Potential Fungal Zoonotic Pathogens in Cetaceans: An Emerging Concern.

Over 60% of emerging infectious diseases in humans are zoonotic, often originating from wild animals. This long-standing ecological phenomenon has accelerated due to human-induced environmental changes. Recent data show a significant increase in fungal infections, with 6.5 million cases annually leading to 3.7 million deaths, indicating their growing impact on global health. Despite the vast diversity of fungal species, only a few are known to infect humans and marine mammals. Fungal zoonoses, especially those involving marine mammals like cetaceans, are of global public health concern. Increased human-cetacean interactions, in both professional and recreational settings, pose risks for zoonotic disease transmission. This review focuses on the epidemiology, clinical manifestations, and zoonotic potential of major fungal pathogens shared in humans and cetaceans, highlighting their interspecies transmission capability and the challenges posed by antifungal resistance and environmental changes. It underscores the need for enhanced awareness and preventative measures in high-risk settings to protect public health and marine ecosystems.

Is Candida auris the first multidrug-resistant fungal zoonosis emerging from climate change?

The emergence and evolutionary path of Candida auris poses an intriguing scientific enigma. Its isolation from a pet dog's oral cavity in Kansas, reported by White et al. (T. C. White, B. D. Esquivel, E. M. Rouse Salcido, A. M. Schweiker, et al., mBio 15:e03080-23, 2024, https://doi.org/10.1128/mbio.03080-23), carries significant implications. This discovery intensifies concerns about its hypothetical capacity for zoonotic transmission, particularly considering the dog's extensive human contact and the absence of secondary animal/human cases in both animals and humans. The findings challenge established notions of C. auris transmissibility and underscore the need for further investigation into the transmission dynamics, especially zooanthroponotic pathways. It raises concerns about its adaptability in different hosts and environments, highlighting potential role of environmental and animal reservoirs in its dissemination. Critical points include the evolving thermal tolerance and the genetic divergence in the isolate. This case exemplifies the necessity for an integrated One Health approach, combining human, animal, and environmental health perspectives, to unravel the complexities of C. auris's emergence and behavior.

The Ecology of Non-Candida Yeasts and Dimorphic Fungi in Cetaceans: From Pathogenicity to Environmental and Global Health Implications.

Cetaceans, which are integral to marine ecosystems, face escalating anthropogenic threats, including climate change and pollution, positioning them as critical sentinel species for ocean and human health. This review explores the neglected realm of non-Candida yeasts in cetaceans, addressing the gaps in the understanding of their prevalence, pathogenicity, and environmental impacts. By examining identified species such as Cryptococcus spp., Paracoccidioides spp., and several dimorphic fungi, this review emphasizes global prevalence, epidemiology and ecology, pathogenicity, and potential zoonotic implications. It also discusses the fine line between yeast commensalism and pathogenicity by considering environmental influences such as pollution, climate shifts, and immune suppression. Environmental impact discussions delve into how rising ocean temperatures and pollution can modify yeast mycobiota, potentially affecting marine host health and broader ecosystem dynamics. The cetacean's unique physiology and ecological niches are considered, highlighting potential impacts on behaviors, reproductive success, and survival rates. Identifying crucial knowledge gaps, the review calls for intensified research efforts, employing advanced molecular techniques to unravel the cetacean mycobiome. Systematic studies on yeast diversity, antifungal susceptibility, and their influence on environmental and ecosystem health are proposed, and the balance between commensal and pathogenic species emphasizes the significance of the One Health approach. In conclusion, as marine mammals face unprecedented challenges, unveiling non-Candida yeasts in cetaceans emerges as a critical endeavor with far-reaching implications for the conservation of marine ecosystems and for both animal and human public health.

Dysimmunity in common variable immunodeficiency is associated with alterations in oral, respiratory, and intestinal microbiota.

