The article describs various features of aspergillosis and a discussed the role of calatases produced by Aspergillus fumigatus during infection. Since a large body of invasive Aspergillus infection occurs as an opportunistic infection in variously impaired defense mechanisms, there is a wide spectrum of histopathological features of lesions demonstrated at the site of infection. Accordingly, histopathology of the lesions can be understood as a phenotypical representation of interaction between differently impaired functions of neutrophils and macrophages and virulence factors of invading Aspergilli. Consideration of previous pathological knowledge regarding infection and inflammation provides much important information to predict the pathophysiology of a patient. Meanwhile, detoxification of hydrogen peroxide by catalases has been proposed as a way to overcome this host response. A. fumigatus produces three active catalases, one from conidia and two from mycelia. CatAp, a spore specific monofunctional catalase, is resistant to heat and metal ions. In spite of their increased sensitivity to H₂O₂, killing of catA conidia by alveolar macrophages, virulence in animals was similar to wild type conidia. In contrast to mycelial Cat1p, and CatAp catalases, the mycelial Cat2p is a bifunctional catalase-peroxidase enzyme and is also sensitive to heat, metal ions and detergent. Surprisingly, the mycelium of the double cat1 cat2 mutant with no catalase activity has only a slightly increased sensitivity to H₂O₂ and was as sensitive to the killing of polymorphonuclear neutrophils as the wild type strain. However, it showed a delayed infection in the rat model of aspergillosis compared to the wild type strain. Consequently, it should be emphasized that conidial catalase is not a virulence factor but that mycelial catalases transiently protect the fungus from the host defence reactions.

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In Cryptococcus neoformans the DNA content of cells having tiny buds varied rather widely, depending on growth phases and strains used. Typically, buds of C. neoformans emerged soon after initiation of DNA synthesis in the early exponential phase. However, bud emergence was delayed to G₂ during transition to the stationary phase, and in the early stationary phase budding scarcely occurred, although roughly half of the cells completed DNA synthesis. The timing of budding in C. neoformans was shifted to later cell cycle points with progression of the growth phase of the culture. Similarly, a deficit in oxygen was demonstrated to delay the timing of budding, prolong the G₂ phase and cause accumulation of cells after DNA synthesis, but before commitment to budding.
The C. neoformans homologue of the main cell cycle control gene CDC28/Cdc2 was isolated using degenerate RT-PCR. The full-length coding region was then amplified using primers to target the regions around the start and stop codons. The gene was called CnCdk1 and was found to have high homologies to S. cerevisiae CDC28 and S. pombe cdc2. To determine its function, its ability to rescue S. cerevisiae cdc28-temperature sensitive mutants was tested. S. cerevisiae cdc28-4 and cdc28-1N strains transformed with the pYES2-CnCdk1 construct exhibited growth at the restrictive temperature. Results of the sequence analysis and the ability of CnCdk1 to complement the S. cerevisiae cdc28-ts mutations support its assumed role as the CDC28/cdc2 homologue in C. neoformans.

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The bacterial behavior system controlled by the cell density is described as quorum-sensing. The system is triggered via autoinducers. Various kinds of autoinducers have been identified from different bacteria. Quorum-sensing signals via autoinducers are involved in regulation of important virulences such as exotoxin, protease, and pigment production. Therefore, this system in pathogenic bacteria has a critical role in the regulation of bacterial pathogenicity.
In the pathogenic fungus Candida albicans, an extracellular quorum-sensing molecule that regulates hyphal formation by this organism has been identified in recent years. Candida albicans has been shown to form biofilm on many medical devices, therefore quorum-sensing in this organism has been especially focused on from the aspect of biofilm formation.

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An important point in the development of an antimicrobial agent is whether its target molecules are essential for growth of the microorganism. From this viewpoint, we focused attention on essential genes as potential targets of antifungal agents in the pathogenic yeast Candida. Here we introduce recent attempts for screening, identification, and characterization of essential genes from a haploid yeast Candida glabrata, using temperature-sensitive mutants. Our experimental results suggesting the essentiality of C. albicans PHO85, the homologue of which is known as a negative regulator of the PHO system and as a non-essential gene in Saccharomyces cerevisiae are also described.

