Fusarium and Neocosmospora: fungal priority pathogens in laboratory diagnosis.

Fusarium and Neocosmospora are two fungal genera recently recognized in the list of fungal priority pathogens. They cause a wide range of diseases that affect humans, animals, and plants. In clinical laboratories, there is increasing concern about diagnosis due to limitations in sample collection and morphological identification. Despite the advances in molecular diagnosis, due to the cost, some countries cannot implement these methodologies. However, recent changes in taxonomy and intrinsic resistance to antifungals reveal the necessity of accurate species-level identification. In this review, we discuss the current phenotypic and molecular tools available for diagnosis in clinical laboratory settings and their advantages and disadvantages.

Polyphasic identification of three new species in Alternaria section Infectoriae causing human cutaneous infection.

BACKGROUND: Cutaneous phaeohyphomycosis is an emerging disease in immunocompromised patients, being Alternaria one of the most common genera reported as a causative agent. Species identification is not carried out mainly due to the complexity of the genus. Analysis of the ITS barcode has become standard for fungal identification, but in Alternaria it is only able to discriminate among species-groups or sections. METHODS: We present three cases of cutaneous infection caused by Alternaria isolates morphologically identified as belonging to section Infectoriae. They have been morphologically characterised and phylogenetically delineated with five molecular markers (ITS, ATPase, gapdh, rpb2 and tef1). RESULTS: Mycotic infections have been diagnosed by repeated cultures and histopathological examination in two of the cases. The polyphasic approach has allowed to delineate three new species of Alternaria section Infectoriae, that is A anthropophila, A atrobrunnea and A guarroi. ATPase has been the only locus able to discriminate most of the species (29 out of 31) currently sequenced in this section, including A infectoria the commonest reported species causing alternariosis. Susceptibility test showed different antifungal patterns for the three species, although terbinafine was the most active in vitro drug against these fungi. CONCLUSIONS: The ATPase gene is recommended as an alternative barcode locus to identify Alternaria clinical isolates in section Infectoriae. Our results reinforce the relevance of identification of Alternaria isolates at the species level and the necessity to carry out antifungal susceptibility testing to determine the most adequate drug for treatment.

A human subcutaneous infection by Microascus ennothomasiorum sp. nov.

A 60-year-old woman presented with a nodular granulomatous skin lesion on her right thumb. It had developed after inoculation of a splinter of wood. Because it was resistant to various therapies, the nodule was finally excised. Complete healing followed this surgery and a melanised filamentous fungus with scopulariopsis-like morphology was recovered from the dermal tissue. Fitting with no known species, the fungus was subjected to extensive morphological, physiological and genetic investigations. It was characterised by resistance to cycloheximide, growth at 37°C, branched conidiophores with cylindrical annellides in brush-like groups producing dark conidia in basipetal chains, and cleistothecia with ellipsoidal to slightly reniform ascospores. Genetically it clustered in a well-supported clade together with Microascus (M.) brunneosporus, Microascus chinensis, Microascus intricatus, Microascus longicollis, Microascus micronesiensis and Microascus onychoides, but formed an independent branch distant from the other Microascus species. Based on its unique genetic characteristics and morphological findings, the isolate is proposed as a new species, Microascus ennothomasiorum. Morphologically it differs from its phylogenetically closest species by its branched conidiophores and ascomata with a peridium of textura intricata. Our observation once again emphasises that dermal granulomas can be caused by uncommon fungi; diagnostics should therefore include appropriate mycological investigations.

Polyphasic data support the splitting of Aspergillus candidus into two species; proposal of Aspergillus dobrogensis sp. nov.

Aspergillus candidus is a species frequently isolated from stored grain, food, indoor environments, soil and occasionally also from clinical material. Recent bioprospecting studies highlighted the potential of using A. candidus and its relatives in various industrial sectors as a result of their significant production of enzymes and bioactive compounds. A high genetic variability was observed among A. candidus isolates originating from various European countries and the USA, that were mostly isolated from indoor environments, caves and clinical material. The A. candidus sensu lato isolates were characterized by DNA sequencing of four genetic loci, and agreement between molecular species delimitation results, morphological characters and exometabolite spectra were studied. Classical phylogenetic methods (maximum likelihood, Bayesian inference) and species delimitation methods based on the multispecies coalescent model supported recognition of up to three species in A. candidus sensu lato. After evaluation of phenotypic data, a broader species concept was adopted, and only one new species, Aspergillus dobrogensis, was proposed. This species is represented by 22 strains originating from seven countries (ex-type strain CCF 4651T=NRRL 62821T=IBT 32697T=CBS 143370T) and its differentiation from A. candidus is relevant for bioprospecting studies because these species have different exometabolite profiles. Evaluation of the antifungal susceptibility of section Candidi members to six antifungals using the reference EUCAST method showed that all species have low minimum inhibitory concentrations for all tested antifungals. These results suggest applicability of a wide spectrum of antifungal agents for treatment of infections caused by species from section Candidi.