Common variable immunodeficiency (CVID) is the most common symptomatic primary immunodeficiency characterized by decreased immunoglobulins and recurrent infections. Its aetiology remains unknown, and some patients present with severe non-infectious autoimmune or inflammatory complications with elevated associated morbimortality. Recently, intestinal dysbiosis has been proposed as a driver of immune dysregulation. In this study, we assessed the oral, respiratory, and gastrointestinal microbiota of 41 CVID patients (24 with dysimmune and 17 with infection complications) and 15 healthy volunteers using 16S rRNA gene sequencing to explore associations between microbiome profiles and CVID phenotypes. Profound differences in the composition of the microbiota in saliva, sputum, and stool were detected between dysimmune CVID patients and healthy individuals. Globally, respiratory species diversity and faecal bacterial richness were lower in CVID individuals with immune complications. Although a single species could not be identified as a robust predictor of dysimmunity, a combination of around 5-7 bacterial species in each type of sample could predict this severe phenotype with an accuracy of around 90% in the study population. Our study provides new insights into these previously unexplored but highly interrelated ecological niches among themselves and with patient profiles. Our data suggest that this disease-related systemic dysbiosis could be implicated in the immune dysregulation associated with severe cases of CVID.

Nanoemulsion Increases the Antifungal Activity of Amphotericin B against Four Candida auris Clades: In Vitro and In Vivo Assays.

Candida auris is an emerging yeast of worldwide interest due to its antifungal resistance and mortality rates. The aim of this study was to analyse the in vitro and in vivo antifungal activity of a nanoemulsion loaded with amphotericin B (NEA) against planktonic cells and biofilm of C. auris clinical isolates belonging to four different clades. In vivo assays were performed using the Galleria mellonella model to analyse antifungal activity and histopathological changes. The in vitro results showed that NEA exhibited better antifungal activity than free amphotericin B (AmB) in both planktonic and sessile cells, with >31% inhibition of mature biofilm. In the in vivo assays, NEA demonstrated superior antifungal activity in both haemolymph and tissue. NEA reduced the fungal load in the haemolymph more rapidly and with more activity in the first 24 h after infection. The histological analysis of infected larvae revealed clusters of yeast, immune cells, melanisation, and granulomas. In conclusion, NEA significantly improved the in vitro and in vivo antifungal activity of AmB and could be considered a promising therapy for C. auris infections.

Climate change, animals, and Candida auris: insights into the ecological niche of a new species from a One Health approach.

BACKGROUND: One of the most puzzling traits of Candida auris is the recent simultaneous and independent emergence of five genetically distinct clades on three continents. Global warming has been proposed as a contributing factor for this emergence owing to high thermotolerance of C. auris compared with phylogenetically close Candida species. This hypothesis postulates that climate change induced an environmental ancestor to become pathogenic through thermal adaptation and was then globally disseminated by an intermediate host. OBJECTIVES: The aim of this review is to compile the current knowledge on the emergence and ecological environmental niches of C. auris and highlight the potential role of animals in transmission. SOURCES: A literature search was conducted using PubMed, MEDLINE, Google Scholar, and Web of Science from May 2022 to January 2023. CONTENT: We discuss the up-to-date data on the ecological niches of this fungus and its mechanisms of emergence, transmission cycle in nature, and worldwide dissemination. We highlight the possibility of an originally intermediate host possibly related to marine or freshwater ecosystems on the basis of recent molecular and microbiological evidence from a One Health perspective. The consequences of harmful human impact on the environment in the rise of new fungal pathogenic species, such as C. auris, are also analysed and compared with other animal precedents. IMPLICATIONS: The present knowledge can prompt the generation of new evidence on the ecological reservoirs of C. auris and its original mechanisms of environmental or interspecies transmission. Further research on the highlighted gaps will help understand the importance of the relationships between human, animal, and ecosystem health as factors involved in the rise and spread of emerging fungal pathogenic species.

Usefulness of Chromogenic Media with Fluconazole Supplementation for Presumptive Identification of Candida auris.

