The first case of fingernail onychomycosis due to Neoscytalidium novaehollandiae, molecular identification and antifungal susceptibility

Onychomycosis is considered a fungal nail infection caused mainly by dermatophytes, yeasts and non-dermatophyte molds including dematiaceous fungi. Onychomycosis caused by non-dermatophyte molds is a health problem in the medical environment as the patients frequently return to outpatient clinics seeking new therapeutic modalities. Here, we report the first case of onychomycosis caused by a black fungus, Neoscytalidium novaehollandiae, in the right hand finger nail of a 52-year-old Iranian female with no history of immunodeficiency and underlying disease. The pattern of nail involvement was recognized as total dystrophic onychomycosis. Examination of nail scrapings with potassium hydroxide revealed brown, septate and branching sub-hyaline to dark-colored hyphae. The black fungus isolated in culture was identified as Neoscytalidium novaehollandiae by molecular analysis. The patient received oral terbinafine plus ciclopirox nail lacquer twice a week and began responding to the treatment three months after initial antifungal therapy. Additional four weeks' use of terbinafine plus ciclopirox nail lacquer completely resolved the clinical manifestations of onychomycosis. After four months, both microscopy and culture were negative.

Two cases of BRAF-mutated, bulbar conjunctival melanoma, and review of the published literature

We describe two patients with BRAF-mutated melanoma of the epithelioid cell type arising from primary acquired melanosis with severe atypia of the right bulbar conjunctiva. Patient 1 was a 71-year-old Japanese man. After adjuvant cryotherapy and enucleation of the right eyeball, therapy with vemurafenib was administered for a distant metastasis to a lumbar vertebra, accompanied by erythema multiforme and two keratinous tumours. The patient died due to metastases to the liver and multiple vertebrae, despite therapy with nivolumab and combination therapy with dabrafenib plus trametinib. Patient 2 was a 72-year-old Japanese man. After adjuvant cryotherapy, periodic mitomycin C eye drops, and excision of the superficial portion of the right parotid gland and the dissection of cervical lymph nodes, he was treated with adjuvant combination therapy with dabrafenib plus trametinib. Dermatologists should be familiar with BRAF-mutated conjunctival melanoma, which is usually located on the bulbar conjunctiva and associated with more frequent distant metastasis.

Mucormycosis in Iran: A six-year retrospective experience

Mucormycosis is a devastating infection caused by Mucoralean fungi (Mucormycotina, Mucorales). Data concerning the global epidemiology of mucormycosis are scarce and little is known about the characteristics of mucormycosis in Iran. In this study, we aimed to understand the distribution of this infection in Iran retrospectively and to ascertain whether the patterns of infection are associated with specific host factors or not. A total of 208 cases were included in this study occurring during 2008-2014 and were validated according to (EORTC/MSG) criteria. A rising trend as significant increase from 9.7% in 2008 to 23.7% in 2014 was observed. The majority of patients were female (51.4%) with median age of 50 and the infections were seen mostly in autumn season (39.4%). Diabetes mellitus (75.4%) was the most common underlying condition and sinus involvement (86%) was the mostly affected site of infection. Amphotericin B (AmB) was the drug of choice for the majority of cases. Sixty four isolates did not show any growth in the lab and only 21 cases were evaluated by ITS sequencing, among them; Rhizopus arrhizus var. arrhizus was the dominant species. Considering the high mortality rate of mucormycosis, early and accurate diagnosis, with the aid of molecular methods may provide accurate treatments and improve the survival rate. Therefore, increased monitoring and awareness of this life-threatening disease is critical.

The first case of onychomycosis in a koala (Phascolarctos cinereus) due to atypical isolates of Microsporum gypseum, a diagnostic challenge

Background and Purpose:

Superficial mycotic infections have been only poorly described in koalas and there are no reliable mycologically confirmed data regarding clinical isolation of dermatophytes in this animal. We report an 11-year-old female koala, kept in a zoo in Tokyo, Japan, and presenting with hyperkeratotic lesions and scaly plaques on forepaw claws and pads reminiscent of fungal infection.

Case Report:

Direct microscopy of the scrapings was indicative of a dermatophyte infection. By culture and subsequent repeated subculturing of clinical specimens on Sabouraud dextrose agar, Mycobiotic agar, and potato dextrose agar, two distinct strains with different colony morphotypes (designed as types I and II) were identified. Macroscopic and microscopic characteristics of the strains were suggestive of three different species, i.e. Microsporum canis, M. gypseum, and M. fulvum. However, partial sequencing of internal transcribed spacer (ITS) region of rDNA, translation elongation factor-1α (Tef-1α), and beta-tubulin (BT2) genes confirmed the identity of both isolates as M. gypseum. The animal was treated with a continuous terbinafine regimen (250 mg/kg) once daily for 12 weeks.

Conclusion:

To the best of our knowledge, the present report is the first confirmed case of dermatophytosis in a koala. The genetics underlying a variety of phenotypic traits in most classical dermatophyte species are unknown, and further studies are needed to understand this phenomenon.

Mycological Microscopic and Culture Examination of 400 Bronchoalveolar Lavage (BAL) Samples

BACKGROUND

The frequency of invasive opportunistic mycoses has increased significantly over the past decades especially in immunocompromised patients. Invasive aspergillosis (IA) has become a major cause of morbidity and mortality among these patients. As bronchoalveolar lavage (BAL) fluid samples are generally useful specimens in the diagnosis of invasive pulmonary aspergillosis (IPA), this study was designed to evaluate the incidence of fungal elements in at-risk patients by direct microscopy and culture of BAL samples.

