An Overview on Candida auris in Healthcare Settings

Emergence, Transmission, and Containment of Candida auris in the Perioperative Setting

Candida auris is an emerging, multidrug-resistant fungus that poses a threat in health care settings because of its persistence on surfaces and ability to cause severe infections, particularly in immunocompromised patients. First identified in Japan in 2009, C auris has since spread globally, leading to numerous outbreaks. Its unique virulence factors, such as biofilm formation and immune evasion, contribute to its resilience and resistance to eradication. The most vulnerable populations include those with underlying conditions and those undergoing operative or other invasive procedures, highlighting the importance of this topic for perioperative personnel. Effective infection prevention strategies, including strict hand hygiene, environmental cleaning, and the use of appropriate personal protective equipment, are essential to prevent the spread of C auris. Early detection, accurate identification, and prompt isolation of infected patients are critical to mitigating outbreaks. Continued research and education are vital to developing more effective prevention and treatment protocols.

A comparative evaluation of CRISPR-Cas9 allele editing systems in Candida auris: challenging research in a challenging bug

Candida auris is an emergent fungal pathogen of significant interest for molecular research because of its unique nosocomial persistence, high stress tolerance and common multidrug resistance. To investigate the molecular mechanisms of these or other phenotypes, a handful of CRISPR-Cas9 based allele editing tools have been optimized for C. auris. Nonetheless, allele editing in this species remains a significant challenge, and different systems have different advantages and disadvantages. In this work, we compare four systems to introduce the genetic elements necessary for the production of Cas9 and the guide RNA molecule in the genome of C. auris, replacing the ENO1, LEU2 and HIS1 loci respectively, while the fourth system makes use of an episomal plasmid. We observed that the editing efficiency of all four systems was significantly different and strain dependent. Alarmingly, we did not detect correct integration of linear CRISPR cassette constructs in integration-based systems, in over 4,900 screened transformants. Still, all transformants, whether correctly edited or not, grew on selective nourseothricin media, suggesting common random ectopic integration of the CRISPR cassette. Although the plasmid-based system showed a low transformation success compared to the other systems, it has the highest editing efficiency with 41.9% correct transformants on average. In an attempt to improve editing efficiencies of integration-based systems by silencing the non-homologous end joining (NHEJ) DNA repair pathway, we deleted two main NHEJ factors, KU70 and LIG4. However, no improved editing or targeting efficiencies were detected in ku70Δ, lig4Δ, or ku70Δ/lig4Δ backgrounds. Our research highlights important challenges in precise genome editing of C. auris and sheds light on the advantages and limitations of several methods with the aim to guide scientists in selecting the most appropriate tool for molecular work in this enigmatic fungal pathogen.

A Novel and Robust Method for Investigating Fungal Biofilm

Candida auris, labeled an urgent threat by the CDC, shows significant resilience to treatments and disinfectants via biofilm formation, complicating treatment/disease management. The inconsistencies in biofilm architecture observed across studies hinder the understanding of its role in pathogenesis. Our novel in vitro technique cultivates C. auris biofilms on gelatin-coated coverslips, reliably producing multilayer biofilms with extracellular polymeric substances (EPS). This method, applicable to other Candida species like C. glabrata and C. albicans, is cost-effective and mimics the niche of biofilm formation. It is suitable for high-throughput drug screening and repurposing efforts, aiding in the development of new therapeutics. Our technique represents a significant advancement in Candida biofilm research, addressing the need for consistent, reproducible biofilm models. We detail a step-by-step procedure for creating a substratum for biofilm growth and measuring biofilm thickness using confocal laser scanning microscopy (CLSM) and ultrastructure by scanning electron microscopy (SEM). This method provides consistent outcomes across various Candida species. Key features • The biofilm formed on gelatin surfaces mimics host conditions, replicating the multilayered structure and EPS, offering a more accurate model for studying C. auris biofilms. • This method is highly reproducible and suitable for drug screening and biofilm analysis through three-dimensional (3D) reconstruction. • This in vitro technique aids in studying biofilm formation, related virulence properties, and drug tolerance of C. auris and other Candida species. • The simple, cost-effective technique is ideal for screening novel inhibitors and repurposed drug libraries, facilitating the design/identification of new therapeutics against Candida species.

