A fatal Candida albicans pericarditis presenting with cardiac tamponade after COVID-19 infection and cardiothoracic surgery

BACKGROUND

Candida pericardial infection is a rare clinical entity usually related to recent cardiothoracic surgery and chronic debilitating conditions. During the COVID-19 pandemic, invasive fungal infections have been on the rise, likely due to a combination of factors such as immunosuppression, underlying conditions like diabetes, and surgical procedures.

CASE PRESENTATION

Herein, we report a 67-year-old diabetic woman with a history of COVID-19 infection who received a high dose of corticosteroids a few months before admission, and previous myocardial infarction for more than 12 years. The patient had a positive cardiac tamponade with signs of dyspnea, chest pain, and low blood pressure. Echocardiographic data were more in favor of constrictive pericarditis. The patient underwent urgent echocardiography-guided pericardiocentesis and then broad-spectrum antibiotic treatment was prescribed. Repeated echocardiography implied a persistent pericardial effusion 10 days later. Subxiphoid aspirates and biopsied tissues showed budding yeast cells and yeast colonies grew on culture media identified as Candida albicans.

CONCLUSION

This report should bring to the attention of physicians toward the possibility of Candida pericardial infection presenting with cardiac tamponade after COVID-19 infection and cardiothoracic surgery. Echocardiographic assessment, prompt pericardiotomy, molecular-based identification of causative agent, and early administration of appropriate antifungal treatment should improve the patient's survival.

In vitro antifungal activity of a novel topical triazole PC945 against emerging yeast Candida auris

Objectives

Management of Candida auris infection is difficult as this yeast exhibits resistance to different classes of antifungals, necessitating the development of new antifungals. The aim of this study was to investigate the susceptibility of C. auris to a novel antifungal triazole, PC945, optimized for topical delivery.

Methods

A collection of 50 clinical isolates was obtained from a tertiary care hospital in North India. Nine isolates from the UK, 10 from a CDC panel (USA) and 3 from the CBS-KNAW culture collection (Japanese and South Korean isolates) were also obtained. MICs (azole endpoint) of PC945 and other triazoles were determined in accordance with CLSI M27 (third edition). Quality control strains were included [Candida parapsilosis (ATCC 22019) and Candida krusei (ATCC 6258)].

Results

Seventy-four percent of isolates tested showed reduced susceptibility to fluconazole (≥64 mg/L). PC945 (geometric mean MIC = 0.058 mg/L) was 7.4-fold and 1.5-fold more potent than voriconazole and posaconazole, respectively (both P < 0.01). PC945 MIC values correlated with those of voriconazole or posaconazole, and only three isolates were found to be cross-resistant between PC945 and other azoles. ERG11 sequence analysis revealed several mutations, but no correlation could be established with the MIC of PC945. Tentative epidemiological cut-off values (ECOFFs) evaluated by CLSI’s ECOFF Finder (at 99%) with 24 h reading of MICs were 1, 4 and 1 mg/L for PC945, voriconazole and posaconazole, respectively. MIC values for quality control strains of all triazoles were in the normal ranges.

Conclusions

PC945 was found to be a more potent inhibitor than posaconazole, voriconazole and fluconazole of C. auris isolates collected globally, warranting further laboratory and clinical evaluations.

Diagnosis, management and prevention of Candida auris in hospitals: position statement of the Australasian Society for Infectious Diseases