METHODS

In a 16-month period, 400 BAL samples were obtained from several groups of different patients with pulmonary and respiratory disorders and examined by using both direct microscopy and culture.

RESULTS

Of the 400 samples, 16 (4%) were positive direct examination with branching septate hyphae and 46 (11.5%) were positive culture: 25 (54%) Aspergillus flavus, 6 (13%) A. fumigatus, 5 (10.9%) A. niger, 1 (2.2%) A. terreus, 3 (6.5%) Penicillium spp. and 6 (13%) mixed A. flavus/A. niger. A. flavus was the most common cause of Aspergillus infection or colonization. Bone marrow transplant (BMT) recipients were the most susceptible group to fungal infection and/or colonization.

CONCLUSION

Among Aspergillus species, A. flavus was the most common isolate in both infections and colonization in Iran. More studies are needed to clarify the epidemiological aspect of aspergillosis in Iran.

Use of Single-enzyme PCR-restriction Digestion Barcode Targeting the Internal Transcribed Spacers (ITS rDNA) to Identify Dermatophyte Species

BACKGROUND

Dermatophytes are the most common causative agents of superficial mycoses. Species identification of these fungi is important from therapeutic and epidemiological point of wive. Traditional approaches for identification of dermatophytes at the species level, relying on macroscopic and microscopic features of the colonies, usually are time-consuming and unreliable in many circumstances. Recently a broad varieties of rapid and accurate DNA-based techniques were successfuly utilized for species delineation of dermatophytes.

METHODS

The ITS1-5.8S-ITS2 region of rDNA from various reference strains of dermatophyte species were amplified using the universal fungal primers ITS1 and ITS4.The PCR products were digested by a single restriction enzyme, MvaI. The enzyme was evaluated in both in silico and practical PCR-RFLP assay to find the exact differentiating restriction profiles for each species. To validate the standardized PCR-RFLP system, all tested strains were subjected to sequencing and sequence analysis.

RESULTS

The obtained RFLP patterns were specific for many species including T. interdigitale, T. rubrum, T. violaceum, M. persicolor, M. audouinii, M. nanum (A. obtusum) and E. floccosum but were similar for some closely related species such as M. canis / M. ferrugineum. Sequencing of the ITS1-5.8S-ITS2 fragment from all type strains affirmed the RFLP findings.

CONCLUSION

It was practically revealed that the ITS-PCR followed by MvaI-RFLP is a useful and reliable schema for identification and differentiation of several pathogenic species and can be used for rapid screening of even closely related species of dermatophytes in clinical and epidemiological settings.

Preliminary Identification and Typing of Pathogenic and Toxigenic Fusarium Species Using Restriction Digestion of ITS1-5.8S rDNA-ITS2 Region

BACKGROUND

Fusarium species are capable of causing a wide range of crop plants infections as well as uncommon human infections. Many species of the genus produce mycotoxins, which are responsible for acute or chronic diseases in animals and humans. Identification of Fusaria to the species level is necessary for biological, epidemiological, pathological, and toxicological purposes. In this study, we undertook a computer-based analysis of ITS1-5.8SrDNA-ITS2 in 192 GenBank sequences from 36 Fusarium species to achieve data for establishing a molecular method for specie-specific identification.

METHODS

Sequence data and 610 restriction enzymes were analyzed for choosing RFLP profiles, and subsequently designed and validated a PCR-restriction enzyme system for identification and typing of species. DNA extracted from 32 reference strains of 16 species were amplified using ITS1 and ITS4 universal primers followed by sequencing and restriction enzyme digestion of PCR products.

RESULTS

The following 3 restriction enzymes TasI, ItaI and CfoI provide the best discriminatory power. Using ITS1 and ITS4 primers a product of approximately 550bp was observed for all Fusarium strains, as expected regarding the sequence analyses. After RFLP of the PCR products, some species were definitely identified by the method and some strains had different patterns in same species.

CONCLUSION

Our profile has potential not only for identification of species, but also for genotyping of strains. On the other hand, some Fusarium species were 100% identical in their ITS-5.8SrDNA-ITS2 sequences, therefore differentiation of these species is impossible regarding this target alone. ITS-PCR-RFLP method might be useful for preliminary differentiation and typing of most common Fusarium species.

Molecular detection of dermatophytes and nondermatophytes in onychomycosis by nested polymerase chain reaction based on 28S ribosomal RNA gene sequences

BACKGROUND

Onychomycosis is often caused by dermatophytes, but the role of nondermatophytes is underestimated due to the difficulty of identifying them by conventional direct microscopy and culture.

OBJECTIVES

This study aims to detect nondermatophytes, as well as dermatophytes, in the nail samples of patients with onychomycosis using a polymerase chain reaction (PCR)-based culture-independent method.

MATERIALS AND METHODS

The nested PCR assay targeting the sequence of the 28S ribosomal RNA gene was used to amplify fungal DNAs from 50 microscopy-positive nail specimens. Newly designed primer sets for dermatophyte universal, Trichophyton rubrum, T. mentagrophytes, Aspergillus spp., Scopulariopsis brevicaulis, Fusarium solani, F. oxysporum, F. verticillioides, Candida albicans and C. tropicalis were used after confirmation of their specificity.

RESULTS

Forty-seven cases (94%) were positive for fungal DNA, among which dermatophytes were detected in 39 cases (83.0%): T. rubrum in 35 cases (74.5%) and T. mentagrophytes in eight cases (17.0%). Surprisingly, nondermatophytes were detected in 18 cases (38.3%), both dermatophytes and nondermatophytes in 10 cases (21.3%) and nondermatophytes alone in eight cases (17.0%). Aspergillus spp. alone was observed in five cases (10.6%).

