Repurposing Benzimidazoles against Causative Agents of Chromoblastomycosis: Albendazole Has Superior In Vitro Activity Than Mebendazole and Thiabendazole.

Chromoblastomycosis (CBM) is a neglected human implantation mycosis caused by several dematiaceous fungal species. Currently available therapy is usually associated with physical methods, especially surgery, and with high refractoriness. Therefore, drug discovery for CBM is essential. Drug repositioning is a strategy used to facilitate the discovery of new treatments for several diseases. The aim of this study was to discover substances with antifungal activity against CBM agents from a collection of drugs previously approved for use in human diseases. A screening was performed with the NIH Clinical Collection against Fonsecaea pedrosoi. Ten substances, with clinical applicability in CBM, inhibited fungal growth by at least 60%. The minimum inhibitory concentration (MIC) of these substances was determined against other CBM agents, and the benzimidazoles albendazole, mebendazole and thiabendazole presented the lowest MIC values. The selectivity index, based on MIC and cytotoxicity of these substances, revealed albendazole to be more selective. To investigate a possible synergism of this benzimidazole with itraconazole and terbinafine, the chequerboard method was used. All interactions were classified as indifferent. Our current results suggest that benzimidazoles have repositioning potential against CBM agents. Albendazole seems to be the most promising, since it presented the highest selectivity against all dematiaceous fungi tested.

New possibilities for chromoblastomycosis and phaeohyphomycosis treatment: identification of two compounds from the MMV Pathogen Box® that present synergism with itraconazole

BACKGROUND Black fungi of the Herpotrichiellaceae family are agents of chromoblastomycosis and phaeohyphomycosis. There are few therapeutic options for these infections and it is common to associate antifungal drugs in their treatment. OBJECTIVES To investigate the Medicines for Malaria Venture (MMV) Pathogen Box® for possible compounds presenting synergism with antifungal drugs used to treat black fungal infections. METHODS An initial screening of the Pathogen Box® compounds was performed in combination with itraconazole or terbinafine at sub-inhibitory concentrations against Fonsecaea pedrosoi. Hits were further tested against eight Herpotrichiellaceae using the checkerboard method. FINDINGS No synergism was observed with terbinafine. MMV687273 (SQ109) and MMV688415 showed synergism with itraconazole against F. pedrosoi. Synergism of these compounds was confirmed with some black fungi by the checkerboard method. SQ109 and itraconazole presented synergism for Exophiala dermatitidis, F. pedrosoi, F. monophora and F. nubica, with fungicidal activity for F. pedrosoi and F. monophora. MMV688415 presented synergism with itraconazole only for F. pedrosoi, with fungicidal activity. The synergic compounds had high selectivity index values when combined with itraconazole. MAIN CONCLUSIONS These compounds in combination, particularly SQ109, are promising candidates to treat Fonsecaea spp. and E. dermatitidis infections, which account for most cases of chromoblastomycosis and phaeohyphomycosis.

A case-series of bloodstream infections caused by the Meyerozyma guilliermondii species complex at a reference center of oncology in Brazil.

Bloodstream infections (BSI) caused by Candida species are the fourth cause of healthcare associated infections worldwide. Non-albicans Candida species emerged in the last decades as agents of serious diseases. In this study, clinical and microbiological aspects of six patients with BSI due to the Meyerozyma (Candida) guilliermondii species complex from an oncology reference center in Brazil, were evaluated. To describe demographic and clinical characteristics, medical records of the patients were reviewed. Molecular identification of the isolates was performed by ITS1-5.8S-ITS2 region sequencing. Antifungal susceptibility was evaluated by the EUCAST method and the minimal inhibitory concentrations (MIC) assessed according to the epidemiological cutoff values. Virulence associated phenotypes of the isolates were also studied. Ten isolates from the six patients were evaluated. Five of them were identified as Meyerozyma guilliermondii and the others as Meyerozyma caribbica. One patient was infected with two M. caribbica isolates with different genetic backgrounds. High MICs were observed for fluconazole and echinocandins. Non-wild type isolates to voriconazole appeared in one patient previously treated with this azole. Additionally, two patients survived, despite infected with non-wild type strains for fluconazole and treated with this drug. All isolates produced hemolysin, which was not associated with a poor prognosis, and none produced phospholipases. Aspartic proteases, phytase, and esterase were detected in a few isolates. This study shows the reduced antifungal susceptibility and a variable production of virulence-related enzymes by Meyerozyma spp. In addition, it highlights the poor prognosis of neutropenic patients with BSI caused by this emerging species complex. LAY ABSTRACT: Our manuscript describes demographic, clinical and microbiological characteristics of patients with bloodstream infection by the Meyerozyma guilliermondii species complex at a reference center in oncology in Brazil.

