Dynamics of in vitro development of azole resistance in Candida tropicalis

Constraint on boric acid resistance and tolerance evolvability in Candida albicans

Boric acid is a broad-spectrum antimicrobial used to treat vulvovaginal candidiasis when patients relapse on the primary azole drug fluconazole. Candida albicans is the most common cause of vulvovaginal candidiasis, colloquially referred to as a "vaginal yeast infection". Little is known about the propensity of C. albicans to develop BA resistance or tolerance (the ability of a subpopulation to grow slowly in high levels of drug). We evolved 96 replicates from eight diverse C. albicans strains to increasing BA concentrations to test the evolvability of BA resistance and tolerance. Replicate growth was individually assessed daily, with replicates passaged when they had reached an optical density consistent with exponential growth. Many replicates went extinct quickly. Although some replicates could grow in much higher levels of BA than the ancestral strains, evolved populations isolated from the highest terminal BA levels (after 11 weeks of passages) surprisingly showed only modest growth improvements and only at low levels of BA. No large increases in resistance or tolerance were observed in the evolved replicates. Overall, our findings illustrate that there may be evolutionary constraints limiting the emergence of BA resistance and tolerance, which could explain why it remains an effective treatment for recurrent yeast infections.

Molecular Evaluation of the mRNA Expression of the ERG11, ERG3, CgCDR1, and CgSNQ2 Genes Linked to Fluconazole Resistance in Candida glabrata in a Colombian Population

INTRODUCTION

The study of Candida glabrata genes associated with fluconazole resistance, from a molecular perspective, increases the understanding of the phenomenon with a view to its clinical applicability.

OBJECTIVE

We sought to establish the predictive molecular profile of fluconazole resistance in Candida glabrata by analyzing the ERG11, ERG3, CgCDR1, and CgSNQ2 genes.

METHOD

Expression was quantified using RT-qPCR. Metrics were obtained through molecular docking and Fisher discriminant functions. Additionally, a predictive classification was made against the susceptibility of C. glabrata to fluconazole.

RESULTS

The relative expression of the ERG3, CgCDR1, and CgSNQ2 genes was higher in the fluconazole-resistant strains than in the fluconazole-susceptible, dose-dependent strains. The gene with the highest relative expression in the fluconazole-exposed strains was CgCDR1, and in both the resistant and susceptible, dose-dependent strains exposed to fluconazole, this was also the case. The molecular docking model generated a median number of contacts between fluconazole and ERG11 that was lower than the median number of contacts between fluconazole and ERG3, -CgCDR1, and -CgSNQ2. The predicted classification through the multivariate model for fluconazole susceptibility achieved an accuracy of 73.5%.

CONCLUSION

The resistant strains had significant expression levels of genes encoding efflux pumps and the ERG3 gene. Molecular analysis makes the identification of a low affinity between fluconazole and its pharmacological target possible, which may explain the lower intrinsic susceptibility of the fungus to fluconazole.

Carbon substrates promotes stress resistance and drug tolerance in clinical isolates of Candida tropicalis

Candida tropicalis is a human pathogen and one of the most prevalent non-Candida albicans Candida (NCAC) species causing invasive infections. Azole antifungal resistance in C. tropicalis is also gradually increasing with the increasing incidence of infections. The pathogenic success of C. tropicalis depends on its effective response in the host microenvironment. To become a successful pathogen, cellular metabolism, and physiological status determine the ability of the pathogen to counter diverse stresses inside the host. However, to date, limited knowledge is available on the impact of carbon substrate metabolism on stress adaptation and azole resistance in C. tropicalis. In this study, we determined the impact of glucose, fructose, and sucrose as the sole carbon source on the fluconazole resistance and osmotic (NaCl), oxidative (H2O2) stress adaptation in C. tropicalis clinical isolates. We confirmed that the abundance of carbon substrates influences or increases drug resistance and osmotic and oxidative stress tolerance in C. tropicalis. Additionally, both azole-resistant and susceptible isolates showed similar stress adaptation phenotypes, confirming the equal efficiency of becoming successful pathogens irrespective of drug susceptibility profile. To the best of our knowledge, our study is the first on C. tropicalis to demonstrate the direct relation between carbon substrate metabolism and stress tolerance or drug resistance.

