Cryptococcus neoformans is an opportunistic human pathogen, which infects the central nervous system causing the fatal disease, meningitis. In order to understand the genetic background of this human pathogen, the basic molecular manipulation techniques of deletion, overexpression, and so on have been developed. URA5, a gene encoding orotate phosphoribosyltransferase, has frequently been used to introduce foreign gene fragments by complementing ura5 mutant strains, which are not, however, stable; reversion to uracil prototroph is thus frequently observed on selective condition. The high possibility of reversion makes it inconvenient to use this mutation to identify appropriate transformants and thus, manipulation in molecular genetics. We report here the isolation of a stable ura5 mutant of C. neoformans, designated as TAD1, by eliminating the URA5 gene by homologous recombination using the biolistic DNA delivery system. The availability of the stable ura5 mutant offers the advantage that no spontaneous reversion occurs so that a satisfactory rate of homologous recombination can be achieved. The strain will allow efficient genomic analysis in C. neoformans.

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Thirty-one members of the Judo Club of a certain university (age: 18∼23) underwent a screening examination for dermatophytosis by Trichophyton tonsurans. Test items were: age, sex, height, weight, living mode, exercise duration, number of judo contestants, presence of foreign contestants, occurrence, if any, of dermatophytosis past or present according to a subject's answers to a questionnaire, medical examinations and mycological examinations (KOH, cellophane tape culture, and hairbrush culture). Twenty-four subjects (77%) replied that they had suffered from dermatophytosis in the past, and 8 subjects (26%) had had head eruption in the past. Eleven subjects (35%) had suspicious dermatophytosis at the time of screening; 3 of them were found positive by direct microscopy, 2 of them were positive by cellophane tape culture. Eleven subjects (35%) were found positive by the hairbrush culture, but only 2 had eruption-like folliculitis. The remaining 9 subjects were free from clinical symptoms and were judged to be asymptomatic carriers. As countermeasures, we recommended cleaning and the use of shampoo containing miconazole nitrate. Subjects with suspicious tinea corporis were treated with antimycotic ointment. The 7 subjects who showed more than 5 colonies by the hairbrush culture were treated with 1-week pulse therapy of 400mg itraconazole, and 3 of these who took a total dose of a pulse became negative through one pulse therapy.

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Case 1 was a 3-year-old with tinea capitis, while Case 2 was a 5-year-old with kerion celsi. These conditions developed between December 1997 and January 1998 when the patients were living in Canada. Case 3 was a 7-year-old who developed kerion celsi in March 1998 in Japan. For Cases 1 and 2, the referring doctor had detected a fungal infection a few weeks previously, and griseofulvin was administered orally to Case 1 for three weeks and Case 2 for one week prior to consultation at our department. Both Cases 1 and 2 visited our department initially on May 7, 1998 with the causative agent separated from their lesions by the referring doctor respectively. The causative agent was identified as Trycophyton violaceum by our department. KOH-prepared direct microscopy and culture were positive for Case 1, but negative for Case 2. Infected hairs of Case 1 showed a chain of large arthrospores arranged in parallel rows inside the hair. Case 3 visited our department initially on May 21, and T. violaceum was also isolated from this patient's lesion.
A reddish purple isolate that was stored for five months after isolation and culture was subcultured using a Sabouraud agar containing thiamin. After two months, brown colonies without red pigment were seen in the reddish purple colonies. Slide culture performed for both colonies showed intercalary and terminal chlamydospores, thus confirming that they were the same fungus. These findings appear to represent the conversion of T. violaceum into T. glabrum.

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Nocardia abscessus, a recently established species, was isolated from patients during 2000. In the course of our taxonomic studies on 121 clinical Nocardia isolates in Japan 5 strains isolated from patients plus one strain isolated from soil in Japan, were found to have similar physiological characteristics to those of N. abscessus. Phylogenetic studies using 16S rRNA gene sequence analysis confirmed that these strains belong to N. abscessus. This is the first isolation report of N. abscessus from soil as well as from clinical samples in Japan.

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Sporothrix schenckii isolates from China, Korea and Spain were investigated for mtDNA types based on restriction fragment length polymorphism patterns with HaeIII. Sixty-one isolates from China, 8 from Korea and 11 from Spain were comprised of 7, 2 and 2 mtDNA types, respectively. All the isolates belonged to Group B.

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