CONCLUSIONS

This study indicates that most of the affected nail plates of patients with onychomycosis were positive for specific fungal DNAs, and suggests that nondermatophytes detected at high rates may be involved in the pathogenesis of onychomycosis.

Phylogenetic relationships among medically important yeasts based on sequences of mitochondrial large subunit ribosomal RNA gene. Phylogenetische Verwandtschaft zwischen medizinisch wichtigen Hefen abgeleitet aus Sequenzierung des Mitochondrien-LsurRNA-Gens

Sequences of the mitochondrial large subunit ribosomal RNA (mtLsurRNA) gene of medically important yeasts were analysed. Sixteen strains of eight species including two varieties were subjected to sequencing. Sequencing enabled us to recognize the differences between all the species and varieties. Alignment analysis revealed that these sequences consisted of three clusters: the Candida albicans group, the C. glabrata group, and the basidiomycetous group. It is possible, therefore, that the mtLsurRNA gene is one of the targets not only for species identification but also for phylogenetic analysis of closely related yeasts. The dendrogram of each group, obtained from this gene, supports the previous study of yeasts based upon the chromosomal genes.

A case of kerion celsi due to Arthroderma benhamiae identified by DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions

We describe a case of a 4-year-old boy with a 1-month history of a purulent lesion on his scalp. His hair samples revealed fungal organisms and Trichophyton mentagrophytes was cultured from the sample. We analysed the DNA sequences of the nuclear ribosomal internal transcribed spacer 1 (ITS1) region of the isolated fungus. These sequences were in accordance with T. mentagrophytes animal 4 type. In mating experiments, our strain only responded to the Arthroderma benhamiae Americano-European race (+) mating type tester. We speculate that the patient was infected from contact with his pet guinea pig. This is the first case of a clinical isolate of A. benhamiae being identified by DNA sequences of nuclear ribosomal ITS1 regions.

A case of pulmonary aspergilloma molecular biological identification and typing of the isolates from antemortem sputa and autopsy fungus ball

Filamentous fungi were isolated from antemortem sputum and an autopsy fungus ball of the lung in a case of aspergilloma. Both of the isolates were analyzed for the sequences of species or strain-specific nuclear ribosomal DNA (partial 28S and ITS1 regions), and were identified as Aspergillus fumigatus. The molecular biological technique saved time and is thought to be a powerful tool in the accurate diagnosis of pulmonary fungal infection to assure effective treatment.

[A Case of central venous catheter-related infection with Malassezia sympodialis]

We report a 63-year-old male with central venous catheter-related infection caused by Malassezia sympodialis after total gastrectomy for a gastric cancer. He had fever and his leukocyte counts and C-reactive protein were elevated 14 days after his operation. After his central venous hyperalimentation catheter was removed, the inflammatory signs immediately disappeared, suggesting an intravenous catheter-related infection. A yeast-like fungus was cultured in brain-heart infection semi-solid agar ten days later, and was diagnosed morphologically as Malassezia sp. This strain was identified as M. sympodialis by Tween assimilation test and was confirmed by whole-sequence of internal transcribed spacer 1 regions (ITS1). This is the first report of catheter-related infection caused by M. sympodialis. This strain grew and was subcultured on CHROMagar Candida, potato dextrose agar and Sabouraud agar. There have been no reports of such a lipid-independent Malassezia sp. except for M. pachydermatis. The mechanism of lipid independence of this strain is undetermined and future work is needed. Malassezia sp. is receiving increased attention as an etiologic pathogen of catheter-related fungemia in clinical microbiology laboratories and infectious disease sections.

[Specific and rapid identification of Malassezia species based on the DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions]

Species identification of genus Malassezia is important in epidemiological and etiological studies, however, is difficult by the conventional system. A specific and rapid identification system based on sequences of internal transcribed spacer 1 of ribosomal DNA has therefore been developed. Using this system, we could identify two or more species mixed in the clinical samples.

Fungal flora on board the Mir-Space Station, identification by morphological features and ribosomal DNA sequences

This report is on the morphological and molecular biological identification, using 18S- and ITS1-rDNA sequences, of the "space fungi" isolated on board the Russian Mir-Space Station as the major constituents of the fungal flora. The six fungal strains were isolated from air by using an air sampler or from condensation. Strains were identified as Penicillium chrysogenum, Aspergillus versicolor, or Penicillium sp. by both methods. The species of space fungi were common saprophytic fungi in our living environment, potential pathogens, and allergens. This study concluded that the environment on board the space station Mir allows the growth of potentially pathogenic fungi as true in residential areas on the earth. Therefore, to prevent infection or other health disorders caused by these fungi, easy and reliable methods should be established to survey the fungal flora in a space station.

Immunohistochemical diagnosis of Cryptococcus neoformans var. gattii infection in chronic meningoencephalitis: the first case in Japan

Cryptococcus neoformans (C. neoformans) var. gattii infection usually occurs in tropical and subtropical areas, and rarely in the northern hemisphere. We report the first Japanese with cryptococcal meningoencephalitis caused by C. neoformans var. gattii infection that occurred during a trip to Australia. This agent was identified in a cerebellar biopsy specimen by immunohistochemical technique with serotype-specific anti-sera. Because the meningitis caused by it did not respond well to conventional therapy, we used an aggressive therapeutic regimen to successfully treat the patient. Even in areas where C. neoformans var. gattii does not exist, this infection should be considered possible as a travel-related infection.