Analysis of CDR1 and MDR1 Gene Expression and ERG11 Substitutions in Clinical Candida tropicalis Isolates from Alexandria, Egypt

INTRODUCTION

Candida tropicalis is a common non-albicans Candida (NAC) species that causes numerous fungal infections. Increasing antifungal resistance to azoles in NAC is becoming a major health problem worldwide; however, in Egypt, almost no data is available regarding fluconazole resistance mechanisms in C. tropicalis. The current study aims to investigate two possible important molecular mechanisms involved in fluconazole resistance in C. tropicalis isolates.

MATERIALS

Fifty-four clinical C. tropicalis isolates were included. Identification and antifungal susceptibility profiles of the isolates were carried out using the VITEK 2 compact system. The molecular investigation of fluconazole resistance included the expression of the CDR1 and MDR1 genes by quantitative real-time RT-PCR as well as the sequence analysis of the ERG11 gene.

RESULTS

Antifungal susceptibility testing identified 30 fluconazole-non-susceptible isolates. Statistically, CDR1 gene expression in fluconazole-non-susceptible isolates was significantly higher than that in fluconazole-susceptible isolates, with MDR1 gene expression levels that were similar in both non-susceptible and susceptible isolates. Sequence analysis of the ERG11 gene of 26 fluconazole-resistant isolates identified two missense mutations: A395T (Y132F) and G1390A (G464S).

CONCLUSIONS

This study has highlighted the role of overexpression of the CDR1 gene and ERG11 gene mutations in fluconazole non-susceptibility. Further studies in Egypt are required to investigate other possible molecular mechanisms involved in azole resistance.

Clonal aggregation of fluconazole-resistant Candida tropicalis isolated from sterile body fluid specimens from patients in Hefei, China

Candida tropicalis, a human conditionally pathogenic yeast, is distributed globally, especially in Asia-Pacific. The increasing morbidity and azole resistance of C. tropicalis have made clinical treatment difficult. The correlation between clonality and antifungal susceptibility of clinical C. tropicalis isolates has been reported. To study the putative correlation in C. tropicalis isolated from normally sterile body fluid specimens and explore the distinct clonal complex (CC) in Hefei, 256 clinical C. tropicalis isolates were collected from four teaching hospitals during 2016-2019, of which 30 were fluconazole-resistant (FR). Genetic profiles of 63 isolates, including 30 FR isolates and 33 fluconazole-susceptible (FS) isolates, were characterized using multilocus sequence typing (MLST). Phylogenetic analysis of the data was conducted using UPGMA (unweighted pair group method with arithmetic averages) and the minimum spanning tree algorithm. MLST clonal complexes (CCs) were analyzed using the goeBURST package. Among 35 differentiated diploid sequence types (DSTs), 16 DSTs and 1 genotype were identified as novel. A total of 35 DSTs were assigned to five major CCs based on goeBURST analysis. CC1 (containing DST376, 505, 507, 1221, 1222, 1223, 1226, and 1229) accounted for 86.7% (26/30) of the FR isolates. However, the genetic relationships among the FS isolates were relatively decentralized. The local FR CC1 belongs to a large fluconazole non-susceptible CC8 in global isolates, of which the putative founder genotype was DST225. The putative correlation between MLST types and antifungal susceptibility of clinical C. tropicalis isolates in Hefei showed that DSTs are closely related to FR clones.

Expression of ERG11, ERG3, MDR1 and CDR1 genes in Candida tropicalis

INTRODUCTION

Drug resistance to azoles is a growing problem in the Candida genus.

OBJECTIVE

To analyze molecularly the genes responsible for fluconazole resistance in Candida tropicalis strains.

MATERIALS AND METHODS

Nineteen strains, with and without exposure to fluconazole, were selected for this study. The expression of MDR1, CDR1, ERG11, and ERG3 genes was analyzed in sensitive, dose-dependent sensitive, and resistant strains exposed to different concentrations of the antifungal drug.

RESULTS

MDR1, ERG11 and ERG3 genes were significantly overexpressed in the different sensitivity groups. CDR1 gene expression was not statistically significant among the studied groups. Seven of the eight fluconazole-resistant strains showed overexpression of one or more of the analyzed genes. In some dose-dependent sensitive strains, we found overexpression of CDR1, ERG11, and ERG3.

CONCLUSION

The frequency of overexpression of ERG11 and ERG3 genes indicates that they are related to resistance. However, the finding of dose-dependent resistant/sensitive strains without overexpression of these genes suggests that they are not exclusive to this phenomenon. More basic research is needed to study other potentially involved genes in the resistance mechanism to fluconazole.

