Colonized patients by Candida auris: Third and largest outbreak in Brazil and impact of biofilm formation

Candida auris is emerging as a prevalent urinary pathogen

Urinary tract infections (UTIs) are one of the most common infections, with a subgroup of these infections, catheter-associated UTIs (CAUTIs), accounting for 40% of nosocomial infections. While the majority of CAUTI pathogens are bacterial, the second most common pathogen is the fungus Candida albicans. However, in recent years, Candida auris has increasingly been isolated from urine, indicating C. auris' potential as a urinary pathogen. C. auris has rapidly emerged as a human pathogen worldwide, becoming a serious health threat. This is of great concern due to its antifungal resistance, adherence to inanimate surfaces, high mortality rates, and the extensive knowledge gap regarding C. auris' prevalence and pathophysiology. To understand whether C. auris is prevalent in the urinary tract, we analyzed 12,996 C. auris clinical strains and their frequency related to urine and urinary catheters. We identified urine as the second most common C. auris isolation source in the United States and the third most common worldwide. Anecdotally, C. auris urine isolates are often associated with urinary catheters and high mortality rates. Furthermore, there has been an early indication of urinary isolates developing echinocandin resistance. With the increasing incidence of uropathogenic C. auris, it is critical to have an in-depth understanding of C. auris pathogenesis in the urinary tract to effectively prevent and treat these infections.

Prevalence of invasive yeast infections in a COVID-19 intensive care unit in northeastern Brazil

The COVID-19 pandemic has caused a global crisis, overwhelming hospitals and intensive care units (ICU) and leading to an increase in nosocomial infections due to prolonged hospitalization and other risk factors. The present study evaluated the prevalence of secondary fungal infections in critically ill patients with COVID-19. This is a retrospective, single-center study conducted in a hospital in northeastern Brazil, which evaluated 1,364 medical records of patients admitted to a COVID-19 ICU during 2020 and 2021. A total of 327 pathogenic yeasts were isolated from 132 (40.4%) respiratory, 70 (21.4%) blood, 124 (37.9%) urine, and one (0.3%) surgical wound samples. Fungal infections were diagnosed in the intermediate (5 to 12 days) or late (≥12 days) stage of hospitalization. The most frequent yeast isolated from critically ill COVID-19 patients was Candida albicans [126 (67.7%) and 60 (42.6%)], followed by Candida tropicalis [25 (13.4%) and 39 (27.7%)]. Candida parapsilosis isolates increased 5.7-fold in 2021 [40 (28.4%)] compared to 2020 [7 (3.8%)]. The least frequently isolated in 2020 and 2021 were Nakaseomyces glabratus [4 (2.2%) and 1 (0.7%)], and Pichia kudriavzevii, which was isolated only in 2021 (1 (0.7%)). During the study period, a decrease in susceptibility to antifungals was observed: susceptibility to voriconazole reduced from 100 to 77.2%, to flucytosine from 99.4 to 78.8%, and to micafungin from 99.4 to 83.6%. The changes in the frequency of species causing secondary infections in critically ill COVID-19 patients and susceptibility to the antifungals indicate the need for early and adequate diagnosis to minimize negative outcomes.

Key Factors to Consider for Candida auris Screening in Healthcare Settings: A Systematic Review

BACKGROUND

Candida auris is an emerging fungal pathogen that is often multidrug-resistant. It can persist on skin and in hospital environments, leading to outbreaks and severe infections for patients at risk. Several countries and institutions are working on establishing guidelines and recommendations for prevention. This review aims to assess the evidence on factors associated with C. auris colonisation or infection, the duration of such colonisation, possible colonisation sites, and the risk of secondary cases to inform screening recommendations.

METHODS

We systematically searched five databases for primary studies and systematic reviews of our four outcomes. We excluded studies on treatment, management, laboratory methods, drug resistance, and environmental screening. From each paper, we extracted relevant data and summarised them in tables. Main findings were described narratively.