Population Structure Based on Microsatellite Length Polymorphism, Antifungal Susceptibility Profile, and Enzymatic Activity of Candida auris Clinical Isolates in Russia

Candida auris is an emerging multidrug-resistant fungal pathogen causing nosocomial transmission and invasive infections with high mortality. This study aimed to investigate the genetic relationships, enzymatic activities, and drug-resistance profiles of C. auris isolates to evaluate the population and epidemiological diversity of candidiasis in Russia. A total of 112 clinical isolates of C. auris were analyzed from May 2017 to March 2023 in 18 hospitals across Saint Petersburg, the Leningrad Region, and Moscow. Species identification was confirmed by ITS sequencing, and genotyping was performed using 12 short tandem repeat (STR) markers. Antifungal susceptibility was tested using Sensititre™ YeastOne™ plates, and hydrolytic enzyme production was measured by the plate method. ITS sequencing confirmed that all isolates belonged to a single ITS cluster (clades I and III). Fifteen distinct STR genotypes were identified, with genotype I being dominant (n = 53). The most variable of the analyzed markers turned out to be M3-Ia, which was represented in the Russian population by eight different variants. Fluconazole resistance was found in 111 isolates, 17% were resistant to amphotericin B, and 3.6% to 5-flucytosine. Phospholipase activity was strong in most strains, especially in urine isolates (p = 0.014). Conclusion: The predominance of STR genotype I and its variability at the M3-Ia locus suggest its association with nosocomial outbreaks and transmissibility in Russia.

Wastewater surveillance of Candida auris in Baltimore

Candida auris (C. auris), an opportunistic fungus causing disease, poses a growing global health concern due to its significant mortality rate, resistance to antifungal treatment, and ability to persist in healthcare settings. Over a span of 47 weeks, untreated wastewater samples were regularly gathered from two wastewater treatment plants (referred to as WWTP-A and WWTP-B) in Baltimore, from July 27, 2022, to June 23, 2023. Throughout the study period, 110 primary influent (PI) samples were collected from both WWTP-A and WWTP-B. A quantitative polymerase chain reaction (qPCR) method was used to analyze C. auris captured on filters (0.45 μm) from these samples. Positive C. auris detection (11.81%) occurred in the influent samples, with a higher frequency of detection in WWTP-B. Influent wastewater concentrations ranged from 1.2 to 7.9 log10 gene copies per liter (gc/L). Interestingly, seasonal analysis showed that C. auris presence in wastewater was more pronounced during the spring season, indicating a sustained existence of the pathogen as seasons changed. Integration of wastewater surveillance and clinical data reveals temporal correlations in C. auris dynamics. The resulting Pearson correlation coefficient of 0.27 reveals a weak positive correlation between the number of new C. auris cases in Baltimore and the quantity of detected gene copies in wastewater. This study marks the first instance of detecting C. auris in Baltimore's wastewater. The results emphasize that wastewater monitoring could serve as an additional early warning tool for anticipating and managing future outbreaks of C. auris.

Alkaloids solenopsins from fire ants display in vitro and in vivo activity against the yeast Candida auris

The urgency surrounding Candida auris as a public health threat is highlighted by both the Center for Disease Control (CDC) and World Health Organization (WHO) that categorized this species as a priority fungal pathogen. Given the current limitations of antifungal therapy for C. auris, particularly due to its multiple resistance to the current antifungals, the identification of new drugs is of paramount importance. Some alkaloids abundant in the venom of the red invasive fire ant (Solenopsis invicta), known as solenopsins, have garnered attention as potent inhibitors of bacterial biofilms, and there are no studies demonstrating such effects against fungal pathogens. Thus, we herein investigated the antibiotic efficacy of solenopsin alkaloids against C. auris biofilms and planktonic cells. Both natural and synthetic solenopsins inhibited the growth of C. auris strains from different clades, including fluconazole and amphotericin B-resistant isolates. Such alkaloids also inhibited matrix deposition and altered cellular metabolic activity of C. auris in biofilm conditions. Mechanistically, the alkaloids compromised membrane integrity as measured by propidium iodide uptake in exposed planktonic cells. Additionally, combining the alkaloids with AMB yielded an additive antifungal effect, even against AMB-resistant strains. Finally, both extracted solenopsins and the synthetic analogues demonstrated protective effect in vivo against C. auris infection in the invertebrate model Galleria mellonella. These findings underscore the potent antifungal activities of solenopsins against C. auris and suggest their inclusion in future drug development. Furthermore, exploring derivatives of solenopsins could reveal novel compounds with therapeutic promise.

Candida auris: Epidemiology Update and a Review of Strategies to Prevent Spread

Candida auris (C. auris) has emerged as a fungal pathogen with great propensity to spread rapidly on a global scale. C. auris infections have also caused significant morbidity and mortality. Strategies to prevent spread and outbreaks are critical. In this review, an update on the epidemiology of C. auris and a discussion of strategies to combat the spread of C. auris are presented. Future directions are also discussed.