Cluster analysis of human and animal pathogenic Microsporum species and their teleomorphic states, Arthroderma species, based on the DNA sequences of nuclear ribosomal internal transcribed spacer 1

We performed a cluster analysis of human and animal pathogenic Microsporum species and their teleomorphic states, Arthroderma species, including A. otae-related species (M. canis, M. audouinii, M. distortum, M. equinum, M. langeronii, and M. ferrugineum) and M. gypseum complex (A. fulvum, A. gypseum, and A. incurvatum) using DNA sequences of nuclear ribosomal internal transcribed spacer 1 (ITS1). The dendrogram showed the members of A. otae-related species to be monophyletic and to construct an extremely closely related cluster with a long horizontal branch. This ITS1-homologous group of A. otae was organized in 6 unique genotypes, while sequences of the members of the ITS1-homologous group of M. gypseum complex are more diverse. This ITS1-based database of Microsporum species and their teleomorphic states will provide a useful and reliable species identification system: it is time-saving (takes two to three days), accurate and applicable even to strains with atypical morphological features or in a non-culturable state.

Species identification system for dermatophytes based on the DNA sequences of nuclear ribosomal internal transcribed spacer 1

This describes a new and reliable species identification and classification system for dermatophytes based on the cluster analysis of nuclear ribosomal internal transcribed spacer 1 (ITS1) DNA sequences. In this system, some phenotypically similar species construct a compact monophyleic cluster which seems to be a species. This ITS1 sequence based species is called an ITS1-genospecies. The classification of genospecies is a practical concept for DNA sequence based species identification. It is possible to perform species identification and/or strain typing of 25 major dermatophytes (anamorphic genera Trichophyton, Microsporum, Epidermophyton, and the teleomorphic genus Arthroderma), some of which are hard to identify from their morphological features, by demonstrating their dendrogram using this system.

[Advances in molecular biology of dermatophytes]

During the 44th meeting of The Japanese Society for Medical Mycology in Nagasaki, 2000, a forum was held entitled Advances in Molecular Biology of Dermatophytes. Based on the subject, target molecules and kind of approach, we selected seven presentations from over 100 of the poster abstracts. Six of them concerned identification and one concerned viability. Summaries of the 7 presentations are given in this article. Of presentations on the identification methods, 5 demonstrated their usefulness: 1) A sequence analysis of ITS 1 region in ribosomal DNA of several Microsporum species showed ITS 1 genospecies Arthroderma otae to be composed of A. otae, M. canis, M. equinum and M. audouinii. 2) RAPD may be useful for identifying isolates which are not clearly identifiable by conventional biological techniques. 3) Sequence analysis of CHS 1 was shown to be a rapid tool for species level identification of M. gypseum. 4) PCR-SSCP analysis was also useful for discrimination of dermatophytes with high reproducibility and sensitivity. 5) Strain identification of A. benhamiae isolates may be possible using RFLP analysis of NTS regions in ribosomal DNA. The other presentation concerning identification pointed out some important problems: RFLP of mitochondrial DNA and ITS sequencing of A. benhamiae showed that the results are sometimes in conflict with those obtained from biological techniques, or in some cases, between other molecular techniques. This implies that our concept of fungal species needs to be re-examined and perhaps amended. The presentation on viability introduced quantitative analysis of mRNA of ACT gene, a new application of a molecular technique. Since the mRNA expresses only in living cells, the method is highly useful as an indicator of fungal viability.

Extensive chromosome translocation in a clinical isolate showing the distinctive carbohydrate assimilation profile from a candidiasis patient

Variation of the electrophoretic karyotype is common among clinical strains of Candida albicans and chromosome translocation is considered one of the causes of karyotypic variation. Such chromosome translocations may be a mechanism to confer phenotypic diversity on the imperfect fungus C. albicans. A clinical strain, TCH23, from a vaginal candidiasis patient shows distinct carbohydrate assimilation profile, serotype B, no chlamydospore formation and an atypical karyotype (Asakura et al., 1991). To examine the taxonomic relationship among C. albicans, Candida dubliniensis and this strain, we sequenced the internal transcribed spacer 1 (ITS1) of nuclear ribosomal DNA. The ITS1 sequence of TCH23 was identical with that of C. albicans but not of C. dubliniensis. Thus, strain TCH23 was classified as a variant of C. albicans with an atypical phenotype. The chromosomal DNAs of this strain were resolved into 13 bands on pulse-field gel electrophoresis (PFGE). Using DNA probes located at or near both ends of each chromosome of C. albicans, we investigated the chromosome organization of this strain. Referring to the SfiI map of C. albicans 1006 (Chu et al., 1993), we found that seven chromosomal DNA bands in strain TCH23 were reciprocal chromosome translocations. One homologue from chromosomes 1, 2 and 6 and both homologues from chromosomes 4 and 7 participated in these events. One translocation product was composed of three SfiI fragments, one each from chromosomes 2, 4 and 7. We deduced the breakpoints of chromosome translocation from the physical map of this strain; between 1J and 1J1, between 2A and 2U, both ends of 4F2, between 6C and 6O and both ends of 7F.

