Fungemia Surveillance in Denmark Demonstrates Emergence of Non-albicans Candida Species and Higher Antifungal Usage and Resistance Rates than in Other Nations

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.

In Vitro Susceptibility Tests in the Context of Antifungal Resistance: Beyond Minimum Inhibitory Concentration in Candida spp

Antimicrobial resistance is a matter of rising concern, especially in fungal diseases. Multiple reports all over the world are highlighting a worrisome increase in azole- and echinocandin-resistance among fungal pathogens, especially in Candida species, as reported in the recently published fungal pathogens priority list made by WHO. Despite continuous efforts and advances in infection control, development of new antifungal molecules, and research on molecular mechanisms of antifungal resistance made by the scientific community, trends in invasive fungal diseases and associated antifungal resistance are on the rise, hindering therapeutic options and clinical cures. In this context, in vitro susceptibility testing aimed at evaluating minimum inhibitory concentrations, is still a milestone in the management of fungal diseases. However, such testing is not the only type at a microbiologist's disposal. There are other adjunctive in vitro tests aimed at evaluating fungicidal activity of antifungal molecules and also exploring tolerance to antifungals. This plethora of in vitro tests are still left behind and performed only for research purposes, but their role in the context of invasive fungal diseases associated with antifungal resistance might add resourceful information to the clinical management of patients. The aim of this review was therefore to revise and explore all other in vitro tests that could be potentially implemented in current clinical practice in resistant and difficult-to-treat cases.

Controlling the Interaction between Fluorescent Gold Nanoclusters and Biointerfaces for Rapid Discrimination of Fungal Pathogens

Nondestructive detection and discrimination of fungal pathogens is essential for rapid and precise treatment, which further effectively prevents antifungal resistance from overused drugs. In this work, fluorescent gold nanoclusters served as the basis for discriminating Candida species. Varied on surface ligands, these gold nanoclusters demonstrated different optical properties as a result of the perturbation effects of ligands. The biointerface interaction between the surface ligands of gold nanoclusters and the cell walls of Candida species can be constructed, and their restriction on ligands perturbation effect produced enhanced fluorescence signals. Owing to the variation of the cell wall composition, cells of different Candida species demonstrated different degrees of association with the gold nanoclusters, leading to discriminable amounts of fluorescence enhancements. The reverse signal response from these gold nanoclusters gives rise to a synergistic and effective assay that allows identification of Candida species.

Candida Spp. in Lower Respiratory Tract Secretions - A Ten Years Retrospective Study

Introduction

Lower respiratory tract secretions (LRTS) like sputum and tracheal aspirates are frequently sent to the microbiology laboratory from patients with various respiratory pathologies. Improper collection techniques can lead to false-positive results, resulting in improper therapy.

Aim of the study

To determine the percentage of contaminated samples sent to the microbiology laboratory, to establish the prevalence of Candida spp. in non-contaminated samples and therefore, the presence of Candida spp. originating in lower respiratory tract infections. Material and

Methods

A 10-year data survey was conducted to assess the differences in Candida prevalence from contaminated versus non-contaminated samples, assessed and categorised by Bartlett grading system, and to emphasise the importance of quality control for potentially contaminated samples. The data were analysed according to gender, age, referring departments, and the species of Candida. For the statistical analysis, Kruskal-Wallis and Fisher tests were used, and the alpha value was set for 0.5.

Results

The prevalence of Candida spp. in all analysed samples was 31.60%. After excluding the contaminated samples, the actual prevalence was 27.66%. Of all sputum samples, 31.6% were contaminated. Patients aged more than 40 years old were more prone to provide contaminated sputum samples. C. albicans is more prevalent in non-contaminated sputum samples. In both sputum and tracheal aspirates, the chances of identifying a single species are higher than the chances of identifying multiple species.

Conclusions

The study emphasises the importance of assessing the quality of sputum samples because of the high number of improperly collected samples sent to the microbiology laboratory.