Overcoming amphotericin B resistance in Candida auris using the antiemetic drug rolapitant

The emergence of Candida auris poses a significant health challenge that has led to a new era of multidrug-resistant fungal infections. Invasive infections caused by C. auris are usually associated with remarkable morbidity and mortality. For many years, amphotericin B (AmB) remained the most efficient and the last line of treatment against most hard-to-treat fungal infections. However, strains of C. auris possess extraordinary resistance to most antifungal agents, including AmB. In this study, we screened ~2,600 FDA-approved drugs and clinical compounds to identify the antiemetic drug rolapitant as a promising enhancer to AmB against C. auris. Rolapitant exhibited potent synergistic interactions with AmB against all tested (29/29) C. auris isolates. In a time-kill assay, rolapitant restored the fungicidal activity of AmB within 4 h. Additionally, the synergistic relationship between rolapitant and AmB was observed against other medically crucial Candida, Cryptococcus, and Aspergillus species. A transcriptomic study revealed that exposure to rolapitant affects oxidation reduction processes, ion transporters, and ATP production. Rolapitant triggers an elevation in cytosolic and mitochondrial calcium levels and induces oxidative stress within fungal cells. An ATP luminescence assay confirmed that rolapitant, at sub-inhibitory concentrations, significantly interfered with ATP production in C. auris. Moreover, rolapitant enhanced the in vivo activity of AmB in a mouse model of disseminated C. auris infection, as the combination reduced the fungal burden in murine kidneys by ~1 log (~90%) colony forming units. Our findings warrant further investigation of using rolapitant to overcome AmB resistance in C. auris and other fungal species.

Emergence of Candida auris in Vietnam: A case series

Candida auris (C. auris), a globally emerging pathogen, has posed a significant threat to hospitalized individuals during the COVID-19 in Vietnam. This case series reported (1) common patterns in five patients with non-multidrug-resistant C. auris infections (multiple comorbidities, severe-to-critical illness, use of broad-spectrum antibiotics, or history of surgery/invasive procedures) and (2) high rate of C. auris-associated mortality in this medical setting (four deaths out of five cases). Further studies are needed to (1) identify risk factors for C. auris infections and mortality and (2) investigate the effects of screening and preventive measures for C. auris, especially in low-resource settings.

Mortality and Associated Risk Factors in Patients With Candida auris: Insights From a Tertiary Care Hospital in Bahrain

Introduction Candida auris poses a significant healthcare challenge due to its high mortality rates, difficulties in identification, and resistance to antifungal treatment. This study aims to identify risk factors associated with 30-day mortality in patients with either invasive Candida auris infection or colonization. Methods We conducted a prospective study at Salmaniya Medical Complex, a tertiary care hospital in Bahrain, from September 2023 to February 2024. The study included 59 patients infected or colonized by Candida auris. Data were systematically collected from patient records, including demographics, clinical characteristics, and outcomes. Risk factors for 30-day mortality were analyzed using both univariate and multivariate statistical methods. Results Among the 59 patients studied, the mean age was 63.9 years, and the cohort was predominantly male (74.6%). Key findings include a high prevalence of multiple indwelling catheters (44.2%) and recent intubation (42.4%). Candida auris was most frequently isolated from the groin (33.9%) and urine (25.4%), with a notable presence in the axillary regions (23.7%). The mortality rate was 44.1%. Univariate and multivariate analyses revealed that age (≥65 years), multiple indwelling catheters, ICU admission for over 24 hours, and recent intubation were significant risk factors for mortality while chronic kidney disease did not retain its significance in the multivariate model. Conclusion The study underscores the critical need for focused infection control and strong antimicrobial stewardship to address the high mortality associated with Candida auris infections. Emphasizing the importance of early detection and a multidisciplinary approach, these strategies are essential for managing and mitigating the impact of Candida auris in healthcare settings.