Mechanisms of fluconazole resistance in Candida albicans isolates from Japanese AIDS patients

Four Candida albicans isolates, TIMM 3163, TIMM 3164, TIMM 3165 and TIMM 3166, with reduced fluconazole susceptibility were obtained from three AIDS patients in Japan, and the mechanisms of their drug resistance were studied. All isolates showed lower levels of intracellular accumulation of fluconazole than ATCC 10231, a susceptible control strain of C. albicans. Increased amounts of CDR1 and CDR2 mRNA encoding putative ATP binding cassette (ABC) transporters were associated with the azole resistance of all TIMM isolates, apart from TIMM 3164. In addition, increased Cdr1p levels were immunodetected in the cell membrane fractions of all the TIMM strains except for TIMM 3164. Gene amplification was not responsible for CDR1 overexpression and there were no significant differences in the mRNA levels of CDR3 or CDR4 (ABC transporters) in the azole-susceptible and -resistant cells. CaMDR1 (a major facilitator superfamily) gene expression was not observed in any of the resistant isolates or the control strain. These results suggest that energy-dependent drug efflux associated with increased expression of CDR1 and CDR2 is involved in the fluconazole resistance mechanisms in two of the four isolates, TIMM 3165 and TIMM 3166. TIMM 3164 demonstrated energy-dependent drug efflux without overexpression of CDR1-4 or CaMDR1, indicating that some other pump may be operating. Despite showing low levels of drug efflux and overexpression of CDR1 and CDR2, efflux in TIMM 3163 was not energy dependent, suggesting that the expressed Cdr1p non-functional Cdr1p and that other resistance mechanisms may operate in this strain.

First isolation of Stephanoascus ciferrii from a cat

The present study deals with the first isolation of Stephanoascus ciferrii from a cat. A 2-year-old female Persian cat weighing 2.25 kg was referred to an animal hospital with a chief complaint of otitis externa of the left ear. Microscopic examination of specimen from the left ear disclosed yeast cells. The colony of the clinical isolate was cream-colored, rough, raised and wrinkled. The microscopic examination of the clinical isolate revealed abundant branched and septated mycelia with small ramified chains of oval blastoconidia, variable in size, and arranged alongside the hyphae. Amplification of the isolate DNA with LSU rDNA primers yielded a fragment of about 570 bp, whose nucleotide sequence of the isolate showed 100% similarity to that of Stephanoascus ciferrii in the GenBank database. Therefore, the isolate was identified as Stephanoascus ciferrii, confirming the result of mycological examination by molecular analysis.

Blood lysate staining, a new microscopic method for diagnosis of fungemia using peripheral blood

We developed a microscopy method for the detection of fungal cells in peripheral blood, termed blood lysate staining, using an approximately 5x5 mm dotted blood lysate. This method was able to detect the emerging fungal pathogen Trichosporon asahii in murine models of systemic fungal infection and fungemia in patients quickly and at minimal cost. Pathogenic yeasts were successfully detected in 6 of 8 blood samples which were taken from feverish immunocompromised patients who were clinically suspected of having fungal infections. Fungal cells were observed as ovoid to elongated, 3x3 to 7x10 microm, and occurred singly, budding, and in short chains and clusters in a periodic acid-Schiff-stained blood smear. The yeast cells were easily distinguished from blood-cell debris by their size, shape and smooth yet rigid outline.

Mycological examination of the hair samples of 11 school-going Nepalese children suspected of tinea capitis

Among 150 students from a semi-urban school in Kathmandu (Nepal), 30 from various age groups and both sexes with symptoms suggestive of scalp ringworm, were examined clinically. Hair samples were collected for mycological examination, using the hair brush method, from 11 of the 30 children (36.7%), aged between 5 and 14 years, who were clinically diagnosed. Four of the cultured samples were positive for isolates of Trichophyton violaceum. This minor study provides evidence that tinea capitis might constitute a substantial infectious dermatological problem in Nepal. The study also indicated T. violaceum as the causative organism of tinea capitis.

[Taxonomy of genus Malassezia: progress and problems]

The genus Malassezia is composed of lipophilic basidiomycetous yeasts which were recently shown to consist of seven species, one lipid-independent species, M. pachydermatis and six lipid-dependent species, M. furfur, M. sympodialis, M. globosa, M. obtusa, M. restricta and M. slooffiae. Based on this classification, we will be able to analyze pathogenicity or relationship between Malassezia-related diseases and each species.

Identification of several clinical isolates of dermatophytes based on the nucleotide sequence of internal transcribed spacer 1 (ITS 1) in nuclear ribosomal DNA

Nucleotide sequences of internal transcribed spacer 1 (ITS 1) in nuclear ribosomal DNA from seven morphologically unidentified dermatophyte isolates were determined. The sequences were compared with those of typical isolates of Trichophyton (T.) mentagrophytes var. interdigitale, T. rubrum, and Epidermophyton floccosum. Two of the isolates were classified as T. rubrum and the other five as T. mentagrophytes var. interdigitale. The results did not conflict with identifications using other molecular techniques, including random amplification of polymorphic DNA (RAPD) analysis and restriction enzyme analysis of mitochondrial DNAs. Thus, the nuclotide sequence of ITS 1 is possibly a good molecular marker for identification of these major anthropophilic dermatophyte species.

Phylogenetic classification and species identification of dermatophyte strains based on DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions

The mutual phylogenetic relationships of dermatophytes of the genera Trichophyton, Microsporum, and Epidermophyton were demonstrated by using internal transcribed spacer 1 (ITS1) region ribosomal DNA sequences. Trichophyton spp. and Microsporum spp. form a cluster in the phylogenetic tree with Epidermophyton floccosum as an outgroup, and within this cluster, all Trichophyton spp. except Trichophyton terrestre form a nested cluster (100% bootstrap support). Members of dermatophytes in the cluster of Trichophyton spp. were classified into three groups with ITS1 homologies, with each of them being a monophyletic cluster (100% bootstrap support). The Arthroderma vanbreuseghemii-Arthroderma simii group consists of A. vanbreuseghemii, A. simii, Trichophyton mentagrophytes isolates from humans, T. mentagrophytes var. quinckeanum, Trichophyton tonsurans, and Trichophyton schoenleinii. Arthroderma benhamiae, T. mentagrophytes var. erinacei, and Trichophyton verrucosum are members of the Arthroderma benhamiae group. Trichophyton rubrum and Trichophyton violaceum form the T. rubrum group. This suggests that these "species" of dermatophytes have been overclassified. The ITS1 sequences of 11 clinical isolates were also determined to identify the species, and all strains were successfully identified by comparison of their base sequences with those in the ITS1 DNA sequence database.