Epidemiology of candidemia in NICE area, France: A five-year study of antifungal susceptibility and mortality

OBJECTIVES

The aim of this study was to investigate the epidemiology of candidemia, the fungal susceptibility, the first-line therapy and the morality rate over 5 years. Knowing the differences of the yeasts in the candidemia local epidemiology, is essential to obtain information on fungal epidemiology to adapt antifungal strategies.

MATERIALS/METHODS

This retrospective study was conducted from January 2014 to December 2018. The susceptibility of the Candida strains were tested for amphotericin B, caspofungin, voriconazole and fluconazole.

RESULTS

The 304 strains were isolated from 290 patients (40 patients in 2014, 65 in 2015, 72 in 2016, 62 in 2017 and 51 in 2018). The three most common Candida spp isolated from blood cultures were Candida albicans (44%), Candida glabrata (22%) and Candida parapsilosis (13%). The proportion of non-albicans Candida decreased from 68% in 2014 to 45% in 2018. C. albicans and C. parapsilosis were to the four antifungals tested. As first-line therapy, 60% of patients received caspofungin and 26% fluconazole. There was no significant difference in the mortality between the two arms of patients (, 27% and 21%, p = 0.47 at 30 days respectively). Thirty day all-cause mortality was 31% and it decreased from 2014 (46%) to 2018 (18%).

CONCLUSIONS

We report that the absence of antifungal resistance of our C. albicans and C. parapsilosis candidemia suggests possible treatment after MALDI-TOF identification with fluconazole as first-line therapy in our hospital, as soon as possible and while continuing to perform the antifungal test.

Antifungal effects of Streptococcus mutans extract on Candida strains susceptible and resistant to fluconazole: An in vivo study

Previous studies showed that the crude extract obtained from Streptococcus mutans inhibited the growth of Candida albicans reference strains. In this study, we evaluated whether the antifungal effects of S. mutans extract can be extended to clinical Candida isolates, including C. albicans and non-abicans strains with different susceptibilities to fluconazole. We verified that S. mutans extract increased the survival of Galleria mellonella larvae infected with C. albicans and C. glabrata and inhibited the fungal cells in hemolymph. These antifungal effects occurred for both fluconazole-susceptible and fluconazole-resistant strains. However, larvae infected by C. krusei were not affected by S. mutans extract.

LAY SUMMARY

Streptococcus mutans crude extract shows antifungal effects on clinical Candida strains susceptible and resistant to fluconazole in Galleria mellonella model.

Characteristics and Management of Candidaemia Episodes in an Established Candida auris Outbreak

The multi-resistant yeast Candida auris has become a global public health threat because of its ease to persist and spread in clinical environments, especially in intensive care units. One of the most severe manifestations of invasive candidiasis is candidaemia, whose epidemiology has evolved to more resistant non-albicansCandida species, such as C. auris. It is crucial to establish infection control policies in order to control an outbreak due to nosocomial pathogens, including the implementation of screening colonisation studies. We describe here our experience in managing a C. auris outbreak lasting more than two and a half years which, despite our efforts in establishing control measures and surveillance, is still ongoing. A total of 287 colonised patients and 47 blood stream infections (candidaemia) have been detected to date. The epidemiology of those patients with candidaemia and the susceptibility of C. auris isolates are also reported. Thirty-five patients with candidaemia (74.5%) were also previously colonised. Forty-three patients (91.5%) were hospitalised (61.7%) or had been hospitalised (29.8%) in the ICU before developing candidaemia. Antifungal therapy for candidaemia consisted of echinocandins in monotherapy or in combination with amphotericin B or isavuconazole. The most common underlying disease was abdominal surgery (29.8%). The thirty-day mortality rate was 23.4% and two cases of endophtalmitis due to C. auris were found. All isolates were resistant to fluconazole and susceptible to echinocandins and amphotericin B. One isolate became resistant to echinocandins two months after the first isolate. Although there are no established clinical breakpoints, minimum inhibitory concentrations for isavuconazole were low (≤ 1 μg/mL).