Molecular identification and antifungal susceptibility testing of Pucciniomycotina red yeast clinical isolates from Rio de Janeiro, Brazil.

Infections caused by Rhodotorula spp. are increasing worldwide. This study identified, through the light of the new taxonomic advances on the subphylum Pucciniomycotina, 16 isolates from blood cultures and compared their antifungal susceptibility on microdilution and gradient diffusion methods. Internal transcriber spacer sequencing identified Rhodotorula mucilaginosa (n = 12), Rhodotorula toruloides (n = 2), Rhodotorula dairenensis (n = 1), and Cystobasidium minutum (n = 1). Amphotericin B was the most effective drug. A good essential agreement was observed on MIC values of amphotericin B and voriconazole determined by the two methods. Therefore, the gradient method is useful for susceptibility tests of R. mucilaginosa against these drugs.

Hepatic Disease with Portal Hypertension and Acute Juvenile Paracoccidioidomycosis: A Report of Two Cases and Literature Review.

Paracoccidioidomycosis (PCM) is a neglected systemic mycosis endemic to Latin America caused by dimorphic fungi of the genus Paracoccidioides. The acute juvenile PCM is a severe type of presentation that usually affects young vulnerable patients and rarely progresses to portal hypertension. Here, two cases of liver disease and portal hypertension as complications of acute juvenile PCM are reported. Diagnosis of PCM was performed by isolation of the fungus and molecular identification of the strains provided through partial sequencing of two protein encoding genes, arf and gp43. Genotypic analysis revealed that Paracoccidioides brasiliensis S1 was the phylogenic species involved in both cases. Patients presented a good clinical response to amphotericin B and sulfamethoxazole-trimethoprim. These results highlight the importance of the interdisciplinary approach in patients with severe forms of PCM to avoid and treat complications, and the necessity of further investigations focusing on host-pathogen interaction in order to explain the broad clinical spectrum in PCM as well as the severity and poor outcome in some clinical cases.

Minimal inhibitory concentration distributions and epidemiological cutoff values of five antifungal agents against Sporothrix brasiliensis

BACKGROUND Sporothrix brasiliensis is the most virulent sporotrichosis agent. This species usually responds to antifungal drugs, but therapeutic failure can occur in some patients. Antifungal susceptibility tests have been performed on this species, but no clinical breakpoints (CBPs) are available. In this situation, minimal inhibitory concentration (MIC) distributions and epidemiological cutoff values (ECVs) support the detection of identification of resistant strains. OBJECTIVES To study the MIC distributions of five antifungal drugs against S. brasiliensis and to propose tentative ECVs. METHODS MICs of amphotericin B (AMB), itraconazole (ITR), ketoconazole (KET), posaconazole (POS), and terbinafine (TRB) against 335 S. brasiliensis strains were determined by the Clinical and Laboratory Standards Institute broth microdilution method. FINDINGS The proposed ECV, in µg/mL, for AMB, ITR, KET, POS, and TRB were 4.0, 2.0, 1.0, 2.0, and 0.25, respectively. Percentages of wild-type strains in our population for the above antifungal drugs were 98.48, 95.22, 95.33, 100, and 97.67%, respectively. MAIN CONCLUSIONS These ECVs will be useful to detect strains with resistance, to define CBPs, and to elaborate specific therapeutic guidelines for S. brasiliensis. Rational use of antifungals is strongly recommended to avoid the emergence of resistant strains and ensure the therapeutic effectiveness of sporotrichosis.

First description of Candida nivariensis in Brazil: antifungal susceptibility profile and potential virulence attributes

This study evaluated the antifungal susceptibility profile and the production of potential virulence attributes in a clinical strain of Candida nivariensis for the first time in Brazil, as identified by sequencing the internal transcribed spacer (ITS)1-5.8S-ITS2 region and D1/D2 domains of the 28S of the rDNA. For comparative purposes, tests were also performed with reference strains. All strains presented low planktonic minimal inhibitory concentrations (PMICs) to amphotericin B (AMB), caspofungin (CAS), and voriconazole. However, our strain showed elevated planktonic MICs to posaconazole (POS) and itraconazole, in addition to fluconazole resistance. Adherence to inert surfaces was conducted onto glass and polystyrene. The biofilm formation and antifungal susceptibility on biofilm-growing cells were evaluated by crystal violet staining and a XTT reduction assay. All fungal strains were able to bind both tested surfaces and form biofilm, with a binding preference to polystyrene (p < 0.001). AMB promoted significant reductions (≈50%) in biofilm production by our C. nivariensis strain using both methodologies. This reduction was also observed for CAS and POS, but only in the XTT assay. All strains were excellent protease producers and moderate phytase producers, but lipases were not detected. This study reinforces the pathogenic potential of C. nivariensis and its possible resistance profile to the azolic drugs generally used for candidiasis management.