Species of Aspergillus section Aspergillus from clinical samples in the United States.

The diversity of Aspergillus species in clinical samples is continuously increasing. Species under the former name Eurotium, currently accommodated in section Aspergillus of the genus Aspergillus, are xerophilic fungi widely found in the human environment and able to grow on substrates with low water activity. However, their prevalence in the clinical setting is poorly known. We have studied the presence of these species in a set of clinical samples from the United States using a multilocus sequence analysis based on the internal transcribed spacer (ITS) region of the rRNA, and fragments of the genes ß-tubulin (BenA), calmodulin (CaM), and polymerase II second largest subunit (RPB2). A total of 25 isolates were studied and identified as follows: A. montevidensis (44%), A. chevalieri (36%), A. pseudoglaucus (8%), and A. costiformis (4%). A new species Aspergillus microperforatus is also proposed, which represented 8% of the isolates studied and is characterized by uniseriate conidial heads, subglobose to pyriform vesicles, rough conidia, globose to subglobose cleistothecia, and lenticular and smooth ascospores. The in vitro antifungal activity of eight clinically available antifungals was also determined against these isolates, with the echinocandins and posaconazole having the most potent activity.

Cryptic Aspergillus from clinical samples in the USA and description of a new species in section Flavipedes.

BACKGROUND: In the last few decades there has been an emergence of cryptic Aspergillus as agents of human infections due to the increase in immunocompromised population and to the improvement of identification tools. METHODS: Continuing our study on Aspergillus isolates from clinical origin deposited in a mycological reference centre in the United States, we selected 37 isolates belonging to less common sections of the genus, to study their species diversity and detect cryptic species by using a polyphasic approach. RESULTS: From this set of isolates, a total of 16 species were identified; the most frequent being A. calidoustus (48.6%, section Usti), A. terreus (13.5%, section Terrei), and A. nidulans (5.7%, section Nidulantes). The remaining isolates corresponded to 13 species of rare or cryptic Aspergillus, i.e. A. europaeus (section Cremei); A. iizukae, A. micronesiensis, A. spelaeus (section Flavipedes); A. pachycristatus, A. quadrilineatus, A. spinulosporus, A. unguis (section Nidulantes); A. alabamensis, A. carneus, A. hortai (section Terrei), A. granulosus (section Usti); and the new species A. suttoniae (section Flavipedes), which is described here. CONCLUSIONS: Correct identification of cryptic species is crucial to reveal new potential pathogens, to gather accurate epidemiological data and to choose an appropriate treatment.

Fungal Olecranon Bursitis in an Immunocompetent Patient by Knoxdaviesia dimorphospora sp. nov.: Case Report and Review.

Bursitis is a common medical condition that can occur either with or without infection. We present a case of fungal olecranon bursitis in an immunocompetent individual caused by the new species Knoxdaviesia dimorphospora. It is a dematiaceous filamentous fungus characterized by the production of two different conidia: hyaline and cylindrical, which rise up from phialidic conidiogenous cells located in the upper part of differentiated and unbranched conidiophores, and pale brown and ellipsoidal conidia produced by phialidic conidiogenous cells which are born directly on hyphae. In addition to its morphological peculiarities, the novelty of the fungus was confirmed by sequence analysis of the internal transcribed spacer (ITS) regions and D1/D2 domains of the 28S of the nuclear rRNA gene. The fungal infection was confirmed by cytological examination and repeated cultures. The infection was resolved by surgical debridement and drainage, and the patient presented a complete functional recovery 3 months later. The in vitro antifungal susceptibility to this new human opportunist is provided, terbinafine being the drug with the most potent activity.

Four new species of Talaromyces from clinical sources.