Candida auris is an emerging drug-resistant yeast responsible for hospital outbreaks. This statement reviews the evidence regarding diagnosis, treatment and prevention of this organism and provides consensus recommendations for clinicians and microbiologists in Australia and New Zealand. C. auris has been isolated in over 30 countries (including Australia). Bloodstream infections are the most frequently reported infections. Infections have crude mortality of 30-60%. Acquisition is generally healthcare-associated and risks include underlying chronic disease, immunocompromise and presence of indwelling medical devices. C. auris may be misidentified by conventional phenotypic methods. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry or sequencing of the internal transcribed spacer regions and/or the D1/D2 regions of the 28S ribosomal DNA are therefore required for definitive laboratory identification. Antifungal drug resistance, particularly to fluconazole, is common, with variable resistance to amphotericin B and echinocandins. Echinocandins are currently recommended as first-line therapy for infection in adults and children ≥2 months of age. For neonates and infants <2 months of age, amphotericin B deoxycholate is recommended. Healthcare facilities with C. auris should implement a multimodal control response. Colonised or infected patients should be isolated in single rooms with Standard and Contact Precautions. Close contacts, patients transferred from facilities with endemic C. auris or admitted following stay in overseas healthcare institutions should be pre-emptively isolated and screened for colonisation. Composite swabs of the axilla and groin should be collected. Routine screening of healthcare workers and the environment is not recommended. Detergents and sporicidal disinfectants should be used for environmental decontamination.

A decade after the emergence of Candida auris: what do we know?

Candida auris is a remarkable emerging pathogen. It has emerged separately, yet simultaneously in different parts of the world, establishing four phylogenetic and geographic distinct clades with a potential fifth clade that was recently reported. C. auris is often perceived as a pathogen in disguise, due to its frequent misidentification and its immune evasion. On the other hand, many of the recovered isolates are multidrug-resistant. In fact, some of these isolates are resistant to the three main antifungal classes: echinocandins, azoles, and polyenes. Moreover, C. auris has the ability to persist and survive on different objects for a long time, aided by different adhering mechanisms including aggregation and biofilm formation, thereby causing outbreaks of invasive infections in hospital settings. However, C. auris ability to maintain its pathogenicity at high temperatures remains among its most unique properties. This is why C. auris represents a challenging threat, and more studies are needed to meet this challenge. This review highlights different characteristics of this emerging yeast with emphasis on its antifungal resistance, its ability to persistent on different surfaces, and its immune evasion capability.

Sertraline as a promising antifungal agent: inhibition of growth and biofilm of Candida auris with special focus on the mechanism of action in vitro

AIM

The aim of this present study was to investigate the antifungal mechanism of sertraline against Candida auris (C. auris) and its effect on biofilm formation.

METHODS AND RESULTS

Sertraline, a repurposing drug with a history of human use for the treatment of depression was screened against three different isolates of C. auris, and was found to possess efficient antifungal activity. The antifungal activity of sertraline was further confirmed by killing kinetics assay and post-antifungal effect (PAFE). Sertraline inhibited C. auris yeast to hyphae conversion and further the inhibition of biofilm formation showed 71% inhibition upon treatment. Cell damage caused due to C. auris after treatment with sertraline was observed using SEM and cell membrane damage was ascertained using flow cytometry by Propidium Iodide (PI) uptake assay. The results of sorbitol protection assay and ergosterol effect assay suggested that sertraline did not affect the cell wall and did not act by binding to membrane ergosterol. The mechanism of action of sertraline against C. auris was understood through in silico docking studies that revealed the binding nature of sertraline to the sterol 14 alpha demethylase which is involved in ergosterol biosynthesis. Ergosterol that was quantified from treated cells showed a 5·5-fold decrease in ergosterol production.

CONCLUSION

Sertraline displayed promising antifungal activity against C. auris involved in candidiasis infection and the mechanism of action was predicted.

SIGNIFICANCE AND IMPACT OF THIS STUDY

The results of this study can encourage for the development of new antifungal agents and can be promising antifungal agent against C. auris infection.

Evaluation of the efficacy of rezafungin, a novel echinocandin, in the treatment of disseminated Candida auris infection using an immunocompromised mouse model

Background

Multiple cases of Candida auris infection have been reported with high mortality rates owing to its MDR nature. Rezafungin (previously CD101) is a novel echinocandin with enhanced stability and pharmacokinetics that achieves high plasma drug exposure and allows for once weekly dose administration.

Objectives

Evaluate the efficacy of rezafungin in the treatment of disseminated C. auris infection using a mouse model of disseminated candidiasis.