FINDINGS

We selected 117 studies for inclusion. Most of the studies were observational studies. Without taking the method of testing into account, the duration of C. auris colonisation varied, with up to and beyond a year being common. The predominant sites of colonisation were the axillae and groin, with the nares and rectum being less common sites. The risk of secondary cases saw considerable variation across the studies, and the secondary cases primarily involved patients and not healthcare workers. Critical care settings, invasive medical devices, recent antimicrobial use, and comorbidities were often associated with C. auris colonisation and infection.

CONCLUSION

Our review highlights that, despite relevant findings on factors influencing C. auris colonisation and infection, substantial gaps remain in the evidence supporting screening practices. Most studies were conducted reactively, in outbreak settings, and lack systematic protocols. Given these limitations, screening guidelines are likely to be more successful if grounded in medical theory and yeast microbiology rather than relying solely on current studies. Rigorous, well-designed research is urgently needed to inform future C. auris screening and control efforts.

Microspheres based on galactomannan and Spondias purpurea L. extract to increase antifungal and antibiofilm efficacy against Candida spp

The ongoing problem of an increasing resistance of Candida spp. to available antifungals, has made it necessary the search for new therapeutic alternatives. The aim of this work was to develop a microsphere based on Caesalpinia ferrea galactomannan and Spondias purpurea L. stem bark extract using the spray drying technique and evaluate its antimicrobial effect on biofilm formation and planktonic cells of Candida spp. Differential scanning calorimetry (DSC), infrared analysis (IR) and scanning electron microscopy (SEM) were used to characterize the microsphere, in addition to the encapsulation efficiency by HPLC to quantify the extract in the microsphere. In microbiological analyses, broth microdilution and antibiofilm tests were carried out. The results of the minimum inhibitory concentration (MIC) for the stem bark extract (SBE) were within 0.5-2 μg mL-1 and the galactomannan microsphere (GMB) 1-8 μg mL-1. As for the biofilm, the microsphere compared to the extract showed a statistically significant improvement at 8xMIC for C. albicans 1, while for C. auris, it was at 4xMIC and 8xMIC. Furthermore, SBE and GMB did not present toxicity. The study revealed that the synthesized microspheres have the potential to be used as an antifungal agent.

Biofilm Resilience: Molecular Mechanisms Driving Antibiotic Resistance in Clinical Contexts

Healthcare-associated infections pose a significant global health challenge, negatively impacting patient outcomes and burdening healthcare systems. A major contributing factor to healthcare-associated infections is the formation of biofilms, structured microbial communities encased in a self-produced extracellular polymeric substance matrix. Biofilms are critical in disease etiology and antibiotic resistance, complicating treatment and infection control efforts. Their inherent resistance mechanisms enable them to withstand antibiotic therapies, leading to recurrent infections and increased morbidity. This review explores the development of biofilms and their dual roles in health and disease. It highlights the structural and protective functions of the EPS matrix, which shields microbial populations from immune responses and antimicrobial agents. Key molecular mechanisms of biofilm resistance, including restricted antibiotic penetration, persister cell dormancy, and genetic adaptations, are identified as significant barriers to effective management. Biofilms are implicated in various clinical contexts, including chronic wounds, medical device-associated infections, oral health complications, and surgical site infections. Their prevalence in hospital environments exacerbates infection control challenges and underscores the urgent need for innovative preventive and therapeutic strategies. This review evaluates cutting-edge approaches such as DNase-mediated biofilm disruption, RNAIII-inhibiting peptides, DNABII proteins, bacteriophage therapies, antimicrobial peptides, nanoparticle-based solutions, antimicrobial coatings, and antimicrobial lock therapies. It also examines critical challenges associated with biofilm-related healthcare-associated infections, including diagnostic difficulties, disinfectant resistance, and economic implications. This review emphasizes the need for a multidisciplinary approach and underscores the importance of understanding biofilm dynamics, their role in disease pathogenesis, and the advancements in therapeutic strategies to combat biofilm-associated infections effectively in clinical settings. These insights aim to enhance treatment outcomes and reduce the burden of biofilm-related diseases.

