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Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil.

ABSTRACT: Rare emerging pathogens such as Saprochaete clavata are associated with invasive fungal diseases, high morbidity, mortality, rapidly fatal infections, and outbreaks. However, little is known about S. clavata infections, epidemiology, risk factors, treatment, biofilms, and disease outcomes. The objective of this study was to describe a new case of severe S. clavata infection in a patient diagnosed at a referral children's hospital in Brazil, including antifungal minimal inhibitory concentration, S. clavata biofilm characterization, and molecular characterization. The S. clavata isolated from an immunocompromised 11-year-old male patient was characterized using MALDI-TOF, Gram staining, scanning electron microscopy (SEM), and next generation sequencing (NGS) of genomic DNA. Biofilm production was also evaluated in parallel with determining minimal inhibitory concentration (MIC) and biofilm sensitivity to antifungal treatment. We observed small to medium, whitish, farinose, dry, filamentous margin colonies, yeast-like cells with bacillary features, and biofilm formation. The MALDI-TOF system yielded a score of ≥ 2,000, while NGS confirmed S. clavata presence at the nucleotide level. The MIC values (in mg L-1) for tested drugs were as follows: fluconazole = 2, voriconazole ≤ 2, caspofungin ≥ 8, micafungin = 2, amphotericin B = 4, flucytosine ≤ 1, and anidulafungin = 1. Amphotericin B can be active against S. clavata biofilm and the fungus can be susceptible to new azoles. These findings were helpful for understanding the development of novel treatments for S. clavata-induced disease, including combined therapy for biofilm-associated infections.

SUBMITTER: Kraft L

PROVIDER: S-EPMC9886229 | biostudies-literature | 2023

REPOSITORIES: biostudies-literature

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Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil.

Kraft Letícia L Ribeiro Victoria Stadler Tasca VST Petroski Luiz Pedro LP Herai Roberto Hirochi RH Peronni Kamila Chagas KC Figueiredo David Livingstone Alves DLA Motta Fábio Araujo FA Tuon Felipe Francisco FF

Revista do Instituto de Medicina Tropical de Sao Paulo 20230130

Rare emerging pathogens such as Saprochaete clavata are associated with invasive fungal diseases, high morbidity, mortality, rapidly fatal infections, and outbreaks. However, little is known about S. clavata infections, epidemiology, risk factors, treatment, biofilms, and disease outcomes. The objective of this study was to describe a new case of severe S. clavata infection in a patient diagnosed at a referral children's hospital in Brazil, including antifungal minimal inhibitory concentration, ...[more]

PMID: 36722674

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Project description:UnlabelledRapidly fatal cases of invasive fungal infections due to a fungus later identified as Saprochaete clavata were reported in France in May 2012. The objectives of this study were to determine the clonal relatedness of the isolates and to investigate possible sources of contamination. A nationwide alert was launched to collect cases. Molecular identification methods, whole-genome sequencing (WGS), and clone-specific genotyping were used to analyze recent and historical isolates, and a case-case study was performed. Isolates from thirty cases (26 fungemias, 22 associated deaths at day 30) were collected between September 2011 and October 2012. Eighteen cases occurred within 8 weeks (outbreak) in 10 health care facilities, suggesting a common source of contamination, with potential secondary cases. Phylogenetic analysis identified one clade (clade A), which accounted for 16/18 outbreak cases. Results of microbiological investigations of environmental, drug, or food sources were negative. Analysis of exposures pointed to a medical device used for storage and infusion of blood products, but no fungal contamination was detected in the unused devices. Molecular identification of isolates from previous studies demonstrated that S. clavata can be found in dairy products and has already been involved in monocentric outbreaks in hematology wards. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen. This report also underlines further the potential of WGS for investigation of outbreaks due to uncommon fungal pathogens.ImportanceSeveral cases of rapidly fatal infections due to the fungus Saprochaete clavata were reported in France within a short period of time in three health care facilities, suggesting a common source of contamination. A nationwide alert collected 30 cases over 1 year, including an outbreak of 18 cases over 8 weeks. Whole-genome sequencing (WGS) was used to analyze recent and historical isolates and to design a clade-specific genotyping method that uncovered a clone associated with the outbreak, thus allowing a case-case study to analyze the risk factors associated with infection by the clone. The possibility that S. clavata may transmit through contaminated medical devices or can be associated with dairy products as seen in previous European outbreaks is highly relevant for the management of future outbreaks due to this newly recognized pathogen.