Antibiotic resistance: a global crisis, problems and solutions

Healthy state is priority in today's world which can be achieved using effective medicines. But due to overuse and misuse of antibiotics, a menace of resistance has increased in pathogenic microbes. World Health Organization (WHO) has announced ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) as the top priority pathogens as these have developed resistance against certain antibiotics. To combat such a global issue, it is utmost important to identify novel therapeutic strategies/agents as an alternate to such antibiotics. To name certain antibiotic adjuvants including: inhibitors of beta-lactamase, efflux pumps and permeabilizers for outer membrane can potentially solve the antibiotic resistance problems. In this regard, inhibitors of lytic domain of lytic transglycosylases provide a novel way to not only act as an alternate to antibiotics but also capable of restoring the efficiency of previously resistant antibiotics. Further, use of bacteriophages is another promising strategy to deal with antibiotic resistant pathogens. Taking in consideration the alternatives of antibiotics, a green synthesis nanoparticle-based therapy exemplifies a good option to combat microbial resistance. As horizontal gene transfer (HGT) in bacteria facilitates the evolution of new resistance strains, therefore identifying the mechanism of resistance and development of inhibitors against it can be a novel approach to combat such problems. In our perspective, host-directed therapy (HDT) represents another promising strategy in combating antimicrobial resistance (AMR). This approach involves targeting specific factors within host cells that pathogens rely on for their survival, either through replication or persistence. As many new drugs are under clinical trials it is advisable that more clinical data and antimicrobial stewardship programs should be conducted to fully assess the clinical efficacy and safety of new therapeutic agents.

Innate immune response to Candida auris

Candida auris, a newly emergent fungal species, has been spreading in health care systems and causing life-threatening infections. Intact innate immunity is essential for protection against many invasive fungal infections, including candidiasis. Here, we highlight recent studies exploring immune interactions with C. auris, including investigations using animal models and ex vivo immune cells. We summarize innate immune studies comparing C. auris and the common fungal pathogen Candida albicans. We also discuss how structures of the C. auris cell wall influence immune recognition, the role of soluble host factors in immune recognition, and areas of future study.

Fungal infections in immunocompromised critically ill patients

Diverse pathogenic fungi can produce severe infections in immunocompromised patients, thereby justifying intensive care unit (ICU) admissions. In some cases, the infections can develop in immunocompromised patients who were previously admitted to the ICU. Aspergillus spp., Pneumocystis jirovecii, Candida spp., and Mucorales are the fungi that are most frequently involved in these infections. Diagnosis continues to be challenging because symptoms and signs are unspecific. Herein, we provide an in-depth review about the diagnosis, with emphasis on recent advances, and treatment of these invasive fungal infections in the ICU setting.

Hand contamination and hand hygiene knowledge and practices among commercial transport users after the SARS-CoV-2 virus (COVID-19) scare, Enugu State, Nigeria

Contaminated hands are one of the most common modes of microorganism transmission that are responsible for many associated infections in healthcare, food industries, and public places such as transportation parks. Public health approaches during COVID-19 pandemic have shown that hand hygiene practices and associated knowledge are critical measure to control the spread of infectious agent. Hence, assessment of commercial transport users' knowledge, belief and practices on hand hygiene, and potential contamination with infectious agents which is the aim of the study, aligns with general health concern of quantifying contamination risk levels to predict disease outbreaks. This study utilized a randomized sampling approach to select 10 frequently used commercial parks within two districts in the State: Enugu and Nsukka. The parameters analysed include a cross-sectional questionnaire survey, hand swab and hand washed samples collected from dominant hand of participants. A total of 600 participants responded to the questionnaire survey, while 100 participants' hand swabs were examined for microbial contamination. This study recorded a high prevalence of fungal (90.0%) and bacterial (87.0%) species; 20 species of fungus were identified with prevalence range of 1% to 14%; 21 bacterial species were isolated with prevalence range of 1% to 16%. These species were identified as either opportunistic, non-invasive, or pathogenic, which may constitute a health concern amongst immunocompromised individuals within the population. Aspergillus spp. (14%), was the most common fungal species that was exclusively found amongst Nsukka commercial users, while E. coli was the most prevalent isolated bacterial species amongst Nsukka (12%) and Enugu (20%) commercial park users. Prevalence of fungal contamination in Nsukka (94.0%; 47/50) and Enugu (86.0%; 43/50) were both high. Prevalence of bacterial contamination was higher in Enugu than Nsukka but not significantly (47[94.0%] vs. 40[80.0%], p = 0.583). A greater number of participants (99.3%) were aware of the importance of hand hygiene, however with low compliance rate aside "after using the toilet" (80%) and "before eating" (90%), other relevant hand washing and sanitizing practices were considered less important. With these observations, we can emphatically say that despite the COVID-19 scare, commercial park users within the sampled population do not efficiently practice quality hand wash and hygiene measures, hence, risking the widespread of infectious agents in situation of disease outbreak or among immunocompromised individuals.

