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Polyketides are important secondary metabolites, many of which exhibit potent pharmacological applications. Biosynthesis of polyketides is carried out by a single polyketide synthase (PKS) or multiple PKSs in successive elongations of enzyme-bound intermediates related to fatty acid biosynthesis. The polyketide gene PKS306 from Pseudallescheria boydii NTOU2362 containing domains of ketosynthase (KS), acyltransferase (AT), dehydratase (DH), acyl carrier protein (ACP) and methyltransferase (MT) was cloned in an attempt to produce novel chemical compounds, and this PKS harbouring green fluorescent protein (GFP) was expressed in Saccharomyces cerevisiae. Although fluorescence of GFP and fusion protein analysed by anti-GFP antibody were observed, no novel compound was detected. 6-methylsalicylic acid synthase (6MSAS) was then used as a template and engineered with PKS306 by combinatorial fusion. The chimeric PKS containing domains of KS, AT, DH and ketoreductase (KR) from 6MSAS with ACP and MT from PKS306 demonstrated biosynthesis of a novel compound. The compound was identified with a deduced chemical formula of C 7 H 10 O 3 , and the chemical structure was named as 2-hydroxy-2-(propan-2-yl) cyclobutane-1,3-dione. The novel compound synthesized by the chimeric PKS in this study demonstrates the feasibility of combinatorial fusion of PKS genes to produce novel polyketides., (© 2019 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.)

Scedosporiosis is an emerging fungal infection caused by Pseudallescheria/Scedosporium complex species (PSC). This pathogen has been drawn significant interest in recent years due to its worldwide prevalence, the seriousness of its infection, associated with high mortality in both immunocompromised and immunocompetent hosts and its cryptic ecology, distribution and epidemiology across the globe. These species complexes can be found in environments impacted by human. The purpose of this review is to describe the characteristics, mode of transmission, ecology, prevalence, global epidemiology of this fungal group in order to increase the awareness of among clinicians and microbiologists, especially in regions with high endemic, as well as to promote further research on all of its aspects., (Copyright © 2018. Published by Elsevier Masson SAS.)

MALDI-ToF mass spectrometry offers fast and reliable species identification for bacteria and yeasts under clinical routine conditions. Here, we produced mass spectra for identification of clinically important species of the Pseudallescheria/Scedosporium complex using the recently suggested new nomenclature and use this example to discuss to what extent the principle of DNA barcoding might be transferred to mass spectrometry., (Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

As various new sibling species within the Pseudallescheria boydii/Scedosporium apiospermum complex have been described recently with differences in their susceptibility to antifungals, this study was conducted in order to determine their respective frequency in cystic fibrosis. Results indicated that P. boydii largely predominated (62%), followed by S. apiospermum (24%), Scedosporium aurantiacum (10%) and Pseudallescheria minutispora (4%). Scedosporium dehoogii was not recovered in this study. The multiple correspondence factor analysis highlighted geographical discrepancies within species distribution: P. boydii was rarely encountered in Northern France, while S. apiospermum was less represented in the west of the country. Additionally, we demonstrated that all species encountered in the cystic fibrosis context were capable to chronically colonize the respiratory tract of patients. Molecular typing of a large set of environmental and clinical isolates should be conducted to delineate the epidemiology of each sibling species in the complex.

The aim of this study was to develop molecular identification tools for currently recognized species of Pseudallescheria and Scedosporium through the use of species-specific primers and RFLP, so as to enhance rapid differentiation of clinically relevant species. The variability of species was established in a set of 681 Internal Transcribed Spacer (ITS) and 349 ß-tubulin (BT2) sequences. Amplified Fragment Length Polymorphism profile clustering matched with BT2 results, whereas ITS grouping was less detailed. ITS was sufficient for the differentiation of most haplotypes of clinically relevant species (P. apiosperma, P. boydii, S. aurantiacum, S. dehoogii, and S. prolificans) and of environmental species (P. minutispora and Lophotrichus fimeti) when Restriction Fragment Length Polymorphism (RFLP) were applied. For the identification of P. apiosperma and P. boydii species-specific BT2 primers were needed. Pseudallescheria fusoidea, P. ellipsoidea and P. angusta remained difficult to distinguish from P. boydii.