Introduction:Candida auris is a major threat to public health. Rapid detection is essential for early treatment and transmission control. The use of chromogenic media allows the presumptive identification of this new species. The aim of this study is to describe the morphological characteristics of C. auris colonies on three commercial chromogenic media. Methods: Nineteen C. auris isolates from different countries/clades and 18 isolates of other species were cultivated in CHROMagarTM Candida Plus, HiCromeTM Candida, CHROMagar-Candida, and fluconazole-supplemented (32 mg/L) CHROMagar-Candida media. Results: On CHROMagarTM Candida Plus and HiCromeTM Candida, C. auris isolates from Colombia, Venezuela, India, Korea, and Japan displayed blue-shaded colonies, while isolates from Spain and Germany exhibited light pink shades with a bluish halo. All isolates showed white to pink colonies on CHROMagar-Candida. On CHROMagar Candida supplemented with fluconazole, whilst C. auris, C. glabrata, or C. krusei showed a similar pink color at 48 h incubation, phenotypic differentiation was possible by the rough, paraffin-like texture or the intense purple color acquired by C. krusei and C. glabrata, respectively. Moreover, in this medium, the presence of C. auris in combination with other species of similar color was not limiting for its early identification, due to this medium selecting only strains resistant to this antifungal. Conclusions: The use of chromogenic media such as CHROMagarTM Candida Plus facilitates a presumptive identification of C. auris. However, this identification can be difficult in the presence of mixed cultures. In these cases, the use of CHROMagarTM Candida medium with 32 mg/L fluconazole offers better performance for the identification of C. auris by inhibiting fluconazole-susceptible strains and selecting rare or high fluconazole MIC (>32 mg/L) isolates.

Current clinical spectrum of common variable immunodeficiency in Spain: The multicentric nationwide GTEM-SEMI-CVID registry.

Common variable immunodeficiency (CVID) constitutes a heterogenic group of primary immunodeficiency disorders with a wide-ranging clinical spectrum. CVID-associated non-infectious morbidity constitutes a major challenge requiring a full understanding of its pathophysiology and its clinical importance and global variability, especially considering the broad clinical, genetic, and regional heterogeneity of CVID disorders. This work aimed to develop a nationwide, multicenter, retrospective study over a 3-year period describing epidemiological, clinical, laboratory, therapeutic, and prognostic features of 250 CVID patients in Spain. The mean diagnostic delay was around 10 years and most patients initially presented with infectious complications followed by non-infectious immune disorders. However, infectious diseases were not the main cause of morbimortality. Non-infectious lung disease was extraordinarily frequent in our registry affecting approximately 60% of the patients. More than one-third of the patients in our cohort showed lymphadenopathies and splenomegaly in their follow-up, and more than 33% presented immune cytopenias, especially Evans' syndrome. Gastrointestinal disease was observed in more than 40% of the patients. Among biopsied organs in our cohort, benign lymphoproliferation was the principal histopathological alteration. Reaching 15.26%, the global prevalence of cancer in our registry was one of the highest reported to date, with non-Hodgkin B lymphoma being the most frequent. These data emphasize the importance of basic and translational research delving into the pathophysiological pathways involved in immune dysregulation and diffuse lymphocytic infiltration. This would reveal new tailored strategies to reduce immune complications, and the associated healthcare burden, and ensure a better quality of life for CVID patients.

Norovirus infection as a model of chronic or recurrent infection in common variable immunodeficiency

Common variable immunodeficiency (CVID) is the most frequent symptomatic primary immunodeficiency (PID) in general population. PID are genetic diseases that share a dysfunction in the immune system entailing a greater risk of both chronic and recurrent infections. These patients can also develop chronic gastrointestinal infections caused by norovirus with persistent viral dissemination, which can be detect ed months after primoinfection. Additionally, a proportion of CVID patients show a typical severe enteropathy presenting with recurrent diarrhoea, intestinal malabsorption, inflammatory lesions, and villous atrophy. Some studies have related this enteropathy with chronic intestinal infection caused by norovirus. (AU)

Current management of CMV infection in cancer patients (solid tumors). Epidemiology and therapeutic strategies