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Membrane-located drug transporters are important components in the multidrug resistance of microbial cells and human tissues. In fungi, clinically important resistance to antifungal drugs most often results from the over-expression of efflux pump proteins in the plasma membrane of the resistant cell. This review describes studies of the ATP binding cassette (ABC) family of membrane efflux pumps in the opportunistic human pathogen Candida albicans and, in particular, examines how changes in the polypeptide sequence can affect pump function. The identification of amino acid residues affecting pump function can provide new insights into efflux pump mechanisms and the relationship between structure and function. Such information will be important for the design of pump inhibitors which could supplement existing antifungal drugs.

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Deep-seated Candida infections and invasive aspergilloma are becoming a serious problem for individuals who need intensive care. The laboratory diagnosis of such infections is sometimes delayed due to relatively slow growth of these yeasts from clinical specimens. Several studies seem to indicate that early detection of deep-seated and invasive fungal infections is possible using genomic amplification methods. In the present study, we used a novel PCR assay that can assay five clinically common species (C. albicans, C. parapsilosis, C. tropicalis, C. glablata, and A. fumigatus) simultaneously. We evaluated the utility of this PCR based diagnosis with seven patients with candidiases.
This assay is more sensitive than the culture result in 26 clinical samples. (χ²=5.16, p<0.05) In the clinical course of each patient, the number of detected fungal species gradually increased. More than two species were detected from single or several clinical specimens, and these patients would die within 14 days compared with the 61 day period individuals with zero or one species would live. (p<0.005) Before super infections of fungus, an antifungal drug could be applied to a suspected patient in the ICU.
To improve sensitivity of this diagnosis from blood samples, we evaluated them after one day incubation at 34°C. We found a PCR product in 10 of 20 blood samples taken from five children after bone marrow transplantation. One of four negative samples became positive after more than 48 hours of incubation.

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Although the opportunity to discuss infectious complications in solid organ transplantation is increasing in Japan as elsewhere, the length of clinical experience in extra-renal transplantation is still short and even experience in living donor organ transplant is very limited except for those involving the kidney or liver transplantation. Risk of invasive fungal infection in organ transplant recipients is highly dependent on the immunocompromised status accompanying end-stage organ failure before transplant operation and on the resultant history of infectious complications. These factors as well as surgical and postoperative should be incorporated in a systematic and dynamic manner to evaluate risk of invasive fungal infection. In addition to prophylactic management based on such risk evaluation, it is desirable that preemptive treatment be started on quantification of clinical symptoms, imaging diagnosis, screening culture, and serological indices. Emergence of newer and more potent antifungal agents with lower toxicity potentially changes the concept of antifungal treatment. On the other hand, early and impression-oriented preemptive treatment has tended to increase. It is still questionable whether the knowledge obtained from Western experience can be directly applied to solid organ transplant medicine in Japan. Extensive and detailed clinical experience is mandatory to pursue diagnosis, epidemiology, and risk factors in Japan and establish our criteria for prophylactic and preemptive use of antifungal agents.

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The clinical effects and tolerability of micafungin sodium in daily practice for the treatment of fungal infection in critically ill patients were evaluated in an open-labeled, non-comparative, observational study. All patients admitted to intensive care units (ICUs) of 3 hospitals in Chiba prefecture between June 2003 and March 2005, who were treated with micafungin because of known or suspected fungal infection, were included in the study. A total of 34 patients received micafungin and 29 cases of them were subjected to analysis. Fungal infections were classified as “proven” in 3 patients (10.3%) and “possible” in 26 (89.7%). Candida was detected in 16 patients, most of them were Candida albicans and 4 cases were non-albicans Candida. Clinical effects of micafungin were “cured” and “improved” in 20 patients (77%), “failure” in 6 (23%), and “undetermined” in 3 cases. Adverse events were reported in 10 patients, but there was no significant event. In conclusion, micafungin was effective in 77% of proven or suspected fungal infections in critically ill patients admitted to the ICU. The drug was well tolerated and discontinuation of its treatment due to adverse events was not experienced during the study period.

