Factors Associated With Candida auris Colonization and Transmission in Skilled Nursing Facilities With Ventilator Units, New York, 2016-2018

Candida auris screening practices at healthcare facilities in the United States: An Emerging Infections Network survey

We surveyed members of the Emerging Infections Network about Candida auris screening practices at US healthcare facilities. Only 37% of respondents reported conducting screening; among these, 75% reported detection of at least 1 C. auris case in the last year. Increased screening could improve C. auris detection and prevent spread.

The laboratory investigation, management, and infection prevention and control of Candida auris: a narrative review to inform the 2024 national guidance update in England

The emergent fungal pathogen Candida auris is increasingly recognised as an important cause of healthcare-associated infections globally. It is highly transmissible, adaptable, and persistent, resulting in an organism with significant outbreak potential that risks devastating consequences. Progress in the ability to identify C. auris in clinical specimens is encouraging, but laboratory diagnostic capacity and surveillance systems are lacking in many countries. Intrinsic resistance to commonly used antifungals, combined with the ability to rapidly acquire resistance to therapy, substantially restricts treatment options and novel agents are desperately needed. Despite this, outbreaks can be interrupted, and mortality avoided or minimised, through the application of rigorous infection prevention and control measures with an increasing evidence base. This review provides an update on epidemiology, the impact of the COVID-19 pandemic, risk factors, identification and typing, resistance profiles, treatment, detection of colonisation, and infection prevention and control measures for C. auris. This review has informed a planned 2024 update to the United Kingdom Health Security Agency (UKHSA) guidance on the laboratory investigation, management, and infection prevention and control of Candida auris. A multidisciplinary response is needed to control C. auris transmission in a healthcare setting and should emphasise outbreak preparedness and response, rapid contact tracing and isolation or cohorting of patients and staff, strict hand hygiene and other infection prevention and control measures, dedicated or single-use equipment, appropriate disinfection, and effective communication concerning patient transfers and discharge.

Navigating the Challenges of Candida auris Colonization in Rehabilitation Settings

ABSTRACT

Candida auris is a highly transmissible yeast that is capable of causing invasive and fatal infections, particularly among persons with underlying medical conditions. Its incidence is rising, especially among patients cared for in post-acute care facilities. Individuals colonized with the yeast may be cared for in inpatient rehabilitation settings, without heightened risk for invasive infection and/or transmission to others, as long as appropriate infection control measures are followed. This article reviews key information for rehabilitation nurses caring for persons with C. auris , including risk factors for infection, the need for contact precautions, appropriate disinfection practices for therapy and diagnostic equipment, and critical components of safe transitions in the care of these patients.

Candida auris Outbreak in a Multidisciplinary Hospital in Romania during the Post-Pandemic Era: Potential Solutions and Challenges in Surveillance and Epidemiological Control

Candida auris is a newly emerging yeast, which is raising public health concerns due to its outbreak potential, lack of protocols for decontamination and isolation of patients or contacts, increased resistance to common antifungals, and associated high mortality. This research aimed to describe the challenges related to identifying the outbreak, limiting further contamination, and treating affected individuals. We retrospectively analyzed all cases of C. auris detected between October 2022 and August 2023, but our investigation focused on a three-month-long outbreak in the department of cardio-vascular surgery and the related intensive care unit. Along with isolated cases in different wards, we identified 13 patients who became infected or colonized in the same area and time, even though the epidemiological link could only be traced in 10 patients, according to the epidemiologic investigation. In conclusion, our study emphasizes the substantial challenge encountered in clinical practice when attempting to diagnose and limit the spread of an outbreak. Therefore, it is crucial to promptly apply contact precaution measures and appropriate environmental cleaning, from the first positive case detected.

Candida auris in US Correctional Facilities

Candida auris is an emerging fungal pathogen that typically affects patients in healthcare settings. Data on C. auris cases in correctional facilities are limited but are needed to guide public health recommendations. We describe cases and challenges of providing care for 13 patients who were transferred to correctional facilities during January 2020-December 2022 after having a positive C. auris specimen. All patients had positive specimens identified while receiving inpatient care at healthcare facilities in geographic areas with high C. auris prevalence. Correctional facilities reported challenges managing patients and implementing prevention measures; those challenges varied by whether patients were housed in prison medical units or general population units. Although rarely reported, C. auris cases in persons who are incarcerated may occur, particularly in persons with known risk factors. Measures to manage cases and prevent C. auris spread in correctional facilities should address setting-specific challenges in healthcare and nonhealthcare correctional environments.

Validation of the prevalence to incidence conversion method for healthcare associated infections in long-term care facilities

INTRODUCTION

Residents of long-term care facilities (LTCFs) are a population at high risk of developing severe healthcare associated infections (HAIs). In the assessment of HAIs in acute-care hospitals, selection bias can occur due to cases being over-represented: patients developing HAIs usually have longer lengths of stays compared to controls, and therefore have an increased probability of being sampled in PPS, leading to an overestimation of HAI prevalence. Our hypothesis was that in LTCFs, the opposite may occur: residents developing HAIs either may have a greater chance of being transferred to acute-care facilities or of dying, and therefore could be under-represented in PPS, leading to an underestimation of HAI prevalence. Our aim was to test this hypothesis by comparing HAI rates obtained through longitudinal and cross-sectional studies.

METHODS

Results from two studies conducted simultaneously in four LTCFs in Italy were compared: a longitudinal study promoted by the European Centre for Disease Prevention and Control (ECDC, HALT4 longitudinal study, H4LS), and a PPS. Prevalence was estimated from the PPS and converted into incidence per year using an adapted version of the Rhame and Sudderth formula proposed by the ECDC. Differences between incidence rates calculated from the PPS results and obtained from H4LS were investigated using the Byar method for rate ratio (RR).

RESULTS

On the day of the PPS, HAI prevalence was 1.47% (95% confidence interval, CI 0.38-3.97), whereas the H4LS incidence rate was 3.53 per 1000 patient-days (PDs, 95% CI 2.99-4.08). Conversion of prevalence rates obtained through the PPS into incidence using the ECDC formula resulted in a rate of 0.86 per 1000 PDs (95% CI 0-2.68). Comparing the two rates, a RR of 0.24 (95% CI 0.03-2.03, p 0.1649) was found.

CONCLUSIONS

This study did not find significant differences between HAI incidence estimates obtained from a longitudinal study and through conversion from PPS data. Results of this study support the validity of the ECDC method.

Can daily bathing with 4% chlorhexidine + daily chlorhexidine wipe for 1 week be effective in decolonizing Candida auris colonization?

BACKGROUND

Herein, it is aimed to present the decolonizing rates of Candida auris colonized cases after daily bathing with 4% chlorhexidine plus daily cleaning with 4% chlorhexidine wipe for 1 week (will be mentioned as DCHX).

METHODS

The study period was from October, 2021, to November, 2022. Inclusion criteria were (i) age > 18, (ii) receiving DCHX, (iii) proven C. auris carrier on auricular, or axillar or inguinal swab surveillance cultures up to 5-day period before DCHX. Cases with three consecutive negative surveillance cultures 3 days apart were considered to be decolonized.