Candida auris Outbreaks: Current Status and Future Perspectives

Candida auris has been identified by the World Health Organization (WHO) as a critical priority pathogen on its latest list of fungi. C. auris infections are reported in the bloodstream and less commonly in the cerebrospinal fluid and abdomen, with mortality rates that range between 30% and 72%. However, no large-scale epidemiology studies have been reported until now. The diagnosis of C. auris infections can be challenging, particularly when employing conventional techniques. This can impede the early detection of outbreaks and the implementation of appropriate control measures. The yeast can easily spread between patients and in healthcare settings through contaminated environments or equipment, where it can survive for extended periods. Therefore, it would be desirable to screen patients for C. auris colonisation. This would allow facilities to identify patients with the disease and take appropriate prevention and control measures. It is frequently unsusceptible to drugs, with varying patterns of resistance observed among clades and geographical regions. This review provides updates on C. auris, including epidemiology, clinical characteristics, genomic analysis, evolution, colonisation, infection, identification, resistance profiles, therapeutic options, prevention, and control.

Enhancing Candida auris Surveillance in High-Risk Settings by Implementing a High-Throughput Molecular Assay on the Hologic Fusion Open Access Platform

Candida auris, a resilient pathogenic yeast with frequent multidrug resistance, presents a persistent challenge in healthcare settings. The timely identification of C. auris is crucial for infection control and prevention, especially in facilities facing unique hurdles, such as our institution, which serves four major hospitals and approximately 80% of the Texas inmate population. Understaffing, communal living, and financial constraints exacerbate infection control issues. To address common staff shortages, streamline testing services, and enhance testing efficiency, there was a pressing need for rapid and high-throughput detection of C. auris. This study presents the validation and utility of an assay implemented on the Hologic Fusion Open Access platform using samples collected from high-risk patients' axilla and groin areas, as well as environmental swab samples from patient rooms. Our assay complemented efforts to control C. auris outbreaks within our healthcare system, providing valuable insights into its presence within surveillance samples. This assay demonstrated the value of high-throughput molecular detection platforms in challenging healthcare environments by aiding infection preventionists in containing the spread of C. auris and preventing nosocomial infections. Our research contributes essential data on the suitability and performance of the Hologic Fusion Open Access platform for C. auris detection. These findings hold significant implications for enhancing surveillance and control measures in high-risk settings, making a significant impact on the field of infection control and prevention.

Diagnosis and management of invasive fungal diseases in non-neutropenic ICU patients, with focus on candidiasis and aspergillosis: a comprehensive review

Invasive fungal diseases pose a significant threat to non-neutropenic ICU patients, with Candida and Aspergillus infections being the most common. However, diagnosing these infections in the ICU population remains challenging due to overlapping clinical features, poor sensitivity of blood cultures, and invasive sampling requirements. The classical host criteria for defining invasive fungal disease do not fully apply to ICU patients, leading to missed or delayed diagnoses. Recent advancements have improved our understanding of invasive fungal diseases, leading to revised definitions and diagnostic criteria. However, the diagnostic difficulties in ICU patients remain unresolved, highlighting the need for further research and evidence generation. Invasive candidiasis is the most prevalent form of invasive fungal disease in non-neutropenic ICU patients, presenting as candidemia and deep-seated candidiasis. Diagnosis relies on positive blood cultures or histopathology, while non-culture-based techniques such as beta-D-glucan assay and PCR-based tests show promise. Invasive aspergillosis predominantly manifests as invasive pulmonary aspergillosis in ICU patients, often associated with comorbidities and respiratory deterioration in viral pneumonia. Diagnosis remains challenging due to poor sensitivity of blood cultures and difficulties in performing lung biopsies. Various diagnostic criteria have been proposed, including mycological evidence, clinical/radiological factors and expanded list of host factors. Non-culture-based techniques such as galactomannan assay and PCR-based tests can aid in diagnosis. Antifungal management involves tailored therapy based on guidelines and individual patient factors. The complexity of diagnosing and managing invasive fungal diseases in ICU patients underscore the importance of ongoing research and the need for updated diagnostic criteria and treatment approaches. Invasive fungal disease, Invasive fungal infection, Invasive candidiasis, Invasive aspergillosis, Antifungal drugs.

The health of mankind and the health of the planet in a historical-ethical perspective: an inseparable relationship and a single destiny

Recent years have seen increasingly severe natural disasters, the consequences of which have been catastrophic. Clearly, our global environment is undergoing major changes. The climate is becoming deranged and pollution on a global scale afflicts air, water, and land. We are faced with an unprecedented shortage of cultivable land and fresh water for drinking, irrigation, and livestock farming, while our marine systems are breaking down. These environmental changes have a very high anthropogenic component; they are induced by human activities that are potentially dangerous for both the environment and human life. Moreover, not only do they have an enormous impact on the environments in which we live and on our way of life, they also have harmful effects on our health. Indeed, we must understand that our body - as Hippocrates explained long ago - is a system that constantly interacts with the surrounding environment.