Post-translational modifications confer amphotericin B resistance in Candida krusei isolated from a neutropenic patient

Neutropenia is a common complication in the treatment of hematological diseases and the most common predisposing factor for invasion by fungi, such as Candida krusei. Recent studies have shown that C. krusei, a life-threatening pathogen, has developed resistance to amphotericin B (AMB). However, the mechanisms that led to the rapid emergence of this AMB-resistant phenotype are unclear. In this study, we found the sensitivity for AMB could be promoted by inhibiting histone acyltransferase activity and western blot analysis revealed differences in the succinylation levels of C. krusei isolated from immunocompromised patients and of the corresponding AMB-resistant mutant. By comparative succinyl-proteome analysis, we identified a total of 383 differentially expressed succinylated sites in with 344 sites in 134 proteins being upregulated in the AMB-resistant mutant, compared to 39 sites in 23 proteins in the wild-type strain. These differentially succinylated proteins were concentrated in the ribosome and cell wall. The critical pathways associated with these proteins included those involved in glycolysis, gluconeogenesis, the ribosome, and fructose and mannose metabolism. In particular, AMB resistance was found to be associated with enhanced ergosterol synthesis and aberrant amino acid and glucose metabolism. Analysis of whole-cell proteomes, confirmed by parallel reaction monitoring, showed that the key enzyme facilitating lysine acylation was significantly upregulated in the AMB-resistant strain. Our results suggest that lysine succinylation may play an indispensable role in the development of AMB resistance in C. krusei. Our study provides mechanistic insights into the development of drug resistance in fungi and can aid in efforts to stifle the emergence of AMB-resistant pathogenic fungi.

The Risk Factors and Mechanisms of Azole Resistance of Candida tropicalis Blood Isolates in Thailand: A Retrospective Cohort Study

In recent decades, an epidemiological shift has been observed from Candida infections to non-albicans species and resistance to azoles. We investigated the associated factors and molecular mechanisms of azole-resistant blood isolates of C. tropicalis. Full-length sequencing of the ERG11 gene and quantitative real-time RT-PCR for the ERG11, MDR1, and CDR1 genes were performed. Male sex (odds ratio, 0.38), leukemia (odds ratio 3.15), and recent administration of azole (odds ratio 10.56) were associated with isolates resistant to azole. ERG11 mutations were found in 83% of resistant isolates, with A395T as the most common mutation (53%). There were no statistically significant differences in the expression of the ERG11, MDR1, and CDR1 genes between the groups resistant and susceptible to azole. The prevalence of azole-resistant isolates was higher than the usage of antifungal drugs, suggesting the possibility of environmental transmission in the healthcare setting. The unknown mechanism of the other 17% of the resistant isolates remains to be further investigated.

Experimental and in-host evolution of triazole resistance in human pathogenic fungi

The leading fungal pathogens causing systemic infections in humans are Candida spp., Aspergillus fumigatus, and Cryptococcus neoformans. The major class of antifungals used to treat such infections are the triazoles, which target the cytochrome P450 lanosterol 14-α-demethylase, encoded by the ERG11 (yeasts)/cyp51A (molds) genes, catalyzing a key step in the ergosterol biosynthetic pathway. Triazole resistance in clinical fungi is a rising concern worldwide, causing increasing mortality in immunocompromised patients. This review describes the use of serial clinical isolates and in-vitro evolution toward understanding the mechanisms of triazole resistance. We outline, compare, and discuss how these approaches have helped identify the evolutionary pathways taken by pathogenic fungi to acquire triazole resistance. While they all share a core mechanism (mutation and overexpression of ERG11/cyp51A and efflux transporters), their timing and mechanism differs: Candida and Cryptococcus spp. exhibit resistance-conferring aneuploidies and copy number variants not seen in A. fumigatus. Candida spp. have a proclivity to develop resistance by undergoing mutations in transcription factors (TAC1, MRR1, PDR5) that increase the expression of efflux transporters. A. fumigatus is especially prone to accumulate resistance mutations in cyp51A early during the evolution of resistance. Recently, examination of serial clinical isolates and experimental lab-evolved triazole-resistant strains using modern omics and gene editing tools has begun to realize the full potential of these approaches. As a result, triazole-resistance mechanisms can now be analyzed at increasingly finer resolutions. This newfound knowledge will be instrumental in formulating new molecular approaches to fight the rapidly emerging epidemic of antifungal resistant fungi.