Enhancing ICU Candida spp. surveillance: a cost-effective approach focused on Candida auris detection

Introduction

Candida auris is an emerging pathogen that represents a worldwide health problem due to its global expansion, multidrug resistance, and difficult laboratory identification. Among the risk factors for colonization/infection by C. auris, a stay in an intensive care unit (ICU) stands out. This prospective multicenter study aimed to monitor the trend of the local epidemiology of Candida spp. and unveil the prevalence of C. auris.

Methods

From 2020 to 2022, axillar/inguinal swabs were collected from adult patients at three points: upon admission (D1) and on the fifth (D5) and eighth (D8) days of their ICU stay. We employed culture-based screening methods combined with molecular techniques to identify Candida spp. down to the species level. Specific screening for Candida auris was conducted using a real-time PCR assay in combination with an improved selective culture medium, mannitol salt agar auris (MSAA). To validate the effectiveness of MSAA, a collection of reference C. auris strains representing the four major geographical clades was used.

Results

We enrolled 675 patients, and 355 Candida isolates were retrieved from the 988 swab samples collected. From those, 185/355 (52.1%) were identified as C. albicans and 170/355 (47.9%) as non-albicans Candida (NAC). MSAA medium showed a specificity of 94.8%, albeit C. auris was not detected in this cohort. The dynamics of Candida spp. colonization by ICU were significant at the three collection points. Upon admission, C. albicans was associated with the Beatriz Ângelo Hospital ICU (p=0.003) and C. tropicalis with the general Hospital Professor Doutor Fernando Fonseca (FFH) ICU (p=0.006). C. parapsilosis and C. lusitaniae were associated with FFH ICUs, with the general ICU at D5 (p=0.047) and surgical ICU at D8 (p=0.012). The dynamics of NAC colonization by ICU were significantly different at D1 (p=0.011), D5 (p=0.047), and D8 (p=0.012).

Conclusion

We developed and implemented a screening protocol for C. auris while uncovering the colonization patterns of Candida in the ICU. Our findings contribute to the optimization of overall patient management, ensuring that ICU protocols are resilient and adaptive to emerging fungal threats.

Current knowledge and practice of Candida auris screening in France: A nationwide survey from the French Society of Medical Mycology (SFMM)

Due to large outbreaks observed worldwide, Candida auris has emerged as a major threat to healthcare facilities. To prevent these phenomena, a systematic screening should be performed in patients transferred from regions where the pathogen is highly endemic. In this study, we recorded and analyzed French mycologists' current knowledge and practice regarding C. auris screening and diagnosis. Thirty-six centers answered an online questionnaire. Only 11 (30.6 %) participants were aware of any systematic screening for C. auris for patients admitted to their hospital. In the case of post-admission screening, axillae/groins (n = 21), nares (n = 7), rectum (n = 9), and mouth (n = 6) alone or various combinations were the body sites the most frequently sampled. Only six centers (8.3 %) reported using a commercially available plate allowing the differentiation of C. auris colonies from that of other Candida species, while five laboratories (13.8 %) had implemented a C. auris-specific qPCR. Considering the potential impact on infected patients and the risk of disorganization in the care of patients, it is crucial to remember to biologists and clinicians the utmost importance of systematic screening on admission.

Screening of the global health priority BoxⓇ reveals potential new disinfectants against the emerging multidrug-resistant pathogen Candida auris

BACKGROUND

Candida auris has been identified by the World Health Organization as a critical pathogen due to its invasive nature, resistance to multiple drugs, and high mortality rates in hospital outbreaks. This fungus can persist on surfaces and human skin for extended periods, complicating infection control efforts. The need for effective disinfection strategies is urgent, as current disinfectants are often ineffective against C. auris biofilms.

OBJECTIVE

The study aimed to identify potential disinfectants from a collection of 240 compounds in the Global Health Priority Box® that are effective against C. auris, particularly strains resistant to existing options.

METHODS

The research employed a screening protocol using a fluconazole-resistant strain of C. auris (149/23). Antifungal activity was assessed using the microdilution method to determine Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs). Additional assays were conducted to evaluate biofilm inhibition, biofilm eradication, cell membrane integrity, nucleotide leakage, sorbitol protection assay, efflux pump inhibition, and hemolysis assay.

