Incidence, characteristics and outcome of ICU-acquired candidemia in India

Candida auris cluster in a large third level Italian hospital: a case series

Objectives

Candida auris has been circulating since 2019 in Northern and Middle-Italy regions.

Design

This report details the first three cases of C. auris isolation in Puglia (Southern Italy), which occurred as a nosocomial outbreak.

Results

The first C. auris specimen was isolated on April 19, 2024 from a blood culture obtained from a 55-year-old male (GM) in an intensive care unit (ICU) of Bari Policlinico General Hospital. The patient had been admitted on April 06, 2024 due to subarachnoid hemorrhage. On April 12, 2024, a blood sample tested positive for multidrug-resistant Klebsiella pneumoniae, requiring isolation and wide-spectrum antibiotic therapy. Exitus occurred on April 17, 2024, but 2 days later, a pre-mortem blood sample tested positive for C. auris, leading to epidemiologic investigation in the whole ICU.A second case was therefore identified (SD), a 36-year-old male admitted on March 21, 2024, shortly after undergoing a dental procedure in Tirana (Albania). Due to the timing of admission, he was identified as the index case.A third case was later found on April 29, 2024 (CM), a 52-year-old woman with a history of acute myeloid leukemia located in the same ICU but on a different floor.A link of transmission was identified via environmental sampling, as the medics' common telephone tested positive for C. auris contamination.

Conclusion

The pathogen's circulation has shown to be inapparent and difficult to track, making it a potential threat even for facilities outside of known high-risk geographical areas. ICUs should be monitored routinely.

Genotyping of oral Candida albicans and Candida tropicalis strains in patients with orofacial clefts undergoing surgical rehabilitation by MALDI-TOF MS: Case-series study

Patients with orofacial clefts are more likely to develop oral fungal diseases due to anatomo-physiological changes and surgical rehabilitation treatment. This case-series study evaluated the genetic diversity and dynamics of oral colonization and spread of C. albicans and C. tropicalis in four patients with orofacial clefts, from the time of hospital admission, perioperative and outpatient follow-up, with specialized physician. Candida biotypes previously identified by CHROMagar Candida and PCR methods were studied by MALDI-TOF MS assays and clustering analyses. Possible correlations with pathogenicity characteristics were observed, including production of hydrolytic exoenzymes and the antifungal sensitivity profiles. Amphotericin B-sensitive and fluconazole-resistant (low frequency) C. tropicalis and C. albicans, including clinically compatible MIC of nystatin, were found in the oral cavity of these patients. Clusters of isolates revealed phenomena of (i) elimination in the operative phase, (ii) maintenance or (iii) acquisition of oral C. tropicalis in the perioperative period and specialized outpatient and medical follow-up. For C. albicans, these phenomena included (i) elimination in the operative phase, (ii) acquisition in the operative phase and propagation from the hospital environment, and (iii) maintenance during hospitalization and operative phase. Amphotericin B and nystatin were shown to be effective in cases of clinical treatment and/or prophylaxis, especially considering the pre-existence of fluconazole-resistant strains. This study confirmed the phenomena of septic maintenance, septic neocolonization and septic elimination involving the opportunistic pathogens. MALDI-TOF MS associated with clustering analysis may assist the monitoring of clinical isolates or groups of epidemiologically important microbial strains in the hospital setting.

Invasive Fungal Infections in Immunocompromised Conditions: Emphasis on COVID-19

The COVID-19 pandemic caused death of 6 million lives globally, primarily from respiratory failure, but also a significant number from invasive fungal co-infections in these patients, owing to the immune dysfunction in hospitalized patients. Such complications occurred more often in critically ill, hospitalized patients particularly those admitted in intensive care units and were reported as the major reason associated with a high mortality rate worldwide. Fungal pathogens most commonly associated with COVID-19 patients comprise members of the Mucorales (such as Rhizopus, Mucor, and Lichtheimia), as well as genera Aspergillus and Candida. In India, the prevalence rate of mucormycosis is relatively high than aspergillosis and candidiasis, and the predisposing risk factors associated with such infections included uncontrolled diabetes, underlying lung disease, leukopenia, neutropenia, malignancies and prolonged steroid therapy. However, co-infection with other fungi, including Alternaria and Scedosporium was also sporadically reported. These devastating invasive fungal infections are associated with differential mortality (high-low) and morbidity rates even after active management. The diagnosis of such infections is often challenging due to lack of sensitivity in contemporary diagnostic methods and poses an enormous challenge to healthcare experts. Thus, the role of early and accurate diagnosis, and management of such fungal infections, is vital in preventing life-threatening situations. Hence, this review focusses primarily on the epidemiology, predisposing risk factors, host environment, diagnosis and treatment of the most common medically important invasive fungal infections in immunocompromised conditions associated with COVID-19.

Candida auris: A focused review for emergency clinicians

INTRODUCTION

Candida auris is an emerging pathogen and human health threat. However, diagnosis and treatment of fungal infection due to C. auris are challenging.

OBJECTIVE

This narrative review provides a focused overview of C. auris for the emergency clinician.

DISCUSSION

C. auris was first identified in 2009 and is currently present on all continents except Antarctica. C. auris possesses multiple genetic factors resulting in antimicrobial resistance, increased virulence and survival within the host, and environmental adaptation. It is readily transmitted from person to person and from the environment to a person, resulting in colonization. Infection may develop days to months following colonization, most commonly in those with immunocompromised state, significant comorbidities or other underlying conditions, healthcare exposure, and recent antimicrobial therapy. Candidemia, device infection (e.g., central venous catheter), soft tissue or wound infection, burn infection, osteomyelitis, myocarditis, meningitis, and urinary tract infection have been associated with C. auris. Samples should be obtained from the suspected site of infection for microbiological culture. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with reference databases to differentiate C. auris from other species is optimal for diagnosis, though other molecular testing methods are available. Treatment is challenging due to antifungal resistance, with over 90% resistant to fluconazole. Echinocandins are most commonly used as the first line therapy. Prevention of colonization and infection are vital and include screening in high-risk populations and strict adherence to infection prevention practices with contact precautions and hand hygiene, as well as appropriate decontamination of patient areas.

CONCLUSION

An understanding of C. auris can assist emergency clinicians in the care of infected or colonized patients.

Antifungal Activity of the Dichloromethane Extract of CaoHuangGuiXiang Formula Against Candida auris by in vitro and in vivo Evaluation

Purpose

CaoHuangGuiXiang (CHGX) formula is a traditional Chinese medicine for the treatment of Candida-related infection. However, its antifungal mechanisms against the emerging fungal pathogen Candida auris remain unclear. This study aimed to evaluate the antifungal activity of the dichloromethane extract of CHGX (CHGX-DME) and clarified its antifungal mechanims against C. auris.

Methods

The major components of CHGX-DME were identified by ultra-performance liquid chromatography tandem mass spectrometry. Then, the minimal inhibitory concentration (MIC) assay and the time-kill kinetic assay were performed to investigate the in vitro antifungal activity of CHGX-DME against C. auris, including 8 isolates of 4 discrete clades and 2 special phenotypes (filamentous and aggregative). Furthermore, the effect of CHGX-DME on biofilm development was examined. In addition, the in vivo toxicity and efficacy of CHGX-DME were evaluated in a Galleria mellonella infection model.

Results

First, 20 major compounds in CHGX-DME were detected and characterized. The MIC50% and MIC90% of CHGX-DME against C. auris isolates ranged from 50-200 mg/L and 100-400 mg/L, respectively. At 400 mg/L, CHGX-DME was able to efficiently kill more than 70% and 90% of C. auris cells after 3 hours and 6 hours of treatment, respectively. This notable antifungal activity exhibited a dosage- and time-dependent manner. Moreover, CHGX-DME not only played a critical role in inhibiting the proliferation of filamentous and aggregative cells, but also showed restricting effect on biofilm development in C. auris. Importantly, it significantly improved the survival rate and reduced the fungal burden in G. mellonella infection models, suggesting a remarkable treatment effect against C. auris infection.

Conclusion

CHGX-DME exhibited potent antifungal activity against C. auris and significantly ameliorated this fungal infection in the G. mellonella model, confirming that it would be a promising antifungal drug for the troublesome and emerging fungal pathogen C. auris.