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To determine drug susceptibility of Trichophyton tonsurans endemic in Japan, in vitro MICs of antifungal drugs against a total of 10 clinical isolates of T. tonsurans collected from dermatophytosis patients were measured by the agar dilution method and the broth microdilution method. The agar dilution method was not appropriate as the growth of T. tonsurans on the agar medium was too slow to determine drug activity, while the broth microdilution method was thought to be an appropriate method for this study. The MIC₉₀ values determined by the broth microdilution method for terbinafine, itraconazole, miconazole and ketoconazole were 0.013, 0.1, 0.8 and 0.4 μg/ml, respectively. Meanwhile, the MIC₉₀ values of lanoconazole and luliconazole, known to be antifungal drugs potent against dermatomycosis, were 0.00078 and 0.00039 μg/ml, respectively. The drug susceptibility of these T. tonsurans isolates to the aforementioned antifungal drugs was found to be on a similar level with that of T. mentagrophytes and T. rubrum, major causative agents of dermatomycosis. The results also demonstrated the strong antifungal activity of lanoconazole and luliconazole against T. tonsurans.

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Fonsecaea pedrosoi, a dematiaceous fungus and the main causative agent of chromoblastomycosis, has been isolated in worldwide from different natural sources in regions where the disease is endemic. In the Amazon region of Maranhão, Brazil, where the disease is prevalent, the breaking of the babassu coconut (Orbignya phalerata Martius) represents an important agricultural activity. In order to determine the presence of this fungus on this plant and on other natural substrates, material was collected in the Fortaleza Village Municipality of Pinheiro, Maranhão, in April and September 2002. A total of 68 samples, including 18 (26.5%) obtained from the shell of the babassu coconut, were analyzed. Samples were cultured using a standard method. Isolates were identified based on macromorphological aspects of the colonies on Sabouraud dextrose agar and based on the micromorphology of the conidia after growth on potato dextrose agar. Exophiala sp. was the most prevalent fungus isolated from the different natural substrates analyzed, while Cladophialophora sp. was only isolated from decomposing wood. Fonsecaea pedrosoi was isolated from one sample of babassu coconut shell suggesting that this coconut represents an important source of infection of chromoblastomycosis during extraction of the plant product in this region.

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Dimethyl sulfoxide (DMSO) is frequently used as a solvent for antifungal drugs in various studies to determine their MICs. Reports on comparative evaluation of methods for the susceptibility testing of antifungal drugs have shown there is poor agreement among methods. Besides other factors which could cause variability in the results, one important factor might be the effect of DMSO on the growth of fungi. The effect of DMSO on the growth of some species of Candida has been reported in the literature. The present study aimed at determination of the effect of different concentrations of DMSO (0.125 to 10%) on the growth of dermatophytes by agar diffusion method. There was no growth of fungi in 10% DMSO, between 1.25 and 5% there was a rather linear dose-related inhibitory effect on the growth, significantly different from the controls, and below 1% there was a variable effect among the species. DMSO down to 0.25% significantly inhibited the growth of most strains of M. canis. The lower concentrations of DMSO, which apparently do not affect the growth of fungi, may potentiate the effect of antifungal drugs.

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The spread of Trichophyton tonsurans infection among high school students and university undergraduates who practice Judo is an emerging problem in Japan and other countries. However, the extent of infection among Judo practitioners in junior high school in Japan is unknown. We conducted an epidemiological study of T. tonsurans infection among students who participated in the national junior high school Judo tournament in 2005. Of the 1,039 tournament participants invited to undergo screening, 496 (218 boys and 278 girls) consented, and 45 participants (9.1%) were found to be positive by hairbrush culture. We found the following to be relative risk factors for T. tonsurans infection: 1) male gender, 2) frequent judo practice in groups at either a high school or a dojo, 3) presence of tinea corporis in practice partners, 4) history of tinea corporis, 5) classification in lower-weight categories. 45 culture positive subjects were offered treatment and re-examined by hairbrush culture 3 months later. All twelve of them had negative cultures after miconazole shampoo treatment. A half of 12 subjects who had systemic antifungal therapy with itraconazole had positive culture. These observations suggest that T. tonsurans infection is rapidly spreading among junior high school Judo players in Japan. We speculate that the outbreak is caused, at least in part, by ignorance of the disease among Judo students, coaches and officials due to the high incidence of carriers and the mild or asymptomatic form of disease seen in infected individuals. Appropriate measures should be taken immediately to prevent more severe outbreak of this disease.

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