Methods

Mice were immunosuppressed 3 days prior to infection and 1 day post-infection. On the day of infection, mice were inoculated with 3 × 10⁷C. auris blastospores via the tail vein. Mice were randomized into four groups (n = 20): rezafungin at 20 mg/kg, amphotericin B at 0.3 mg/kg, micafungin at 5 mg/kg and a vehicle control. Treatments were administered 2 h post-infection. Rezafungin was given additionally on days 3 and 6 for a total of three doses, while the remaining groups were treated every day for a total of seven doses. Five mice from each group were sacrificed on days 1, 4, 7 and 10 of the study. Kidneys were removed from each mouse to determine the number of cfu for each respective day.

Results

Rezafungin had significantly lower average log₁₀ cfu/g of tissue compared with amphotericin B- and vehicle-treated mice on all days when kidneys were harvested. Additionally, rezafungin-treated mice had significantly lower average log₁₀ cfu/g of tissue compared with micafungin-treated mice on day 10.

Conclusions

Our findings show that rezafungin possesses potent antifungal activity against C. auris in a disseminated model of candidiasis.

Candida auris-the growing menace to global health

A paradigm shift of candidiasis from Candida albicans to non-albicans Candida species has fundamentally increased with the advent of C. auris. C. auris, despite being a newly emerged multidrug-resistant fungal pathogen, is associated with severe invasive infections and outbreaks with high mortality rates. Initially reported from Japan in 2009, C. auris have now been found in different countries on all the continents except Antarctica. Due to its capability of nosocomial transmission and forming adherent biofilms on clinically important substrates, a high number of related hospital outbreaks have been reported worldwide. As C. auris is a multidrug-resistant pathogen and is prone to misidentification by available conventional methods, it becomes difficult to detect and manage C. auris infection and also limits the therapeutic options against this deadly pathogen. The emergence of multidrug-resistant C. auris advocates and amplifies the vigilance of early diagnosis and appropriate treatment of fungal infections. In this review, we discussed the nine-year-old history of C. auris-its trends in global emergence, epidemiological relatedness, isolation, mortality, associated risk factors, virulence factors, drug resistance and susceptibility testing, diagnostic challenges, microbiological characteristics, therapeutic options and infection prevention and control associated with this pathogen.

Candida auris: An Emerging Yeast Pathogen Posing Distinct Challenges for Laboratory Diagnostics, Treatment, and Infection Prevention

CONTEXT.—

Candida auris is an emerging yeast species that was first described in 2009. This ascomycetous yeast is notable for resistance to azole antifungal agents, for environmental persistence, and for its ability to contaminate health care environments, resulting in patient colonization and nosocomial infections.

OBJECTIVE.—

To review the state of current knowledge addressing challenges in the accurate identification of C auris in the diagnostic microbiology laboratory, including application of phenotypic, proteomic, and genomic methodologies; characteristics that may predispose the human host to acquiring C auris; transmission; clinical presentations; treatment modalities; environmental decontamination; and infection prevention in health care settings.

DATA SOURCES.—

The PubMed search engine was used to access peer-reviewed literature published from 2009 to 2019.

CONCLUSIONS.—

The rapid emergence of C auris has presented unique challenges for the areas of laboratory diagnostics and infection prevention and in options for antifungal treatment, which are limited. The current lack of established antifungal susceptibility test breakpoints complicates therapeutic decision making. Enhanced awareness of this pathogen is essential to monitor outbreaks and to reduce the risk of spread within health care environments.

A multicentre study of antifungal susceptibility patterns among 350 Candida auris isolates (2009-17) in India: role of the ERG11 and FKS1 genes in azole and echinocandin resistance

Background

Candida auris has emerged globally as an MDR nosocomial pathogen in ICU patients.

Objectives

We studied the antifungal susceptibility of C. auris isolates (n = 350) from 10 hospitals in India collected over a period of 8 years. To investigate azole resistance, ERG11 gene sequencing and expression profiling was conducted. In addition, echinocandin resistance linked to mutations in the C. auris FKS1 gene was analysed.

Methods

CLSI antifungal susceptibility testing of six azoles, amphotericin B, three echinocandins, terbinafine, 5-flucytosine and nystatin was conducted. Screening for amino acid substitutions in ERG11 and FKS1 was performed.