Short Tandem Repeat Genotyping of Medically Important Fungi: A Comprehensive Review of a Powerful Tool with Extensive Future Potential

Fungal infections pose an increasing threat to public health. New pathogens and changing epidemiology are a pronounced risk for nosocomial outbreaks. To investigate clonal transmission between patients and trace the source, genotyping is required. In the last decades, various typing assays have been developed and applied to different medically important fungal species. While these different typing methods will be briefly discussed, this review will focus on the development and application of short tandem repeat (STR) genotyping. This method relies on the amplification and comparison of highly variable STR markers between isolates. For most common fungal pathogens, STR schemes were developed and compared to other methods, like multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) and whole genome sequencing (WGS) single nucleotide polymorphism (SNP) analysis. The pros and cons of STR typing as compared to the other methods are discussed, as well as the requirements for the development of a solid STR typing assay. The resolution of STR typing, in general, is higher than MLST and AFLP, with WGS SNP analysis being the gold standard when it comes to resolution. Although most modern laboratories are capable to perform STR typing, little progress has been made to standardize typing schemes. Allelic ladders, as developed for Aspergillus fumigatus, facilitate the comparison of STR results between laboratories and develop global typing databases. Overall, STR genotyping is an extremely powerful tool, often complimentary to whole genome sequencing. Crucial details for STR assay development, its applications and merit are discussed in this review.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Epidemiology of Candidemia in Mashhad, Northeast Iran: A Prospective Multicenter Study (2019-2021)

Candidemia is a major cause of morbidity and mortality in health care settings, and its epidemiology is changing. In the last two decades, the proportion of non-albicans Candida (NAC) yeasts in candidemia has increased. These yeasts more often display resistance to common antifungals. In many western countries, candidemia is mainly caused by susceptible C. albicans, while in resource-limited countries, including Iran, the candidemia species distribution is studied less often. Here, we investigated the species distribution, resistance levels, and characteristics of patients with candidemia in five hospitals in Mashhad (northeast Iran) for two years (2019-2021). Yeast isolates from blood were identified with MALDI-TOF MS and subjected to antifungal susceptibility testing (AFST) using the broth microdilution method, while molecular genotyping was applied to Candida parapsilosis isolates. In total, 160 yeast isolates were recovered from 160 patients, of which the majority were adults (60%). Candidemia was almost equally detected in men (48%) and women (52%). Almost half of patients (n = 67, 49%) were from intensive care units (ICUs). C. parapsilosis (n = 58, 36%) was the most common causative agent, surpassing C. albicans (n = 52, 33%). The all-cause mortality rate was 53%, with C. albicans candidemia displaying the lowest mortality with 39%, in contrast to a mortality rate of 59% for NAC candidemia. With microbroth AFST, nearly all tested isolates were found to be susceptible, except for one C. albicans isolate that was resistant to anidulafungin. By applying short tandem repeat (STR) genotyping to C. parapsilosis, multiple clusters were found. To summarize, candidemia in Mashhad, Iran, from 2019 to 2021, is characterized by common yeast species, in particular C. parapsilosis, for which STR typing indicates potential nosocomial transmission. The overall mortality is high, while resistance rates were found to be low, suggesting that the high mortality is linked to limited diagnostic options and insufficient medical care, including the restricted use of echinocandins as the first treatment option.

Comparative efficacies of the three echinocandins for Candida auris candidemia: real world evidence from a tertiary centre in India

Though echinocandins are the first line of therapy for C. auris candidemia, there is little clinical data to guide the choice of therapy within this class. This was the first study to compare the three echinocandins in terms of efficacy and outcomes for C. auris candidemia. This was a retrospective analysis of 82 episodes of candidemia caused by C. auris comparing outcomes across the three echinocandins. Majority patients in our study were treated with micafungin. Susceptibility rates were the lowest for caspofungin (35.36% resistance), with no resistance reported for the other two echinocandins. When a susceptible echinocandin was chosen, caspofungin resistance was not a factor significantly associated with mortality. Also, when a susceptible echinocandin was used for therapy, the choice within the class did not affect clinical cure, microbiological cure, or mortality (P > 0.05 for all). Failure to achieve microbiological cure (P = 0.018) and receipt of immune-modulatory therapy (P = 0.01) were significantly associated with increased mortality. Significant cost variation was noted among the echinocandins. Considering the significant cost variation, comparable efficacies can be reassuring for the prescribing physician.

A lateral flow immunoassay for the rapid identification of Candida auris from isolates or directly from surveillance enrichment broths

Introduction

Candida auris is a recently discovered yeast with a multi-drug resistant profile associated with high mortality rates. The rapid identification of Candida auris in hospital settings is crucial to allow appropriate therapeutic and rapid implementation of infection management measures. The aim of this study was to develop a lateral flow immunoassay (LFIA) for the rapid identification of Candida auris.

Methods

Highly specific monoclonal antibodies were obtained by immunizing mice with membrane proteins from Candida auris which were then used to develop a LFIA whose performance was assessed by testing 12 strains of Candida auris and 37 strains of other Candida species. Isolates were grown on either Sabouraud dextrose, CHROMagarTM Candida Plus or HardyCHROMTM Candida + auris agar plates. The strains were also cultured on salt sabouraud-dextrose with chloramphenicol or a commercially available Salt-Sabouraud Dulcitol Broth with chloramphenicol and gentamicin, and processed using a simple centrifugation protocol to recover a pellet. Finally, the colonies or yeast extract were transferred to the LFIA to determine the specificity and sensitivity of the assay.

Results

The LFIA reached 100% specificity and sensitivity from solid agar plates. For both enrichment broths, some Candida non-auris species were able to grow, but the LFIA remained 100% specific. The use of a dextrose-based sabouraud broth resulted in earlier identification with the LFIA, with most of the Candida auris strains detected at 24 h.

Conclusion

The developed LFIA prototype represents a powerful tool to fight the emerging threat of Candida auris. Clinical validation represents the next step.

Emerging trends of invasive yeast infections and azole resistance in Beijing intensive care units

BACKGROUND

Invasive fungal infections pose a substantial threat to patients in healthcare settings globally. Recent changes in the prevalence of fungal species and challenges in conducting reference antifungal susceptibility testing emphasize the importance of monitoring fungi and their antifungal resistance.

METHODS

A two-phase surveillance project was conducted in Beijing, China, involving 37 centres across 12 districts, from January 2012 to December 2013 and from January 2016 to December 2017.

FINDINGS

We found that the proportion of Candida albicans in intensive care units (ICUs) during 2016-2017 exhibited a significant decline compared with the 2012-2013 period, although it remained the most predominant pathogen. In contrast, the prevalence of Nakaseomyces glabratus (formerly Candida glabrata) and Candida tropicalis notably increased during the two-phase surveillance. The high prevalence of C. tropicalis and its resistance to azole drugs posed a serious threat to patients in ICUs. The pathogens causing invasive fungal infections in Beijing were relatively sensitive to echinocandins. While C. albicans continued to exhibit susceptibility to azoles, the resistance and growth rates of C. tropicalis towards azoles were particularly prominent. Concerns were raised due to the emergence of multiple, short-term isolates of Clavispora lusitaniae and Candida parapsilosis complex in neonatal ICUs, given their similarity in antifungal susceptibilities. Such occurrences point towards the potential for transmission and persisting presence of these pathogens within the ICU environment.

CONCLUSIONS

Our study complements existing data on the epidemiology of invasive fungal infections. It is imperative to exercise cautious medication management for ICU patients in Beijing, paying particular attention to azole resistance in C. tropicalis.