Little evidence is available regarding the incidence of CMV disease in patients with solid cancers. Latest data show that approximately 50 % of these patients with CMV PCR positivity developed clinically relevant CMV-viremia, and would require specific therapy. In the clinical arena, CMV reactivation is an important differential diagnosis in the infectological work up of these patients, but guidelines of management on this subject are not yet available. CMV reactivation should be considered during differential diagnosis for patients with a severe decline in lymphocyte counts when receiving chemoradiotherapy or immunochemotherapy with lymphocyte-depleting or blocking agents. Monitoring of CMV reactivation followed by the implementation of preemptive strategies or the establishment of early antiviral treatment improves the prognosis and reduces the morbidity and mortality of these patients. (AU)

Resistance to beta-lactams in Gram-negative bacilli: relevance and potential therapeutic alternatives

The indiscriminate and massive antibiotic use in the clinical practice and in agriculture or cattle during the past few decades has produced a serious world health problem that entails high morbidity and mortality: the antibiotic multi-drug resistance. In 2017 and 2019, the World Health Organization published a list of urgent threats and priorities in the context of drug resistance, which only included Gram-negative bacteria and specially focused on carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa, as well as carbapenem and third generation cephalosporin-resistant Enterobacteriaceae. This scenario emphasizes the need of developing and testing new antibiotics from different families, such as new beta-lactams, highlighting cefiderocol and its original mechanism of action; new beta-lactamase inhibitors, with vaborbactam or relebactam among others; new quinolones such as delafloxacin, and also omadacycline or eravacycline, as members of the tetracycline family. The present work reviews the importance and impact of Gram-negative bacterial infections and their resistance mechanisms, and analyzes the current therapeutic paradigm as well as the role of new antibiotics with a promising future in the era of multi and pan-drug resistance. (AU)

Etiology, diagnosis, and management of pneumonia in immunosuppressed patients

Patients with a compromised immune system suffer awide variety of insults. Pulmonary complications remain amajor cause of both morbidity and mortality in immunocompromised patients. When such individuals present with radiographic infiltrates, the clinician faces a diagnostic challenge.The differential diagnosis in this setting is broad and includesboth infectious and non-infectious conditions. Evaluation ofthe immunocompromised host with diffuse pulmonary infiltrates can be difficult, frustrating, and time-consuming. Thiscommon and serious problem results in significant morbidityand mortality, approaching 90%. Infections are the most common causes of both acute and chronic lung diseases leading torespiratory failure. Non-invasive diagnostic methods for evaluation are often of little value, and an invasive procedure (suchas bronchoalveolar lavage, transbronchial biopsy or even openlung biopsy) is therefore performed to obtain a microbiologicand histologic diagnosis. Bronchoscopy allows certain identification of some aetiologies, and often allows the exclusion ofinfectious agents. Early use of computed tomography scanning is able to demonstrate lesions missed by conventionalchest X-ray. However, even when a specific diagnosis is made,it might not impact patient’s overall survival and outcomes (AU)

Integrating Clinics, Laboratory, and Imaging for the Diagnosis of Common Variable Immunodeficiency-Related Granulomatous-Lymphocytic Interstitial Lung Disease.

Background: Granulomatous-lymphocytic interstitial lung disease (GLILD) is a distinct clinic-radio-pathological interstitial lung disease (ILD) that develops in 9% to 30% of patients with common variable immunodeficiency (CVID). Often related to extrapulmonary dysimmune disorders, it is associated with long-term lung damage and poorer clinical outcomes. The aim of this study was to explore the potential use of the integration between clinical parameters, laboratory variables, and developed CT scan scoring systems to improve the diagnostic accuracy of non-invasive tools. Methods: A retrospective cross-sectional study of 50 CVID patients was conducted in a referral unit of primary immune deficiencies. Clinical variables including demographics and comorbidities; analytical parameters including immunoglobulin levels, lipid metabolism, and lymphocyte subpopulations; and radiological and lung function test parameters were collected. Baumann's GLILD score system was externally validated by two observers in high-resolution CT (HRCT) scans. We developed an exploratory predictive model by elastic net and Bayesian regression, assessed its discriminative capacity, and internally validated it using bootstrap resampling. Results: Lymphadenopathies (adjusted OR 9.42), splenomegaly (adjusted OR 6.25), Baumann's GLILD score (adjusted OR 1.56), and CD8+ cell count (adjusted OR 0.9) were included in the model. The larger range of values of the validated Baumann's GLILD HRCT scoring system gives it greater predictability. Cohen's κ statistic was 0.832 (95% CI 0.70-0.90), showing high concordance between both observers. The combined model showed a very good discrimination capacity with an internally validated area under the curve (AUC) of 0.969. Conclusion: Models integrating clinics, laboratory, and CT scan scoring methods may improve the accuracy of non-invasive diagnosis of GLILD and might even preclude aggressive diagnostic tools such as lung biopsy in selected patients.