Results

Overall, 90% of C. auris were fluconazole resistant (MICs 32 to ≥64 mg/L) and 2% and 8% were resistant to echinocandins (≥8 mg/L) and amphotericin B (≥2 mg/L), respectively. ERG11 sequences of C. auris exhibited amino acid substitutions Y132 and K143 in 77% (n = 34/44) of strains that were fluconazole resistant whereas WT genotypes, i.e. without substitutions at these positions, were observed in isolates with low fluconazole MICs (1-2 mg/L) suggesting that these substitutions confer a phenotype of resistance to fluconazole similar to that described for Candida albicans. No significant expression of ERG11 was observed, although expression was inducible in vitro with fluconazole exposure. Echinocandin resistance was linked to a novel mutation S639F in FKS1 hot spot region I.

Conclusions

Overall, 25% and 13% of isolates were MDR and multi-azole resistant, respectively. The most common resistance combination was azoles and 5-flucytosine in 14% followed by azoles and amphotericin B in 7% and azoles and echinocandins in 2% of isolates.

Candida auris: An emerging drug resistant yeast - A mini-review

Candida auris is an emerging fungal pathogen responsible for nosocomial invasive infection outbreaks on five continents. Large healthcare-related outbreaks of C. auris infection and colonization have been reported from different countries. Whole genome sequence analysis identified strong phylogeographic C. auris clades specific to particular geographical areas suggesting transmission of particular clades within countries. However, the mode of transmission within the healthcare environment is not clear and is likely to be multifactorial. The emergence of C. auris is alarming because this organism can harbor or develop multidrug resistance. This explains why C. auris infections are difficult to treat. In addition, difficulties in its identification in the routine diagnostic laboratory have a significant impact on outbreak detection and management. This mini-review highlights the available literature on C. auris, with particular insight into its epidemiology and the problems caused by its antifungal resistance.

Candida auris: A systematic review and meta-analysis of current updates on an emerging multidrug-resistant pathogen

From 2009, Candida auris has emerged as a multidrug‐resistant ascomycete yeast pathogen with the capacity for easy transmission between patients and hospitals, as well as persistence on environmental surfaces. Its association with high mortalities, breakthrough and persistent candidaemia, inconsistencies in susceptibility testing results, misidentification by available commercial identification systems and treatment failure, complicates its management and detection. Within the last nine years, C. auris has been increasingly reported from far‐Eastern Asia, the Middle East, Africa, Europe, South and North America with substantial fatalities and misidentification. Herein, I provide a systematic and thorough review of this emerging pathogen. Meta‐analysis showed that at least 742 C. auris isolates have been reported in 16 countries, with most of these being from India (≥243), USA (≥232) and UK (≥103) (p‐value = .0355) within 2013–2017. Most isolates were from males (64.76%) (p‐value = .0329) and blood (67.48%) (p‐value < .0001), with substantial crude mortality (29.75%) (p‐value = .0488). Affected patients presented with other comorbidities: diabetes (≥52), sepsis (≥48), lung diseases (≥39), kidney diseases (≥32) etc. (p‐value < .0001). Resistance to fluconazole (44.29%), amphotericin B (15.46%), voriconazole (12.67%), caspofungin (3.48%) etc. were common (p‐value = .0059). Commonly used diagnostic tools included PCR (30.38%), Bruker MALDI‐TOF MS (14.00%), Vitek 2 YST ID (11.93%), AFLP (11.55%) and WGS (10.04%) (p‐value = .002). Multidrug resistance, high attributable mortality and persistence are associated with C. auris infections. Two novel drugs, SCY‐078 and VT‐1598, are currently in the pipeline. Contact precautions, strict infection control, periodic surveillance and cleaning with chlorine‐based detergents, efficient, faster and cheaper detection tools are necessary for prevention, containment and early diagnosis of C. auris infections.