Comparative fitness trade-offs associated with azole resistance in Candida auris clinical isolates

Multidrug-resistant yeast Candida auris is a serious threat to public health with documented survival in various hospital niches. The dynamics of this survival benefit and its trade off with drug resistance are still unknown for this pathogen. In this study we investigate the oxidative stress response (OSR) in fluconazole-resistant C. auris and compare its relative fitness with fluconazole-susceptible strains. A total of 351 C. auris clinical isolates (61 fluconazole-susceptible and 290 fluconazole-resistant) were screened for stress tolerance by spot assay and 95.08 % fluconazole-susceptible isolates were hyper-resistant to oxidative stress while majority (94.5 %) fluconazole-resistant isolates had lower oxidative tolerance. Expression of Hog1 and Cta1 gene transcript levels and cellular catalase levels were significantly higher in fluconazole-susceptible isolates and a corresponding higher intracellular reactive oxygen species level (iROS) was accumulated in the fluconazole-resistant isolates. Biofilm formation and cell viability under oxidative stress revealed higher biofilm formation and better viability in fluconazole-susceptible isolates. Fluconazole-resistant isolates had higher basal cell wall chitin. On comparison of virulence, the % cytotoxicity in A549 cell line was higher in fluconazole-susceptible isolates and the median survival of the infected larvae in G. mellonella infection model was higher in fluconazole-resistant (5; IQR:4.5-5 days) vs. fluconazole-susceptible C. auris (2; IQR:1.5-2.5 days). All organisms evolve with changes in their environmental conditions, to ensure an optimal balance between proliferation and survival. Development of tolerance to a certain kind of stress example antifungal exposure in yeast can leads to a compensatory decrease in tolerance for other stresses. This study provides useful insights into the comparative fitness and antifungal susceptibility trade off in C. auris. We report a negative association between H2O2 tolerance and fluconazole susceptibility. Using in-vitro cell cytotoxicity and in-vivo survival assays we also demonstrate the higher virulence potential of fluconazole-susceptible C. auris isolates corroborating the negative correlation between susceptibility and pathogen survival or virulence. These findings could also be translated to clinical practice by investigating the possibility of using molecules targeting stress response and fitness regulating pathways for management of this serious infection.

Candida tropicalis-A systematic review to inform the World Health Organization of a fungal priority pathogens list

In response to the growing global burden of fungal infections with uncertain impact, the World Health Organization (WHO) established an Expert Group to identify priority fungal pathogens and establish the WHO Fungal Priority Pathogens List for future research. This systematic review aimed to evaluate the features and global impact of invasive candidiasis caused by Candida tropicalis. PubMed and Web of Science were searched for studies reporting on criteria of mortality, morbidity (defined as hospitalization and disability), drug resistance, preventability, yearly incidence, diagnostics, treatability, and distribution/emergence from 2011 to 2021. Thirty studies, encompassing 436 patients from 25 countries were included in the analysis. All-cause mortality due to invasive C. tropicalis infections was 55%-60%. Resistance rates to fluconazole, itraconazole, voriconazole and posaconazole up to 40%-80% were observed but C. tropicalis isolates showed low resistance rates to the echinocandins (0%-1%), amphotericin B (0%), and flucytosine (0%-4%). Leukaemia (odds ratio (OR) = 4.77) and chronic lung disease (OR = 2.62) were identified as risk factors for invasive infections. Incidence rates highlight the geographic variability and provide valuable context for understanding the global burden of C. tropicalis infections. C. tropicalis candidiasis is associated with high mortality rates and high rates of resistance to triazoles. To address this emerging threat, concerted efforts are needed to develop novel antifungal agents and therapeutic approaches tailored to C. tropicalis infections. Global surveillance studies could better inform the annual incidence rates, distribution and trends and allow informed evaluation of the global impact of C. tropicalis infections.

A correlative study of the genomic underpinning of virulence traits and drug tolerance of Candida auris

Candida auris is an opportunistic fungal pathogen with high mortality rates which presents a clear threat to public health. The risk of C. auris infection is high because it can colonize the body, resist antifungal treatment, and evade the immune system. The genetic mechanisms for these traits are not well known. Identifying them could lead to new targets for new treatments. To this end, we present an analysis of the genetics and gene expression patterns of C. auris carbon metabolism, drug resistance, and macrophage interaction. We chose to study two C. auris isolates simultaneously, one drug sensitive (B11220 from Clade II) and one drug resistant (B11221 from Clade III). Comparing the genomes, we confirm the previously reported finding that B11220 was missing a 12.8 kb region on chromosome VI. This region contains a gene cluster encoding proteins related to alternative sugar utilization. We show that B11221, which has the gene cluster, readily assimilates and utilizes D-galactose and L-rhamnose as compared to B11220, which harbors the deletion. B11221 exhibits increased adherence and drug resistance compared to B11220 when grown in these sugars. Transcriptomic analysis of both isolates grown on glucose or galactose showed that the gene cluster was upregulated when grown on D-galactose. These findings reinforce growing evidence of a link between metabolism and drug tolerance. B11221 resists phagocytosis by macrophages and exhibits decreased β-1,3-glucan exposure, a key determinant that allows Candida to evade the host immune system, as compared to B11220. In a transcriptomic analysis of both isolates co-cultured with macrophages, we find upregulation of genes associated with transport and transcription factors in B11221. Our studies show a positive correlation between membrane composition and immune evasion, alternate sugar utilization, and drug tolerance in C. auris.

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

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

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.

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.

Antifungal drug resistance in Candida: a special emphasis on amphotericin B

Invasive fungal infections in humans caused by several Candida species, increased considerably in immunocompromised or critically ill patients, resulting in substantial morbidity and mortality. Candida albicans is the most prevalent species, although the frequency of these organisms varies greatly according to geographic region. Infections with C. albicans and non-albicans Candida species have become more common, especially in the past 20 years, as a result of aging, immunosuppressive medication use, endocrine disorders, malnourishment, extended use of medical equipment, and an increase in immunogenic diseases. Despite C. albicans being the species most frequently associated with human infections, C. glabrata, C. parapsilosis, C. tropicalis, and C. krusei also have been identified. Several antifungal drugs with different modes of action are approved for use in clinical settings to treat fungal infections. However, due to the common eukaryotic structure of humans and fungi, only a limited number of antifungal drugs are available for therapeutic use. Furthermore, drug resistance in Candida species has emerged as a result of the growing use of currently available antifungal drugs against fungal infections. Amphotericin B (AmB), a polyene class of antifungal drugs, is mainly used for the treatment of serious systemic fungal infections. AmB interacts with fungal plasma membrane ergosterol, triggering cellular ion leakage via pore formation, or extracting the ergosterol from the plasma membrane inducing cellular death. AmB resistance is primarily caused by changes in the content or structure of ergosterol. This review summarizes the antifungal drug resistance exhibited by Candida species, with a special focus on AmB.

Advanced genetic techniques in fungal pathogen research

Although fungi have been important model organisms for solving genetic, molecular, and ecological problems, recently, they are also becoming an important source of infectious disease. Despite their high medical burden, fungal pathogens are understudied, and relative to other pathogenic microbes, less is known about how their gene functions contribute to disease. This is due, in part, to a lack of powerful genetic tools to study these organisms. In turn, this has resulted in inappropriate treatments and diagnostics and poor disease management. There are a variety of reasons genetic studies were challenging in pathogenic fungi, but in recent years, most of them have been overcome or advances have been made to circumvent these barriers. In this minireview, we highlight how recent advances in genetic studies in fungal pathogens have resulted in the discovery of important biology and potential new antifungals and have created the tools to comprehensively study these important pathogens.

Decoding the role of oxidative stress resistance and alternative carbon substrate assimilation in the mature biofilm growth mode of Candida glabrata

BACKGROUND

Biofilm formation is viewed as a vital mechanism in C. glabrata pathogenesis. Although, it plays a significant role in virulence but transcriptomic architecture and metabolic pathways governing the biofilm growth mode of C. glabrata remain elusive. The present study intended to investigate the genes implicated in biofilm growth phase of C. glabrata through global transcriptomic approach.