RESULTS

A total of 38 cases [14 female, aged 61.8 ± 15.5 years] fulfilled the inclusion criteria. Six (15.8%), 23 (60.1%), and 22 cases (57.8%) were postauricular, inguinal, and axillary culture positive, respectively. Only three cases (7.9%) were triple culture positive. Nine cases (23.7%) had three consequent negative surveillance cultures after DCHX and were considered to be decolonized. There was no significant difference in decolonization rates of concomitant only antibiotic receiving cohort vs. concomitant antifungal + antibiotic receiving cohort (5/16 vs. 2/8, p = 1) were decolonized similarly. Of the nine C. auris decolonized cases, two developed C. auris infection in 30 days follow-up after decolonization. However, 10 (34.5%) of 29 non-decolonized cases developed C. auris infection (p: 0.450) within 30 days after surveillance culture positivity. Over all cohorts, day 30 mortality was 23.7% (9/38).

CONCLUSION

In conclusion, based on our observational and relatively small uncontrolled series, it appears that DCHX is not very effective in decolonizing C. auris carriers (especially in cases who are C. auris colonized in > 1 areas), although it is not completely ineffective.

Candida auris: Emerging fungal pathogen in the US

ABSTRACT

Candida auris (C. auris) is a human pathogen that can colonize the skin and various body sites without signs or symptoms or cause serious invasive infections with high mortality. The number of cases involving drug-resistant C. auris infections have increased in the US in recent years. This article provides an overview of C. auris and important infection prevention and control measures.

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.

The skin mycobiome and intermicrobial interactions in the cutaneous niche

Mammalian microbiomes have coevolved with their host to establish a stable homeostatic relationship. Multifaceted commensal-host and commensal-commensal interactions contribute to the maintenance of the equilibrium with an impact on diverse host physiological processes. Despite constant exposure to physical and chemical insults from the environment, the skin harbors a surprisingly stable microbiome. The fungal compartment of the skin microbiome, the skin mycobiome, is unique in that it is dominated by a single fungus, Malassezia. The lack in diversity suggests that the skin may provide a unique niche for this fungal genus and that Malassezia may efficiently outcompete other fungi from the skin. This opinion article examines aspects in support of this hypothesis, discusses how changes in niche conditions associate with skin mycobiome dysregulation, and highlights an emerging example of Malassezia being displaced from the skin by the emerging fungal pathogen C. auris, thereby generating a predisposing situation for fatal-invasive infection.

Impact of In-house Candida auris Polymerase Chain Reaction Screening on Admission on the Incidence Rates of Surveillance and Blood Cultures With C. auris and Associated Cost Savings

Background

The impact of strategies for rapid diagnostic screening of Candida auris on hospital operations has not been previously characterized. We describe the implementation of in-house polymerase chain reaction (PCR) testing on admission for screening of colonization with C. auris, associated process improvements, and financial impact.

Methods

This study was conducted across an integrated health system. Patients were tested based on risk factors for C. auris carriage. Pre-intervention, the PCR was sent out to a reference laboratory, and postintervention was performed in-house. Changes in the incidence rates (IRs) of C. auris present on admission (CA-POA) and C. auris hospital-onset fungemia (CA-HOF) were assessed using interrupted time series analysis. The economic impact on isolation and testing costs was calculated.

Results

Postintervention, the IR of CA-POA doubled (IRR, 2.57; 95% CI, 1.16-5.69; P = .02) compared with the pre-intervention period. The baseline rate of CA-HOF was increasing monthly by 14% (95% CI, 1.05-1.24; P = .002) pre-intervention, while during the postintervention period there was a change in slope with a monthly decrease in IR of 13% (95% CI, 0.80-0.99; P = .02). The median turnaround time (TAT) of the results (interquartile range) was reduced from 11 (8-14) days to 2 (1-3) days. Savings were estimated to be between $772 513.10 and $3 730 480.26.

Conclusions

By performing in-house PCR for screening of C. auris colonization on admission, we found a doubling of CA-POA rates, a subsequent decrease in CA-HOF rates, reduced TAT for PCR results, and more efficient use of infection control measures. In-house testing was cost-effective in a setting of relatively high prevalence among individuals with known risk factors.

Outbreaks of Fungal Infections in Hospitals: Epidemiology, Detection, and Management

Nosocomial clusters of fungal infections, whilst uncommon, cannot be predicted and are associated with significant morbidity and mortality. Here, we review reports of nosocomial outbreaks of invasive fungal disease to glean insight into their epidemiology, risks for infection, methods employed in outbreak detection including genomic testing to confirm the outbreak, and approaches to clinical and infection control management. Both yeasts and filamentous fungi cause outbreaks, with each having general and specific risks. The early detection and confirmation of the outbreak are essential for diagnosis, treatment of affected patients, and termination of the outbreak. Environmental sampling, including the air in mould outbreaks, for the pathogen may be indicated. The genetic analysis of epidemiologically linked isolates is strongly recommended through a sufficiently discriminatory approach such as whole genome sequencing or a method that is acceptably discriminatory for that pathogen. An analysis of both linked isolates and epidemiologically unrelated strains is required to enable genetic similarity comparisons. The management of the outbreak encompasses input from a multi-disciplinary team with epidemiological investigation and infection control measures, including screening for additional cases, patient cohorting, and strict hygiene and cleaning procedures. Automated methods for fungal infection surveillance would greatly aid earlier outbreak detection and should be a focus of research.

Tools and techniques to identify, study, and control Candida auris

Candida auris, is an emerging fungal pathogen that can cause life-threatening infections in humans. Unlike many other Candida species that colonize the intestine, C. auris most efficiently colonizes the skin. Such colonization contaminates the patient's environment and can result in rapid nosocomial transmission. In addition, this transmission can lead to outbreaks of systemic infections that have mortality rates between 40% and 60%. C. auris isolates resistant to all known classes of antifungals have been identified and as such, understanding the underlying biochemical mechanisms of how skin colonization initiates and progresses is critical to developing better therapeutic options. With this review, we briefly summarize what is known about horizontal transmission and current tools used to identify, understand, and control C. auris infections.

Candida auris Genetics and Emergence

Candida auris is a multidrug-resistant fungal pathogen that presents a serious threat to global human health. Since the first reported case in 2009 in Japan, C. auris infections have been reported in more than 40 countries, with mortality rates between 30% and 60%. In addition, C. auris has the potential to cause outbreaks in health care settings, especially in nursing homes for elderly patients, owing to its efficient transmission via skin-to-skin contact. Most importantly, C. auris is the first fungal pathogen to show pronounced and sometimes untreatable clinical drug resistance to all known antifungal classes, including azoles, amphotericin B, and echinocandins. In this review, we explore the causes of the rapid spread of C. auris. We also highlight its genome organization and drug resistance mechanisms and propose future research directions that should be undertaken to curb the spread of this multidrug-resistant pathogen.