Host-pathogen interactions upon Candida auris infection: fungal behaviour and immune response in Galleria mellonella.

Candida auris has globally emerged as a multidrug-resistant fungus linked to healthcare-associated outbreaks. There is still limited evidence on its virulence, pathogenicity determinants, and complex host-pathogen interactions. This study analyzes the in vivo fungal behaviour, immune response, and host-pathogen interactions upon C. auris infection compared to C. albicans and C. parapsilosis in G. mellonella. This was performed by immunolabelling fungal structures and larval plasmatocytes and using a quantitative approach incorporating bioinformatic morphometric techniques into the study of microbial pathogenesis. C. auris presents a remarkably higher immunogenic activity than expected at its moderate degree of tissue invasion. It induces a greater inflammatory response than C. albicans and C. parapsilosis at the expense of plasmatocyte nodule formation, especially in non-aggregative strains. It specifically invades the larval respiratory system, in a pattern not previously observed in other Candida species, and presents inter-phenotypic tissue tropism differences. C. auris filaments in vivo less frequently than C. albicans or C. parapsilosis mostly through pseudohyphal growth. Filamentation might not be a major pathogenic determinant in C. auris, as less virulent aggregative phenotypes form pseudohyphae to a greater extent. C. auris has important both interspecific and intraspecific virulence and phenotype heterogeneity, with aggregative phenotypes of C. auris sharing characteristics with low pathogenic species such as C. parapsilosis. Our work suggests that C. auris owns an important morphogenetic plasticity that distinguishes it from other yeasts of the genus. Routine phenotypic identification of aggregative or non-aggregative phenotypes should be performed in the clinical setting as it may impact patient management.

Ten-year Spanish cohort of diving-related injuries in a non-hyperbaric tertiary hospital on the Spanish Mediterranean coast.

INTRODUCTION: Global evidence on the epidemiology of prevalent diving-related injuries (DRI) different from decompression sickness (DCS) and other fatalities is lacking. This study aimed to perform a comprehensive review of DRIs in the year-period between 2010-2020 in a non-hyperbaric tertiary hospital in the Spanish Mediterranean coast, in addition to identifying patient risk factors for severe middle ear barotrauma. METHODS: The study was conducted via a retrospective review of medical records during a 10-year period (2010-2020) at the University and Polytechnic Hospital La Fe (UPHLF) of Valencia. We performed a case-control study recruiting controls through an online survey to identify independent predictors for severe middle ear barotrauma. RESULTS: A total of 68 patients with DRI attended the emergency department of our tertiary referral hospital. Barotrauma accounted for more than 80% of DRI, followed by unrecognized DCS and animal-related injuries. Most patients required neither hospital admission nor surgery; appropriate treatment could be carried out largely on an outpatient basis. The presence of subsequent sequelae was minimal. Previous presence of significant ear, nose and throat (ENT) comorbidities (OR 3.05 - CI 95% 1.11 - 8.35), and older age (OR of younger age 0.94 - CI 95% 0.91 - 0.98) were identified as independent risk factors for severe middle ear barotrauma, with an acceptable discrimination capacity (AUC 0.793, 95% CI 0.71 - 0.87). CONCLUSION: The incidence of DRI may be higher than previously thought, and the need to know their epidemiology, their associated morbidity, and the deficiencies of the diving management system is becoming steadily important in order to develop prevention, diagnostic and therapeutic protocols in non-hyperbaric hospitals of these regions.