RESULTS

Functional analysis of Differentially expressed genes (DEGs) using gene ontology and pathways analysis revealed that upregulated genes are involved in the glyoxylate cycle, carbon-carbon lyase activity, pre-autophagosomal structure membrane and vacuolar parts whereas, down- regulated genes appear to be associated with glycolysis, ribonucleoside biosynthetic process, ribosomal and translation process in the biofilm growth condition. The RNA-Seq expression of eight selected DEGs (CgICL1, CgMLS1, CgPEP1, and CgNTH1, CgERG9, CgERG11, CgTEF3, and CgCOF1) was performed with quantitative real-time PCR (RT-qPCR). The gene expression profile of selected DEGs with RT-qPCR displayed a similar pattern of expression as observed in RNA-Seq. Phenotype screening of mutant strains generated for genes CgPCK1 and CgPEP1, showed that Cgpck1∆ failed to grow on alternative carbon substrate (Glycerol, Ethanol, Oleic acid) and similarly, Cgpep1∆ unable to grow on YPD medium supplemented with hydrogen peroxide. Our results suggest that in the absence of glucose, C. glabrata assimilate glycerol, oleic acid and generate acetyl coenzyme-A (acetyl-CoA) which is a central and connecting metabolite between catabolic and anabolic pathways (glyoxylate and gluconeogenesis) to produce glucose and fulfil energy requirements.

CONCLUSIONS

The study was executed using various approaches (transcriptomics, functional genomics and gene deletion) and it revealed that metabolic plasticity of C. glabrata (NCCPF-100,037) in biofilm stage modulates its virulence and survival ability to counter the stress and may promote its transition from commensal to opportunistic pathogen. The observations deduced from the present study along with future work on characterization of the proteins involved in this intricate process may prove to be beneficial for designing novel antifungal strategies.

Stephanoascus ciferrii Complex: The Current State of Infections and Drug Resistance in Humans

In recent years, the incidence of fungal infections in humans has increased dramatically, accompanied by an expansion in the number of species implicated as etiological agents, especially environmental fungi never involved before in human infection. Among fungal pathogens, Candida species are the most common opportunistic fungi that can cause local and systemic infections, especially in immunocompromised individuals. Candida albicans (C. albicans) is the most common causative agent of mucosal and healthcare-associated systemic infections. However, during recent decades, there has been a worrying increase in the number of emerging multi-drug-resistant non-albicans Candida (NAC) species, i.e., C. glabrata, C. parapsilosis, C. tropicalis, C. krusei, C. auris, and C. ciferrii. In particular, Candida ciferrii, also known as Stephanoascus ciferrii or Trichomonascus ciferrii, is a heterothallic ascomycete yeast-like fungus that has received attention in recent decades as a cause of local and systemic fungal diseases. Today, the new definition of the S. ciferrii complex, which consists of S. ciferrii, Candida allociferrii, and Candida mucifera, was proposed after sequencing the 18S rRNA gene. Currently, the S. ciferrii complex is mostly associated with non-severe ear and eye infections, although a few cases of severe candidemia have been reported in immunocompromised individuals. Low susceptibility to currently available antifungal drugs is a rising concern, especially in NAC species. In this regard, a high rate of resistance to azoles and more recently also to echinocandins has emerged in the S. ciferrii complex. This review focuses on epidemiological, biological, and clinical aspects of the S. ciferrii complex, including its pathogenicity and drug resistance.

Candidemia in Adult Patients in the ICU: A Reappraisal of Susceptibility Testing and Antifungal Therapy

OBJECTIVE

To provide updates on the epidemiology and recommendations for management of candidemia in patients with critical illness.

DATA SOURCES

A literature search using the PubMed database (inception to March 2023) was conducted using the search terms "invasive candidiasis," "candidemia," "critically ill," "azoles," "echinocandin," "antifungal agents," "rapid diagnostics," "antifungal susceptibility testing," "therapeutic drug monitoring," "antifungal dosing," "persistent candidemia," and "Candida biofilm."

STUDY SELECTION/DATA EXTRACTION

Clinical data were limited to those published in the English language. Ongoing trials were identified through ClinicalTrials.gov.

DATA SYNTHESIS

A total of 109 articles were reviewed including 25 pharmacokinetic/pharmacodynamic studies and 30 studies including patient data, 13 of which were randomized controlled clinical trials. The remaining 54 articles included fungal surveillance data, in vitro studies, review articles, and survey data. The current 2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Management of Candidiasis provides recommendations for selecting empiric and definitive antifungal therapies for candidemia, but data are limited regarding optimized dosing strategies in critically ill patients with dynamic pharmacokinetic changes or persistent candidemia complicated.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Outcomes due to candidemia remain poor despite improved diagnostic platforms, antifungal susceptibility testing, and antifungal therapy selection for candidemia in critically ill patients. Earlier detection and identification of the species causing candidemia combined with recognition of patient-specific factors leading to dosing discrepancies are crucial to improving outcomes in critically ill patients with candidemia.

CONCLUSIONS

Treatment of candidemia in critically ill patients must account for the incidence of non-albicans Candida species and trends in antifungal resistance as well as overcome the complex pathophysiologic changes to avoid suboptimal antifungal exposure.

Microbial Profile, Antimicrobial Susceptibility, and Prevalence of MDR/XDR Pathogens Causing Medical Device Associated Infections: A Single Center Study

Background

There is a scarcity of studies evaluating the microbial profile, antimicrobial susceptibility, and prevalence of MDR/XDR pathogens causing medical device-associated infections (MDAIs). The present study was sought in this regard.

Materials and methods

An ambispective-observational, site-specific, surveillance-based study was performed for a period of 2 years in the intensive care unit (ICU) and high dependency unit (HDU) (medicine/surgery) of a Tertiary-care University Hospital. Three commonly encountered MDAIs including central-line-associated bloodstream infections (CLABSI), catheter-associated urinary tract infections (CAUTI), and ventilator-associated pneumonia (VAP), were targeted.

Results and conclusion

Of the total 90 patients, 46 (51.1%) were admitted to the ICU (medicine/surgery), and the remaining 44 (48.8%) were admitted to the HDU (medicine/surgery). The median (P25-P75) age of the total patients was 55 (43.1-62.3) years. Male 61 (67.8%) preponderance was observed. Sixty-two of 90 (68.9%) were immunocompromised. A total of 104 pathogens causing MDAIs were isolated. Staphylococcus epidermidis (CoNS), and Staphylococcus capitis were commonly isolated multi-drug resistant (MDR) gram-positive pathogens causing MDAIs. Similarly, carba-resistant Klebsiella pneumoniae, Stenotrophomonas maltophilia, and carba-resistant Acinetobacter baumanni were commonly isolated MDR gram-negative pathogens causing MDAIs. Five of 9 (55.5%) K. pneumoniae and three of 9 (33.3%) S. maltophilia isolates were found to be extensively drug resistant. Among Candida, C. parapsilosis was the most prevalent fungal pathogen causing CLABSI and CAUTI in patients admitted to ICU/HDU.

How to cite this article

Suryawanshi VR, Pawar A, Purandare B, Vijayvargiya N, Sancheti S, Philip S, et al. Microbial Profile, Antimicrobial Susceptibility, and Prevalence of MDR/XDR Pathogens Causing Medical Device Associated Infections: A Single Center Study. Indian J Crit Care Med 2024;28(2):152-164.

The Development of a Clinical Registry Digital Database on Invasive Fungal Infections in India: Advancing Epidemiological Understanding and Patient Care

A well-structured digital database is essential for any national priority project as it can provide real-time data analysis and facilitate quick decision making. In recent times, particularly after the COVID-19 pandemic, invasive fungal infections (IFIs) have emerged as a significant public health challenge in India, affecting vulnerable population, including immunocompromised individuals. The lack of comprehensive and well-structured data on IFIs has hindered efforts to understand their true burden and optimize patient care. To address this critical knowledge gap, the ICMR has undertaken a Pan-India pioneer initiative to develop a network of Advanced Mycology Diagnostic research centres in different geographical zones of the country (ICMR-MycoNet). Under the aegis of this project, a clinical registry on IFIs in the ICUs is initiated. This process paper presents a detailed account of the steps involved in the establishment of a web-based data entering and monitoring platform to capture data electronically, ensuring robust and secure data collection and management. This system not only allows participating ICMR-MycoNet centres to enter patient information directly into the database using standardized Case Report Form (CRF) but also includes data validation checks to ensure the accuracy and completeness of entered data. It is complemented by a real-time, web-based, and adaptable data visualization platform. This registry aims to provide crucial epidemiological insights, promote evidence-based hospital infection control programs, and ultimately improve patient outcomes in the face of this formidable healthcare challenge.