Broad susceptibility of Candida auris strains to 8-hydroxyquinolines and mechanisms of resistance

The fungal pathogen Candida auris represents a severe threat to hospitalized patients. Its resistance to multiple classes of antifungal drugs and ability to spread and resist decontamination in healthcare settings make it especially dangerous. We screened 1,990 clinically approved and late-stage investigational compounds for the potential to be repurposed as antifungal drugs targeting C. auris and narrowed our focus to five Food and Drug Administration (FDA)-approved compounds with inhibitory concentrations under 10 µM for C. auris and significantly lower toxicity to three human cell lines. These compounds, some of which had been previously identified in independent screens, include three dihalogenated 8-hydroxyquinolines: broxyquinoline, chloroxine, and clioquinol. A subsequent structure-activity study of 32 quinoline derivatives found that 8-hydroxyquinolines, especially those dihalogenated at the C5 and C7 positions, were the most effective inhibitors of C. auris. To pursue these compounds further, we exposed C. auris to clioquinol in an extended experimental evolution study and found that C. auris developed only twofold to fivefold resistance to the compound. DNA sequencing of resistant strains and subsequent verification by directed mutation in naive strains revealed that resistance was due to mutations in the transcriptional regulator CAP1 (causing upregulation of the drug transporter MDR1) and in the drug transporter CDR1. These mutations had only modest effects on resistance to traditional antifungal agents, and the CDR1 mutation rendered C. auris more susceptible to posaconazole. This observation raises the possibility that a combination treatment involving an 8-hydroxyquinoline and posaconazole might prevent C. auris from developing resistance to this established antifungal agent. IMPORTANCE The rapidly emerging fungal pathogen Candida auris represents a growing threat to hospitalized patients, in part due to frequent resistance to multiple classes of antifungal drugs. We identify a class of compounds, the dihalogenated 8-hydroxyquinolines, with broad fungistatic ability against a diverse collection of 13 strains of C. auris. Although this compound has been identified in previous screens, we extended the analysis by showing that C. auris developed only modest twofold to fivefold increases in resistance to this class of compounds despite long-term exposure; a noticeable difference from the 30- to 500-fold increases in resistance reported for similar studies with commonly used antifungal drugs. We also identify the mutations underlying the resistance. These results suggest that the dihalogenated 8-hydroxyquinolines are working inside the fungal cell and should be developed further to combat C. auris and other fungal pathogens. Lohse and colleagues characterize a class of compounds that inhibit the fungal pathogen C. auris. Unlike many other antifungal drugs, C. auris does not readily develop resistance to this class of compounds.

Various arrangements of mobile genetic elements among CC147 subpopulations of Klebsiella pneumoniae harboring blaNDM-1: a comparative genomic analysis of carbapenem resistant strains

BACKGROUND

Certain clonal complexes (CCs) of Klebsiella pneumoniae such as CC147 (ST147 and ST392) are major drivers of blaNDM dissemination across the world. ST147 has repeatedly reported from our geographical region, but its population dynamics and evolutionary trajectories need to be further studied.

METHODS

Comparative genomic analysis of 51 carbapenem-nonsusceptible strains as well as three hypervirulent K. pneumoniae (hvKp) recovered during 16-months of surveillance was performed using various bioinformatics tools. We investigated the genetic proximity of our ST147 strains with publicly available corresponding genomes deposited globally and from neighbor countries in our geographic region.

RESULTS

While IncL/M plasmid harboring blaOXA-48 was distributed among divergent clones, blaNDM-1 was circulated by twenty of the 25 CC147 dominant clone and were mostly recovered from the ICU. The NDM-1 core structure was bracketed by a single isoform of mobile genetic elements (MGEs) [ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403] and was located on Col440I plasmid in 68.7% of ST392. However, various arrangements of MGEs including MITESen1/MITESen1 composite transposon or combination of MITESen1/ISSen4/IS903B/IS5/ISEhe3 on IncFIb (pB171) were identified in ST147. It seems that ST392 circulated blaNDM-1 in 2018 before being gradually replaced by ST147 from the middle to the end of sample collection in 2019. ST147 strains possessed the highest number of resistance markers and showed high genetic similarity with four public genomes that harbored blaNDM-1 on the same replicon type. Mainly, there was a convergence between clusters and isolated neighboring countries in the minimum-spanning tree. A conserved arrangement of resistance markers/MGEs was linked to methyltransferase armA which was embedded in class 1 integron in 8 isolates of ST147/ST48 high-risk clones.

CONCLUSION

Our findings highlight the dynamic nature of blaNDM-1 transmission among K. pneumoniae in Iran that occurs both clonally and horizontally via various combinations of MGEs. This is the first analysis of Iranian ST147/NDM + clone in the global context.

Public Health Research Priorities for Fungal Diseases: A Multidisciplinary Approach to Save Lives

Fungal infections can cause severe disease and death and impose a substantial economic burden on healthcare systems. Public health research requires a multidisciplinary approach and is essential to help save lives and prevent disability from fungal diseases. In this manuscript, we outline the main public health research priorities for fungal diseases, including the measurement of the fungal disease burden and distribution and the need for improved diagnostics, therapeutics, and vaccines. Characterizing the public health, economic, health system, and individual burden caused by fungal diseases can provide critical insights to promote better prevention and treatment. The development and validation of fungal diagnostic tests that are rapid, accurate, and cost-effective can improve testing practices. Understanding best practices for antifungal prophylaxis can optimize prevention in at-risk populations, while research on antifungal resistance can improve patient outcomes. Investment in vaccines may eliminate certain fungal diseases or lower incidence and mortality. Public health research priorities and approaches may vary by fungal pathogen.

Candida auris admission screening pilot in select units of New York City health care facilities, 2017-2019

BACKGROUND

This pilot project implemented admission screening for Candida auris (C. auris) using real-time polymerase chain reaction (rt-PCR) in select high-risk units within health care facilities in New York City.

METHODS

An admission screening encounter consisted of collecting 2 swabs, to be tested by rt-PCR, and a data collection form for individuals admitted to ventilator units at 2 nursing homes (NHA and NHB), and the ventilator/pulmonary unit, intensive care unit, and cardiac care unit at a hospital (Hospital C) located in New York City from November 2017 to November 2019.

RESULTS

C. auris colonization was identified in 6.9% (n = 188/2,726) of admissions to participating units. Rates were higher among admissions to NHA and NHB (20.7% and 22.0%, respectively) than Hospital C (3.6%). Within Hospital C, the ventilator/pulmonary unit had a higher rate (5.7%) than the intensive care unit (3.8%) or cardiac care unit (2.5%).

DISCUSSION

Consistent with prior research, we found that individuals admitted to ventilator units were at higher risk of C. auris colonization.

CONCLUSIONS

This project demonstrates the utility of admission screening using rt-PCR testing to rapidly identify C. auris colonization among admissions to health care facilities so that appropriate transmission-based precautions and control measures can be implemented rapidly to help decrease transmission.

Intra-clade Heterogeneity in Candida auris: Risk of Management

Candida auris has emerged as a significant nosocomial fungal pathogen with a high risk of pathogenicity. Since the initial detection of C. auris in 2009, it gained lots of attention with a recent alert by the Centers for Disease Control and Prevention (CDC) due to its high infectivity and drug resistance. Several studies showed the capability of C. auris to secrete lytic enzymes, germinate, and form a biofilm that eventually results in interactions with the host cells, leading to serious infections. Other studies demonstrated a decrease in susceptibility of C. auris strains to available antifungals, which may be caused by mutations within the target genes, or the drug efflux pumps. However, the contribution of C. auris heterogeneity in pathogenicity and drug resistance is not well studied. Here, we shed light on the factors contributing to the development of heterogeneity in C. auris. These include phenotypic changes, biofilm formation, mechanisms of drug resistance, host invasion, mode of transmission, and expression of virulence factors. C. auris exhibits different phenotypes, particularly aggregative, and non-aggregative forms that play an important role in fungal heterogeneity, which significantly affects drug resistance and pathogenicity. Collectively, heterogeneity in C. auris significantly contributes to ineffective treatment, which in turn affects the fungal pathogenicity and drug resistance. Therefore, understanding the underlying reasons for C. auris heterogeneity and applying effective antifungal stewardship could play a major role in controlling this pathogen.