The Pseudallescheria boydii complex, comprising environmental pathogens with Scedosporium anamorphs, has recently been subdivided into five main species: Scedosporium dehoogii, S. aurantiacum, Pseudallescheria minutispora, P. apiosperma, and P. boydii, while the validity of some other taxa is being debated. Several Pseudallescheria and Scedosporium species are indicator organisms of pollution in soil and water. Scedosporium dehoogii in particular is enriched in soils contaminated by aliphatic hydrocarbons. In addition, the fungi may cause life-threatening infections involving the central nervous system in severely impaired patients. For screening purposes, rapid and economic tools for species recognition are needed. Our aim is to establish rolling circle amplification (RCA) as a screening tool for species-specific identification of Pseudallescheria and Scedosporium. With this aim, a set of padlock probes was designed on the basis of the internal transcribed spacer (ITS) region, differing by up to 13 fixed mutations. Padlock probes were unique as judged from sequence comparison by BLAST search in GenBank and in dedicated research databases at CBS (Centraalbureau voor Schimmelcultures Fungal Biodiversity Centre). RCA was applied as an in vitro tool, tested with pure DNA amplified from cultures. The species-specific padlock probes designed in this study yielded 100% specificity. The method presented here was found to be an attractive alternative to identification by restriction fragment length polymorphism (RFLP) or sequencing. The rapidity (<1 day), specificity, and low costs make RCA a promising screening tool for environmentally and clinically relevant fungi.

The PCR-RLB (reverse line blot hybridisation) was applied as a molecular technique for the detection of members of Pseudallescheria and Scedosporium from sputum of patients with cystic fibrosis (CF). Fifty-nine sputum samples were collected from 52 CF patients, which were analysed by culture and PCR-RLB. Conventional and semi-selective culture yielded five positive samples, but the PCR-RLB hybridisation assay permitted the detection of members of Pseudallescheria/Scedosporium in 32 out of 52 patients (61.5%). In total, PCR-RLB yielded 47 positives. Pseudallescheria apiosperma was detected in 20 samples, while Pseudallescheria boydii and Pseudallescheria aurantiacum were detected in 17 and eight samples, respectively. Six samples gave a positive reaction with two distinct species-specific probes and one sample with three probes. In conclusion, the PCR-RLB assay described in this study allows the detection of Scedosporium spp. in CF sputum samples and the identification of Pseudallescheria apiosperma, P. boydii, S. aurantiacum, Scedosporium prolificans and Pseudallescheria minutispora., (© 2011 Blackwell Verlag GmbH.)

Representatives of the genus Pseudallescheria (anamorph: Scedosporium) are saprobes and the aetiologic agent of invasive mycosis in humans. After dissemination, the central nervous system (CNS) is one of the most affected organs. Prerequisites for the survival of Pseudallescheria/Scedosporium in the host are the ability to acquire nutrients and to evade the immune attack. The cleavage of complement compounds via the secretion of fungal proteases might meet both challenges since proteolytic degradation of proteins can provide nutrients and destroy the complement factors, a fast and effective immune weapon in the CNS. Therefore, we studied the capacity of different Pseudallescheria/Scedosporium species to degrade key elements of the complement cascade in the cerebrospinal fluid and investigated a correlation with the phylogenetic background. The majority of the Pseudallescheria apiosperma isolates tested were demonstrated to efficiently eliminate proteins like complement factors C3 and C1q, thus affecting two main components of a functional complement cascade, presumably by proteolytic degradation, and using them as nutrient source. In contrast, the tested strains of Pseudallescheria boydii have no or only weak capacity to eliminate these complement proteins. We hypothesise that the ability of Pseudallescheria/Scedosporium strains to acquire nutrients and to undermine the complement attack is at least partly phylogenetically determined., (© 2011 Blackwell Verlag GmbH.)

The laboratory identification of Pseudallescheria and Scedosporium isolates at the species level is important for clinical and epidemiological purposes. This study used semiautomated repetitive sequence-based polymerase chain reaction (rep-PCR) to identify Pseudallescheria/Scedosporium. Reference strains of Pseudallescheria boydii (n = 12), Scedosporium prolificans (n = 8), Scedosporium apiospermum (n = 9), and clinical/environmental isolates (P. boydii, 7; S. prolificans, 7; S. apiospermum, 7) were analyzed by rep-PCR. All clinical isolates were identified by morphological and phenotypic characteristics and by sequence analysis. Species identification of reference strains was based on the results of available databases. Rep-PCR studies were also conducted with various molds to differentiate Pseudallescheria/Scedosporium spp. from other commonly encountered filamentous fungi. All tested Pseudallescheria/Scedosporium isolates were distinguishable from the other filamentous fungi. All Scedosporium prolificans strains clustered within the cutoff of 85%, and species identification by rep-PCR showed an agreement of 100% with sequence analysis. However, several isolates of P. boydii and S. apiospermum did not cluster within the 85% cutoff with the same species by rep-PCR. Although the identification of P. boydii and S. apiospermum was not correct, the semiautomated rep-PCR system is a promising tool for the identification of S. prolificans isolates.