Nanotechnology-based fungal detection and treatment: current status and future perspective

Fungal infections impose a significant impact on global health and encompass major expenditures in medical treatments. Human mycoses, a fungal co-infection associated with SARS-CoV-2, is caused by opportunistic fungal pathogens and is often overlooked or misdiagnosed. Recently, there is increasing threat about spread of antimicrobial resistance in fungus, mostly in hospitals and other healthcare facilities. The diagnosis and treatment of fungal infections are associated with several issues, including tedious and non-selective detection methods, the growth of drug-resistant bacteria, severe side effects, and ineffective drug delivery. Thus, a rapid and sensitive diagnostic method and a high-efficacy and low-toxicity therapeutic approach are needed. Nanomedicine has emerged as a viable option for overcoming these limitations. Due to the unique physicochemical and optical properties of nanomaterials and newer biosensing techniques, nanodiagnostics play an important role in the accurate and prompt differentiation and detection of fungal diseases. Additionally, nano-based drug delivery techniques can increase drug permeability, reduce adverse effects, and extend systemic circulation time and drug half-life. This review paper is aimed at highlighting recent, promising, and unique trends in nanotechnology to design and develop diagnostics and treatment methods for fungal diseases.

Application of machine learning for mortality prediction in patients with candidemia: Feasibility verification and comparison with clinical severity scores

BACKGROUND

Clinical severity scores, such as acute physiology, age, chronic health evaluation II (APACHE II), sequential organ failure assessment (SOFA), Pitt Bacteremia Score (PBS), and European Confederation of Medical Mycology Quality (EQUAL) score, may not reliably predict candidemia prognosis owing to their prespecified scorings that can limit their adaptability and applicability.

OBJECTIVES

Unlike those fixed and prespecified scorings, we aim to develop and validate a machine learning (ML) approach that is able to learn predictive models adaptively from available patient data to increase adaptability and applicability.

METHODS

Different ML algorithms follow different design philosophies and consequently, they carry different learning biases. We have designed an ensemble meta-learner based on stacked generalisation to integrate multiple learners as a team to work at its best in a synergy to improve predictive performances.

RESULTS

In the multicenter retrospective study, we analysed 512 patients with candidemia from January 2014 to July 2019 and compared a stacked generalisation model (SGM) with APACHE II, SOFA, PBS and EQUAL score to predict the 14-day mortality. The cross-validation results showed that the SGM significantly outperformed APACHE II, SOFA, PBS, and EQUAL score across several metrics, including F1-score (0.68, p < .005), Matthews correlation coefficient (0.54, p < .05 vs. SOFA, p < .005 vs. the others) and the area under the curve (AUC; 0.87, p < .005). In addition, in an independent external test, the model effectively predicted patients' mortality in the external validation cohort, with an AUC of 0.77.

CONCLUSIONS

ML models show potential for improving mortality prediction amongst patients with candidemia compared to clinical severity scores.

Risk factors, antifungal susceptibility, complications, and outcome of Candida auris bloodstream infection in a tertiary care center in the western region of Saudi Arabia

BACKGROUND

Candida auris, an emerging multidrug-resistant fungus species that grows as yeast, causes bloodstream infection, and is associated with high mortality rates. In this study, we identified risk factors associated with C. auris bloodstream infection, antifungal susceptibility pattern, complications, and outcome of the infection.

METHODS

This single-center cross-sectional retrospective study was conducted at King Abdulaziz Medical City, a tertiary care facility in Jeddah, Saudi Arabia, which included all patients 18 years or above who have had one or more blood cultures for C. auris between January 2021 and December 2022. We aimed to identify the risk factors associated with C. auris bloodstream infection, antifungal susceptibility patterns, complications, and outcomes at our center.

RESULTS

Forty-six patients with C. auris-positive blood cultures were included. All the patients had healthcare-associated infections. The mean age was 64.67 years, and the majority of patients were male (73.9 %). The most common concomitant hospital-acquired infections were skin and soft tissue infections (37 %), followed by hospital-acquired pneumonia (34.8 %) and intra-abdominal infections (26.1 %). The mean total white blood cell count, procalcitonin, and C-reactive protein was 10.5 ± 5.99 × 109/L, 2.63 ± 4.82 μg/L, and 90.3 ± 64.1 mg/L, respectively. Hypertension (73.9 %) was the most common comorbidity, followed by diabetes mellitus (58.7 %) and renal dysfunction (54.3 %). Risk factors associated with C. auris candidemia included antibiotic use (91.3 %), especially for > 14 days (78.3 %), C. auris colonization (60.9 %), use of central venous catheters, especially when the catheter was in place for >30 days (80.4 %), ICU admission in the last 30 days before C. auris-positive blood culture (93.5 %), especially for more than two weeks (76.1 %), mechanical ventilation (89.1 %), total parenteral nutrition (13 %), previous intra-abdominal surgery (30.4 %), and immunosuppressive therapy (56.5 %). A total of 97.8 % of C. auris isolates were resistant to fluconazole and 17.4 % were resistant to amphotericin B. Endocarditis and endophthalmitis were reported in one (2.2 %) patient each. The all-cause mortality at 30 days was 47.8 %.

CONCLUSION

Our study is one of the few studies available globally on C. auris bloodstream infection that investigated risk factors, antifungal susceptibility, complications, and outcomes. A thorough screening and risk assessment strategy should aid infection control, preventing it from becoming a major concern in the future.

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.

Fruits are vehicles of drug-resistant pathogenic Candida tropicalis

IMPORTANCE

Of 123 identified isolates from the fruit surface, C. tropicalis was the most frequently found species, followed by Meyerozyma caribbica and Candida krusei. All three fluconazole-resistant C. tropicalis were non-susceptible to voriconazole and belonged to the same predominant genotype of azole-resistant C. tropicalis causing candidemia in patients in Taiwan. Our findings provide evidence that fruit should be washed before eaten not only to remove chemicals but also potential drug-resistant pathogenic microbes, especially for immunocompromised individuals. To keep precious treatment options in patients, we not only continuously implement antimicrobial stewardship in hospitals but also reducing/stopping the use of agricultural fungicide classes used in human medicine.

Candida auris infection; diagnosis, and resistance mechanism using high-throughput sequencing technology: a case report and literature review

Background

Candida auris (C. auris), a recently developing fungal disease with high virulence, easy transmission, and substantial medication resistance in hospitals, poses a growing danger to human health. In 2009, the initial documentation of this disease was made when it was discovered in the ear canal of an elderly Japanese patient. Since its initial isolation, the presence of C. auris across six continents has been a cause for severe concern among medical professionals and scientists. According to recent findings, C. auris is connected with five geographically different lineages and significant rates of antifungal resistance. Furthermore, C. auris infections in healthcare settings lack appropriate treatment options and standardized strategies for prevention and control. This results in many treatment failures and hinders the elimination of C. auris in healthcare institutions. To examine the drug resistance mechanism of C. auris and to aid in clinical therapy, we provide a case of C. auris infection along with a short review of the relevant literature.

Clinical presentation

An 81-year-old female with cerebral hemorrhage was admitted to the hospital and diagnosed with a urinary catheter-related C. auris. The sample was evaluated and reported in terms of culture, identification, drug sensitivity, and gene sequencing. We also evaluated the relationship between the morphology of the isolated strains and their drug resistance. Whole-genome sequencing yielded the genes ERG11-Y132F, CDR1-E709D, TAC1B-Q503E, and TAC1B-A583S; however, no additional loci included alterations of concern, according to our results. ERG11-Y132F and TAC1B-A583S are drug-resistant gene loci, whereas CDR1-E709D and TAC1B-Q503E are unidentified variants.

Conclusion

We discover a C. auris case of specific a strain in an old female that has some drug-resistant genes, and some genes may be different from already reported gene sites. Gene locus, mutation, and drug resistance mechanism studies may contribute to the creation of innovative drugs and therapeutic treatments. Clinicians and microbiologists must be aware of this globally spreading yeast, which poses substantial hospital diagnostic, treatment, and infection control challenges. Future multicenter research must be performed to uncover this health threat and provide new, effective treatments.