Invasive Candida infection: epidemiology, clinical and therapeutic aspects of an evolving disease and the role of rezafungin

INTRODUCTION

Invasive Candida Infections (ICIs) have undergone a series of significant epidemiological, pathophysiological, and clinical changes during the last decades, with a shift toward non-albicans species, an increase in the rate of exogenous infections and clinical manifestations ranging from candidemia to an array of highly invasive and life-threatening clinical syndromes. The long-acting echinocandin rezafungin exhibits potent in-vitro activity against most wild-type and azole-resistant Candida spp. including C.auris.

AREAS COVERED

The following topics regarding candidemia only and ICIs were reviewed and addressed: i) pathogenesis; ii) epidemiology and temporal evolution of Candida species; iii) clinical approach; iv) potential role of the novel long-acting rezafungin in the treatment of ICIs.

EXPERT OPINION

Authors' expert opinion focused on considering the potential role of rezafungin in the evolving context of ICIs. Rezafungin, which combines a potent in-vitro activity against Candida species, including azole-resistant strains and C.auris, with a low likelihood of drug-drug interactions and a good safety profile, may revolutionize the treatment of candidemia/ICI. Indeed, it may shorten the length of hospital stays when clinical conditions allow and extend outpatient access to treatment of invasive candidiasis, especially when prolonged treatment duration is expected.

Host defense mechanisms against Candida auris

INTRODUCTION

Candida auris is a pathogen of growing public health concern given its rapid spread across the globe, its propensity for long-term skin colonization and healthcare-related outbreaks, its resistance to a variety of antifungal medications, and the high morbidity and mortality associated with invasive disease. Despite that, the host immune response mechanisms that operate during C. auris skin colonization and invasive infection remains poorly understood.

AREAS COVERED

In this manuscript, we review the available literature in the growing research field pertaining to C. auris host defenses and we discuss what is known about the ability of C. auris to thrive on mammalian skin, the role of lymphoid cell-mediated, IL-17-dependent defenses in controlling cutaneous colonization, and the contribution of myeloid phagocytes in curtailing systemic infection.

EXPERT OPINION

Understanding the mechanisms by which the host immune system responds to and controls colonization and infection with C. auris and developing a deeper knowledge of tissue-specific host-C. auris interactions and of C. auris immune-evading mechanisms may help devise improved strategies for decolonization, prognostication, prevention, vaccination, and/or directed antifungal treatment in vulnerable patient populations.

Risk factors and mortality of the newly emerging Candida auris in a university hospital in Saudi Arabia

Candida auris presents a global health threat. We investigated risk factors and mortality of Candida auris infections in a retrospective study in Saudi Arabia. We included 27 patients ≥14  with invasive Candida auris from 2015-2022, with median age 58, and 66.7% males. All patients had indwelling devices. The most common infection sources were central line-associated bloodstream infection in 17 (63.0%), and urinary tract infections in four (12%). Fever and shock were observed in nine patients (33.3%) each, and 22 (81%) were admitted to the intensive care unit. Common comorbidities were diabetes and heart disease in 13 (48.1%) patients each. The median hospital stay was 78 days, and the median Charlson index was 4. The C. auris cultures were 100% susceptible to voriconazole, caspofungin, and amphotericin, while three were fully susceptible to fluconazole (11.1%). Despite treatment, 18 (66.7%) patients died. In conclusion, invasive C. auris infection had varied presentations. All patients had indwelling devices, and many had lengthy hospital stays. All isolates were susceptible to amphotericin and echinocandins, while few were fully susceptible to fluconazole.

Worsening Spread of Candida auris in the United States, 2019 to 2021

BACKGROUND

Candida auris is an emerging fungal threat that has been spreading in the United States since it was first reported in 2016.

OBJECTIVE

To describe recent changes in the U.S. epidemiology of C auris occurring from 2019 to 2021.

DESIGN

Description of national surveillance data.

SETTING

United States.

PATIENTS

Persons with any specimen that was positive for C auris.

MEASUREMENTS

Case counts reported to the Centers for Disease Control and Prevention by health departments, volume of colonization screening, and antifungal susceptibility results were aggregated and compared over time and by geographic region.

RESULTS

A total of 3270 clinical cases and 7413 screening cases of C auris were reported in the United States through 31 December 2021. The percentage increase in clinical cases grew each year, from a 44% increase in 2019 to a 95% increase in 2021. Colonization screening volume and screening cases increased in 2021 by more than 80% and more than 200%, respectively. From 2019 to 2021, 17 states identified their first C auris case. The number of C auris cases that were resistant to echinocandins in 2021 was about 3 times that in each of the previous 2 years.

LIMITATION

Identification of screening cases depends on screening that is done on the basis of need and available resources. Screening is not conducted uniformly across the United States, so the true burden of C auris cases may be underestimated.

CONCLUSION

C auris cases and transmission have risen in recent years, with a dramatic increase in 2021. The rise in echinocandin-resistant cases and evidence of transmission is particularly concerning because echinocandins are first-line therapy for invasive Candida infections, including C auris. These findings highlight the need for improved detection and infection control practices to prevent spread of C auris.

PRIMARY FUNDING SOURCE

None.

Health Care-Associated Infections in Older Adults: Epidemiology and Prevention

Health care-associated infections (HAIs) are a global public health threat, which disproportionately impact older adults. Host factors including aging-related changes, comorbidities, and geriatric syndromes, such as dementia and frailty, predispose older individuals to infection. The HAI risks from medical interventions such as device use, antibiotic use, and lapses in infection control follow older adults as they transfer among a network of interrelated acute and long-term care facilities. Long-term care facilities are caring for patients with increasingly complex needs, and the home-like communal environment of long-term care facilities creates distinct infection prevention challenges.

Increasing Number of Cases Due to Candida auris in North Italy, July 2019-December 2022

Candida auris is an emerging fungus that represents a serious health threat globally. In Italy, the first case was detected in July 2019. Then, one case was reported to the Ministry of Health (MoH) on January 2020. Nine months later, a huge number of cases were reported in northern Italy. Overall, 361 cases were detected in 17 healthcare facilities between July 2019 and December 2022 in the Liguria, Piedmont, Emilia-Romagna, and Veneto regions, including 146 (40.4%) deaths. The majority of cases (91.8%) were considered as colonised. Only one had a history of travel abroad. Microbiological data on seven isolates showed that all but one strain (85.7%) were resistant to fluconazole. All the environmental samples tested negative. Weekly screening of contacts was performed by the healthcare facilities. Infection prevention and control (IPC) measures were applied locally. The MoH nominated a National Reference Laboratory to characterise C. auris isolates and store the strains. In 2021, Italy posted two messages through the Epidemic Intelligence Information System (EPIS) to inform on the cases. On February 2022, a rapid risk assessment indicated a high risk for further spread within Italy, but a low risk of spread to other countries.

