Revista Iberoamericana De Micologia最新文献

Background

Paracoccidioidomycosis is an endemic mycosis caused by members of the Paracoccidioides genus. Brazil remains the focus area and, to a lesser extent, the disease has been reported from Argentina, Colombia and Venezuela.

Aims

A Venezuelan Paracoccidioides brasiliensis strain, isolated from a patient diagnosed with chronic multifocal paracoccidioidomycosis, was subjected to whole genome sequencing to provide more insight about Paracoccidioides outside the endemic focus area.

Methods

P. brasiliensis strain CBS 118890 was whole genome sequenced using nanopore; library preparation with the ‘native barcoding genomic DNA kit’ was followed by sequencing on Flongle and MinION flowcells. Batches of strain CBS 118890 were re-identified by sequencing the internal transcribed spacer (ITS) region, and final identification was made based on phylogenetic analysis.

Results

Surprisingly, the Venezuelan P. brasiliensis strain CBS 118890 turned out to be a Nannizziopsis species. The batches of this strain were ITS sequenced followed by phylogenetic analysis and resulted in the final identification of Nannizziopsis arthrosporioides.

Conclusions

Nannizziopsis infections are commonly seen in a wide variety of reptiles, but are particularly rare in human infections. This case underlines the need for molecular characterization of cases that clinically mimic paracoccidioidomycosis but that are serologically negative for Paracoccidioides.

Background

Candida bloodstream infection (CBSI) is a growing problem among patients with cancer.

Aim

To describe the main clinical and microbiological characteristics in patients with cancer who suffer CBSI.

Methods

We reviewed the clinical and microbiological characteristics of all patients with CBSI diagnosed between January 2010 and December 2020, at a tertiary-care oncological hospital. Analysis was done according to the Candida species found. Multivariate logistic regression analysis was used to determine the risk factors associated with 30-day mortality.

Results

There were 147 CBSIs diagnosed, 78 (53%) in patients with hematologic malignancies. The main Candida species identified were Candida albicans (n = 54), Candida glabrata (n = 40) and Candida tropicalis (n = 29). C. tropicalis had been mainly isolated from patients with hematologic malignancies (79.3%) who had received chemotherapy recently (82.8%), and in patients with severe neutropenia (79.3%). Seventy-five (51%) patients died within the first 30 days, and the multivariate analysis showed the following risk factors: severe neutropenia, a Karnofsky Performance Scale score under 70, septic shock, and not receiving appropriate antifungal treatment.

Conclusions

Patients with cancer who develop CBSI had a high mortality related with factors associated with their malignancy. Starting an empirical antifungal therapy the soonest is essential to increase the survival in these patients.

The domestic cat is the most susceptible host to Sporothrix infection, developing severe clinical forms. Few effective antifungal agents are available for treating feline sporotrichosis, and cases of treatment failure are common. Treatment success depends on cat health status, therapy-related factors, as well as social/economic issues, but it is mainly contingent upon the host–fungus interaction. The owner's adherence is critical and should be reinforced throughout the treatment to increase the chances of a successful outcome. The antifungal agents described for feline sporotrichosis are most often used in monotherapy regimens. Due to cases in which the treatment with itraconazole failed, the use of antifungal agents in combination should be considered to achieve synergy. The combination of itraconazole and potassium iodide represents an important option for the treatment of naïve cats presenting multiple cutaneous lesions, nasal mucosal lesions and/or respiratory signs, as well as for refractory cases. However, the therapeutic options for unsuccessfully treated cases are scarce. Therefore new options are needed, even more taking into account that there are many in vitro potential molecules not available for use in cats yet. More studies are necessary to correlate in vitro antifungal susceptibility tests results and the outcome of cats treated due to sporotrichosis. This review will briefly discuss both the antifungal drugs and treatment protocols used in cats with sporotrichosis, as well as the determinants of treatment failure.

Background

The emergence of resistant isolates has brought challenges to the treatment of sporotrichosis, prompting the search for new therapeutic strategies. Previous studies reported that nonsteroidal anti-inflammatory drugs (NSAIDs) show in vitro activity against several pathogenic fungi, including species of Candida, Cryptococcus, and Trichosporon.

Aims

This study aimed to investigate the in vitro efficacy of three NSAIDs (acetylsalicylic acid, diclofenac sodium, and ibuprofen), alone and in combination with itraconazole, against eleven clinical isolates of Sporothrix brasiliensis and Sporothrix schenckii.

Methods

Minimal inhibitory concentrations were determined by the broth microdilution method. Drug interactions and the fractional inhibitory concentration index of NSAIDs and itraconazole were assessed by the checkerboard method.

Results

When used alone, ibuprofen was the most active NSAID, followed by acetylsalicylic acid. Combinations of NSAIDs with itraconazole showed synergistic antifungal activity against nine isolates. It was also found that itraconazole combined with acetylsalicylic acid, diclofenac sodium, or ibuprofen, led to resistance reversal in two, three, and five of the six drug-resistant isolates, respectively.

Conclusions

The results indicate that the combination of itraconazole and the evaluated NSAIDs are a promising strategy for the treatment of sporotrichosis.

Background

Neoscytalidium dimidiatum is an opportunistic dematiaceous fungus belonging to the class Dothideomycetes.

Case report

We report a case of N. dimidiatum cerebral phaeohyphomycosis post COVID-19 infection in a 32-year-old male from Iran. The causative agent was identified by cytopathology, routine mycological methods, and DNA sequencing of the internal transcribed spacer (ITS) region of rDNA. Apart from COVID-19 complications and the corticosteroid therapy, no underlying condition was diagnosed. The symptoms suggesting the fungal infection were shown two weeks after being discharged from COVID-19 hospital stay. Magnetic resonance of the brain showed a multi-focal central nervous system infection. The delayed identification of the fungus and, thus, a late starting of the antifungal treatment with amphotericin B, might have affected the patient outcome as he finally died.

Conclusions

Considering the rare incidence of N. dimidiatum infections, this case should aware us about them, leading to a timely antifungal management.

Background

Staphylococcus aureus and Candida albicans have been co-isolated from biofilm-associated diseases such as denture stomatitis, periodontitis, and burn wound infections, as well as from medical devices. However, the polymicrobial biofilm of both microorganisms has not been fully characterized.

Aims

To characterize the polymicrobial biofilm of C. albicans and S. aureus in terms of microbial density, synergy, composition, structure, and stability against antimicrobials and chemical agents.

Methods

Crystal violet assay was used to measure the biofilm formation. Scanning electron microscopy and confocal microscopy were used to analyze the structure and chemical composition of the biofilms, respectively.

Results

Supplemented media with fetal bovine serum (FBS) decreased the biofilm formation of S. aureus and the polymicrobial biofilm. For C. albicans, depending on the culture media, the addition of glucose or FBS had a positive effect in biofilm formation. FBS decreased the adhesion to polystyrene wells for both microorganisms. Supplementing the media with glucose and FBS enhanced the growth of C. albicans and S. aureus, respectively. It seems that C. albicans contributes the most to the adhesion process and to the general structure of the biofilms on all the surfaces tested, including a catheter model. Interestingly, S. aureus showed a great adhesion capacity to the surface of C. albicans in the biofilms. Proteins and β-1,6-linked polysaccharides seem to be the most important molecules in the polymicrobial biofilm.

Conclusions

The polymicrobial biofilm had a complex structure, with C. albicans serving as a scaffold where S. aureus adheres, preferentially to the hyphal form of the fungus. Detection of polymicrobial infections and characterization of biofilms will be necessary in the future to provide a better treatment.