Objectives: The aim of this study is to highlight the importance of infections caused by members of the genera Pseudallescheria/Scedosporium in HIV-positive patients., Methods: We describe a case of a fatal scedosporiosis in a treatment-naïve HIV patient and review all previously reported cases of pseudallescheriosis/scedosporiosis from a search of the PubMed and Deutsches Institut für Medizinische Dokumentation und Information (DIMDI) databases, applying the terms 'Pseudallescheria', 'Scedosporium', 'Allescheria', 'Monosporium', 'Petriellidium', 'boydii', 'prolificans', 'inflatum', cross-referenced with 'HIV' and 'AIDS'., Results: Detection of Scedosporium and Pseudallescheria species has been reported in 22 HIV-positive patients. Fourteen isolates belonged to the Pseudallescheria boydii complex and eight to Scedosporium prolificans. Invasive scedosporiosis (IS) was proven in 54.5% of the patients. Among them dissemination was observed in 66.7%. Pseudallescheria/Scedosporium species were mainly isolated from male individuals. Patients with proven IS showed CD4+ cell counts <100/μl and a higher co-infection rate as compared to colonized patients. Patients with central nervous system (CNS) manifestations showed CD4+ cell counts <50/μl. The mortality rate for patients with proven IS was 75% and was 100% for patients with dissemination/CNS manifestations. The fatality rate for patients treated with antifungal drugs plus surgery was lower compared to patients treated with antimycotic agents alone., Conclusions: IS only occurred in HIV-positive patients with a strongly impaired immune system. The survival rates of patients with advanced HIV disease and invasive scedosporiosis can be improved by rapid diagnosis by biopsy and requires complex therapy with a combination of active antifungal drugs, surgery and supportive immune augmentation., (Copyright © 2011 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

The major clinically relevant species in Scedosporium (teleomorph Pseudallescheria) are Pseudallescheria boydii, Scedosporium aurantiacum, Scedosporium apiospermum, and Scedosporium prolificans, while Pseudallescheria minutispora, Petriellopsis desertorum, and Scedosporium dehoogii are exceptional agents of disease. Three molecular methods targeting the partial β-tubulin gene were developed and evaluated to identify six closely related species of the S. apiospermum complex using quantitative real-time PCR (qPCR), PCR-based reverse line blot (PCR-RLB), and loop-mediated isothermal amplification (LAMP). qPCR was not specific enough for the identification of all species but had the highest sensitivity. The PCR-RLB assay was efficient for the identification of five species. LAMP distinguished all six species unambiguously. The analytical sensitivities of qPCR, PCR-RLB, and LAMP combined with MagNAPure, CTAB (cetyltrimethylammonium bromide), and FTA filter (Whatman) extraction were 50, 5 × 10(3), and 5 × 10(2) cells/μl, respectively. When LAMP was combined with a simplified DNA extraction method using an FTA filter, identification to the species level was achieved within 2 h, including DNA extraction. The FTA-LAMP assay is therefore recommended as a cost-effective, simple, and rapid method for the identification of Scedosporium species.

Members of the Pseudallescheria/Scedosporium species complex are emerging opportunistic fungal pathogens which have the capacity to colonize patients with damaged airways, including those with cystic fibrosis (CF). Assuming human infection is acquired via inhalation of fungal spores from the environment, we performed a qualitative environmental survey encompassing 25 urban, semirural and rural sites in the greater Sydney region to determine the prevalence of Pseudallescheria/Scedosporium species. Soil sampling revealed an abundance of Pseudallescheria/Scedosporium, particularly in locations associated with high human activity. No variation was noted during repeated sampling at different times of the year. Strains of Scedosporium aurantiacum were most frequently isolated (54.6%), followed by Scedosporium prolificans (43%), P. boydii (2.1%) and S. dehoogii (0.3%). The findings coincide with the relatively high prevalence of Scedosporium infections in Australia and their presence as colonizers in CF patients. They emphasize the importance of environmental studies to assess the clinical risk of infection.