Role of Microbiota in the Skin Colonization of Candida auris

Candida auris is an emerging multidrug-resistant fungal pathogen that can cause life-threatening infections in humans. Unlike other Candida species that colonize the gut, C. auris efficiently colonizes the skin and contaminates the patient's environment, resulting in rapid nosocomial transmission and outbreaks of systemic infections. As the largest organ of the body, the skin harbors beneficial microbiota that play a critical role to protect from invading pathogens. However, the role of skin microbiota in the colonization and pathogenesis of C. auris remains to be explored. With this perspective, we review and discuss recent insights into skin microbiota and their potential interactions with the immune system in the context of C. auris skin colonization. Understanding microbiota, C. auris, and host interactions in the skin is important to develop microbiome-based therapeutic approaches to prevent and treat this emerging fungal pathogen in humans.

Broad sensitivity of Candida auris strains to quinolones and mechanisms of resistance

The fungal pathogen Candida auris represents a severe threat to hospitalized patients. Its resistance to multiple classes of antifungal drugs and ability to spread and resist decontamination in health-care settings make it especially dangerous. We screened 1,990 clinically approved and late-stage investigational compounds for the potential to be repurposed as antifungal drugs targeting C. auris and narrowed our focus to five FDA-approved compounds with inhibitory concentrations under 10 µM for C. auris and significantly lower toxicity to three human cell lines. These compounds, some of which had been previously identified in independent screens, include three dihalogenated 8-hydroxyquinolines: broxyquinoline, chloroxine, and clioquinol. A subsequent structure-activity study of 32 quinoline derivatives found that 8-hydroxyquinolines, especially those dihalogenated at the C5 and C7 positions, were the most effective inhibitors of C. auris . To pursue these compounds further, we exposed C. auris to clioquinol in an extended experimental evolution study and found that C. auris developed only 2- to 5-fold resistance to the compound. DNA sequencing of resistant strains and subsequent verification by directed mutation in naive strains revealed that resistance was due to mutations in the transcriptional regulator CAP1 (causing upregulation of the drug transporter MDR1 ) and in the drug transporter CDR1 . These mutations had only modest effects on resistance to traditional antifungal agents, and the CDR1 mutation rendered C. auris more sensitive to posaconazole. This observation raises the possibility that a combination treatment involving an 8-hydroxyquinoline and posaconazole might prevent C. auris from developing resistance to this established antifungal agent.

Abstract Importance

The rapidly emerging fungal pathogen Candida auris represents a growing threat to hospitalized patients, in part due to frequent resistance to multiple classes of antifungal drugs. We identify a class of compounds, the dihalogenated hydroxyquinolines, with broad fungistatic ability against a diverse collection of 13 strains of C. auris . Although this compound has been identified in previous screens, we extended the analysis by showing that C. auris developed only modest 2- to 5-fold increases in resistance to this class of compounds despite long-term exposure; a noticeable difference from the 30- to 500- fold increases in resistance reported for similar studies with commonly used antifungal drugs. We also identify the mutations underlying the resistance. These results suggest that the dihalogenated hydroxyquinolines are working inside the fungal cell and should be developed further to combat C. auris and other fungal pathogens.

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Lohse and colleagues characterize a class of compounds that inhibit the fungal pathogen C. auris . Unlike many other antifungal drugs, C. auris does not readily develop resistance to this class of compounds.

Strategies to Prevent Transmission of Candida auris in Healthcare Settings

Purpose of Review

Candida auris, a recently recognized yeast pathogen, has become a major public health threat due to the problems associated with its accurate identification, intrinsic and acquired resistance to antifungal drugs, and its potential to easily contaminate the environment causing clonal outbreaks in healthcare facilities. These outbreaks are associated with high mortality rates particularly among older patients with multiple comorbidities under intensive care settings. The purpose of this review is to highlight strategies that are being adapted to prevent transmission of C. auris in healthcare settings.

Recent Findings

Colonized patients shed C. auris into their environment which contaminates surrounding equipment. It resists elimination even by robust decontamination procedures and is easily transmitted to new patients during close contact resulting in outbreaks. Efforts are being made to rapidly identify C. auris-infected/C. auris-colonized patients, to determine its susceptibility to antifungals, and to perform effective cleaning and decontamination of the environment and isolation of colonized patients to prevent further transmission.

Summary

Rapid and accurate identification of hospitalized patients infected/colonized with C. auris, rapid detection of its susceptibility patterns, and appropriate use of infection control measures can help to contain the spread of this highly pathogenic yeast in healthcare settings and prevent/control outbreaks.

Candida auris in skilled nursing facilities

Candida auris is a fungal organism resistant to several classes of antifungals. Since its identification in 2009, it has gained worldwide attention in healthcare for its virulence and resistance to commonly used antifungal therapeutics. Although its origin and mechanisms of transmission are not fully elucidated, it is widely recognized as a high priority healthcare-associated pathogen. Infection control efforts in skilled nursing facilities have been very challenging due to the tendency of C. auris to persist in the environment and colonize residents. In this narrative review, we discuss the epidemiology and infection prevention of C. auris in skilled nursing facilities. We also identify challenges in the diagnosis and management of both symptomatic infections and asymptomatic colonization.

Reimagining Infection Control in U.S. Nursing Homes in the Era of COVID-19

Residents of nursing homes (NHs) are susceptible to infection, and these facilities, particularly those that provide post-acute care services, are high-risk settings for the rapid spread of communicable respiratory and gastrointestinal illnesses, as well as antibiotic-resistant bacteria. The complexity of medical care delivered in most NHs has increased dramatically over the past 2 decades; however, the structure and resources supporting the practice of infection prevention and control in these facilities has failed to keep pace. Rising numbers of infections caused by Clostridioides difficile and multidrug-resistant organisms, as well as the catastrophic effects of COVID-19 have pushed NH infection control resources to a breaking point. Recent changes to federal regulations require NHs to devote greater resources to the facility infection control program. However, additional changes are needed if sustained improvements in the prevention and control of infections and antibiotic resistance in NHs are to be achieved.

Candida auris and some Candida parapsilosis strains exhibit similar characteristics on CHROMagarTMCandida Plus

Candida auris is considered a public health problem due to its resistance and its tendency to cause nosocomial outbreaks. CHROMagarTMCandida Plus has recently been marketed as capable of presumptively identifying C. auris. The objective of this work was to analyze the ability of this new chromogenic medium to differentiate C. auris from other members of the C. haemulonii complex and from other yeasts commonly isolated in clinical practice. A collection of 220 strains including species of the C. haemulonii (n = 83) and C. parapsilosis (n = 80) complexes was studied. The strains were identified by molecular methods and cultured as individual or as mixed aqueous inoculum on CHROMagarTMCandida Plus plates. Colony morphotypes were evaluated at 5 time points. CHROMagarTMCandida Plus was a helpful tool for presumptive identification for C. auris. Better reading results were obtained after 48 hours of incubation at 35°C. It is able to easily differentiate C. auris from other closely related species of the C. haemulonii complex and other yeasts. This chromogenic medium would be also useful as screening and surveillance tool for C. auris colonization. However, we demonstrated that it would be a possible misidentification of C. parapsilosis as C. auris (44.3% showed similar morphotypes). To reduce false positives when it is used in a context of a C. auris outbreak, we propose to supplement the chromogenic medium with 8 μg/ml fluconazole. This modified medium was tested and it clearly differentiate C. parapsilosis from C. auris.

