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1.
Trichosporon species are usually opportunistic pathogens. Here, we present a case of esophagitis caused by T. inkin in a 54-year-old woman with pulmonary cancer and severe neutropenia in whom the susceptibility profile of the isolate against azoles and polyenes was verified. The patient was diagnosed with esophagitis grade I of Wilcox, presenting scattered whitish plaques and exudates in upper two-thirds of the esophageal mucosa. Antifungal therapy involving oral fluconazole (150 mg/day for 14 days) was ineffective. In vitro, the isolate showed no resistance to this azole and sensitivity to amphotericin B. Since T. inkin is of growing importance as an agent of invasive infections in immunocompromised patients, we stress that the diagnosis of esophagitis by this species should be followed by an assessment of the therapeutic sensitivity of the strain involved.  相似文献   

2.
Unusual fungal agents that exist environmentally as saprophytes can often lead to opportunistic infections. Hyalohyphomycosis is a group of fungal infections caused by fungi characterized by hyaline septate hyphae and can infect both immunocompetent as well as immunocompromised patients. Many a times it becomes difficult to distinguish a pathogenic and a contaminant fungus, because many such agents can assume clinical significance depending on circumstances. Subcutaneous and invasive fungal infection due to the emerging hyalohyphomycotic fungus, Acremonium, has drawn the attention of clinicians and microbiologists, as a potential pathogen in patients with and without underlying risk factors. Generally considered to be minimally invasive in the past, genus Acremonium has been responsible for eumycotic mycetomas and focal infections in otherwise healthy individuals. It has also been increasingly implicated in systemic fungal diseases. The management with different antifungals in various clinical situations has been very conflicting and hence needs to be carefully evaluated. This overview is an endeavor to consolidate the available clinical infections due to Acremonium and the recommendations on treatment.  相似文献   

3.
Onychomycosis, a fungal infection of the finger or toenails, is predominantly caused by Trichophyton rubrum. Treatment is difficult due to high recurrence rates and problems with treatment compliance. For these reasons, alternative therapies are needed. Here we describe the photoactivation of Rose Bengal (RB) using a green laser (λ = 532 nm) at fluences of 68, 133 and 228 J/cm2, and assess its fungicidal activity on T. rubrum spore suspensions. A 140 µM RB solution was able to induce a fungicidal effect on T. rubrum when photosensitized with the fluence of 228 J/cm2. RB photosensitization using a green laser provides a potential novel treatment for T. rubrum infections. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

4.
The currently accepted type species of the genusTrichosporon Behrend isT. beigelii. This species has formerly been regarded as identical toT. cutaneum. However, these fungi are now known to represent separate species with different ecology. The first species described inTrichosporon wasT. ovoides, an agent of human white piedra. A neotype strain is designated for this species, while a lectotype strain is indicated forT. cutaneum. The nameT. beigelii is considered as doubtful and consequently cannot be maintained.  相似文献   

5.
Healthcare-associated invasive fungal infections are increasing and are a cause of significant patient morbidity and mortality. Nosocomial infections due to Candida species, followed by Aspergillus species, are the most common causes of these infections in hospitalized patients. Hospital epidemiologists and infection control practitioners must recognize that similar to bacterial pathogens, fungal infections can be the cause of hospital outbreaks, and issues of resistance are increasing. Efforts to best identify patients at risk for developing fungal infections or those at risk of having a resistant organism are ongoing. Better diagnostics and tools to aid prevention are needed in addition to usual infection prevention and control standards.  相似文献   

6.
Phomopsis longicolla (Hobbs) causes Phomopsis seed decay and stem lesions in soybean (Glycine max). In this study, a novel, high‐throughput adaptation of RAD‐seq termed MoNSTR‐seq (Mutation analysis via Next‐generation DNA Sequencing of T‐DNA Regions) was developed to determine the genomic location of T‐DNA insertions in P. longicolla mutants. Insertional mutants were created via Agrobacterium tumefaciens‐mediated transformation, and one mutant, strain PL343, was further investigated due to impaired stem lesion formation. Mutation analysis via Next‐generation DNA Sequencing of T‐DNA Regions, in which DNA libraries are created with two distinct restriction enzymes and customized adapters to simultaneously enrich both T‐DNA insertion borders, was developed to characterize the genomic lesion in strain PL343. MoNSTR‐seq successfully identified a T‐DNA insertion in the predicted promoter region of a gene encoding a cellobiose dehydrogenase (CDH1), and the position of the T‐DNA insertion in strain PL343 was confirmed by Sanger sequencing. Thus, MoNSTR‐seq represents an effective tool for molecular genetics in P. longicolla, and is readily adaptable for use in diverse fungal species.