Selected animal models: vaginal candidosis, Pneumocystis pneumonia, dermatophytosis and trichosporosis

A clear understanding of the pathogenesis of fungal disease remains elusive. While technological advances in molecular biology and microbial genetics have provided scientists with major new insights into both microbial virulence factors as well as host susceptibility to infection, there is currently no substitute for animal models in elucidating microbe-host interactions. Animal models are also essential for the evaluation of new antimicrobial agents, including studies of efficacy, adverse reactions and pharmacokinetics. The single most important advance in animal models in the last decade, has been the availability of genetically unique strains of animals as alternative to animals treated with immunosuppressive drugs for use in studies on microbial virulence and host defence mechanisms. These unique strains of test animals also enhance our understanding of the modes of action of antifungal drugs and their metabolism. Some of these advances will be discussed in this symposium.

Molecular diagnosis and epidemiology of fungal infections

A variety of methods are utilized for DNA strain subtyping of Candida spp. because no 'gold standard' exists. Random amplified polymorphic DNA (RAPD) or restriction enzyme analysis (REA) are useful to determine the source of an outbreak, but more reproducible and discriminatory methods such as Southern hybridization and pulsed field gel electrophoresis (PFGE) may be required. When applied to some nosocomial Candida infections, multiple strains and species have been identified. Microevolution of yeast species occurs and epidemiologically related isolates may show minor pattern differences, creating uncertainty as to whether they are distinct strains. Approximately 1000 isolates of Aspergillus fumigatus from environmental and clinical sources were typed by REA probed with an A. fumigatus-specific retrotransposon-like sequence. Patients with no symptom of aspergillosis may carry several strains, whereas patients with pulmonary aspergillosis may carry one or two strains; nocosomial transmission of aspergillosis was proven in 39% of the patients studied; any given environmental strain can be infectious; the environmental population of A. fumigatus is extremely diverse and no specific niche was found in the hospital. A PCR assay was designed to target conserved 18S-ribosomal DNA (rDNA) sequences shared by most fungi and a 687 bp product was amplified from 25 medically important fungal species. Studies with blood, cerebrospinal fluid and sputum specimens from patients with mycoses indicated that the PCR assay is more sensitive in diagnosing invasive fungal infections than blood culture methods. More specific identification is obtainable with genus/species-specif c probes designed from within the PCR-amplified sequences for C. albicans, C. krusei, C. lusitaniae, Pneumocystis carinii, Cryptococcus neoformans, Aspergillus/Penicillium spp. and C. glabrata/Saccharomyces cerevisiae. A. fumigatus and A. niger were differentiated by denaturing gradient gel electrophoresis. In situ hybridization (ISH) detected a 648 bp fragment of the 18S rDNA of C. neoformans and a 568 bp fragment of the alkaline proteinase gene of A. fumigatus in tissues from experimentally infected animals. In ISH, the entire process can be automated, making this procedure rapid and easy. The difficulty in establishing a diagnosis of invasive candidiasis has prompted the quest for a clinically useful PCR test for candidaemia. The universal fungal oligonucleotide primer pair, ITS3 and ITS4, amplifies portions of the 5.8S ad 28S rDNA subunits, and the ITS2 region. Although rRNA genes are highly conserved, the ITS regions are distinctive. DNA probes were designed from ITS2 that were specific for 16 different Candida species. Simple, rapid sample preparation was suitable for PCR analysis of BacT/Alert blood culture bottles. Sample preparation, PCR, and EIA detection of the amplicon from five different Candida species was accomplished in 7 h, 2.5 days sooner than by conventional culture methods. As well as saving time, minor yeast species among a major species, or among bacteria, were simultaneously detected. PCR-EIA using a microtitration plate format had sensitivity 10-times greater than that obtained with ethidium bromide-stained agarose gels. Taqman combines in one step PCR, probe hybridization, and fluorescent signal generation. Taqman PCR had sensitivity equivalent to PCR-EIA and required only 5 h, including sample preparation.

Phylogenetic classification of Trichophyton mentagrophytes complex strains based on DNA sequences of nuclear ribosomal internal transcribed spacer 1 regions

Using internal transcribed spacer 1 (ITS1) region ribosomal DNA sequences from 37 stock strains and clinical isolates provisionally termed Trichophyton mentagrophytes complex in Japan, we demonstrated the mutual phylogenetic relationships of these strains. Members of this complex were classified into 3 ITS1-homologous groups and 13 ITS1-identical groups by their sequences. ITS1-homologous group I consists of Arthroderma vanbreuseghemii, T. mentagrophytes human isolates, and several strains of T. mentagrophytes animal isolates. Five strains of Arthroderma simii form a cluster comprising ITS1-homologous group II. The Americano-European and African races of Arthroderma benhamiae, T. mentagrophytes var. erinacei, and one strain of a T. mentagrophytes animal isolate constitute ITS1-homologous group III. According to the phylogenetic tree constructed with Trichophyton rubrum as an outgroup, ITS1-homologous groups I and II comprised a monophyletic cluster and ITS1-homologous group III constituted another cluster which was rather distant from the others in the complex. This system was applicable to the phylogenetic analysis of closely related strains. Using this technique, human and animal isolates of T. mentagrophytes were also clearly distinguishable from each other.