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

INTRODUCTION

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

MATERIALS

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

RESULTS

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

CONCLUSIONS

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

A Bibliometric Review on Candida auris of the First Fifteen Years of Research (2009-2023)

Introduction

Candida auris is a relatively novel pathogen first described in 2009 in Japan. It has increased its presence worldwide, becoming a public health concern due to its innate resistance to antifungals and outbreak potential.

Methods

We performed a query using the word "Candida auris" from the Scopus database, further performing a bibliometric analysis with the open-source R package Bibliometrix.

Results

907 original articles were retrieved, allowing us to map the principal authors, papers, journals, and countries involved in this yeast research, as well as analyze current and future trends and the number of published articles.

Conclusion

C. auris will continue to be a pivotal point in fungal resistance research, either for a better understanding of its resistance and pathogenic mechanisms or for developing novel drugs.

Clinical safety and efficacy of novel antifungal, fosmanogepix, for the treatment of candidaemia: results from a Phase 2 trial

BACKGROUND

Fosmanogepix is a first-in-class antifungal targeting the fungal enzyme Gwt1, with broad-spectrum activity against yeasts and moulds, including multidrug-resistant fungi, formulated for intravenous (IV) and oral administration.

METHODS

This global, multicenter, non-comparative study evaluated the safety and efficacy of fosmanogepix for first-line treatment of candidaemia in non-neutropenic adults. Participants with candidaemia, defined as a positive blood culture for Candida spp. within 96 h prior to study entry, with ≤2 days of prior systemic antifungals, were eligible. Participants received fosmanogepix for 14 days: 1000 mg IV twice daily on Day 1, followed by maintenance 600 mg IV once daily, and optional switch to 700 mg orally once daily from Day 4. Eligible participants who received at least one dose of fosmanogepix and had confirmed diagnosis of candidaemia (<96 h of treatment start) composed the modified intent-to-treat (mITT) population. Primary efficacy endpoint was treatment success at the end of study treatment (EOST) as determined by the Data Review Committee. Success was defined as clearance of Candida from blood cultures with no additional antifungal treatment and survival at the EOST.

RESULTS

Treatment success was 80% (16/20, mITT; EOST) and Day 30 survival was 85% (17/20; 3 deaths unrelated to fosmanogepix). Ten of 21 (48%) were switched to oral fosmanogepix. Fosmanogepix was well tolerated with no treatment-related serious adverse events/discontinuations. Fosmanogepix had potent in vitro activity against baseline isolates of Candida spp. (MICrange: CLSI, 0.002-0.03 mg/L).

CONCLUSIONS

Results from this single-arm Phase 2 trial suggest that fosmanogepix may be a safe, well-tolerated, and efficacious treatment for non-neutropenic patients with candidaemia, including those with renal impairment.

Biofilm Formation in Medically Important Candida Species

Worldwide, the number of infections caused by biofilm-forming fungal pathogens is very high. In human medicine, there is an increasing proportion of immunocompromised patients with prolonged hospitalization, and patients with long-term inserted drains, cannulas, catheters, tubes, or other artificial devices, that exhibit a predisposition for colonization by biofilm-forming yeasts. A high percentage of mortality is due to candidemia caused by medically important Candida species. Species of major clinical significance include C. albicans, C. glabrata, C. tropicalis, C. parapsilosis, C. krusei, and C. auris. The association of these pathogenic species in the biofilm structure is a serious therapeutic problem. Candida cells growing in the form of a biofilm are able to resist persistent therapy thanks to a combination of their protective mechanisms and their ability to disseminate to other parts of the body, thus representing a threat from the perspective of a permanent source of infection. The elucidation of the key mechanisms of biofilm formation is essential to progress in the understanding and treatment of invasive Candida infections.

Genotyping and susceptibility testing uncovers large azole-resistant Candida tropicalis clade in Alexandria, Egypt

OBJECTIVES

Candida tropicalis is an emerging medically relevant Candida species. The yeast primarily causes opportunistic infections in intensive care units and is highly prevalent in tropical countries. The genetic diversity within this species is high, and nosocomial transmission has been reported. C. tropicalis genotyping of isolates from low- and middle-income countries is underrepresented when compared with that from high-income countries. Also, in Egypt, only limited genotyping has been conducted for C. tropicalis isolates, while antifungal resistance seems to increase, especially against azoles.

METHODS

Antifungal susceptibility testing was performed on 64 C. tropicalis isolates from ICU patients collected from multiple hospitals in Alexandria, Egypt. Genotyping by means of short tandem repeat (STR) and whole genome sequencing (WGS) single nucleotide polymorphism (SNP) analysis was performed.

RESULTS

Using antifungal susceptibility testing, fluconazole resistance was observed in 24 isolates (38%), of which 23 harboured an ERG11 G464S substitution, previously shown to cause resistance in Candida albicans. STR genotyping showed that these 23 isolates were related, forming a distinct resistant clade. WGS SNP analysis subsequently confirmed this genetic relationship, although isolates within this clade differed in at least 429 SNPs, suggesting that these were independently introduced.

CONCLUSION

Overall, STR and WGS SNP analysis of this collection indicates limited C. tropicalis nosocomial transmission in Alexandria, while the presence of this large azole-resistant C. tropicalis clade within this city hampers the treatment of intensive care unit patients.

Candida auris: a global pathogen that has taken root in Colombia

Candida auris has been recognized as an emerging multidrug-resistant pathogen with a significant public health burden, causing cases of invasive infection and colonization due to its persistence on inanimate surfaces, ability to colonize skin of some patients, and high transmissibility in healthcare settings. The first sporadic report of the isolation of this species from the ear canal of a patient in Asia was in 2009 and reports from other regions of the world soon followed. However, it was not until 2015 that global epidemiological alerts were communicated as a result of an increasing number of reports of invasive infections caused by C. auris in several countries. Colombia was soon added to this list in 2016 after an unusual increase in the number of C. haemulonii isolates was reported, later confirmed as C. auris. Since the issuing of a national alert by the Colombian National Institute of Health together with the Ministry of Health in 2016, the number of cases reported reached over 2,000 by 2022. Colombian isolates have not shown pan resistance to available antifungals, unlike C. auris strains reported in other regions of the world, which leaves patients in Colombia with therapeutic options for these infections. However, increasing fluconazole resistance is being observed. Whole-genome sequencing of Colombian C. auris isolates has enhanced molecular epidemiological data, grouping Colombian isolates in clade IV together with other South American isolates.

Fluconazole and echinocandin resistance of Candida species in invasive candidiasis at a university hospital during pre-COVID-19 and the COVID-19 outbreak

Antifungal susceptibility of Candida species is decreasing. Successful treatment for antifungal-resistant candida infection is challenging and associated with significant mortality. We performed a prospective observational study to identify the species and antifungal susceptibilities of invasive isolates of Candida species over a 5-year period at a university hospital in southern Thailand. Between 2017 and 2021, the species distribution was 39.1% Candida tropicalis, 24.8% Candida albicans, 20.3% Candida parapsilosis complex, 10.5% Candida glabrata, and 5.2% miscellaneous Candida spp. Notable observations include elevated minimal inhibitory concentration (MIC) and decrease susceptibility of C. tropicalis and C. glabrata to echinocandin and all tested triazoles. A shift of MIC90 value in the COVID-19 era was seen in C. albicans and C. tropicalis with azoles and echinocandins. Azole resistance increased among C. tropicalis isolates, and echinocandin resistance also increased among C. parapsilosis and C. glabrata isolates. Novel alterations in FKS1 HS1 and HS2 were detected in both isolates of anidulafungin-resistant C. parapsilosis. As Candida species have become more resistant to azoles and less susceptible to echinocandin development, the need arose to observe the emergence of resistance to both antifungal classes in candida clinical isolates, for a more effective infection control in the hospital.

Candida auris Blood stream infection- a descriptive study from Qatar

BACKGROUND

Candida auris is an emerging yeast pathogen that can cause invasive infections, particularly candidemia, in healthcare settings. Candida auris is characterized by resistance to multiple classes of antifungal drugs and high mortality.

OBJECTIVE

To describe the risk factors, clinical characteristics, antifungal susceptibility pattern and outcomes of Candida auris blood stream infection.