RESULTS

Two compounds, Hydramethylnon (MMV1577471) and Flufenerim (MMV1794206), demonstrated significant inhibitory effects against C. auris. Hydramethylnon exhibited potent antifungal activity, inhibiting up to 93 % of fungal growth with an MFC of 16 μg/mL. Flufenerim inhibited up to 58 % of fungal growth, showing fungistatic action with an MFC greater than 4 μg/mL. Biofilm inhibition tests showed that both compounds significantly inhibited biofilm formation, with increased efficacy at higher concentrations. Both compounds showed eradication rates in both stages. Furthermore, Hydramethylnon and Flufenerim did not affect cell membrane integrity or nucleotide leakage, suggesting a mode of action not reliant on disrupting these cellular components. The sorbitol protection assay revealed that neither compound caused cell wall damage. In the efflux pump inhibition assay, Hydramethylnon did not activate efflux pumps, while Flufenerim activated efflux pumps, reducing its effectiveness. Hemocompatibility assay showed safety.

CONCLUSION

The study highlights Hydramethylnon and Flufenerim as promising candidates for further development as disinfectants, offering potential solutions to the urgent need for effective disinfection agents against C. auris. The findings underscore the value of screening compound collections to identify novel antifungal agents and understand their mechanisms of action, thereby contributing to the advancement of new disinfection strategies in healthcare settings.

Clinical and microbiological characteristics of a hospital outbreak of Candida auris in a referral hospital in Lima, Peru

BACKGROUND

Candida auris, a multidrug-resistant fungal pathogen, has received considerable attention owing to its recent surge, especially in South America, which coincides with the ongoing global COVID-19 pandemic. Understanding the clinical and microbiological characteristics of outbreaks is crucial for their effective management and control.

OBJECTIVE

This retrospective observational study aimed to characterize a C. auris outbreak at a Peruvian referral hospital between January 2021 and July 2023.

METHODS

Data were collected from hospitalized patients with positive C. auris culture results. Microbiological data and antifungal susceptibility test results were analysed. Additionally, infection prevention and control measures have been described. Statistical analysis was used to compare the characteristics between the infected and colonized patients.

RESULTS

Thirty-three patients were identified, mostly male (66.7%), with a median age of 53 years. Among them, 18 (54.5%) were colonized, and 15 (45.5%) were infected. Fungemia was the predominant presentation (80%), with notable cases of fungemia in tuberculosis patients with long-stay devices for parenteral anti-tuberculosis therapy. Seventy-five percent of the isolates exhibited fluconazole resistance. Echinocandins were the primary treatment, preventing fungemia recurrence within 30 days. Infected patients had significantly longer hospital stays than colonized patients (100 vs. 45 days; p = .023). Hospital mortality rates were 46.7% and 25% in the infected and fungemia patients, respectively. Simultaneous outbreaks of multidrug-resistant bacteria were documented.

CONCLUSIONS

This study underscores the severity of a C. auris outbreak at a referral hospital in Peru, highlighting its significant impact on patient outcomes and healthcare resources. The high prevalence of fluconazole-resistant isolates, leading to prolonged hospital stay and high mortality rates, particularly in cases of fungemia, underscores the critical need for effective infection prevention and control strategies.

Unmasking the Antifungal Activity of Anacardium occidentale Leaf Extract against Candida albicans

Invasive fungal disease causes high morbidity and mortality among immunocompromised patients. Resistance to conventional antifungal drugs and the toxicity associated with high doses highlight the need for effective antifungal therapies. In this study, the antifungal potential of the ethanolic extract of Anacardium occidentale (Cashew Leaf) leaves were evaluated against Candida albicans and C. auris. The antifungal activity was tested by the broth microdilution method and growth kinetic test. To further explore its antifungal action mode, spectrofluorophotometry, confocal microscopy and scanning and transmission electron microscopy were performed. Additionally, heterozygous knockout strains associated with resistance to oxidative stress were included in the study. We found that A. occidentale could inhibit the proliferation and growth of C. albicans at concentrations of 62.5 and 125 μg/mL. The doubling time was also drastically affected, going from 2.8 h to 22.5 h, which was also observed in C. auris. The extract induced the accumulation of intracellular reactive oxygen species (ROS), resulting in endoplasmic reticulum stress and mitochondrial dysfunction, while it did not show cytotoxicity or hemolytic activity at the concentrations evaluated. Our work preliminarily elucidated the potential mechanisms of A. occidentale against C. albicans on a cellular level, and might provide a promising option for the design of a new treatment for invasive candidiasis.