The genus Talaromyces constitutes an important group of molds with species that are mainly found in soil, indoor environments and food products. Traditionally, it has been considered, together with Eupenicillium, the teleomorphic state of Penicillium. However, the taxonomy of these fungi has changed considerably, and Talaromyces currently includes sexually and asexually reproducing species. In a previous study of the occurrence of penicillium-like fungi from clinical samples in the USA, we used the combined phylogeny of the internal transcribed spacer (ITS) region of the rDNA and ß-tubulin (BenA) gene to identify 31 isolates of Talaromyces, 85 of Penicillium and two of Rasamsonia. However, seven isolates of Talaromyces were assigned to the corresponding sections but not to any particular species. In this study, we have resolved the taxonomy of these isolates through a multilocus sequence analysis of the ITS, fragments of the BenA, calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2) genes, and a detailed phenotypic study. As a result, four new species are described and illustrated, ie Talaromyces alveolaris, T. georgiensis, T. minnesotensis and T. rapidus.

Identification and Antifungal Susceptibility of Penicillium-Like Fungi from Clinical Samples in the United States.

Penicillium species are some of the most common fungi observed worldwide and have an important economic impact as well as being occasional agents of human and animal mycoses. A total of 118 isolates thought to belong to the genus Penicillium based on morphological features were obtained from the Fungus Testing Laboratory at the University of Texas Health Science Center in San Antonio (United States). The isolates were studied phenotypically using standard growth conditions. Molecular identification was made using two genetic markers, the internal transcribed spacer (ITS) and a fragment of the ß-tubulin gene. In order to assess phylogenetic relationships, maximum likelihood and Bayesian inference assessments were used. Antifungal susceptibility testing was performed according to CLSI document M38-A2 for nine antifungal drugs. The isolates were identified within three genera, i.e., Penicillium, Talaromyces, and Rasamsonia The most frequent species in our study were Penicillium rubens, P. citrinum, and Talaromyces amestolkiae The potent in vitro activity of amphotericin B (AMB) and terbinafine (TRB) and of the echinocandins against Penicillium and Talaromyces species might offer a good therapeutic alternative for the treatment of infections caused by these fungi.

Acrophialophora, a poorly known fungus with clinical significance.

Acrophialophora fusispora is an emerging opportunistic fungus capable of causing human infections. The taxonomy of the genus is not yet resolved and, in order to facilitate identification of clinical specimens, we have studied a set of clinical and environmental Acrophialophora isolates by morphological and molecular analyses. This set included the available type strains of Acrophialophora species and similar fungi, some of which were considered by various authors to be synonyms of A. fusispora. Sequence analysis of the large subunit (LSU) and internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and a fragment of the ß-tubulin (Tub) gene revealed that Acrophialophora belongs in the family Chaetomiaceae and comprises three different species, i.e., A. fusispora, Acrophialophora levis, and Acrophialophora seudatica; the latter was previously included in the genus Ampullifera. The most prevalent species among clinical isolates was A. levis (72.7%), followed by A. fusispora (27.3%), both of which were isolated mostly from respiratory specimens (72.7%), as well as subcutaneous and corneal tissue samples. In general, of the eight antifungal drugs tested, voriconazole had the greatest in vitro activity, while all other agents showed poor in vitro activity against these fungi.

Humicola sp. as a Cause of Peritoneal Dialysis-Associated Peritonitis.

Peritoneal dialysis is the renal replacement modality used by ∼20% of patients with end-stage kidney disease (S. McDonald, P. Clayton, and K. Hurst, p. 6.2-6.27, in ANZDATA 2012 Annual Report, 35th ed., 2012). A major complication of peritoneal dialysis is the development of peritonitis. We describe a case of Humicola sp. causing peritoneal dialysis (PD)-associated peritonitis, successfully treated with a prolonged course of antifungal therapy.

Cladosporium Species Recovered from Clinical Samples in the United States.

Cladosporium species are ubiquitous, saprobic, dematiaceous fungi, only infrequently associated with human and animal opportunistic infections. We have studied a large set of Cladosporium isolates recovered from clinical samples in the United States to ascertain the predominant species there in light of recent taxonomic changes in this genus and to determine whether some could possibly be rare potential pathogens. A total of 92 isolates were identified using phenotypic and molecular methods, which included sequence analysis of the internal transcribed spacer (ITS) region and a fragment of the large subunit (LSU) of the nuclear ribosomal DNA (rDNA), as well as fragments of the translation elongation factor 1 alpha (EF-1α) and actin (Act) genes. The most frequent species was Cladosporium halotolerans (14.8%), followed by C. tenuissimum (10.2%), C. subuliforme (5.7%), and C. pseudocladosporioides (4.5%). However, 39.8% of the isolates did not correspond to any known species and were deemed to comprise at least 17 new lineages for Cladosporium. The most frequent anatomic site of isolation was the respiratory tract (54.5%), followed by superficial (28.4%) and deep tissues and fluids (14.7%). Species of the two recently described cladosporiumlike genera Toxicocladosporium and Penidiella are reported for the first time from clinical samples. In vitro susceptibility testing of 92 isolates against nine antifungal drugs showed a variety of results but high activity overall for the azoles, echinocandins, and terbinafine.