We report a case of disseminated Scedosporium/Pseudallescheria infection due to Pseudallescheria boydii sensu stricto after lung transplantation in a patient with cystic fibrosis. Dissemination occurred under voriconazole. Despite surgery and combination therapy with voriconazole, caspofungin, and terbinafine, the patient died 8 months after transplantation. Previously reported cases are reviewed.

Scedosporium apiospermum has traditionally been thought of as the anamorph of Pseudallescheria boydii (Microascaceae, Ascomycota), but recent molecular studies has demonstrated that they are different species. Since a teleomorph was not observed among isolates recently identified as S. apiospermum, we investigated whether this species could be heterothallic. In this study, 15 isolates of S. apiospermum were paired in all possible combinations, including self-pairings. Several combinations produced fertile ascomata typical of the genus Pseudallescheria, while all isolates were self-sterile. The isolates were grouped into two different mating types. Crosses among F1 progeny ascospores demonstrated a bi-allelic heterothallic mating system. The new species Pseudallescheria apiosperma, teleomorph of S. apiospermum, is proposed and described.

The ubiquitous Pseudallescheria boydii (anamorph Scedosporium apiospermum) is a saprophytic filamentous fungus recognized as a potent etiologic agent of a wide variety of infections in immunocompromised as well as in immunocompetent patients. Very little is known about the virulence factors expressed by this fungal pathogen. The present review provides an overview of recent discoveries related to the identification and biochemical characterization of potential virulence attributes produced by P. boydii, with special emphasis on surface and released molecules. These structures include polysaccharides (glucans), glycopeptides (peptidorhamnomannans), glycolipids (glucosylceramides) and hydrolytic enzymes (proteases, phosphatases and superoxide dismutase), which have been implicated in some fundamental cellular processes in P. boydii including growth, differentiation and interaction with host molecules. Elucidation of the structure of cell surface components as well as the secreted molecules, especially those that function as virulence determinants, is of great relevance to understand the pathogenic mechanisms of P. boydii.

This study aims to determine the occurrence of Pseudallescheria and Scedosporium species in natural and human-dominated environments. Habitats (136 sampling sites) in a transect with increasing human impact were investigated (natural areas, agricultural soils, urban playgrounds, industrial areas). Physico-chemical parameters were measured to characterize the different areas included in this investigation. Fungal identification was performed by morphology and sequence data analysis. Comparative description of virulence was largely based on the database of the ECMM/ISHAM Working Group on Pseudallescheria/Scedosporium Infections. Pseudallescheria and Scedosporium species were most abundant in industrial areas, followed by urban playgrounds and agricultural areas. None of the species were isolated from natural habitats. The abundance of Pseudallescheria and Scedosporium species could be correlated with increasing nitrogen concentrations (P<0.01) and decreasing pH (P<0.05) within a pH range of 6.1-7.5. In general, frequency of the different Pseudallescheria and Scedosporium species in the environment is strongly enhanced by human activities, and largely differs from species distribution in clinical settings, suggesting that these species have different degrees of virulence. Pseudallescheria boydii is relatively frequently found as agent of human disease, while Scedosporium dehoogii is found almost exclusively in the environment. Scedosporium apiospermum is responsible for the majority of infections and is found at comparable frequency in the environment; S. aurantiacum and P. minutispora showed similar spectra, but at much lower frequencies.

Fungal infections caused by the members of the genera Pseudallescheria and/or Scedosporium are important complications in patients after near-drowning. As the taxonomy of Pseudallescheria and Scedosporium has been revised, clinical isolates from 11 patients, after near-drowning, previously identified as P. boydii or S. apiospermum had to be re-identified. S. apiospermum, now separated from P. boydii as a distinct species, was found most frequently (n = 8), while S. aurantiacum, recently described as new species and P. boydii were less common (n = 2 and n = 1, respectively). Three patients near-drowned during the Tsunami 2004 were infected by different species of the P. boydii complex. In vitro testing resulted in lowest minimal inhibitory concentration (MICs) for voriconazole (range 0.25-2.0 microg ml(-1)).

Osteomyelitis resulting from a mold infection often presents as a chronic and indolent disease process. Described here for the first time is a case of osteomyelitis of the foot caused by the mold Pseudallescheria fusoidea, which resulted from traumatic implantation after an injury sustained 3 years earlier.