Successful polymerase chain reaction-based diagnosis of fungal meningitis in a patient with chronic granulomatous disease

Meningitis is not a common complication of chronic granulomatous disease (CGD). Here, we present details of a 3-year-old boy with X-linked CGD, who suffered from fungal meningitis. While 19 samplings using conventional cerebrospinal fluid (CSF) cultures failed to detect any organisms, fungal DNA was identified in the CSF by a new polymerase chain reaction (PCR)-based method. The patient recovered without any sequelae after treatment with a combination of antifungal agents, interferon-gamma and granulocyte infusions. This case report demonstrates that fungal meningitis must be included in the differential diagnosis of infections in CGD patients and that the PCR-based detection of fungal DNA is a powerful tool for diagnosis.

Development of reference procedures for broth microdilution antifungal susceptibility testing of yeasts with standardized endpoint determination

Standard guidelines for the broth microdilution antifungal susceptibility testing of amphotericin B, flucytosine, fluconazole, miconazole and itraconazole are reported. These are a modification of the method developed by the National Committee for Clinical Laboratory Standards (NCCLS) on the following two points: standardization of the means of endpoint determination and the inclusion of miconazole and itraconazole in the testing. MIC was determined to be when the positive control had a turbidity of 0.2 at the 630 nm wavelength. The endpoint was 80% inhibition for azoles and 100% inhibition for other drugs. The method provided good reproducibility, and a wide range of MIC distribution was observed in all antifungal agents except amphotericin B.

Experimental disseminated trichosporonosis in mice: tissue distribution and therapy with antifungal agents

Mice treated with cyclophosphamide were infected intravenously with titrated doses of Trichosporon asahii TIMM3140 or TIMM3144. Mortality and survival time correlated with inoculum size and fungal growth was found in the lung, heart, liver, spleen, kidney and brain. Fluconazole and amphotericin B prolonged survival time and reduced the CFU in the kidney, with fluconazole being superior to amphotericin B. The serum level of (1-->3)-beta-D-glucan was reduced by antifungal therapy and correlated well with the CFU/organ in kidney, but not CFU/ml in blood.

[Genetic diagnosis of aspergillosis]

Aspergillosis is an opportunistic infection caused by pathogenic Aspergillus species (spp.) and is a major hazard for immunocompromised patients and even for non-immunocompromised individuals. Clinical diagnosis of aspergillosis, especially invasive pulmonary aspergillosis (IPA) is difficult and is largely presumptive, typically based on spiking fevers not responding to antibiotics in a patient with the risk factors. It is well known that Aspergillus spp. can be only infrequently cultured from clinical specimens, and that the cultural examination is laborious and time-consuming. Moreover, positive culture from bronchoalveolar lavage or sputa is indicative, but not proof of infection. The criterion for diagnosis of pulmonary infection by aspergilli requires repeated isolation of the same species of Aspergillus from respiratory specimens. There have been some successful attempts using serological assays to detect circulating antibodies to Aspergillus spp. in the noninvasive form of the disease, but these are generally negative in an acute phase IPA patient. A currently available serodiagnostic kit, Pastrex Aspergillus is limited in clinical usefulness because of low sensitivity and specificity in spite of being simple and rapid. Contamination of clinical specimens with various saprophytic filamentous fungi other than aspergilli also often give false positive. Diagnostic methods using such molecular biological techniques, as polymerase chain reaction (PCR) have recently been employed to identify DNA from a number of pathogens when diagnostic means are limited. PCR is known as the most sensitive and specific technique by which to detect a specific DNA sequence. In this paper we have reviewed new genetic methods of diagnosing aspergillosis including PCR and in situ hybridization.

Partial sequences of large subunit ribosomal DNA of a new yeast species, Trichosporon domesticum and related species

We determined the partial sequences of large subunit rDNA of a new yeast species, Trichosporon domesticum, which was isolated from the house of a summer-type hypersensitivity pneumonitis patient. Phylogenetically, T. domesticum was positioned in the taxonomic group containing T. montevideense and T. brassicae, which indicated an identical serotype. A phylogenetic relationship among all species of the genus Trichosporon which belong to the basidiomycetous yeast is clarified.

[The antigen (CANDTEC antigen) detected by CAND TEC test for diagnosis of candidiasis]

Most guinea pigs inoculated with 5.4 x 10(9) of C. albicans intraperitoneally, produce CANDTEC antigen (GPCANDTECAG) in sera. The antigen is heat-labile (at 56 degrees C for 30 min) as is that in humans. According to gel filtration, the molecule size of the antigen from guinea pigs was 4000KDa or more. ELISA revealed the antigen-positive gel fractions to contain a small amount of mannan from the yeasts and C3. ELISA using rabbit anti-GPCANDTECAG serum indicated that the two CANDTEC antigens from guinea pigs and humans shared determinants. Gel filtration indicated that the CANDTEC antigen from patients was from 4000KDa to 3000KDa. In the antigen-positive gel fractions, IgM was detected by ELISA, but mannan and C3 were not detected. However, immunoblotting analysis on the antigen-positive fraction revealed a unique band of 200KDa, stained with concanavalin A-ALP. These findings indicate that CANDTEC antigens in guinea pigs and humans are immune complexes formed after infection of Candida, although the antigens have different components.