Significance and Impact of the Study

This study describes MoNSTR‐seq (Mutation analysis via Next‐generation DNA Sequencing of T‐DNA Regions), an adaptation of restriction site‐associated DNA sequencing (RAD‐seq) to identify the position of transfer‐DNA (T‐DNA) insertions in the genome of Phomopsis longicolla, an important pathogen of soybean. The technique enables high‐throughput characterization of mutants generated via Agrobacterium tumefaciens‐mediated transformation (ATMT), thus accelerating gene discovery via forward genetics. This technique represents a significant advancement over existing approaches to characterize T‐DNA insertions in fungal genomes. With minor modifications, this technique could be easily adapted to taxonomically diverse fungal pathogens and additional mutagenesis cassettes.  相似文献   

7.
The production of prostaglandins (PGs) during fungal infections could be an important suppressor factor of host immune response. Host cells are one source of prostaglandin E2 (PGE2); however another potential source of PGE2 is the fungal pathogen itself. Thus, both host and fungal PGE2 production is theorized to play a role in pathogenesis, being critical for growth of the fungus and to modulate the host immune response. The purpose of this work was to investigate if high and low virulent strains of Paracoccidioides brasiliensis have the capacity to produce PGE2 in vitro, and if this production was related to the fungal growth. The results demonstrated that both strains of P. brasiliensis produce high levels of PGE2 and the treatment with indomethacin, a cyclooxygenase inhibitor, significantly reduced the production of this mediator, as well as the viability of the fungus. Thus, our data indicate that PGE2 is produced by P. brasiliensis by a cyclooxygenase–dependent metabolic pathway, and its production is required for fungal survival. This discovery reveals an important factor that has potentially great implications for understanding the mechanisms of immune deviation during infection.  相似文献   

8.
Candida albicans is an opportunistic fungal pathogen of humans causing superficial mucosal infections and life‐threatening systemic disease. The fungal cell wall is the first point of contact between the invading pathogen and the host innate immune system. As a result, the polysaccharides that comprise the cell wall act as pathogen associated molecular patterns, which govern the host–pathogen interaction. The cell wall is dynamic and responsive to changes in the external environment. Therefore, the host environment plays a critical role in regulating the host–pathogen interaction through modulation of the fungal cell wall. This review focuses on how environmental adaptation modulates the cell wall structure and composition, and the subsequent impact this has on the innate immune recognition of C. albicans.  相似文献   

9.
BackgroundThe molecular reclassification of the order Trichosporonales placed the medically relevant Trichosporon species into three genera of the family Trichosporonaceae: Cutaneotrichosporon, Trichosporon, and Apiotrichum. From the clinical and epidemiological standpoint, it is important to identify any species of the family Trichosporonaceae because they present different antifungal susceptibility profiles. In Mexico, little is known about trichosporonosis etiology because the fungi are identified through phenotypic methods.AimsTo identify at a molecular level 12 yeast isolates morfologically compatible with Trichosporon, obtained from patients with superficial infections.MethodsThe yeast isolates were obtained from patients with white piedra, onychomycosis, and hand and foot dermatomycosis, and were identified morphologically and genotypically (sequencing of the IGS1 region and phylogenetic analysis using the Maximum Likelihood Method). The phylogenetic analysis included 40 yeast sequences from the order Trichosporonales and one from Cryptococcus neoformans as outgroup.ResultsBased on the molecular analysis, we identified three (25%) Trichosporon inkin isolates, two (16.7%) Trichosporon asteroides, two (16.7%) Cutaneotrichosporon mucoides, and one each (8.3%) of Trichosporon aquatile, Trichosporon asahii, Apiotrichum montevideense, Cutaneotrichosporon cutaneum, and Cutaneotrichosporon jirovecii.ConclusionsThe molecular characterization of the isolates showed a broad diversity of species within the order Trichosporonales, particularly among onychomycosis. It is essential to identify these yeasts at the species level to delve into their epidemiology.  相似文献   