Occurrence of Ochroconis and Verruconis species in clinical specimens from the United States.

Ochroconis is a dematiaceous fungus able to infect immunocompetent people. Recently, the taxonomy of the genus has been reevaluated, and the most relevant species, Ochroconis gallopava, was transferred to the new genus Verruconis. Due to the important clinical implications of these fungi and based on the recent classification, it was of interest to know the spectra of Ochroconis and Verruconis species in clinical samples received in a reference laboratory in the United States. A set of 51 isolates was identified morphologically and molecularly based on sequence analyses of the nuclear ribosomal RNA (nrRNA), actin, and ß-tubulin genes. Verruconis gallopava was the most common species (68.6%), followed by Ochroconis mirabilis (21.5%). One isolate of Ochroconis cordanae was found, being reported for the first time in a clinical setting. The most common anatomical site of isolation was the lower respiratory tract (58.8%), followed by superficial and deep tissues at similar frequencies (21.6 and 19.6%, respectively). Interestingly, three new species were found, which are Ochroconis olivacea and Ochroconis ramosa from clinical specimens and Ochroconis icarus of an environmental origin. The in vitro antifungal susceptibilities of eight antifungal drugs against the Ochroconis isolates revealed that terbinafine and micafungin were the most active drugs.

Phylogeny of the clinically relevant species of the emerging fungus Trichoderma and their antifungal susceptibilities.

A set of 73 isolates of the emerging fungus Trichoderma isolated from human and animal clinical specimens were characterized morphologically and molecularly using a multilocus sequence analysis that included the internal transcribed spacer (ITS) regions of the nuclear ribosomal DNA and fragments of the translation elongation factor 1 alpha (Tef1), endochitinase CHI18-5 (Chi18-5), and actin 1 (Act1) genes. The most frequent species was Trichoderma longibrachiatum (26%), followed by Trichoderma citrinoviride (18%), the Hypocrea lixii/Trichoderma harzianum species complex (15%), the newly described species Trichoderma bissettii (12%), and Trichoderma orientale (11%). The most common anatomical sites of isolation in human clinical specimens were the respiratory tract (40%), followed by deep tissue (30%) and superficial tissues (26%), while all the animal-associated isolates were obtained from superficial tissue samples. Susceptibilities of the isolates to eight antifungal drugs in vitro showed mostly high MICs, except for voriconazole and the echinocandins.

Pithomyces species (Montagnulaceae) from clinical specimens: identification and antifungal susceptibility profiles.

The fungal genus Pithomyces comprises numerous dematiaceous saprobic species commonly found on dead leaves and stems of a great variety of plants. Occasionally, they have been recovered from clinical specimens. We morphologically and molecularly (rDNA sequences) investigated a set of 42 isolates tentatively identified as Pithomyces recovered from clinical specimens in the United States. The predominant species were P. chartarum and P. sacchari (33.3% each), followed by Pithomyces sp. I (28.6%) and P. maydicus (4.8%). Most of the isolates were obtained from samples of superficial tissue (50%), the respiratory tract (21.4%), and the nasal region (19%). In general, these fungi were highly susceptible in vitro to the eight antifungal agents tested.

Acremonium with catenate elongate conidia: phylogeny of Acremonium fusidioides and related species.

Acremonium is one of the largest and most complex genera of hyphomycetes. Its taxonomy is not yet resolved and the phylogenetic value of the most distinctive morphological features is unknown. The species of this genus produce conidia in chains or form slimy heads or both. We have studied a set of clinical and environmental Acremonium strains morphologically characterized by producing mostly catenate, elongate, more or less fusiform conidia. Based on phenotypic data and in the analysis of the sequences of the ITS region, the D1/D2 domains of the 28S rRNA gene and a fragment of the ß-tubulin gene, three new species morphologically similar to Acremonium fusidioides and belonging to the family Bionectriaceae (Hypocreales) are described and illustrated; they are Acremonium pilosum, Acremonium parvum and Acremonium citrinum. The first species produces two kinds of conidia: clavate with smooth walls and globose with abundant filiform projections. Acremonium parvum is characterized by slow growth and pyriform or slightly lanceolate conidia with an elongate and truncate base. Acremonium citrinum produces a diffusible yellow pigment and obovoid conidia.