Candida auris Pan-Drug-Resistant to Four Classes of Antifungal Agents

Candida auris is an urgent antimicrobial resistance threat due to its global emergence, high mortality, and persistent transmissions. Nearly half of C. auris clinical and surveillance cases in the United States are from the New York and New Jersey Metropolitan area. We performed genome, and drug-resistance analysis of C. auris isolates from a patient who underwent multi-visceral transplantation. Whole-genome comparisons of 19 isolates, collected over 72 days, revealed closed similarity (Average Nucleotide Identity > 0.9996; Aligned Percentage > 0.9764) and a distinct subcluster of NY C. auris South Asia Clade I. All isolates had azole-linked resistance in ERG11(K143R) and CDR1(V704L). Echinocandin resistance first appeared with FKS1(S639Y) mutation and then a unique FKS1(F635C) mutation. Flucytosine-resistant isolates had mutations in FCY1, FUR1, and ADE17. Two pan-drug-resistant C. auris isolates had uracil phosphoribosyltransferase deletion (FUR1[1Δ33]) and the elimination of FUR1 expression, confirmed by a qPCR test developed in this study. Besides ERG11 mutations, four amphotericin B-resistant isolates showed no distinct nonsynonymous variants suggesting unknown genetic elements driving the resistance. Pan-drug-resistant C. auris isolates were not susceptible to two-drug antifungal combinations tested by checkerboard, Etest, and time-kill methods. The fungal population pattern, discerned from SNP phylogenetic analysis, was consistent with in-hospital or inpatient evolution of C. auris isolates circulating locally and not indicative of a recent introduction from elsewhere. The emergence of pan-drug-resistance to four major classes of antifungals in C. auris is alarming. Patients at high risk for drug-resistant C. auris might require novel therapeutic strategies and targeted pre-and/or posttransplant surveillance.

Transcriptional Response of Candida auris to the Mrr1 Inducers Methylglyoxal and Benomyl

Candida auris is an urgent threat to human health due to its rapid spread in health care settings and its repeated development of multidrug resistance. Diseases that increase risk for C. auris infection, such as diabetes, kidney failure, or immunocompromising conditions, are associated with elevated levels of methylglyoxal (MG), a reactive dicarbonyl compound derived from several metabolic processes. In other Candida species, expression of MG reductase enzymes that catabolize and detoxify MG are controlled by Mrr1, a multidrug resistance-associated transcription factor, and MG induces Mrr1 activity. Here, we used transcriptomics and genetic assays to determine that C. aurisMRR1a contributes to MG resistance, and that the main Mrr1a targets are an MG reductase and MDR1, which encodes a drug efflux protein. The C. auris Mrr1a regulon is smaller than Mrr1 regulons described in other species. In addition to MG, benomyl (BEN), a known Mrr1 stimulus, induces C. auris Mrr1 activity, and characterization of the MRR1a-dependent and -independent transcriptional responses revealed substantial overlap in genes that were differentially expressed in response to each compound. Additionally, we found that an MRR1 allele specific to one C. auris phylogenetic clade, clade III, encodes a hyperactive Mrr1 variant, and this activity correlated with higher MG resistance. C. aurisMRR1a alleles were functional in Candida lusitaniae and were inducible by BEN, but not by MG, suggesting that the two Mrr1 inducers act via different mechanisms. Together, the data presented in this work contribute to the understanding of Mrr1 activity and MG resistance in C. auris.

IMPORTANCECandida auris is a fungal pathogen that has spread since its identification in 2009 and is of concern due to its high incidence of resistance against multiple classes of antifungal drugs. In other Candida species, the transcription factor Mrr1 plays a major role in resistance against azole antifungals and other toxins. More recently, Mrr1 has been recognized to contribute to resistance to methylglyoxal (MG), a toxic metabolic product that is often elevated in different disease states. MG can activate Mrr1 and its induction of Mdr1 which can protect against diverse challenges. The significance of this work lies in showing that MG is also an inducer of Mrr1 in C. auris, and that one of the major pathogenic C. auris lineages has an activating Mrr1 mutation that confers protection against MG.

Prevalence, Risk Factors, Treatment and Outcome of multidrug resistance Candida auris Infections in Coronavirus Disease (COVID-19) Patients: A Systematic Review

BACKGROUND

Candida auris is an emerging multidrug-resistant pathogen in intensive care settings (ICU). During the coronavirus disease 19 (COVID-19) pandemic, ICU admissions were overwhelmed, possibly contributing to the C. auris outbreak in COVID-19 patients.

OBJECTIVES

The present systematic review addresses the prevalence, underlying diseases, iatrogenic risk factors, treatment and outcome of C. auris infections in COVID-19 patients.

METHODS

MEDLINE, Scopus, Embase, Web of Science and LitCovid databases were systematically searched with appropriate keywords from 1^st January 2020 to 31^st December 2021.

RESULTS

A total of 97 cases of C. auris were identified in COVID-19 patients. The prevalence of C. auris infections in COVID-19 patients was 14%. The major underlying diseases were diabetes mellitus (42.7%), hypertension (32.9%), and obesity (14.6%), followed by the iatrogenic risk factors such as a central venous catheter (76.8%%) intensive care unit (ICU) stay (75.6%), and broad-spectrum antibiotic usage (74.3%). There were no significant differences in underlying disease and iatrogenic risk factors among C. auris non-candidemia/colonisation and C. auris candidemia cases. The mortality rate of the total cohort is 44.4%, whereas, in C. auris candidemia patients, the mortality was 64.7%.

CONCLUSION

This study shows that the prevalence of C. auris infections remains unchanged in the COVID-19 pandemic. Hospital-acquired risk factors may contribute to the clinical illness. Proper infection control practices and hospital surveillance may stop future hospital outbreaks during the pandemic.

A description of the first Candida auris-colonized individuals in New York State, 2016-2017

Candida auris (C. auris) is a globally emerging multidrug-resistant yeast. New York State (NYS) first detected C. auris in July 2016 and is the state most affected. This brief report describes characteristics of the first 114 individuals colonized with C. auris identified through active surveillance/screening by NYS Department of Health. "Colonized/screened" individuals were old (median age, 74 year), had extensive health care exposures and underlying conditions (multiple health care facility admissions in the 90 days prior with more than 80% requiring mechanical ventilation), and had 30- and 90-day mortality rates of 17.5% and 37.7%, respectively (with approximately 60% expired in the 2-year follow-up period). This description is helpful to inform additional prevention measures and add to the collective understanding of C. auris in the United States.

Tools for detecting a "superbug": updates on Candida auris testing

Candida auris is an emerging yeast species that has the unique characteristics of patient skin colonization and rapid transmission within healthcare facilities and the ability to rapidly develop antifungal resistance. When C. auris first started appearing in clinical microbiology laboratories, it could only be identified using DNA sequencing. In the decade since its first identification outside of Japan there have been many improvements in the detection of C. auris. These include the expansion of MALDI-TOF databases to include C. auris, the development of both laboratory-developed tests and commercially available kits for its detection, and special CHROMagar for identification from laboratory specimens. Here we discuss the current tools and resources that are available for C. auris identification and detection.