Project description:ObjectivesThe antifungal susceptibility testing (AFST) of yeast pathogen alerts clinicians about the potential emergence of resistance. In this study, we compared two commercial microdilution AFST methods: Sensititre YeastOne read visually (YO) and MICRONAUT-AM read visually (MN) or spectrophotometrically (MNV), interpreted with Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing criteria, respectively.MethodsOverall, 97 strains from 19 yeast species were measured for nine antifungal drugs including a total of 873 observations. First, the minimal inhibitory concentration (MIC) was compared between YO and MNV, and between MNV and MN, either directly or by assigning them to five susceptibility categories. Those categories were based on the number of MIC dilutions around the breakpoint or epidemiological cut-off reference values (ECOFFs or ECVs). Second, YO and MNV methods were evaluated for their ability to detect the elevation of MICs due to mutation in antifungal resistance genes, thanks to pairs or triplets of isogenic strains isolated from a single patient along a treatment previously analyzed for antifungal resistance gene mutations. Reproducibility measurement was evaluated, thanks to three quality control (QC) strains.ResultsYO and MNV direct MIC comparisons obtained a global agreement of 67%. Performing susceptibility category comparisons, only 22% and 49% of the MICs could be assigned to categories using breakpoints and ECOFFs/ECVs, respectively, and 40% could not be assigned due to the lack of criteria in both consortia. The YO and MN susceptibility categories gave accuracies as low as 50%, revealing the difficulty to implement this method of comparison. In contrast, using the antifungal resistance gene sequences as a gold standard, we demonstrated that both methods (YO and MN) were equally able to detect the acquisition of resistance in the Candida strains, even if MN showed a global lower MIC elevation than YO. Finally, no major differences in reproducibility were observed between the three AFST methods.ConclusionThis study demonstrates the valuable use of both commercial microdilution AFST methods to detect antifungal resistance due to point mutations in antifungal resistance genes. We highlighted the difficulty to conduct conclusive analyses without antifungal gene sequence data as a gold standard. Indeed, MIC comparisons taking into account the consortia criteria of interpretation remain difficult even after the effort of harmonization.

Project description:BackgroundChromoblastomycosis (CBM) is a difficult-to-treat chronic subcutaneous mycosis. In Brazil, the main agent of this disease is Fonsecaea pedrosoi, which is phenotypically very similar to other Fonsecaea species, differing only genetically. The correct species identification is relevant since different species may differ in their epidemiologic aspects, clinical presentation, and treatment response.Methodology/principal findingsPartial sequencing of the internal transcribed spacer (ITS) was used to identify twenty clinical isolates of Fonsecaea spp. Their in vitro antifungal susceptibility was determined using the broth microdilution method, according to the M38-A2 protocol. Amphotericin B (AMB), flucytosine (5FC), terbinafine (TRB), fluconazole (FLC), itraconazole (ITC), ketoconazole (KTC), posaconazole (POS), voriconazole (VRC), ravuconazole (RVC), caspofungin (CAS), and micafungin (MFG) were tested. The association between ITC/TRB, AMB/5FC, and ITC/CAS was studied by the checkerboard method to check synergism. The available patients' data were correlated with the obtained laboratory results. Fonsecaea monophora (n = 10), F. pedrosoi (n = 5), and F. nubica (n = 5) were identified as CBM' agents in the study. TRB and VRC were the drugs with the best in vitro activity with minimal inhibitory concentrations (MIC) lower than 0.25 mg/L. On the other hand, FLC, 5FC, AMB, and MFG showed high MICs. The AMB/5FC combination was synergistic for three F. monophora strains while the others were indifferent. Patients had moderate or severe CBM, and ITC therapy was not sufficient for complete cure in most of the cases, requiring adjuvant surgical approaches.Conclusions/significanceF. monophora, the second most frequent Fonsecaea species in South America, predominated in patients raised and born in Rio de Janeiro, Brazil, without cerebral involvement in these cases. TRB, VRC, and the AMB/5FC combination should be further investigated as a treatment option for CBM.

Dataset Information

Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil.

Publications

Saprochaete clavata invasive infection: characterization, antifungal susceptibility, and biofilm evaluation of a rare yeast isolated in Brazil.

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