Handbook Part 2 - International Mycological Association
Handbook Part 2 - International Mycological Association
Handbook Part 2 - International Mycological Association
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PS2PS4 - 0593<br />
Genetic diversity and detection of the neurotropic black yeast Exophiala dermatitidis.<br />
M. Sudhadham1, G. S. de Hoog 1, A.H.G. Gerrits van den Ende 1, S. Prakitsin 2<br />
1 Centraalbureau voor Schimmelcultures, Utecht, Netherlands, 2 Chulalongkorn University, Bangkok, Thailand<br />
The black yeast Exophiala dermatitidis is an uncommon etiologic agent of fatal infections of the central nervous<br />
system in otherwise healthy, mainly adolescent patients in East Asia. The route of infection is still a mystery. The steam<br />
bath apparently provides a novel environmental opportunity for this fungus, but it is uncommonly distributed by air or<br />
steam and thus inhalative infection from the steam bath is unlikely. Rapid screening of a diversity of environments is<br />
therefore essential. Two preponderant ITS rDNA genotypes are known. It is our aim to enhance detection of the<br />
genotypes in natural and human-dominated environments.<br />
Strains were isolated by pre-incubation in Raulin’s solution, and subsequently on Erythritol-Chloramphenicol Agar<br />
(ECA) at 40°C. Strains were purified with Tween 0.1%. For phenetic identification, assimilation of nitrate was tested.<br />
Genotype-specific assays were developed using Amplified Fragment Length Polymorphism (AFLP), by Single-Strand<br />
Confirmation Polymorphism (SSCP), by restriction analysis (RFLP) and by applying selective primers.<br />
Growth at 40°C and absence of assimilation of nitrate separate Exophiala dermatitidis and E. phaeomuriformis from<br />
all other black yeasts. An RFLP assay for detection of the preponderant genotypes and a genotype with a 30 bp Indel<br />
in ITS1 was developed. Digestion with Taq I revealed two different types, by which the genotypes I and II could be<br />
recognized easily. A third genotype was recognized by a small band shift. Genotype detection was enhanced by the<br />
use of specific primers and SSCP. With AFLP a further subdivision of genotypes was possible.<br />
RFLP combined with simple phenetic data enabled precise recognition of E. dermatitidis down to the genotype level.<br />
Specific PCR assay enable detection without culturing. In combination the methods will enhance large-scale<br />
screening of clinical and environmental samples<br />
PS2PS5 - 0069<br />
Outbreak of Tinea Corporis Gladiatorum in Tehran<br />
Shahindokht Bassiri Jahromi, Ali Asghar Khaksar<br />
Medical Mycology Department, Pasteur Institute of Iran<br />
In recent years, skin diseases in wrestling have finally received the attention it deserves. Outbreaks of tinea corporis are<br />
often associated with sports such as wrestling that involve extensive bodily contact. Tinea corporis gladiatorum,<br />
caused in most by Triclophyton tonsurans, infect wrestlers at alarming rates. The management of skin infections in<br />
wrestlers and other athletes in sports involving skin-to-skin contact is challenging, from making an accurate diagnosis<br />
to determining eligibility for play. To control the outbreak, we conducted an epidemiologic investigation. The purpose<br />
of this article is to determine the prevalence of tinea corporis gladiatorum in wrestlers club in Tehran.<br />
A study of dermatophytosis among wrestlers was carried out during the period March 2001 to December 2005 in 612<br />
mycologically proven cases of dermatophytosis in wrestlers in Tehran. The wrestler mycologically examination<br />
consisting of direct microscopic observation and culture of pathologic material. Diagnosis was based on the macroand<br />
microscopic characteristics of the colonies.<br />
Trichophyton tonsurans was the predominant dermatophyte,accounting for >90% of all tinea corporis gladiatorum<br />
isolates in each of the 5 years analysed.Tinea corporis gladiatorum was found to be more frequent in 10-30 age groups<br />
(94.6%).The wrestlers with corporis gladiatorum were mostly from wrestler clubs in south and south-east of<br />
Tehran.Transmission of tinea corporis is primarily through skin-to- skin contact.<br />
The rapid identification and treatment of tinea corporis gladiatorum is vital to minimize disruption in team practices<br />
and competition, are paramount. . Because infection with dermatophytes can disqualify a wrestler from competing<br />
in matches, vigilant surveillance and rapid initiation of therapy can reduce the suspension of a team’s practice and<br />
competition.<br />
1015-1115 – 0762<br />
PLENARY 4<br />
Mating in fungi<br />
Regina Kahmann<br />
Germany<br />
In my lecture I will give a brief overview of the conserved mating systems present in diverse groups of fungi and<br />
describe how these loci determine cell identity and promote outbreeding. Special emphasis will be given to the<br />
bipolar and tetrapolar mating systems of the Basidiomycetes where multiple specificities arise through recombination.<br />
The developmental pathways which are regulated by the mating type genes will be outlined using the smut fungus<br />
Ustilago maydis as prime example. In this organism the b mating type genes control morphogenesis and pathogenic<br />
development. In their active form the b proteins exist as heterodimeric transcription factors that trigger a regulatory<br />
cascade comprising about 250 genes. Many of these genes have unknown functions and this percentage is<br />
especially high among genes whose products are predicted to be secreted. I will present evidence that some of these<br />
novel proteins have essential functions during pathogenesis.<br />
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