10.
Candida albicans is one of the most frequent causes of fungal infections in humans. Significant correlation between candiduria and invasive candidiasis has previously been described. The existing diagnostic methods are often time-consuming, cost-intensive and lack in sensitivity and specificity. In this study, the profile of low-molecular weight volatile compounds in the headspace of C. albicans-urine suspensions of four different fungal cell concentrations compared to nutrient media and urine without C. albicans was determined using proton-transfer reaction mass spectrometry (PTR-MS). At fungal counts of ≥1.5 × 105 colony forming units (CFU)/ml signals at 45, 47 and 73 atomic mass units (amu) highly significantly increased. At fungal counts of <1.5 × 105 CFU/ml signals at 47 and 73 amu also increased, but only at 45 amu a statistically significant increase was seen. Time course alterations of signal intensities dependent on different cell concentrations and after addition of Sabouraud nutrient solution were analysed. Recommendations for measurement conditions are given. Our study is the first to describe headspace profiling of C. albicans-urine suspensions of different fungal cell concentrations. PTR-MS represents a promising approach to rapid, highly sensitive and non-invasive clinical diagnostics allowing qualitative and quantitative analysis.  相似文献   

11.
Fungal infections remain a serious clinical problem with a high disease and financial burden, especially among immunocompromised and critically ill patients. Numerous efforts have not fully identified clinical and laboratory risk factors for increased susceptibility to fungal infections. The recent acquisition of knowledge about innate immune responses to fungi and genetic alterations in immunologic mechanisms has revealed additional genetic risk factors and has shed more light on the predisposition of individuals to fungal infections. The aim of this review is to address the findings of recent studies associating genetic factors with susceptibility to fungal infections, focusing on the most common opportunistic fungi, Candida and Aspergillus species.  相似文献   

12.
Lin YP  Yang YP  Huang WM  Chen YH  Li SF  Fan YM 《Mycopathologia》2011,172(5):381-387
The pathogenicity of Trichosporon dermatis isolated from skin lesions of a patient has been examined in mice. Balb/c mice were treated with two intraperitoneal injections of 100 mg/kg cyclophosphamide on days 4 and 1 and one subcutaneous injection of 10 mg/kg dexamethasone on day 1 pre-inoculation, and then challenged with 0.2 ml T. dermatis inoculum (1 × 108 CFU/ml) by topical application on an abrasive wound in the dermabrasive group and by hypodermic injection in the subcutaneous group. In the intravenous group, 0.2 ml of high (1 × 108 CFU/ml) or low (1 × 10CFU/ml) inoculum was injected into the tail vein. Histopathology and inverse fungal culture were performed on the skin lesion and viscera, and renal fungal burden was also determined. Inoculated sites developed localized infections after dermabrasive and subcutaneous challenge in all mice, but the maximum area of skin lesions, and number of positive cultures from the lesions, were higher for immunocompromised mice. In the intravenous group, all immunocompetent animals survived during the four-week period, whereas 100 and 70% of immunocompromised animals died by 3 and 5 days in the high and low-inoculum groups, respectively. The incidence of disseminated infection and the renal fungal burden of immunocompromised mice were higher than those of immunocompetent mice. Our results demonstrate that subcutaneous and intravenous injection of T. dermatis can successfully establish cutaneous and systemic infection models in immunocompromised mice, with the kidney and lung being most susceptible.  相似文献   

