Summary The objectives of the present study were: (i) to assess the frequency of oral colonisation by Candida species in HIV‐positive patients and to compare it with a population of HIV‐negative individuals, (ii) to determine the prevalence of C. dubliniensis in both populations and (iii) to determine the susceptibility of C. dubliniensis and other Candida species isolated from HIV‐positive patients to the most commonly used antifungal agents. Oral samples were obtained from 101 HIV‐positive and 108 HIV‐negative subjects. For yeast identification, we used morphology in cornmeal agar, the API 20C Aux, growth at 45 °C, d‐xylose assimilation, morphology in sunflower seed agar and PCR. The frequency of isolation of Candida in HIV‐positive patients was: C. albicans, 60.7%; C. dubliniensis, 20.2%; C. glabrata, 5.6%; C. krusei, 5.6%; C. tropicalis, 4.5%; others, <5%. The frequency of isolation of Candida in HIV‐negative patients was: C. albicans, 73.9%; C. tropicalis, 15.5%; C. dubliniensis, 2.1%; C. glabrata, 2.1%; C. parapsilosis, 2.1%; others, <5%. The oral colonisation by yeast in the HIV‐positive patients was higher than that in the HIV‐negative subjects. The susceptibilities of 42 Candida isolates to three antifungal agents were determined. All isolates of C. dubliniensis were susceptible to fluconazole, although several individuals had been previously treated with this drug. Out of the 42 Candida isolates, 10 presented resistance to fluconazole and 10 to itraconazole. The presence of Candida species, resistant to commonly used antifungal agents, represents a potential risk in immunocompromised patients.

Sudden death syndrome (SDS) of soybean has become a serious constraint to the production of this crop in North and South America. Phenotypic and multilocus molecular phylogenetic analyses, as well as pathogenicity experiments, have demonstrated that four morphologically and phylogenetically distinct fusaria can induce soybean SDS. Published molecular diagnostic assays for the detection and identification of these pathogens have reported these pathogens as F. solani, F. solani f. sp. glycines, or F. solani f. sp. phaseoli, primarily because the species limits of these four pathogens were only recently resolved. In light of the recent discovery that soybean SDS and Phaseolus and mung bean root rot (BRR) are caused by four and two distinct species, respectively, multilocus DNA sequence analyses were conducted to assess whether any of the published molecular diagnostic assays were species-specific. Comparative DNA sequence analyses of the soybean SDS and BRR pathogens revealed that highly conserved regions of three loci were used in the design of these assays, and therefore none were species-specific based on our current understanding of species limits within the SDS-BRR clade. Prompted by this finding, we developed a high-throughput multilocus genotyping (MLGT) assay which accurately differentiated the soybean SDS and two closely related Phaseolus and mung BRR pathogens based on nucleotide polymorphism within the nuclear ribosomal intergenic spacer region rDNA and two anonymous intergenic regions designated locus 51 and 96. The single-well diagnostic assay, employing flow cytometry and a novel fluorescent microsphere array, was validated by independent multilocus molecular phylogenetic analysis of a 65 isolate design panel. The MLGT assay was used to reproducibly type a total of 262 soybean SDS and 9 BRR pathogens. The validated MLGT array provides a unique molecular diagnostic for the accurate identification and molecular surveillance of these economically important plant pathogens.

Trichosporon species are emerging pathogens capable of causing severe infections in immunocompromised patients. In this paper, we report a case of systemic infection in a liver transplant patient caused by Trichosporon asahii to show the etiologic agent's aggressiveness and poor therapeutic results with the different antifungals employed.

The adherence of different Candida strains isolated from the human gastrointestinal tract was studied. The 23 Candida strains isolated from faeces were C. albicans (12), C. glabrata (2), C. krusei (2), C. parapsilosis (2), C. tropicalis (2), C. colliculosa (1), C. kefyr (1) and C. lusitaniae (1). Buccal epithelial cells from different healthy donors were used. Adherence values were maximal for C. albicans and minimal for C. krusei. A relation exists between yeast adherence capacity and the ability to colonize mucosal surfaces.

Adherence to host cells is essential for yeasts to develop their full pathogenic potential since it triggers the process that leads to colonization and enables their persistence in the host. The aim of this work was to study the in vitro adherence of Candida dubliniensis and other Candida species, as well as the relation of adherence with the colonization and dissemination of these yeasts in an experimental mice model. Clinical isolates of Candida dubliniensis, Candida albicans, Candida glabrata, Candida krusei, Candida parapsilosis and Candida tropicalis were tested for their in vitro ability to adhere to buccal epithelial cells and in vivo to colonize and disseminate in an experimental infant mice model. Although C. dubliniensis isolates showed variable adherence values, their ability to colonize and disseminate in mice tissue was almost null. All C. albicans strains showed high levels of adherence and a prolonged gastrointestinal (GI) tract colonization. Both C. glabrata and C. krusei, showed a minor in vitro adherence and limited colonization time in infant mice GI tract. C. albicans and C. parapsilosis demonstrated a higher ability to disseminate, but the other non-C. albicans Candida strains showed a lower ability to disseminate. This study demonstrates that C. dubliniensis has a low GI tract colonization ability, as well as low dissemination ability in relation to C. albicans.