Invasive Candidiasis Species Distribution and Trends, United States, 2009-2017

BACKGROUND

Invasive candidiasis (IC) is a growing concern among US healthcare facilities. A large-scale study evaluating incidence and trends of IC in the United States by species and body site is needed to understand the distribution of infection.

METHODS

An electronic medical record database was used to calculate incidence and trends of IC in the United States by species and infection site from 2009 through 2017. Hospital incidence was calculated using total unique inpatient hospitalizations in hospitals reporting at least 1 Candida case as the denominator. IC incidence trends were assessed using generalized estimating equations with exchangeable correlation structure to fit Poisson regression models, controlling for changes in hospital characteristics and case mix over time.

RESULTS

Candida albicans remains the leading cause of IC in the United States, followed by Candida glabrata. The overall incidence of IC was 90/100 000 patients, which did not change significantly over time. There were no changes in incidence among C. albicans, C. glabrata, C. parapsilosis, or C. tropicalis; the incidence of other Candida spp. as a whole increased 7.2% annually. While there was no change in candidemia 2009-2017, abdominal and nonabdominal sterile site IC increased significantly.

CONCLUSIONS

Nonbloodstream IC is increasing in the United States. Understanding the epidemiology of IC should facilitate improved management of infected patients.

Roles of Elm1 in antifungal susceptibility and virulence in Candida glabrata

Elm1 is a serine/threonine kinase involved in multiple cellular functions, including cytokinesis, morphogenesis, and drug resistance in Saccharomyces cerevisiae; however, its roles in pathogenic fungi have not been reported. In this study, we created ELM1-deletion, ELM1-reconstituted, ELM1-overexpression, and ELM1-kinase-dead strains in the clinically important fungal pathogen Candida glabrata and investigated the roles of Elm1 in cell morphology, stress response, and virulence. The elm1Δ strain showed elongated morphology and a thicker cell wall, with analyses of cell-wall components revealing that this strain exhibited significantly increased chitin content relative to that in the wild-type and ELM1-overexpression strains. Although the elm1Δ strain exhibited slower growth than the other two strains, as well as increased sensitivity to high temperature and cell-wall-damaging agents, it showed increased virulence in a Galleria mellonella-infection model. Moreover, loss of Elm1 resulted in increased adhesion to agar plates and epithelial cells, which represent important virulence factors in C. glabrata. Furthermore, RNA sequencing revealed that expression levels of 30 adhesion-like genes were elevated in the elm1Δ strain. Importantly, all these functions were mediated by the kinase activity of Elm1. To our knowledge, this is the first report describing the functional characterization of Elm1 in pathogenic fungi.

The life and times of yeasts in traditional food fermentations

Yeasts are eukaryotic microorganisms which have a long history in the biotechnology of food production, as they have been used since centuries in bread-making or in the production of alcoholic beverages such as wines or beers. Relative to this importance, a lot of research has been devoted to the study of yeasts involved in making these important products. The role of yeasts in other fermentations in association with other microorganisms - mainly lactic acid bacteria - has been relatively less studied, and often it is not clear if yeasts occurring in such fermentations are contaminants with no role in the fermentation, spoilage microorganisms or whether they actually serve a technological or functional purpose. Some knowledge is available for yeasts used as starter cultures in fermented raw sausages or in the production of acid curd cheeses. This review aimed to summarize the current knowledge on the taxonomy, the presence and potential functional or technological roles of yeasts in traditional fermented plant, dairy, fish and meat fermentations.

Evolution of fungemia in an Italian region

BACKGROUND

Fungemia represents a public health concern. Knowing aetiology and activity of the antifungals is critical for the management of bloodstream infections. Therefore, surveillance on local/international levels is desirable for a prompt administration of appropriate therapy.