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

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

Prospective cohort study on hospitalised patients with suspected urinary tract infection and risk factors por multidrug resistance.

Urinary tract infections (UTIs) are among the most common bacterial infections and a frequent cause for hospitalization in the elderly. The aim of our study was to analyse epidemiological, microbiological, therapeutic, and prognostic of elderly hospitalised patients with and to determine independent risk factors for multidrug resistance and its outcome implications. A single-centre observational prospective cohort analysis of 163 adult patients hospitalized for suspected symptomatic UTI in the Departments of Internal Medicine, Infectious Diseases and Short-Stay Medical Unit of a tertiary hospital was conducted. Most patients currently admitted to hospital for UTI are elderly and usually present high comorbidity and severe dependence. More than 55% met sepsis criteria but presented with atypical symptoms. Usual risk factors for multidrug resistant pathogens were frequent. Almost one out of five patients had been hospitalized in the 90 days prior to the current admission and over 40% of patients had been treated with antibiotic in the previous 90 days. Infection by MDR bacteria was independently associated with the previous stay in nursing homes or long-term care facilities (LTCF) (OR 5.8, 95% CI 1.17-29.00), permanent bladder catheter (OR 3.55, 95% CI 1.00-12.50) and urinary incontinence (OR 2.63, 95% CI 1.04-6.68). The degree of dependence and comorbidity, female sex, obesity, and bacteraemia were independent predictors of longer hospital stay. The epidemiology and presentation of UTIs requiring hospitalisation is changing over time. Attention should be paid to improve management of urinary incontinence, judicious catheterisation, and antibiotic therapy.

Characterization of the Differential Pathogenicity of Candida auris in a Galleria mellonella Infection Model.

Candida auris is an emergent multidrug-resistant fungal pathogen considered a severe global threat due to its capacity to cause nosocomial outbreaks and deep-seated infections with high transmissibility and mortality. However, evidence on its pathogenicity and the complex host-pathogen interactions is still limited. This study used the in vivo invertebrate model in Galleria mellonella to assess its virulence, exploring the mortality kinetics, melanization response, and morphological changes after fungal infection compared to Candida albicans and Candida parapsilosis, with known high and low pathogenicity, respectively. All C. auris isolates presented less virulence than C. albicans strains but higher than that induced by C. parapsilosis isolates. Increased pathogenicity was observed in nonaggregative phenotypes of C. auris, while the melanization response of the larvae to fungal infection was homogeneous and independent of the causing species. C. auris was able to filament in the in vivo animal model G. mellonella, with aggregative and nonaggregative phenotypes presenting various pseudohyphal formation degrees as pathogenicity determinants in a strain-dependent manner. Histological invasiveness of C. auris mimicked that observed for C. albicans, with effective dissemination since the early stages of infection both in yeast and filamented forms, except for a remarkable respiratory tropism not previously observed in other yeasts. These characteristics widely differ between strains and advocate the hypothesis that the morphogenetic variability of C. auris is an indicator of its flexibility and adaptability, contributing to its emergence and rising worldwide prevalence. IMPORTANCE Candida auris is an emergent fungus that has become a global threat due to its multidrug resistance, mortality, and transmissibility. These unique features make it different from other Candida species, but we still do not fully know the degree of virulence and, especially, the host-pathogen interactions. In this in vivo insect model, we found that it presents an intermediate degree of virulence compared to known high- and low-virulence Candida species but with significant variability between aggregative and nonaggregative strains. Although it was previously considered unable to filament, we documented in vivo filamentation as an important pathogenic determinant. We also found that it is able to disseminate early through the host, invading both the circulatory system and many different tissues with a remarkable respiratory tropism not previously described for other yeasts. Our study provides new insights into the pathogenicity of an emergent fungal pathogen and its interaction with the host and supports the hypothesis that its morphogenetic variability contributes to its rising global prevalence.