Screening of Candida spp. in wastewater in Brazil during COVID-19 pandemic: workflow for monitoring fungal pathogens

Fungal diseases are often linked to poverty, which is associated with poor hygiene and sanitation conditions that have been severely worsened by the COVID-19 pandemic. Moreover, COVID-19 patients are treated with Dexamethasone, a corticosteroid that promotes an immunosuppressive profile, making patients more susceptible to opportunistic fungal infections, such as those caused by Candida species. In this study, we analyzed the prevalence of Candida yeasts in wastewater samples collected to track viral genetic material during the COVID-19 pandemic and identified the yeasts using polyphasic taxonomy. Furthermore, we investigated the production of biofilm and hydrolytic enzymes, which are known virulence factors. Our findings revealed that all Candida species could form biofilms and exhibited moderate hydrolytic enzyme activity. We also proposed a workflow for monitoring wastewater using Colony PCR instead of conventional PCR, as this technique is fast, cost-effective, and reliable. This approach enhances the accurate taxonomic identification of yeasts in environmental samples, contributing to environmental monitoring as part of the One Health approach, which preconizes the monitoring of possible emergent pathogenic microorganisms, including fungi.

Multicenter Candida auris outbreak caused by azole-susceptible clade IV in Pernambuco, Brazil

BACKGROUND

Candida auris is an emerging multidrug-resistant yeast, frequently causing outbreaks in health care facilities. The pathogen persistently colonises human skin and inanimate surfaces such as catheters, aiding to its spread. Moreover, colonisation is a risk factor to develop invasive infection.

OBJECTIVES

We investigated 61 C. auris strains isolated from non-sterile human body sites (n = 53) and the hospital environment (n = 8), originating from four different centres in a single Brazilian state.

MATERIALS AND METHODS

Antifungal susceptibility testing (AFST) against common antifungals was performed, and resistance-associated genes were evaluated. Genetic relatedness was investigated with short tandem repeat (STR) genotyping and validated with whole-genome sequencing (WGS) single nucleotide polymorphism (SNP) analysis.

RESULTS

Antifungal susceptibility testing demonstrated that all isolates were susceptible to azoles, echinocandins and amphotericin B. No mutations were detected in ERG11 and FKS1 genes. With STR typing, isolates were allocated to clade IV and appeared closely related. This was confirmed by WGS SNP analysis of 6 isolates, which demonstrated a maximal difference of only 41 SNPs between these strains. Furthermore, the Brazilian isolates formed a distinct autochthonous branch within clade IV, excluding recent introductions from outside the country. A molecular clock analysis of clade IV isolates from various countries suggests that early in the previous century there was a unique event causing environmental spread of a C. auris ancestor throughout the Latin-American continent, followed by human introduction during the last decades.

CONCLUSION

We report the emergence of C. auris patient colonisation in multiple centres by fluconazole-susceptible clade IV close-related strains in Pernambuco State, Brazil.

Potential Environmental Reservoirs of Candida auris: A Systematic Review

Candida auris, a multidrug-resistant yeast, poses significant challenges in healthcare settings worldwide. Understanding its environmental reservoirs is crucial for effective control strategies. This systematic review aimed to review the literature regarding the natural and environmental reservoirs of C. auris. Following the PRISMA guidelines, published studies until October 2023 were searched in three databases: PubMed, Web of Science, and Scopus. Information regarding the origin, sampling procedure, methods for laboratory identification, and antifungal susceptibility was collected and analyzed. Thirty-three studies published between 2016 and 2023 in 15 countries were included and analyzed. C. auris was detected in various environments, including wastewater treatment plants, hospital patient care surfaces, and natural environments such as salt marshes, sand, seawater, estuaries, apples, and dogs. Detection methods varied, with molecular techniques often used alongside culture. Susceptibility profiles revealed resistance patterns. Phylogenetic studies highlight the potential of environmental strains to influence clinical infections. Despite methodological heterogeneity, this review provides valuable information for future research and highlights the need for standardized sampling and detection protocols to mitigate C. auris transmission.