13.
Candida species are opportunistic human fungal pathogens that cause acute and chronic infections against which only few antifungal agents are available. Here we have elucidated the antifungal effect of Syzygium samarangense leaf extracts (SSLE). Antifungal activity of SSLE was studied against Candida albicans, C. krusei, C. parapsilosis, C. glabrata, C. auris and C. tropicalis. Following experiments were performed: minimum fungicidal concentration (MFC) determination, agar well disc diffusion assays, fungal morphology analysis using scanning electron microscope (SEM), ex vivo fungal survival assays on porcine tongue and skin and in vivo fungal survival assays using Drosophila melanogaster fly model. Results demonstrated MFC of SSLE ranges between 100 and 125 mg ml−1. SEM images showed cell wall degradation of C. albicans when treated with SSLE. Around 75% decrease in C. albicans viability was observed when infected porcine tongue and skin were treated using SSLE. The C. albicans infected D. melanogaster when fed with SSLE showed significant decrease (around 80%) of fungal count than the infected control. Furthermore, agar plate disc diffusion assays demonstrated that the antifungal activity of SSLE could be due to chalcone, which is one of the active constituents in SSLE. Our study demonstrated that SSLE could be used for the topical treatment of Candida infections.  相似文献   

14.
Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent deep mycosis in Latin America. Production of eicosanoids during fungal infections plays a critical role on fungal biology as well as on host immune response modulation. The purpose of our study was to assess whether P. brasiliensis strains with different degree of virulence (Pb18, Pb265, Bt79, Pb192) produce prostaglandin Ex (PGEx). Moreover, we asked if P. brasiliensis could use exogenous sources of arachidonic acid (AA), as well as metabolic pathways dependent on cyclooxygenase (COX) enzyme, as reported for mammalian cells. A possible association between this prostanoid and fungus viability was also assessed. Our results showed that all strains, independently of their virulence, produce high PGEx levels on 4 h culture that were reduced after 8 h. However, in both culture times, higher prostanoid levels were detected after supplementation of medium with exogenous AA. Treatment with indomethacin, a COX inhibitor, induced a reduction on PGEx, as well as in fungus viability. The data provide evidence that P. brasiliensis produces prostaglandin-like molecules by metabolizing either endogenous or exogenous AA. Moreover, the results suggest the involvement of these mediators on fungal viability.  相似文献   

15.
Physically disturbed Triatoma infestans (Hemiptera: Reduviidae) adults, as well as adults of other Chagas' disease vectors, secrete a mix of volatile organic compounds (VOCs) with alarm and possible sexual and defence functions. The aim of the present research was to test whether infection with the entomopathogenic fungus Beauveria bassiana (Ascomycota: Hypocreales: Clavicipitaceae) has an effect on VOC secretion in disturbed T. infestans and on the expression of two genes (Ti‐brnq and Ti‐bckdc) potentially involved in VOC biosynthesis. The volatiles released by insects at different time periods after fungal treatment were identified and their relative amounts measured. Isobutyric acid was the most abundant volatile found in both healthy and fungus‐infected insects and underwent no significant relative changes through the infection process. The secretion of propionic acid, however, was significantly higher at 1–4 days post‐infection (d.p. i.) compared with that in controls. A slight induction of both Ti‐brnq and Ti‐bckdc genes was found by real‐time polymerase chain reaction at 4 d.p. i., with expression values reaching up to three‐fold those in controls. The early stages of fungal infection seem to affect the composition of the alarm pheromone by changing the expression pattern of both genes analysed. These results help to elucidate the impact of fungal infections on the chemical ecology of triatomine bugs.  相似文献   

16.
Cryptococcus gattii is an emerging fungal pathogen in the Pacific Northwest of North America, where it has caused more than 50 human infections since its emergence in 2004. Among residents of British Columbia, where the disease emerged in 1999 on Vancouver Island, many infections have occurred in immunocompetent persons. The cause for the emergence is currently unknown. The pathogenic profile of Cryptococcus gattii in North American patients appears to be different from that seen previously for C. gattii and from the profile of infection among patients with Cryptococcus neoformans. Treatment duration and the need for patient follow-up may be different between patients infected with C. gattii and C. neoformans. For this reason, physicians treating atypical patients with Cryptococcal spp infection, particularly HIV-uninfected patients, should obtain a travel history and obtain a species identity for Cryptococcus isolates.  相似文献   

17.
We retrospectively evaluated the epidemiology of onychomycosis and/or paronychia in 172 patients attending the Clinic of Dermatology and Venereology over a 5 year period. Although yeast isolates, belonging to the Candida species, represented the most frequent etiologic agents of these infections, an increasing prevalence of fungal infections due to emerging fungal pathogens (EFP) was noted throughout this time period. In particular, EFP as causative agents of these infections increased from 0 to 28.4% from 1998 to 2002.  相似文献   