METHODS

We conducted a retrospective review of electronic medical records of C. auris fungemia cases in the facilities under Hamad Medical corporation, Qatar from 1/11/2018 to 31/7/2021. Demographic data, risk factors, antibiogram and 30-day outcome are described.

RESULTS

We identified 36 patients with C. auris fungemia. Most of the patients were in intensive care unit following severe COVID-19 pneumonia and had received steroids and broad-spectrum antibiotics. Most cases were central line related. Over 90% of isolates were non-susceptible to fluconazole, while amphotericin B resistance reached 85%. Factors associated with high mortality included initial SOFA score of 9 or above and absence of source control.

CONCLUSION

Our study reveals a concerning 41.6% mortality rate within 30 days of C. auris candidemia. Furthermore, the prevalence of amphotericin B resistance in Qatar exceeds what has been reported in the literature necessitating further exploration. Echinocandins retains nearly 100% susceptibility and should be prioritized as the treatment of choice. These findings emphasize the need for vigilant monitoring and appropriate management strategies to combat C. auris infections and improve patient outcomes.

Overcoming clinical challenges in the management of invasive fungal infections in low- and middle-income countries (LMIC)

INTRODUCTION

The management of invasive fungal infections (IFIs) in low- and middle-income countries (LMIC) is a serious challenge due to limited epidemiology studies, sub-optimal laboratory facilities, gap in antifungal management training and resources. Limited studies highlighted distinctive epidemiology of IFIs in those countries, and difficulty in distinguishing from closely related infections. To overcome the gaps for appropriate management of IFIs, innovative approaches are required.

AREAS COVERED

Extensive literature search and discussion with experts have helped us to summarize the epidemiology, diagnostic and management difficulties in managing IFIs in LMIC, and recommend certain solutions to overcome the challenges.

EXPERT OPINION

The strategies to overcome the challenges in diagnosis may include local epidemiology study, training of healthcare workers, association of fungal infections with already existing budgeted national programs, development and incorporation of point-of-care test (POCT) for prompt diagnosis, simplifying clinical diagnostic criteria suitable for LMIC, judicious use of available expertise, and diagnostic stewardship. For management strategies judicious use of antifungal, partnering with industry for inexpensive antifungal agents, development of LMIC specific guidelines for cost-effective management of IFIs and fungal outbreaks, improvement of infection control practices, advocacy for implementation of WHO recommended antifungal use, and integration of IFIs with public health.

Heightened Efficacy of Anidulafungin When Used in Combination with Manogepix or 5-Flucytosine against Candida auris In Vitro

Candida auris is an emerging, multidrug-resistant fungal pathogen that causes refractory colonization and life-threatening, invasive nosocomial infections. The high proportion of C. auris isolates that display antifungal resistance severely limits treatment options. Combination therapies provide a possible strategy by which to enhance antifungal efficacy and prevent the emergence of further resistance. Therefore, we examined drug combinations using antifungals that are already in clinical use or are undergoing clinical trials. Using checkerboard assays, we screened combinations of 5-flucytosine and manogepix (the active form of the novel antifungal drug fosmanogepix) with anidulafungin, amphotericin B, or voriconazole against drug resistant and susceptible C. auris isolates from clades I and III. Fractional inhibitory concentration indices (FICI values) of 0.28 to 0.75 and 0.36 to 1.02 were observed for combinations of anidulafungin with manogepix or 5-flucytosine, respectively, indicating synergistic activity. The high potency of these anidulafungin combinations was confirmed using live-cell microfluidics-assisted imaging of the fungal growth. In summary, combinations of anidulafungin with manogepix or 5-flucytosine show great potential against both resistant and susceptible C. auris isolates.

Epidemiology and susceptibility of Nakaseomyces (formerly Candida) glabrata bloodstream isolates from hospitalised adults in South Africa

During 2016-2017, Nakaseomyces glabrata (formerly Candida glabrata) caused 14% of cases of candidaemia in South Africa. We aimed to describe the clinical characteristics of adults with N. glabrata candidaemia at 20 sentinel hospitals (accounting for 20% (172/917) of cases) and the antifungal susceptibility of the corresponding isolates. A higher proportion of patients with N. glabrata candidaemia were older (median age: 55 years [interquartile range (IQR): 41-65 years] vs. 49 years [IQR: 35-63 years]; p = 0.04), female (87/164, 53% vs. 283/671, 42%; p = 0.01), admitted to a public-sector hospital (152/172, 88% vs. 470/745, 63%; p < 0.001), treated with fluconazole only (most with suboptimal doses) (51/95, 54% vs. 139/361, 39%; p < 0.001), and had surgery (47/172, 27% vs. 123/745, 17%; p = 0.001) and a shorter hospital stay (median 7 days [IQR: 2-20 days] vs. 13 days [IQR: 4-27 days]; p < 0.001) compared to patients with other causes of candidaemia. Eight N. glabrata isolates (6%, 8/131) had minimum inhibitory concentrations in the intermediate or resistant range for ≥ 1 echinocandin and a R1377K amino acid substitution encoded by the hotspot 2 region of the FKS2 gene. Only 11 isolates (8%, 11/131) were resistant to fluconazole. Patients with confirmed N. glabrata candidaemia are recommended to be treated with an echinocandin (or polyene), thus further guideline training is required.

Asymptomatic Candida glabrata urinary tract infection in an immunocompetent young female: A case report

INTRODUCTION

Fungal urinary tract infections (UTIs) are becoming increasingly common in hospitalized patients and Candida species are the most prevalent organisms. However, recurrent candiduria in young healthy outpatients is rare thus require further examination to find the etiologic factors.

CASE PRESENTATION

We described a case of recurrent asymptomatic c caused by azole-resistant C. glabrata in a healthy young female who only had previous use of antibiotics without other risk factors. However, after removal of the predisposing factor and the use of sensitive antifungal agents, the patient's urine cultures remained positive. This phenomenon indicated to us that the patient might have an immune-related genetic deficiency. We found a novel caspase-associated recruitment domain-containing protein 9 (CARD9) gene mutation (c.808-11G > T) which might be the cause of recurrent asymptomatic candiduria in this immune-competent young female without any underlying diseases.

CONCLUSIONS

We report a case of recurrent asymptomatic candiduria caused by azole-resistant Candida glabrata in a young healthy female with a novel CARD9 mutation. A functional study of this mutation should be performed in the future to determine its effect on asymptomatic fungal UTIs.

Emerging threat of candida resistance among neonates at a teaching institute of Jharkhand

Purpose

In the past few decades, candidemia has escalated to worrisome levels, leading to substantial morbidity and mortality in neonates. The rise in anti-fungal drug resistance demands prompt diagnosis and treatment. This study aimed to determine the speciation and susceptibility pattern of Candida species recovered from special care new-born units and identify risk factors for developing candidemia in neonates.

Method

A total of 580 blood samples from clinically suspected septicemic neonates were collected and subjected to culture. Cultures positive for yeasts were sub-cultured on Sabouraud dextrose agar. Identification of a suspected purified colony of Candida was confirmed to the species level by both conventional and automated techniques matrix-assisted laser desorption and ionization time-of-flight mass spectrometry. Anti-fungal susceptibility of isolates was performed by an automated method (VITEK 2 system) using VITEK 2 cards. Multi-variate logistic regression analysis was used to identify risk factors associated with candidemia.

Result

A total of 56 (9.66%) isolates of Candida species were recovered from 580 blood cultures. Non-albicans Candida species predominated with 82.14% of cases, whereas 17.86% of cases were caused by Candida albicans. Candida tropicalis (46.42%) was the most common isolate recovered, followed by Candida albicans (17.8%). Risk factor analyses identified a very low birth weight [odds ratio (OR) =4.05, 95% confidence interval (CI) =2.03-8.08] and prolonged antibiotic therapy (OR = 3.79, 95% CI = 1.7-8.7) among others as significant predictors of candidemia. All the Candida isolates showed 100% sensitivity to voriconazole and micafungin, whereas the overall sensitivities for fluconazole, amphotericin B, caspofungin, and flucytosine were 85.71%, 96.43%, 96.43%, and 91.07%, respectively.

Conclusion

Candidemia is a life-threatening condition in neonates. Identification of Candida species and routine anti-fungal susceptibility is a must to select a suitable and effective anti-fungal therapy to revoke emerging resistance to anti-fungals.