New species of Cordana and epitypification of the genus.

Two interesting fungi belonging to the genus Cordana have been isolated recently in Spain from plant debris. Both are proposed here as new species, described and illustrated. Cordana mercadiana sp. nov. produces 0-1-septate conidia, with a prominent basal scar. Cordana verruculosa sp. nov. differs from the other species of the genus by its unique combination of aseptate, verruculose and small conidia. Both species are compared morphologically with other species of Cordana and their identities supported by the analysis of rDNA sequences. LSU sequence analysis revealed the congeneric relationship of Cordana and Pseudobotrytis; the members of both genera are in a well supported monophyletic lineage that appears to be related to the Coniochaetales but remains incertae sedis within the Sordariomycetes. To establish nomenclatural stability of the genus Cordana, an isolate of C. pauciseptata is designed here as epitype and the two species of Pseudobotrytis are transferred to Cordana. A dichotomous key is provided to identify the currently accepted species of Cordana.

Sunken Riches: Ascomycete Diversity in the Western Mediterranean Coast through Direct Plating and Flocculation, and Description of Four New Taxa.

The Mediterranean Sea stands out as a hotspot of biodiversity, whose fungal composition remains underexplored. Marine sediments represent the most diverse substrate; however, the challenge of recovering fungi in culture hinders the precise identification of this diversity. Concentration techniques like skimmed milk flocculation (SMF) could represent a suitable solution. Here, we compare the effectiveness in recovering filamentous ascomycetes of direct plating and SMF in combination with three culture media and two incubation temperatures, and we describe the fungal diversity detected in marine sediments. Sediments were collected at different depths on two beaches (Miracle and Arrabassada) on the Spanish western Mediterranean coast between 2021 and 2022. We recovered 362 strains, and after a morphological selection, 188 were identified primarily with the LSU and ITS barcodes, representing 54 genera and 94 species. Aspergillus, Penicillium, and Scedosporium were the most common genera, with different percentages of abundance between both beaches. Arrabassada Beach was more heterogeneous, with 42 genera representing 60 species (Miracle Beach, 28 genera and 54 species). Although most species were recovered with direct plating (70 species), 20 species were exclusively obtained using SMF as a sample pre-treatment, improving our ability to detect fungi in culture. In addition, we propose three new species in the genera Exophiala, Nigrocephalum, and Queenslandipenidiella, and a fourth representing the novel genus Schizochlamydosporiella. We concluded that SMF is a useful technique that, in combination with direct plating, including different culture media and incubation temperatures, improves the chance of recovering marine fungal communities in culture-dependent studies.

Scopulariopsis, a poorly known opportunistic fungus: spectrum of species in clinical samples and in vitro responses to antifungal drugs.

Ninety-nine isolates of clinical origin, tentatively identified as Scopulariopsis or Microascus, were morphologically and molecularly characterized by a combined analysis of the D1/D2 domains of the 28S rRNA gene and a fragment of the elongation factor 1-α gene (EF1-α) sequences. The most prevalent species was Scopulariopsis brevicaulis (49.4%), followed by Scopulariopsis gracilis (14.4%), Scopulariopsis brumptii (7.2%), Microascus cinereus (5.2%), the Scopulariopsis candida species complex (3.1%), and Microascus cirrosus (2.1%). The most common anatomic sites of isolation were the respiratory tract (61.6%), superficial tissue (19.2%), and deep tissue or fluid samples (19.2%). The antifungal susceptibilities of the isolates to eight drugs were tested in vitro, with all the drugs generally showing poor activity.

Mixed infection caused by Lecythophora canina sp. nov. and Plectosphaerella cucumerina in a German shepherd dog.

We describe an opportunistic, disseminated infection in a German shepherd dog associated with two fungal organisms not previously reported to cause disease. Lecythophora canina, a new species here described, was isolated from an osteolytic bone lesion. A fine needle aspirate of the lesion demonstrated septate hyphae. Plectospharella cucumerina (anamorph Plectosporium tabacinum) was isolated from a urine sample. Clinical manifestations were blindness, altered mentation, and osteomyelitis. Treatment with itraconazole and terbinafine for greater than one year resulted in stable clinical disease.