Based on the morphological, physiologic, and molecular (beta-tubulin gene) study of 141 isolates of the Pseudallescheria boydii species complex (including several synonyms) and relatives, the new species Scedosporium dehoogii is proposed. Scedosporium apiospermum and P. boydii are considered two different species and the new name Scedosporium boydii is proposed for the anamorph of the latter species. A summary of the key morphological and physiological features for distinguishing the species of Pseudallescheria/Scedosporium is provided.

In order to establish intraspecific diversity of Pseudallescheria boydii and Scedosporium apiospermum, and to develop tools for their identification, variability within P. boydii and related species was investigated at different levels of diversity. Sequences of the D1/D2 region of large subunit (LSU) and of the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) gene were analyzed for a set of 57 strains, as well as partial sequences of the elongation factor 1-alpha (EF 1-alpha). Incongruence among 3 locus lineages was detected by partition homogeneity test (PHT). The maximum parsimony (MP) tree of the combined sequence data set, with the exception of strain CBS 499.90, formed 3 clades with high bootstrap support, corresponding to previously described nuclear DNA (nDNA)/DNA reassociation groups. These groups are known to differ slightly in predilection and temperature relations. Using Structure software, population genetic analysis revealed 3 clusters within the complex on the basis of multi-locus genotype data. Strain distribution in the clusters was concordant with that in the 3 clades of combined multi-locus MP tree. Recombination among individuals of a clade in evolutional history was found in 2 of the 3 clades. There was population differentiation among the 3 clades. Restriction fragment length polymorphism (RFLP) analysis of the intergenic spacer (IGS) region of rDNA gene was added to further characterize subspecific entities. When the IGS regions of 22 strains were digested with the restriction endonucleases Hae III and Mbo I, seven and five distinct patterns were detected, respectively. This subtyping did not reveal any correspondence with geographic origin or clinical appearance. Though we need more evidence to locate the 3 clades of the P. boydii complex at species or population level, the sequence of the D1/D2 region is sufficiently variable for identification of taxa belonging to the P. boydii complex.

The prevalence of new species of Pseudallescheria and Scedosporium in a collection of 46 clinical isolates was analyzed. Strain identification was done by morphological and molecular methods. Four Scedosporium aurantiacum isolates were detected among the panel of clinical strains. The susceptibility profile of S. aurantiacum was similar to that of Scedosporium apiospermum.

The main purpose of the present paper is to establish the connection between phylogenetic and morphological data and ecological features of strains of Pseudallescheria, Petriella, and Scedosporium. For the phylogenetic analysis sequences of the ITS region and the large subunit (partial sequences) of the rDNA were used. Cultural characteristics were observed on MEA 2 % and Weitzman-Silva Hutner Agar. Results showed, that three major groups could be differentiated, corresponding to Pseudallescheria, Petriella and S. prolificans. Among Petriella species only Pe. setifera is reasonably delimited. Pe. musispora was found to be synonymous with Pe. setifera. S. prolificans proved to be a homogenous species on the basis of ITS-sequences. Morphologically, Pseudallescheria and Petriella are distinguished by ostiolate vs non-ostiolate ascomata, a bipartition reflected also in ITS sequence data. We hypothesise a secondary loss of the ostiole of Pseudallescheria due to its ecological preferences. Infraspecific grouping within the highly variable species P. boydii is consistent for at least one clade in the ITS tree. The evolution of lineages with increased virulence within P. boydii is discussed.

Pseudallescheria boydii (anamorph Scedosporium apiospermum) is the species responsible for human scedosporiosis, a fungal infection with a high mortality rate and which is difficult to treat. Recently, it has been demonstrated that high genetic variation exists within this species. We have performed a morphological and molecular study involving numerous strains of clinical or environmental origins and from different countries. The analysis of partial sequences of the beta-tubulin (two loci) and calmodulin genes and the internal transcribed spacer region of the rRNA gene has demonstrated that P. boydii is a species complex. The combined analysis of the sequences of the four loci of 60 strains has showed the presence of 44 haplotypes in the in group. Three species morphologically related to P. boydii sensu stricto, i.e., Pseudallescheria angusta, Pseudallescheria ellipsoidea, and Pseudallescheria fusoidea, which had previously been considered synonyms, could be differentiated genetically from P. boydii in our study. It is relevant that two of the three strains now included in P. ellipsoidea have caused invasive infections. The species Pseudallescheria minutispora and Scedosporium aurantiacum are clearly phylogenetically separated from the other species studied and are here proposed as new. Morphological features support this proposal. All the strains included in S. aurantiacum species have a clinical origin, while those included in P. minutispora are environmental. Further studies are needed to demonstrate whether all the species included in the P. boydii complex have different clinical spectra and antifungal susceptibility.