METHODS

Data on fungi responsible for fungemia and antifungal susceptibility profiles were collected from a laboratory-based surveillance over 2016-2017 in 12 hospitals located in Lombardia, Italy. The trend of this infection in twenty years was analysed.

RESULTS

A total of 1024 episodes were evaluated. Rate of candiaemia progressively increased up to 1.46/1000 admissions. C.albicans was the most common species (52%), followed by C. parapsilosis (15%) and C glabrata (13%). As in the previous surveys the antifungal resistance is rare (echinocandins<2%, fluconazole 6%, amphotericin B 0.6%). Fungi other than Candida were responsible for 18 episodes: Cryptococcus neoformans (5 cases), Fusarium spp. (4), Magnusiomyces clavatus (3), Saccharomyces cerevisiae (3), Rhodotorula spp. (2), Exophiala dermatitidis (1). All fungi, except S.cerevisiae, were intrinsically resistant to echinocandins. Some isolates showed also elevated azole MIC.

CONCLUSIONS

No particular changes in terms of species distribution and antifungal susceptibility patterns was noted. However, surveillance programs are needed to monitor trends in antifungal resistance, steer stewardship activities, orient empirical treatment.

Epidemiology and antifungal susceptibility testing of non-albicansCandida species colonizing mucosae of HIV-infected patients in Yaoundé (Cameroon)

Non-albicans Candida (NAC) species have emerged as potent pathogenic yeasts among HIV-infected patients. Authors evaluated the epidemiology and antifungal susceptibility testing of non-albicansCandida species colonizing Yaoundé (capital of the Republic of Cameroon, Central Africa) HIV-infected patients. The mucosal specimens were collected and submitted to the mycological diagnosis. Yeast isolates were identified by the Matrix Assisted Laser Desorption Ionisation - Time of Flight Mass Spectrometry (MALDI-TOF MS). The antifungal susceptibility testing was achieved by the CLSI-M27 protocols, and the interpretation of clinical break points (CBPs) and epidemiological cutoff values were in accordance with the CLSI-M60 and M59 recommendations. Four hundred and two patients were recruited and 1218 samples collected. The colonisation frequency was 24.1% and 304 yeasts isolated. Yeast isolates were 113 (37.2%) C. albicans, 2 (0.7%) C. africana and 172 (56.6%) NAC isolates. The NAC isolates were grouped into 13 species including C. krusei (18.1%), C. glabrata (10.9%), C. tropicalis (8.5%) and C. parapsilosis (5.9%) as the major ones. All the isolates appeared to be wild-type for amphotericin B and itraconazole. One (1/33) isolate of C. glabrata was resistant to fluconazole. C. arapsilosis isolates appeared all susceptible to fluconazole. C. tropicalis isolates presented 50% (13/26) resistance to fluconazole. The achieved results bring out new insights about epidemiology of NAC species in Cameroon. The results also highlight the resistance of NAC species to current antifungal drugs.

The continuous changes in the aetiology and epidemiology of invasive candidiasis: from familiar Candida albicans to multiresistant Candida auris

Recent changes in the aetiology and epidemiology of invasive candidiasis have serious implications for current and future diagnosis, treatment and prognosis. The aim of the current review was to discuss the epidemiology of invasive candidiasis, the distribution of Candida species in different regions of the world, the medical concerns of the changing aetiology and the emergence of antifungal resistance. Overall burden of invasive candidiasis remains high, especially in vulnerable persons, such as the elderly, immunosuppressed or debilitated patients. Moreover, there is a progressive shift in the aetiology of invasive candidiasis from Candida albicans to other species of Candida, probably related to the increased use of azole drugs with a clear trend towards increased antifungal resistance. Finally, the emergence and rise of multiresistant species, such as Candida auris or Candida glabrata, is a major threat making necessary invasive candidiasis worldwide surveillances. These changes have serious implications for the diagnosis, treatment and prognosis of invasive candidiasis. Updated knowledge of the current local epidemiology of invasive candidiasis is critical for the clinical management.