Experimental evolution of drug resistance in human fungal pathogens

Experimental evolution in vitro is a powerful tool to uncover the factors that contribute to resistance evolution and understand the genetic basis of adaptation. Here, we discuss recent experimental evolution studies from human fungal pathogens. We synthesize the results to highlight the common threads that influence resistance acquisition. The picture that emerges is that drug resistance consistently appears readily and rapidly. Mutations are often found in an overlapping set of genes and genetic pathways known to be involved in drug resistance, including whole or partial chromosomal aneuploidy. The likelihood of acquiring resistance and cross-resistance between drugs seems to be influenced by the specific drug (not just drug class), level of drug, and strain genetic background. We discuss open questions, such as the potential for increases in drug tolerance to evolve in static drugs. We highlight opportunities to use this framework to probe how different factors influence the rate and nature of adaptation to antifungal drugs in fungal microbes through a call for increased reporting on all replicates that were evolved, not just those that acquired resistance.

Mechanisms of azole antifungal resistance in clinical isolates of Candida tropicalis

This study was designed to understand the molecular mechanisms of azole resistance in Candida tropicalis using genetic and bioinformatics approaches. Thirty-two azole-resistant and 10 azole-susceptible (S) clinical isolates of C. tropicalis were subjected to mutation analysis of the azole target genes including ERG11. Inducible expression analysis of 17 other genes potentially associated with azole resistance was also evaluated. Homology modeling and molecular docking analysis were performed to study the effect of amino acid alterations in mediating azole resistance. Of the 32 resistant isolates, 12 (37.5%) showed A395T and C461T mutations in the ERG11 gene. The mean overexpression of CDR1, CDR3, TAC1, ERG1, ERG2, ERG3, ERG11, UPC2, and MKC1 in resistant isolates without mutation (R-WTM) was significantly higher (p<0.05) than those with mutation (R-WM) and the sensitive isolates (3.2–11 vs. 0.2–2.5 and 0.3–2.2 folds, respectively). Although the R-WTM and R-WM had higher (p<0.05) CDR2 and MRR1 expression compared to S isolates, noticeable variation was not seen among the other genes. Protein homology modelling and molecular docking revealed that the mutations in the ERG11 gene were responsible for structural alteration and low binding efficiency between ERG11p and ligands. Isolates with ERG11 mutations also presented A220C in ERG1 and together T503C, G751A mutations in UPC2. Nonsynonymous mutations in the ERG11 gene and coordinated overexpression of various genes including different transporters, ergosterol biosynthesis pathway, transcription factors, and stress-responsive genes are associated with azole resistance in clinical isolates of C. tropicalis.

Competitiveness during Dual-Species Biofilm Formation of Fusarium oxysporum and Candida albicans and a Novel Treatment Strategy

During an infection, a single or multispecies biofilm can develop. Infections caused by non-dermatophyte molds, such as Fusarium spp. and yeasts, such as Candida spp., are particularly difficult to treat due to the formation of a mixed biofilm of the two species. Fusarium oxysporum is responsible for approximately 20% of human fusariosis, while Candida albicans is responsible for superficial mucosal and dermal infections and for disseminated bloodstream infections with a mortality rate above 40%. This study aims to investigate the interactions between C. albicans and F. oxysporum dual-species biofilm, considering variable formation conditions. Further, the ability of the WMR peptide, a modified version of myxinidin, to eradicate the mixed biofilm when used alone or in combination with fluconazole (FLC) was tested, and the efficacy of the combination of WMR and FLC at low doses was assessed, as well as its effect on the expression of some biofilm-related adhesin and hyphal regulatory genes. Finally, in order to confirm our findings in vivo and explore the synergistic effect of the two drugs, we utilized the Galleria mellonella infection model. We concluded that C. albicans negatively affects F. oxysporum growth in mixed biofilms. Combinatorial treatment by WMR and FLC significantly reduced the biomass and viability of both species in mature mixed biofilms, and these effects coincided with the reduced expression of biofilm-related genes in both fungi. Our results were confirmed in vivo since the synergistic antifungal activity of WMR and FLC increased the survival of infected larvae and reduced tissue invasion. These findings highlight the importance of drug combinations as an alternative treatment for C. albicans and F. oxysporum mixed biofilms.

