Malassezia formed one cluster in this tree, meaning that the concepts of this genus reflect its evolution. The mitochondrial cytochrome b gene analysis was valuable for the identification and phylogenetic analysis of the genus.
Malassezia species are associated with pityriasis (tinea) versicolor, seborrheic dermatitis, and atopic dermatitis. Presently, eleven species are accepted in the genus Malassezia. Of these, M. globosa and M. restricta co...Malassezia species are associated with pityriasis (tinea) versicolor, seborrheic dermatitis, and atopic dermatitis. Presently, eleven species are accepted in the genus Malassezia. Of these, M. globosa and M. restricta colonize the skin surface in atopic dermatitis patients, suggesting that they play a significant role in exacerbating the condition. The two species have different genotypes in the intergenic spacer (IGS) region of the rRNA gene, which correspond to patients and healthy individuals. In addition, the antifungal susceptibilities of the genotypic strains to itraconazole and ketoconazole differ. We found a new analytically significant role of the rRNA gene in Malassezia species, in addition to its use for fungal taxonomy and identification.