Candida auris: a Review of the Literature

The emerging pathogen Candida auris has been associated with nosocomial outbreaks on five continents. Genetic analysis indicates the simultaneous emergence of separate clades of this organism in different geographical locations. Invasive infection and colonization have been detected predominantly in patients in high-dependency settings and have garnered attention due to variable antifungal resistance profiles and transmission within units instituting a range of infection prevention and control measures. Issues with the identification of C. auris using both phenotypic and molecular techniques have raised concerns about detecting the true scale of the problem. This review considers the literature available on C. auris and highlights the key unknowns, which will provide direction for further work in this field.

Candida auris: An emerging multidrug-resistant pathogen

Candida aurisis an emerging multidrug-resistant pathogen that can be difficult to identify using traditional biochemical methods. C. auris is capable of causing invasive fungal infections, particularly among hospitalized patients with significant medical comorbidities. Echinocandins are the empiric drugs of choice for C. auris, although not all isolates are susceptible and resistance may develop on therapy. Nosocomial C. auris outbreaks have been reported in a number of countries and aggressive infection control measures are paramount to stopping transmission.

Candida auris: a worrisome, globally emerging pathogen

INTRODUCTION

Candida auris is a recently discovered, rapidly emerging fungal pathogen. Infections due to C. auris are hospital-acquired, multidrug resistant and associated with high mortality. Areas covered: This review highlights epidemiology, pathogenesis, microbiological characteristics, clinical presentation, diagnostic challenges and treatment options of C. auris infections. Infection prevention measures to prevent spread of C. auris and special measures during an outbreak situation have also been reviewed. Expert commentary: Rapid emergence of hospital onset C. auris is worrisome. Early diagnosis of C. auris is essential for better outcomes and the implementation of infection prevention measures. Lack of widespread awareness, absence of general availability of diagnostic testing methods, and limited options for treatment of C. auris infections make it a difficult-to-treat pathogen. Further studies are needed for better understanding of this emerging pathogen.

The first cases of Candida auris candidaemia in Oman

Candida auris has been recognised as a problematic healthcare-associated emerging yeast which is often misidentified as Candida haemulonii by commercial systems. Correct early identification of C. auris is important for appropriate antifungal treatment and implementing effective infection control measures. Here we report emergence of the first C. auris cases in Oman, initially misidentified as C. haemulonii.

The Emerging Pathogen Candida auris: Growth Phenotype, Virulence Factors, Activity of Antifungals, and Effect of SCY-078, a Novel Glucan Synthesis Inhibitor, on Growth Morphology and Biofilm Formation

Candidaauris, a new multidrug-resistant Candida spp. which is associated with invasive infection and high rates of mortality, has recently emerged. Here, we determined the virulence factors (germination, adherence, biofilm formation, phospholipase and proteinase production) of 16 C. auris isolates and their susceptibilities to 11 drugs belonging to different antifungal classes, including a novel orally bioavailable 1,3-β-d-glucan synthesis inhibitor (SCY-078). We also examined the effect of SCY-078 on the growth, ultrastructure, and biofilm-forming abilities of C. auris. Our data showed that while the tested strains did not germinate, they did produce phospholipase and proteinase in a strain-dependent manner and had a significantly reduced ability to adhere and form biofilms compared to that of Candida albicans (P = 0.01). C. auris isolates demonstrated reduced susceptibility to fluconazole and amphotericin B, while, in general, they were susceptible to the remaining drugs tested. SCY-078 had an MIC₉₀ of 1 mg/liter against C. auris and caused complete inhibition of the growth of C. auris and C. albicans. Scanning electron microscopy analysis showed that SCY-078 interrupted C. auris cell division, with the organism forming abnormal fused fungal cells. Additionally, SCY-078 possessed potent antibiofilm activity, wherein treated biofilms demonstrated significantly reduced metabolic activity and a significantly reduced thickness compared to the untreated control (P < 0.05 for both comparisons). Our study shows that C. auris expresses several virulence determinants (albeit to a lesser extent than C. albicans) and is resistant to fluconazole and amphotericin B. SCY-078, the new orally bioavailable antifungal, had potent antifungal/antibiofilm activity against C. auris, indicating that further evaluation of this antifungal is warranted.