The many faces of Candida auris: Phenotypic and strain variation in an emerging pathogen

Candida auris is an emerging fungal pathogen with unusual evolutionary history-there are multiple distinct phylogeographic clades showing a near simultaneous transition from a currently unknown reservoir to nosocomial pathogen. Each of these clades has experienced different selective pressures over time, likely resulting in selection for genotypes with differential fitness or phenotypic consequences when introduced to new environments. We also observe diversification within clades, providing additional opportunities for phenotypic differences. These differences can have large impacts on pathogenic potential, drug resistance profile, evolutionary trajectory, and transmissibility. In recent years, there have been significant advances in our understanding of strain-specific behavior in other microbes, including bacterial and fungal pathogens, and we have an opportunity to take this strain variation into account when describing aspects of C. auris biology. Here, we critically review the literature to gain insight into differences at both the strain and clade levels in C. auris, focusing on phenotypes associated with clinical disease or transmission. Our goal is to integrate clinical and epidemiological perspectives with molecular perspectives in a way that would be valuable for both audiences. Identifying differences between strains and understanding which phenotypes are strain specific will be crucial for understanding this emerging pathogen, and an important caveat when describing the analysis of a singular isolate.

The Gordian Knot of C. auris: If You Cannot Cut It, Prevent It

Since its first description in 2009, Candida auris has, so far, resulted in large hospital outbreaks worldwide and is considered an emerging global public health threat. Exceptionally for yeast, it is gifted with a profoundly worrying invasive potential and high inter-patient transmissibility. At the same time, it is capable of colonizing and persisting in both patients and hospital settings for prolonged periods of time, thus creating a vicious cycle of acquisition, spreading, and infection. It exhibits various virulence qualities and thermotolerance, osmotolerance, filamentation, biofilm formation and hydrolytic enzyme production, which are mainly implicated in its pathogenesis. Owing to its unfavorable profile of resistance to diverse antifungal agents and the lack of effective treatment options, the implementation of robust infection prevention and control (IPC) practices is crucial for controlling and minimizing intra-hospital transmission of C. auris. Rapid and accurate microbiological identification, adherence to hand hygiene, use of adequate personal protective equipment (PPE), proper handling of catheters and implantable devices, contact isolation, periodical environmental decontamination, targeted screening, implementation of antimicrobial stewardship (AMS) programs and communication between healthcare facilities about residents' C. auris colonization status are recognized as coherent strategies for preventing its spread. Current knowledge on C. auris epidemiology, clinical characteristics, and its mechanisms of pathogenicity are summarized in the present review and a comprehensive overview of IPC practices ensuring yeast prevention is also provided.

Phenotypic Investigation of Virulence Factors, Susceptibility to Ceragenins, and the Impact of Biofilm Formation on Drug Efficacy in Candida auris Isolates from Türkiye

Candida auris has emerged as a significant fungal threat due to its rapid worldwide spread since its first appearance, along with its potential for antimicrobial resistance and virulence properties. This study was designed to examine virulence characteristics, the efficacy of ceragenins, and biofilm-derived drug resistance in seven C. auris strains isolated from Turkish intensive care patients. It was observed that none of the tested strains exhibited proteinase or hemolysis activity; however, they demonstrated weak phospholipase and esterase activity. In addition, all strains were identified as having moderate to strong biofilm formation characteristics. Upon determining the minimum inhibitory concentrations (MIC) of ceragenins, it was discovered that CSA-138 exhibited the highest effectiveness with a MIC range of 1-0.5 µg/mL, followed by CSA-131 with a MIC of 1 µg/mL. Also, antimicrobial agents destroyed mature biofilms at high concentrations (40-1280 µg/mL). The investigation revealed that the strains isolated from Türkiye displayed weak exoenzyme activities. Notably, the ceragenins exhibited effectiveness against these strains, suggesting their potential as a viable treatment option.