[Hansenula anomala fungemia in a patient undergoing IVH-treatment with ascending colon carcinoma]

A case of catheter-related fungemia due to Hansenula anomala is reported. A 61-year-old male was diagnosed as having stage 3 ascending colon carcinoma stenosing the colon severely and was admitted to our hospital to receive an operation of the carcinoma. Just after admission, an intravenous hyperalimentation (IVH) catheter was inserted and IVH was started to prevent development of ileus and to prepare for laparotomy. Nine days later, he developed a fever. On the next day, the IVH catheter was removed and cultures of blood and the catheter revealed the presence of yeast-like organisms that were identified as H. anomala. Laboratory data showed hypogranulocytemia, slight disturbances of liver and kidney, a prolongation of PT, an increase of FDP and positive reaction of candida antigen by CAND-TEC. He improved after the removal of the catheter, and treatment with intravenous infusion of fluconazole 2 days after the removal was thought to be useful for recovery and to prevent the reappearance of infection though susceptibility to fluconazole was not good. Human infections due to H. anomala are rare and this is the 8th case of H. anomala fungemia in Japan. From this report and a review of the literature, risk factors for developing this fungemia include the use and abuse of central venous catheters such as IVH-catheter. It appears that H. anomala has recently emerged as a potential pathogen in the immunocompromised hosts and patients after insertion of central venous catheters and that these organisms should be added to the growing list of unusual fungal pathogens in these patients.

Catheter-related infections by Hansenula anomala in children

During August and September, 1992, we experienced 4 cases of Hansenula anomala (H. anomala, synonym Pichia anomala) fungemia in immunocompromised patients. Two patients had been suffering from a malignant disease, 3 of them had received broad-spectrum antibiotics and a central venous catheter (CVC) had been inserted in all of them. H. anomala was isolated as the sole pathogen from all 4 patients. Three of them responded favorably to fluconazole after withdrawal of the catheter, but one failed. H. anomala should be considered as a possible cause of catheter-related infections.

Specific detection of Aspergillus and Penicillium species from respiratory specimens by polymerase chain reaction (PCR)

A polymerase chain reaction (PCR) method capable of detecting both Aspergillus fumigatus infections, pulmonary non-fumigatus Aspergillus species (spp.) and Penicillium spp. from clinical specimens was established. The primer pair was designed on the basis of the sequence of the 18S-ribosomal RNA gene of A. fumigatus and P. notatum. A 385 bp product was successfully amplified by this PCR method from all of 12 medically important Aspergillus spp. and Penicillium spp. (38 strains), but not from human, calf, Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), any of 14 medically important yeastlike fungal species tested (32 strains) including Candida albicans, several non-albicans Candida and Saccharomyces cerevisiae, Cryptococcus neoformans, Mucor spp. or Pneumocystis carinii. This specificity was subsequently confirmed by Southern hybridization analysis. The established PCR can detect such a small amount as 1 pg of A. fumigatus DNA by staining the PCR product with ethidium bromide. With sputum specimens from clinically diagnosed aspergilloma patients, this PCR technique was demonstrated to be a more sensitive diagnostic method for Aspergillus infections than conventional culture techniques.

Detection of a wide range of medically important fungi by the polymerase chain reaction

A polymerase chain reaction (PCR) method was developed that was capable of detecting a wide range of medically important fungi from clinical specimens. The primer pair was designed in conserved sequences of 18S-ribosomal RNA genes shared by most fungi. The lower limit of detection of this PCR technique was 1 pg of Candida albicans genomic DNA by ethidium bromide staining and 100 fg after Southern analysis. A 687-bp product was amplified successfully by PCR from all 78 strains of 25 medically important fungal species studies, including Candida spp., Hansenula spp., Saccharomyces cerevisiae, Cryptococcus neoformans, Trichosporon beigelii, Malassezia furfur, Pneumocystis carinii, Aspergillus spp., and Penicillium spp., but not from any strains of Mucor spp., Escherichia coli, or methicillin-resistant Staphylococcus aureus (MRSA), calf thymus or human placenta. This specificity was subsequently confirmed by Southern analysis. PCR analysis of blood specimens collected from mice systemically infected with C. albicans and clinical samples including blood, cerebrospinal fluid and sputum appeared to be a more sensitive diagnostic method for invasive fungal infections than a conventional blood culture technique.

Mapping of Marek's disease virus genome: identification of junction sequences between unique and inverted repeat regions

Polymerase chain reaction (PCR) to amplify MDV DNA and subsequent sequencing identified the junction of TRL/UL, UL/IRL, IRS/US, and US/TRS. The TRL/UL junction is located 192 bp downstream of the last EcoRI site in the TRL region, while the UL/IRL junction is located 192 bp upstream of the first EcoRI restriction enzyme site in the IRL region. The IRS/US junction is located 950 bp downstream of the second EcoRI site in the IRS region, while the US/TRS junction is located 950 bp upstream of the first EcoRI restriction enzyme site in the TRS region. BamHI restriction enzyme mapping of one of the PCR products identified two novel DNA subfragments, BamHI-U2 and -P4, upstream of the US/TRS junction of the MDV genome. Sequencing of the BamHI-D fragment revealed a novel open reading frame (ORF) encoding a 155 amino acid protein. The TRL/UL junction is located in this ORF. The N-terminal 65 amino acids of this protein is homologous to the N-terminal region of the previously reported pp38, which is located in the UL/IRL region. Computer-assisted analysis indicated that both are transmembrane proteins and that they share an antigenic domain.