Prognostic Trends and Current Challenges in Candidemia: A Comparative Analysis of Two Multicenter Cohorts within the Past Decade

Candidemia remains a major public health challenge due to its high mortality rates, especially in developing countries. Monitoring epidemiological trends may provide insights for better clinical outcomes. This study aimed to describe trends in the epidemiology, therapeutic practices, and mortality in candidemia through a retrospective comparative analysis between two surveillance cohorts of all candidemic adults at eleven tertiary hospitals in Brazil, from 2010-2011 (Period I) versus 2017-2018 (Period II). A total of 616 cases were diagnosed, with 247 being from Period II. These patients were more likely to have three or more coexisting comorbidities [72 (29.1%) vs. 60 (16.3%), p < 0.001], had a prior history of in-hospital admissions more often [102 (40.3%) vs. 79 (21.4%), p = 0.001], and presented with candidemia earlier after admission, within 15 days (0-328) vs. 19 (0-188), p = 0.01. Echinocandins were more frequently prescribed [102 (41.3%) vs. 50 (13.6%), p = 0.001], but time to antifungal initiation [2 days (0-14) vs. 2 (0-13), p = 0.369] and CVC removal within 48 h [90/185 (48.6%) vs. 148/319 (46.4%), p = 0.644] remained unchanged. Additionally, many patients went untreated in both periods I and II [87 (23.6%) vs. 43 (17.4%), p = 0.07], respectively. Unfortunately, no improvements in mortality rates at 14 days [123 (33.6%) vs. 93 (37.7%), p = 0.343] or at 30 days [188 (51.4%) vs. 120 (48.6%), p = 0.511] were observed. In conclusion, mortality rates remain exceedingly high despite therapeutic advances, probably associated with an increase in patients' complexity and suboptimal therapeutic interventions. Management strategies should be tailored to suit epidemiological changes, expedite diagnosis to reduce the number of untreated eligible patients and guarantee early antifungal initiation and source control.

A Modular Cloning Toolkit Including CRISPRi for the Engineering of the Human Fungal Pathogen and Biotechnology Host Candida glabrata

The yeast Candida glabrata is an emerging, often drug-resistant opportunistic human pathogen that can cause severe systemic infections in immunocompromised individuals. At the same time, it is a valuable biotechnology host that naturally accumulates high levels of pyruvate─a valuable chemical precursor. Tools for the facile engineering of this yeast could greatly accelerate studies on its pathogenicity and its optimization for biotechnology. While a few tools for plasmid-based expression and genome engineering have been developed, there is no well-characterized cloning toolkit that would allow the modular assembly of pathways or genetic circuits. Here, by characterizing the Saccharomyces cerevisiae-based yeast molecular cloning toolkit (YTK) in C. glabrata and by adding missing components, we build a well-characterized CgTK (C. glabrata toolkit). We used the CgTK to build a CRISPR interference system for C. glabrata that can be used to generate selectable phenotypes via single-gRNA targeting such as is required for genome-wide library screens.

Predictive factors and prognostic value of candiduria in critically-ill patients with solid and hematological malignancies

PURPOSE

To investigate the epidemiology of candiduria in critically-ill patients with solid/hematological malignancies and to assess its predictive factors and prognostic value.

METHODS

All adult patients with confirmed solid/hematological malignancy admitted in the intensive care units (ICUs) for more than 48 h were retrospectively included. Urine cultures were sampled on admission and then whenever signs of sepsis were identified. Two groups were compared: (candiduria (+)) and (candiduria (-)).

RESULTS

One-hundred-seventy-three patients were included. Solid cancer was the underlying oncological disease for 147 patients (85%) while 26 patients (15%) had hematological malignancies. Twenty-nine patients (16.8%) were diagnosed with candiduria, and 31 urinary samples grew Candida spp. Candida spp represented 55.8% of the total urinary isolates. Fourteen isolates (45.2%) of Candida albicans were identified. Among the 17 non-albicans isolates, Candida tropicalis was the most predominant (41.9%). Six patients (3.5%) had candidemia with no significant difference between candiduria(+) and candiduria(-) groups (respectively, 6.9% and 2.8%; p = 0.264). In multivariate analysis, previous exposure to quinolones (OR = 3.8, CI95% [1.4-8.3]; p = 0.008), mechanical ventilation (OR = 4.1, CI95% [1.1-14.7]; p = 0.034) and renal replacement therapy (OR = 3.5, 95%CI [1.2-9.7]; p = 0.017) were identified as independent factors predicting candiduria. Candiduria was associated with significantly higher ICU-mortality after adjusting for SAPSII score on admission (OR = 2.9 CI95% [1.3-6.8]; p = 0.009).

CONCLUSION

Candiduria is common in cancer critically-ill patients. We reported an increased rate of non-albicans species, over albicans species. Patients with candiduria had higher ICU mortality, probably related to higher frailty and clinical severity.

Risk Factors for Candidemia in Intensive Care Unit: A Matched Case Control Study from North-Western India

Candidemia is one of the significant causes of mortality amongst critically ill patients in Intensive Care Units (ICUs). This study aimed to assess the incidence, risk factors and antifungal susceptibility pattern in candidemia cases admitted in ICU in a tertiary care hospital in Jaipur, Rajasthan from June 2021 to November 2021. Candida species isolated from blood culture of clinically suspected patients of sepsis were defined as candidemia cases. Blood culture and antifungal susceptibility testing were performed as per standard laboratory protocol. Analyses of risk factors was done between candidemia cases and matched controls in a ratio of 1 : 3. Forty-six candidemic cases and 150 matched controls were included in the study. C. tropicalis was the most prevalent species (22/46; 48%) followed by C. auris (8/46; 17%) and C. albicans (7/46; 15%). Candida species showed good sensitivity to echinocandins (97%) followed by amphotericin B (87%) and voriconazole (80%). In multivariate analysis, longer stay in ICU, presence of an indwelling device, use of immunosuppressive drugs and positive SARS-CoV-2 infection were associated with increased risk of candidemia. The constant evaluation of risk factors is required as prediction of risks associated with candidemia may help to guide targeted preventive measures with reduced morbidity and mortality.

Candida auris as an Emergent Public Health Problem: A Current Update on European Outbreaks and Cases

Candida auris is considered to be an emerging fungal pathogen and is related to high mortality rates, persistent candidemia, inconsistencies in susceptibility testing results and misidentification by available commercial identification systems. Multidrug-resistant (MDR) and pandrug-resistant (PDR) strains are increasingly detected. In Europe, hospital outbreaks caused by C. auris have been reported in the United Kingdom (UK), Italy and Spain; however, several cases have been sporadically detected in all European countries. C. auris is difficult to control despite enhanced control measures due to its ability to survive for a long time in environments and colonize patients for prolonged periods. An adequate laboratory diagnostic capacity and national surveillance are fundamental to rapidly detect new C. auris cases and to apply the correct measures to circumscribe them and prevent their spread. Our narrative review aims to highlight the primary C. auris outbreaks and case reports that have occurred in Europe.

Psychogenetic, genetic and epigenetic mechanisms in Candida auris: Role in drug resistance

In recent years, we are facing the challenge of drug resistance emergence in fungi. The availability of limited antifungals and development of multi-drug resistance in fungal pathogens has become a serious concern in the past years in the health sector. Although several cellular, molecular, and genetic mechanisms have been proposed to explain the drug resistance mechanism in fungi, but a complete understanding of the molecular and genetic mechanisms is still lacking. Besides the genetic mechanism, epigenetic mechanisms are pivotal in the fungal lifecycle and disease biology. However, very little is understood about the role of epigenetic mechanisms in the emergence of multi-drug resistance in fungi, especially in Candida auris (C. auris). The current narrative review summaries the clinical characteristics, genomic organization, and molecular/genetic/epigenetic mechanisms underlying the emergence of drug resistance in C. auris. A very few studies have attempted to evaluate the role of epigenetic mechanisms in C. auris. Furthermore, advanced genetic tools such as the CRISP-Cas9 system can be utilized to elucidate the epigenetic mechanisms and their role in the emergence of multi-drug resistance in C. auris.