Colonization by Candida auris in critically ill patients: role of cutaneous and rectal localization during an outbreak

BACKGOROUND

Candida auris infections were reported worldwide since the pathogen was isolated in 2009. In a hospital setting of a C. auris epidemic, we analyzed incidence of cutaneous and intestinal colonization, and connection with infections by the organism.

METHODS

This was a retrospective study in intensive care units at a 1200-bed Italian hospital. The incidence of cutaneous positive swabs, and cutaneous carriers, for C. auris was compared to that of rectal positive swabs, and intestinal carriers, and both were correlated to C. auris infections.

FINDINGS

A total of 399 patients were included. Seventy-seven patients were infected by C. auris. Ratio of C. auris positive skin swabs from screening in ICUs was 24%. The ratio obtained from infected patients and intestinal C. auris carriers was 49.1%, likewise rectal swabs from similar cohort of patients (P = 0.373). 39.7% and 5.5% of this cohort was colonized only in skin and in rectum, respectively, while 54.8% was colonized in both sites. 12.3% and 83.6% of skin swabs was, respectively, always positive and variable over time in single subject, while 31.5% and 41.1% of rectal swabs were always positive and variable (P = 0.000). Intestinal colonization was associated with increased risk for C. auris urinary infections (P = 0.006).

CONCLUSIONS

C. auris intestinal carriers were fewer than cutaneous carriers, but more continously colonized. Rectal and skin swabs can be good tools for surveillance, respectively, of colonization and of hygiene measures effectiveness. Urinary tract infections by C. auris appeared increasing with gastrointestinal presence of the yeast.

Rapid Assessment and Containment of Candida auris Transmission in Postacute Care Settings-Orange County, California, 2019

BACKGROUND

Candida auris, a multidrug-resistant yeast, can spread rapidly in ventilator-capable skilled-nursing facilities (vSNFs) and long-term acute care hospitals (LTACHs). In 2018, a laboratory serving LTACHs in southern California began identifying species of Candida that were detected in urine specimens to enhance surveillance of C auris, and C auris was identified in February 2019 in a patient in an Orange County (OC), California, LTACH. Further investigation identified C auris at 3 associated facilities.

OBJECTIVE

To assess the prevalence of C auris and infection prevention and control (IPC) practices in LTACHs and vSNFs in OC.

DESIGN

Point prevalence surveys (PPSs), postdischarge testing for C auris detection, and assessments of IPC were done from March to October 2019.

SETTING

All LTACHs (n = 3) and vSNFs (n = 14) serving adult patients in OC.

PARTICIPANTS

Current or recent patients in LTACHs and vSNFs in OC.

INTERVENTION

In facilities where C auris was detected, PPSs were repeated every 2 weeks. Ongoing IPC support was provided.

MEASUREMENTS

Antifungal susceptibility testing and whole-genome sequencing to assess isolate relatedness.

RESULTS

Initial PPSs at 17 facilities identified 44 additional patients with C auris in 3 (100%) LTACHs and 6 (43%) vSNFs, with the first bloodstream infection reported in May 2019. By October 2019, a total of 182 patients with C auris were identified by serial PPSs and discharge testing. Of 81 isolates that were sequenced, all were clade III and highly related. Assessments of IPC identified gaps in hand hygiene, transmission-based precautions, and environmental cleaning. The outbreak was contained to 2 facilities by October 2019.

LIMITATION

Acute care hospitals were not assessed, and IPC improvements over time could not be rigorously evaluated.

CONCLUSION

Enhanced laboratory surveillance and prompt investigation with IPC support enabled swift identification and containment of C auris.

PRIMARY FUNDING SOURCE

Centers for Disease Control and Prevention.

What Do We Know about Candida auris? State of the Art, Knowledge Gaps, and Future Directions

Candida auris has unprecedently emerged as a multidrug resistant fungal pathogen, considered a serious global threat due to its potential to cause nosocomial outbreaks and deep-seated infections with staggering transmissibility and mortality, that has put health authorities and institutions worldwide in check for more than a decade now. Due to its unique features not observed in other yeasts, it has been categorised as an urgent threat by the Centers for Disease Control and Prevention and other international agencies. Moreover, epidemiological alerts have been released in view of the increase of healthcare-associated C. auris outbreaks in the context of the COVID-19 pandemic. This review summarises the current evidence on C. auris since its first description, from virulence to treatment and outbreak control, and highlights the knowledge gaps and future directions for research efforts.

Skin Metagenomic Sequence Analysis of Early Candida auris Outbreaks in U.S. Nursing Homes

Candida auris is a human fungal pathogen classified as an urgent threat to the delivery of health care due to its extensive antimicrobial resistance and the high mortality rates associated with invasive infections. Global outbreaks have occurred in health care facilities, particularly, long-term care hospitals and nursing homes. Skin is the primary site of colonization for C. auris. To accelerate research studies, we developed microbiome sequencing protocols, including amplicon and metagenomic sequencing, directly from patient samples at health care facilities with ongoing C. auris outbreaks. We characterized the skin mycobiome with a database optimized to classify Candida species and C. auris to the clade level. While Malassezia species were the predominant skin-associated fungi, nursing home residents also harbored Candida species, including C. albicans, and C. parapsilosis. Amplicon sequencing was concordant with culturing studies to identify C. auris-colonized patients and provided further resolution that distinct clades of C. auris are colonizing facilities in New York and Illinois. Shotgun metagenomic sequencing from a clinical sample with a high fungal bioburden generated a skin-associated profile of the C. auris genome. Future larger scale clinical studies are warranted to more systematically investigate the effects of commensal microbes and patient risk factors on the colonization and transmission of C. auris.

IMPORTANCECandida auris is a human pathogen of high concern due to its extensive antifungal drug resistance and high mortality rates associated with invasive infections. Candida auris skin colonization and persistence on environmental surfaces make this pathogen difficult to control once it enters a health care facility. Residents in long-term care hospitals and nursing homes are especially vulnerable. In this study, we developed microbiome sequencing protocols directly from surveillance samples, including amplicon and metagenomic sequencing, demonstrating concordance between sequencing results and culturing.

Metagenomic Sequencing for Direct Identification of Candida auris Colonization

Candida auris is an emerging multidrug-resistant yeast that is associated with skin colonization and deadly bloodstream infections, especially in ventilator skilled nursing facilities. An ongoing question is how this organism colonizes the skin of these patients and whether the skin microbiome provides a measure of colonization resistance against C. auris. Now, Huang et al. (X. Huang, R. M. Welsh, C. Deming, D. M. Proctor, et al., mSphere 6:e00287-21, 2021, https://doi.org/10.1128/mSphere.00287-21) demonstrate a method for shotgun metagenomic analysis of the skin to generate a profile of fungal colonization that is highly correlative with culture-based methods. These methods are likely to assist in the diagnosis of C. auris and the identification of microbiome-associated risk factors that predict invasive disease.