Synthesis and Evaluation of the Antifungal and Toxicological Activity of Nitrofuran Derivatives

Fungal diseases affect more than 1 billion people worldwide. The constant global changes, the advent of new pandemics, and chronic diseases favor the diffusion of fungal pathogens such as Candida, Cryptococcus, Aspergillus, Trichophyton, Histoplasma capsulatum, and Paracoccidioides brasiliensis. In this work, a series of nitrofuran derivatives were synthesized and tested against different fungal species; most of them showed inhibitory activity, fungicide, and fungistatic profile. The minimal inhibitory concentration (MIC90) values for the most potent compounds range from 0.48 µg/mL against H. capsulatum (compound 11) and P. brasiliensis (compounds 3 and 9) to 0.98 µg/mL against Trichophyton rubrum and T. mentagrophytes (compounds 8, 9, 12, 13 and 8, 12, 13, respectively), and 3.9 µg/mL against Candida and Cryptococcus neoformans strains (compounds 1 and 5, respectively). In addition, all compounds showed low toxicity when tested in vitro on lung cell lines (A549 and MRC-5) and in vivo in Caenorhabditis elegans larvae. Many of them showed high selectivity index values. Thus, these studied nitrofuran derivatives proved to be potent against different fungal species, characterized by low toxicity and high selectivity; for these reasons, they may become promising compounds for the treatment of mycoses.

Azole and echinocandin resistance mechanisms and genotyping of Candida tropicalis in Japan: cross-boundary dissemination and animal-human transmission of C. tropicalis infection

OBJECTIVES

To assess the prevalence and genetic basis of antifungal resistance mechanisms as well as the genotyping of Candida tropicalis from clinical and non-clinical sources in Japan.

METHODS

Eighty C. tropicalis isolates, including 32 clinical isolates recovered from 29 patients and 48 non-clinical isolates recovered from 24 different sources (animals and the environment) were evaluated. All isolates were tested phenotypically for resistance to a wide range of antifungals and genotypically for resistance mechanisms to azole and echinocandin. Furthermore, all the isolates were genotyped by multilocus sequence typing (MLST).

RESULTS

Phenotypically, 30.2% (16/53) of the isolates were azole-resistant, with high levels of azole resistance among clinical isolates (51.7%; 15/29) and low levels (4.2%; 1/24) among non-clinical isolates. None of the isolates were reported as echinocandin resistant, with 60.4% (32/53) of the isolates intermediate to caspofungin. Azole resistance was basically attributed to high expression levels of drug efflux transporter genes (CDR2 and CDR3), transcription factors (TAC1 and UPC2) and ergosterol biosynthesis pathway HMG gene. No FKS1 hot spot 1 (HS1) or HS2 missense mutations were detected in any of the isolates. MLST analysis revealed 36 different sequence types (STs), with the first identification of 23 new STs. Phylogenetic analysis confirmed the close relationship between the clinical and non-clinical isolates, with identifications of ST232 and ST933 among patients and marine mammals.

CONCLUSION

Our results confirmed the emergence of azole resistance in C. tropicalis in Japan. Furthermore, phylogenetic analysis confirmed the transboundary dissemination and cross-transmission of C. tropicalis between humans and animals.

Participation of the ABC Transporter CDR1 in Azole Resistance of Candida lusitaniae

Candida lusitaniae is an opportunistic pathogen in humans that causes infrequent but difficult-to-treat diseases. Antifungal drugs are used in the clinic to treat C. lusitaniae infections, however, this fungus can rapidly acquire antifungal resistance to all known antifungal drugs (multidrug resistance). C. lusitaniae acquires azole resistance by gain-of-function (GOF) mutations in the transcriptional regulator MRR1. MRR1 controls the expression of a major facilitator transporter (MFS7) that is important for fluconazole resistance. Here, we addressed the role of the ATP Binding Cassette (ABC) transporter CDR1 as additional mediator of azole resistance in C. lusitaniae. CDR1 expression in isolates with GOF MRR1 mutations was higher compared to wild types, which suggests that CDR1 is an additional (direct or indirect) target of MRR1. CDR1 deletion in the azole-resistant isolate P3 (V688G GOF) revealed that MICs of long-tailed azoles, itraconazole and posaconazole, were decreased compared to P3, which is consistent with the role of this ABC transporter in the efflux of these azoles. Fluconazole MIC was only decreased when CDR1 was deleted in the background of an mfs7Δ mutant from P3, which underpins the dominant role of MFS7 in the resistance of the short-tailed azole fluconazole. With R6G efflux readout as Cdr1 efflux capacity, our data showed that R6G efflux was increased in P3 compared to an azole-susceptible wild type parent, and diminished to background levels in mutant strains lacking CDR1. Milbemycin oxim A3, a known inhibitor of fungal ABC transporters, mimicked efflux phenotypes of cdr1Δ mutants. We therefore provided evidence that CDR1 is an additional mediator of azole resistance in C. lusitaniae, and that CDR1 regulation is dependent on MRR1 and associated GOF mutations.