Identification and typing of the emerging pathogen Candida auris by matrix-assisted laser desorption ionisation time of flight mass spectrometry

Candida auris is an emerging antifungal resistant yeast species causing nosocomial and invasive infections, emphasising the need of improved diagnostics and epidemiological typing methods. We show that MALDI-TOF VITEK-MS followed by amplified length polymorphisms allows for accurate species identification and subsequent epidemiological characterisation of strains encountered during potential outbreaks.

Evidence of genotypic diversity among Candida auris isolates by multilocus sequence typing, matrix-assisted laser desorption ionization time-of-flight mass spectrometry and amplified fragment length polymorphism

Candida auris is a multidrug-resistant nosocomial bloodstream pathogen that has been reported from Asian countries and South Africa. Herein, we studied the population structure and genetic relatedness among 104 global C. auris isolates from India, South Africa and Brazil using multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) fingerprinting and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). RPB1, RPB2 and internal transcribed spacer (ITS) and D1/D2 regions of the ribosomal DNA were sequenced for MLST. Further, genetic variation and proteomic assessment was carried out using AFLP and MALDI-TOF MS, respectively. Both MLST and AFLP typing clearly demarcated two major clusters comprising Indian and Brazilian isolates. However, the South African isolates were randomly distributed, suggesting different genotypes. MALDI-TOF MS spectral profiling also revealed evidence of geographical clustering but did not correlate fully with the genotyping methods. Notably, overall the population structure of C. auris showed evidence of geographical clustering by all the three techniques analysed. Antifungal susceptibility testing by the CLSI microbroth dilution method revealed that fluconazole had limited activity against 87% of isolates (MIC90, 64 mg/L). Also, MIC90 of AMB was 4 mg/L. Candida auris is emerging as an important yeast pathogen globally and requires reproducible laboratory methods for identification and typing. Evaluation of MALDI-TOF MS as a typing method for this yeast is warranted.

Multidrug-Resistant Candida auris Misidentified as Candida haemulonii: Characterization by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and DNA Sequencing and Its Antifungal Susceptibility Profile Variability by Vitek 2, CLSI Broth Microdilution, and Etest Method

Candida auris is a multidrug-resistant yeast that causes a wide spectrum of infections, especially in intensive care settings. We investigated C. auris prevalence among 102 clinical isolates previously identified as Candida haemulonii or Candida famata by the Vitek 2 system. Internal transcribed spacer region (ITS) sequencing confirmed 88.2% of the isolates as C. auris, and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) easily separated all related species, viz., C. auris (n = 90), C. haemulonii (n = 6), C. haemulonii var. vulnera (n = 1), and Candida duobushaemulonii (n = 5). The in vitro antifungal susceptibility was determined using CLSI broth microdilution (CLSI-BMD), the Vitek 2 antifungal susceptibility test, and the Etest method. C. auris isolates revealed uniformly elevated fluconazole MICs (MIC50, 64 μg/ml), and an alarming percentage of isolates (37%) exhibited elevated caspofungin MICs by CLSI-BMD. Notably, 34% of C. auris isolates had coexisting elevated MICs (≥2 μg/ml) for both fluconazole and voriconazole, and 10% of the isolates had elevated coexisting MICs (≥2 μg/ml) to two additional azoles, i.e., posaconazole and isavuconazole. In contrast to reduced amphotericin B MICs by CLSI-BMD (MIC50, 1 μg/ml) for C. auris, elevated MICs were noted by Vitek 2 (MIC50, 8 μg/ml), which were statistically significant. Candida auris remains an unnoticed pathogen in routine microbiology laboratories, as 90% of the isolates characterized by commercial identification systems are misidentified as C. haemulonii. MALDI-TOF MS proved to be a more robust diagnostic technique for rapid identification of C. auris. Considering that misleading elevated MICs of amphotericin B by the Vitek AST-YS07 card may lead to the selection of inappropriate therapy, a cautionary approach is recommended for laboratories relying on commercial systems for identification and antifungal susceptibility testing of rare yeasts.