Integrated genomic, epidemiologic investigation of Candida auris skin colonization in a skilled nursing facility

Candida auris is a fungal pathogen of high concern due to its ability to cause healthcare-associated infections and outbreaks, its resistance to antimicrobials and disinfectants and its persistence on human skin and in the inanimate environment. To inform surveillance and future mitigation strategies, we defined the extent of skin colonization and explored the microbiome associated with C. auris colonization. We collected swab specimens and clinical data at three times points between January and April 2019 from 57 residents (up to ten body sites each) of a ventilator-capable skilled nursing facility with endemic C. auris and routine chlorhexidine gluconate (CHG) bathing. Integrating microbial-genomic and epidemiologic data revealed occult C. auris colonization of multiple body sites not targeted commonly for screening. High concentrations of CHG were associated with suppression of C. auris growth but not with deleterious perturbation of commensal microbes. Modeling human mycobiome dynamics provided insight into underlying alterations to the skin fungal community as a possible modifiable risk factor for acquisition and persistence of C. auris. Failure to detect the extensive, disparate niches of C. auris colonization may reduce the effectiveness of infection-prevention measures that target colonized residents, highlighting the importance of universal strategies to reduce C. auris transmission.

Regional Spread of blaNDM-1-Containing Klebsiella pneumoniae ST147 in Post-Acute Care Facilities

BACKGROUND

Carbapenem-resistant Enterobacterales (CRE) harboring blaKPC have been endemic in Chicago-area healthcare networks for more than a decade. During 2016-2019, a series of regional point-prevalence surveys identified increasing prevalence of blaNDM-containing CRE in multiple long-term acute care hospitals (LTACHs) and ventilator-capable skilled nursing facilities (vSNFs). We performed a genomic epidemiology investigation of blaNDM-producing CRE to understand their regional emergence and spread.

METHODS

We performed whole-genome sequencing on New Delhi metallo-beta-lactamase (NDM)+ CRE isolates from 4 point-prevalence surveys across 35 facilities (LTACHs, vSNFs, and acute care hospital medical intensive care units) in the Chicago area and investigated the genomic relatedness and transmission dynamics of these isolates over time.

RESULTS

Genomic analyses revealed that the rise of NDM+ CRE was due to the clonal dissemination of an sequence type (ST) 147 Klebsiella pneumoniae strain harboring blaNDM-1 on an IncF plasmid. Dated phylogenetic reconstructions indicated that ST147 was introduced into the region around 2013 and likely acquired NDM around 2015. Analyzing the relatedness of strains within and between facilities supported initial increases in prevalence due to intrafacility transmission in certain vSNFs, with evidence of subsequent interfacility spread among LTACHs and vSNFs connected by patient transfer.

CONCLUSIONS

We identified a regional outbreak of blaNDM-1 ST147 that began in and disseminated across Chicago area post-acute care facilities. Our findings highlight the importance of performing genomic surveillance at post-acute care facilities to identify emerging threats.

Positive correlation between Candida auris skin-colonization burden and environmental contamination at a ventilator-capable skilled nursing facility in Chicago

BACKGROUND

Candida auris is an emerging multidrug-resistant yeast that contaminates healthcare environments causing healthcare-associated outbreaks. The mechanisms facilitating contamination are not established.

METHODS

C. auris was quantified in residents' bilateral axillary/inguinal composite skin swabs and environmental samples during a point-prevalence survey at a ventilator-capable skilled-nursing facility (vSNF A) with documented high colonization prevalence. Environmental samples were collected from all doorknobs, windowsills and handrails of each bed in 12 rooms. C. auris concentrations were measured using culture and C. auris-specific qPCR. The relationship between C. auris concentrations in residents' swabs and associated environmental samples were evaluated using Kendall's tau-b (τb) correlation coefficient.

RESULTS

C. auris was detected in 70 /100 tested environmental samples and 31/ 57 tested resident skin swabs. The mean C. auris concentration in skin swabs was 1.22 x 10 5 cells/mL by culture and 1.08 x 10 6 cells/mL by qPCR. C. auris was detected on all handrails of beds occupied by colonized residents, as well as 10/24 doorknobs and 9/12 windowsills. A positive correlation was identified between the concentrations of C. auris in skin swabs and associated handrail samples based on culture (τb = 0.54, p = 0.0004) and qPCR (τb = 0.66, p = 3.83e -6). Two uncolonized residents resided in beds contaminated with C. auris.

CONCLUSIONS

Colonized residents can have high C. auris burdens on their skin, which was positively related with contamination of their surrounding healthcare environment. These findings underscore the importance of hand hygiene, transmission-based precautions, and particularly environmental disinfection in preventing spread in healthcare facilities.

Candida auris: Epidemiology, Diagnosis, Pathogenesis, Antifungal Susceptibility, and Infection Control Measures to Combat the Spread of Infections in Healthcare Facilities

Candida auris, a recently recognized, often multidrug-resistant yeast, has become a significant fungal pathogen due to its ability to cause invasive infections and outbreaks in healthcare facilities which have been difficult to control and treat. The extraordinary abilities of C. auris to easily contaminate the environment around colonized patients and persist for long periods have recently resulted in major outbreaks in many countries. C. auris resists elimination by robust cleaning and other decontamination procedures, likely due to the formation of 'dry' biofilms. Susceptible hospitalized patients, particularly those with multiple comorbidities in intensive care settings, acquire C. auris rather easily from close contact with C. auris-infected patients, their environment, or the equipment used on colonized patients, often with fatal consequences. This review highlights the lessons learned from recent studies on the epidemiology, diagnosis, pathogenesis, susceptibility, and molecular basis of resistance to antifungal drugs and infection control measures to combat the spread of C. auris infections in healthcare facilities. Particular emphasis is given to interventions aiming to prevent new infections in healthcare facilities, including the screening of susceptible patients for colonization; the cleaning and decontamination of the environment, equipment, and colonized patients; and successful approaches to identify and treat infected patients, particularly during outbreaks.

Exploring Candida auris in its habitat

Candida auris colonizes human skin and causes life-threatening fungal bloodstream infections. In this issue of Cell Host & Microbe, Huang et al. introduce a murine model of C. auris skin colonization to explore the role of distinct clades, immune signaling pathways, antibiotics, and disinfectants on fungal persistence in or clearance from its habitat.

Colonisation and Transmission Dynamics of Candida auris among Chronic Respiratory Diseases Patients Hospitalised in a Chest Hospital, Delhi, India: A Comparative Analysis of Whole Genome Sequencing and Microsatellite Typing

Candida auris is a nosocomial pathogen responsible for an expanding global public health threat. This ascomycete yeast has been frequently isolated from hospital environments, representing a significant reservoir for transmission in healthcare settings. Here, we investigated the relationships among C. auris isolates from patients with chronic respiratory diseases admitted in a chest hospital and from their fomites, using whole-genome sequencing (WGS) and multilocus microsatellite genotyping. Overall, 37.5% (n = 12/32) patients developed colonisation by C. auris including 9.3% of the screened patients that were colonised at the time of admission and 75% remained colonised till discharge. Furthermore, 10% of fomite samples contained C. auris in rooms about 8.5 days after C. auris colonised patients were admitted. WGS and microsatellite typing revealed that multiple strains contaminated the fomites and colonised different body sites of patients. Notably, 37% of C. auris isolates were resistant to amphotericin B and a novel amino acid substitution, G145D in ERG2 gene, was detected in all amphotericin B resistant isolates. In addition, 55% of C. auris isolates had two copies of the MDR1 gene. Our results suggest significant genetic and ecological diversities of C. auris in healthcare setting. The WGS and microsatellite genotyping methods provided complementary results in genotype identification.