Rapid detection of ERG11 polymorphism associated azole resistance in Candida tropicalis

Increasing reports of azole resistance in Candida tropicalis, highlight the development of rapid resistance detection techniques. Nonsynonymous mutations in the lanosterol C14 alpha-demethylase (ERG11) gene is one of the predominant mechanisms of azole resistance in C. tropicalis. We evaluated the tetra primer-amplification refractory mutation system-PCR (T-ARMS-PCR), restriction site mutation (RSM), and high-resolution melt (HRM) analysis methods for rapid resistance detection based on ERG11 polymorphism in C. tropicalis. Twelve azole-resistant and 19 susceptible isolates of C. tropicalis were included. DNA sequencing of the isolates was performed to check the ERG11 polymorphism status among resistant and susceptible isolates. Three approaches T-ARMS-PCR, RSM, and HRM were evaluated and validated for the rapid detection of ERG11 mutation. The fluconazole MICs for the 12 resistant and 19 susceptible isolates were 32–256 mg/L and 0.5–1 mg/L, respectively. The resistant isolates showed A339T and C461T mutations in the ERG11 gene. The T-ARMS-PCR and RSM approaches discriminated all the resistant and susceptible isolates, whereas HRM analysis differentiated all except one susceptible isolate. The sensitivity, specificity, analytical sensitivity, time, and cost of analysis suggests that these three methods can be utilized for the rapid detection of ERG11 mutations in C. tropicalis. Additionally, an excellent concordance with DNA sequencing was noted for all three methods. The rapid, sensitive, and inexpensive T-ARMS-PCR, RSM, and HRM approaches are suitable for the detection of azole resistance based on ERG11 polymorphism in C. tropicalis and can be implemented in clinical setups for batter patient management.

Camphor and Eucalyptol-Anticandidal Spectrum, Antivirulence Effect, Efflux Pumps Interference and Cytotoxicity

Candidaalbicans represents one of the most common fungal pathogens. Due to its increasing incidence and the poor efficacy of available antifungals, finding novel antifungal molecules is of great importance. Camphor and eucalyptol are bioactive terpenoid plant constituents and their antifungal properties have been explored previously. In this study, we examined their ability to inhibit the growth of different Candida species in suspension and biofilm, to block hyphal transition along with their impact on genes encoding for efflux pumps (CDR1 and CDR2), ergosterol biosynthesis (ERG11), and cytotoxicity to primary liver cells. Camphor showed excellent antifungal activity with a minimal inhibitory concentration of 0.125-0.35 mg/mL while eucalyptol was active in the range of 2-23 mg/mL. The results showed camphor's potential to reduce fungal virulence traits, that is, biofilm establishment and hyphae formation. On the other hand, camphor and eucalyptol treatments upregulated CDR1;CDR2 was positively regulated after eucalyptol application while camphor downregulated it. Neither had an impact on ERG11 expression. The beneficial antifungal activities of camphor were achieved with an amount that was non-toxic to porcine liver cells, making it a promising antifungal compound for future development. The antifungal concentration of eucalyptol caused cytotoxic effects and increased expression of efflux pump genes, which suggests that it is an unsuitable antifungal candidate.

Candida tropicalis endocarditis successfully treated with AngioVac and micafungin followed by long-term isavuconazole suppression

We provide a review of current literature of native valve Candida tropicalis endocarditis.

A 41-year old man presented with C. tropicalis candidemia complicated by superior vena cava mass and right main pulmonary artery thrombus. The patient achieved clinical and microbiologic cure with AngioVac of the mass and echinocandin for six weeks. Long-term suppression was challenging given the C. tropicalis strain was resistant to fluconazole, voriconazole and posaconazole. Additional susceptibilities were obtained and he remained relapse-free at 12 months with isavuconazole.