Identification of fungi in tissue sections can be difficult. In particular, species of Aspergillus, Fusarium, and Pseudallescheria all appear as septate, branched hyphae. However, their differentiation can have significant clinical implications, as the latter two groups are often resistant to commonly used antifungal agents. In situ hybridization may assist in rapidly distinguishing these organisms in the absence of available culture. Oligonucleotide DNA probes were directed against the 5S, 18S, or 28S rRNA sequences of three groups of fungi with a high degree of specificity for each. Probes were tested on 26 formalin-fixed, paraffin-embedded tissue specimens, each with culture-proven involvement by one of these organisms: Fusarium species, n = 12; Pseudallescheria boydii, n = 5; Aspergillus species, n = 9 ( probe set validated in an earlier study). Accuracy of both ISH and morphology was compared with culture. Morphologic examination (GMS and PAS) showed a greater sensitivity in detecting fungi (100%) as compared with in situ hybridization (84.6%). When detected, however, DNA probes allowed definitive identification of organisms. While there was no ability to distinguish between the three groups of organisms by morphologic features, ISH probes showed 100% positive predictive value (PPV, 19/19 organisms identified correctly). No cross-reactivity was observed when the probes were tested against other genera (100% specificity). Furthermore, the use of ISH allowed the detection of mixed fungal infections involving multiple organism types in two cases, demonstrating another advantage over morphology. In situ hybridization, directed against rRNA sequences, provides a rapid and accurate technique for distinguishing commonly encountered, nonpigmented filamentous fungi in histologic sections. While less sensitive than morphology, ISH is highly accurate and may help to distinguish between organisms that have similar or identical morphologic features by light microscopy.

The sequences of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) domain data obtained by restriction fragment length polymorphism analysis with 18S rDNA and fingerprinting (M13) for clinical and environmental strains of Pseudallescheria boydii (anamorph, Scedosporium apiospermum) were compared to those for related species of Pseudallescheria, Petriella, and Scedosporium. The infraspecific variability of P. boydii was considerable. There were five different lengths in the 18S rDNAs within P. boydii due to the occurrence of introns. In several cases, strains isolated from a single pond or ditch proved to be genetically very different. Nevertheless, some lineages had a regional distribution. The variability found is unlikely to be explained by meiotic recombination alone. Pseudallescheria fusoidea, Pseudallescheria ellipsoidea, and Pseudallescheria angusta were found to be synonyms for P. boydii. Scedosporium prolificans was found amid Petriella species in the ITS tree and showed no infraspecific variability. The type strain of Rhinocladium lesnei proved to be identical to Graphium putredinis. Acladium castellanii, which is morphologically reminiscent of S. apiospermum, was also found to be a separate species, but with an unknown affiliation.

Pseudallescheria boydii (anamorph: Scedosporium apiospermum) and S. prolificans can cause severe infections in both the immunocompromized host and accidentally injured people. A species-specific polymerase chain reaction (PCR) enabling detection and discrimination of these fungi has not been available to date. In view of the difficult treatment especially of S. prolificans infections, a PCR-based detection system has been developed. Based on results of partial sequencing of ribosomal DNA, Scedosporium DNA could be amplified, either at the genus or at the species level. Hybridization probes for the identification of the PCR-products were established.

Genetic relatedness of 10 strains of opportunistic human pathogenic fungi in the genera Pseudallescheria and Scedosporium and related fungi including Petriella setifera, Graphium tectonae and Ceratocystis fimbriata, were tested by sequencing the entire SSU rDNA. From these molecular data, the imperfect genus Scedosporium can be divided in two, S. prolificans being separable from the S. apiospermum complex. Nearest sexual relatives of S. prolificans seem to be in the microascalean genus Petriella. Strains of Ps. boydii and S. apiospermum, although differing by their previously known DNA/DNA reassociation values, were not separable from each other once a 380 nucleotide long insertion had been removed from the sequence of the two S. apiospermum strains tested. The SSU rDNA of Ps. ellipsoidea is identical to that of Ps. boydii. Fungi which have been known to have Graphium anamorphs can be divided in at least three groups, one of which is related to Petriella and includes Graphium tectonae.