18.
Candida albicans is a major human fungal pathogen causing mucosal and deep tissue infections of which the majority is associated with biofilm formation on medical implants. Biofilms have a huge impact on public health, as fungal biofilms are highly resistant against most antimycotics. Animal models of biofilm formation are indispensable for improving our understanding of biofilm development inside the host, their antifungal resistance and their interaction with the host immune defence system. In currently used models, evaluation of biofilm development or the efficacy of antifungal treatment is limited to ex vivo analyses, requiring host sacrifice, which excludes longitudinal monitoring of dynamic processes during biofilm formation in the live host. In this study, we have demonstrated for the first time that non‐invasive, dynamic imaging and quantification of in vitro and in vivo C. albicans biofilm formation including morphogenesis from the yeast to hyphae state is feasible by using growth‐phase dependent bioluminescent C. albicans strains in a subcutaneous catheter model in rodents. We have shown the defect in biofilm formation of a bioluminescent bcr1 mutant strain. This approach has immediate applications for the screening and validation ofantimycotics under in vivo conditions, for studying host–biofilm interactions in different transgenic mouse models and for testing the virulence of luminescent C. albicans mutants, hereby contributing to a better understanding of the pathogenesis of biofilm‐associated yeast infections.  相似文献   

19.
Invasive infections caused by Trichosporon spp. have increased considerably in recent years, especially in neutropenic and critically ill patients using catheters and antibiotics. The genus presents limited sensitivity to different antifungal agents, but triazoles are the first choice for treatment. Here, we investigated the biofilm production and antifungal susceptibility to triazoles and amphotericin B of 54 Trichosporon spp. isolates obtained from blood samples (19), urine (20) and superficial mycosis (15). All isolates and 7 reference strains were identified by sequence analysis and phylogenetic inferences of the IGS1 region of the rDNA. Biofilms were grown on 96-well plates and quantitation was performed using crystal violet staining, complemented with Scanning Electron Microscopy (SEM). Susceptibility tests for fluconazole, itraconazole, voriconazole and amphotericin B were processed using the microdilution broth method (CLSI) for planktonic cells and XTT reduction assay for biofilm-forming cells. Our results showed that T. asahii was the most frequent species identified (66.7%), followed by T. faecale (11.1%), T. asteroides (9.3%), T. inkin (7.4%), T. dermatis (3.7%) and one T. coremiiforme (1.8%). We identified 4 genotypes within T. asahii isolates (G1, G3, G4 and G5) and 2 genotypes within T. faecale (G1 and G3). All species exhibited high adhesion and biofilm formation capabilities, mainly T. inkin, T. asteroides and T. faecale. Microscopy images of high biofilm-producing isolates showed that T. asahii presented mainly hyphae and arthroconidia, whereas T. asteroides exhibited mainly short arthroconidia and few filaments. Voriconazole exhibited the best in vitro activity against all species tested. Biofilm-forming cells of isolates and reference strains were highly resistant to all antifungals tested. We concluded that levels of biofilm formation by Trichosporon spp. were similar or even greater than those described for the Candida genus. Biofilm-forming cells were at least 1,000 times more resistant to antifungals than planktonic cells, especially to voriconazole.  相似文献   

20.
Trichosporon spp. are widely distributed in nature and can occasionally belong to the human microbiota. For many years, the unique species of the genus, Trichosporon beigelli, was only known as an environmental and saprophytic fungus occasionally found as the etiological agent of white piedra. However, case reports of invasive trichosporonosis have been frequently published and the genus is currently considered the second most common agent of yeasts disseminated infections. Based on molecular analysis, the taxon T. beigelli was replaced by several species and the taxonomy of the genus was progressively modified. Despite the reported increase of Trichosporon infections refractory to conventional antifungal drugs, there are only a few studies investigating in vitro susceptibility of Trichosporon spp. to new compounds. Difficulties on different species identification as well as the lack of standardized sensitivity tests in vitro, contribute to the limited information available on epidemiology, diagnosis and therapeutics of trichosporonosis.  相似文献   

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