Emerging therapeutics: The imidazo[1,2-b]pyridazine scaffold as a novel drug candidate for eumycetoma, a neglected tropical disease.

Mycetoma is a neglected invasive infection endemic in tropical and subtropical regions, presenting as a chronic subcutaneous inflammatory mass that can spread to deeper structures, leading to deformities, disabilities, and potentially mortality. The current treatment of eumycetoma, the fungal form of mycetoma, involves antifungal agents, such as itraconazole, combined with surgical intervention. However, this approach has limited success, with low cure rates and a high risk of recurrence. This study addresses to the urgent need for more effective therapeutics by designing and synthesising 47 diversely pharmacomodulated imidazo [1,2-b]pyridazine derivatives using a simple synthetic pathway with good yields and purity. Of these, 17 showed promising in vitro activity against Madurella mycetomatis, the prime causative agent of eumycetoma, with IC50 ≤ 5 µM and demonstrated significantly lower cytotoxicity compared to standard treatments in NIH-3T3 fibroblasts. Notably, compound 14d exhibited an excellent activity with an IC50 of 0.9 µM, in the same order then itraconazole (IC50 = 1.1 µM), and achieved a favourable selectivity index of 16 compared to 0.8 for itraconazole. These promising results warrant further research to evaluate the clinical potential of these novel compounds as safer, more effective treatments for eumycetoma, thus addressing a profound gap in current therapeutic strategies.

Description of a Murine Model of Pneumocystis Pneumonia.

Pneumocystis pneumonia is a serious lung infection caused by an original ubiquitous fungus with opportunistic behavior, referred to as Pneumocystis jirovecii. P. jirovecii is the second most common fungal agent among invasive fungal infections after Candida spp. Unfortunately, there is still an inability to culture P. jirovecii in vitro, and so a great impairment to improve knowledge on the pathogenesis of Pneumocystis pneumonia. In this context, animal models have a high value to address complex interplay between Pneumocystis and the components of the host immune system. Here, we propose a protocol for a murine model of Pneumocystis pneumonia. Animals become susceptible to Pneumocystis by acquiring an immunocompromised status induced by iterative administration of steroids within drinking water. Thereafter, the experimental infection is completed by an intranasal challenge with homogenates of mouse lungs containing Pneumocystis murina. The onset of clinical signs occurs within 5 weeks following the infectious challenge and immunosuppression can then be withdrawn. At termination, lungs and bronchoalveolar lavage (BAL) fluids from infected mice are analyzed for fungal load (qPCR) and immune response (flow cytometry and biochemical assays). The model is a useful tool in studies focusing on immune responses initiated after the establishment of Pneumocystis pneumonia.

Deep-seated dermatophytosis caused by Trichophyton rubrum in patient with Becker muscular dystrophy.

Trichophyton rubrum is a common fungal pathogen that usually causes superficial infection limited to epidermis only, so called dermatophytosis. However in immunocompromised patients, dermatophytosis can be exceptionally more invasive with extensive lesions involving deep tissues and generating sometimes systemic course. We report the case of a 43-year-old heart transplanted man, who presented with multiple deep-seated nodules and papules in the inguinal areas and in the buttocks. Involvement of Trichophyton rubrum was confirmed by culture, DNA sequencing and histological examination that showed granulomatous inflammatory infiltrates with the presence of hyphae in the dermis. Antifungal therapy with oral terbinafine for four weeks was successful; in spite of initial remnant atrophic scars, the lesions were completely cleared after four month evolution. Deep-seated invasive dermatophytosis is rare, but should be considered with immunocompromised conditions, especially when history of previous superficial dermatophytosis is present.

Multiplex PCR assay targeting Trichomonas vaginalis: need for biological evaluation and interpretation.

In a retrospective study, we used sequencing to investigate Trichomonas vaginalis-positive specimens (genital, rectal and pharyngeal) with the Allplex™ STI Essential or the Anyplex™-II-STI-7 assays. Our results confirm that majority of T. vaginalis-positive genital and pharyngeal specimens contained T. vaginalis DNA and actually T. tenax DNA, respectively.

Challenges to establish the diagnosis of aspergillosis in non-laboratory animals: looking for alternatives in veterinary medicine and demonstration of feasibility through two concrete examples in penguins and dolphins.

Aspergillosis remains difficult to diagnose in animals. Laboratory-based assays are far less developed than those for human medicine, and only few studies have been completed to validate their utility in routine veterinary diagnostics. To overcome the current limitations, veterinarians and researchers have to propose alternative methods including extrapolating from human diagnostic tools and using innovative technology. In the present overview, two specific examples were complementarily addressed in penguins and dolphins to illustrate how is challenging the diagnosis of aspergillosis in animals. Specific focus will be made on the novel application of simple testing in blood based on serological assays or protein electrophoresis and on the new information garnered from metabolomics/proteomics to discover potential new biomarkers. In conclusion, while the diagnostic approach of aspergillosis in veterinary medicine cannot be directly taken from options developed for human medicine, it can certainly serve as inspiration.

Aspergillosis in a colony of Humboldt penguins (Spheniscus humboldti) under managed care: a clinical and environmental investigation in a French zoological park.

Aspergillosis is pervasive in bird populations, especially those under human care. Its management can be critically impacted by exposure to high levels of conidia and by resistance to azole drugs. The fungal contamination in the environment of a Humboldt penguin (Spheniscus humboldti) group, housed in a French zoological park next to numerous large crop fields, was assessed through three serial sessions of surface sampling in nests, in 2018-20: all isolates were counted and characterized by sequencing. When identified as Aspergillus fumigatus, they were systematically screened for resistance mutations in the cyp51A gene and tested for minimal inhibitory concentrations (MICs) determination. At the same time, the clinical incidence of aspergillosis was evaluated in the penguin population by the means of systematic necropsy and mycological investigations. A microsatellite-based analysis tracked the circulation of A. fumigatus strains. Environmental investigations highlighted the substantial increase of the fungal load during the summer season (>12-fold vs. the other timepoints) and a large overrepresentation of species belonging to the Aspergillus section Fumigati, ranging from 22.7 to 94.6% relative prevalence. Only one cryptic species was detected (A. nishimurae), and one isolate exhibited G138S resistance mutation with elevated MICs. The overall incidence of aspergillosis was measured at ∼3.4% case-years, and mostly in juveniles. The analysis of microsatellite polymorphism revealed a high level of genetic diversity among A. fumigatus clinical isolates. In contrast, one environmental strain appeared largely overrepresented during the summer sampling session. In all, the rural location of the zoo did not influence the emergence of resistant strains.

Pneumocystis Pneumonia: Pitfalls and Hindrances to Establishing a Reliable Animal Model.

Pneumocystis pneumonia is a severe lung infection that occurs primarily in largely immunocompromised patients. Few treatment options exist, and the mortality rate remains substantial. To develop new strategies in the fields of diagnosis and treatment, it appears to be critical to improve the scientific knowledge about the biology of the Pneumocystis agent and the course of the disease. In the absence of in vitro continuous culture system, in vivo animal studies represent a crucial cornerstone for addressing Pneumocystis pneumonia in laboratories. Here, we provide an overview of the animal models of Pneumocystis pneumonia that were reported in the literature over the last 60 years. Overall, this review highlights the great heterogeneity of the variables studied: the choice of the host species and its genetics, the different immunosuppressive regimens to render an animal susceptible, the experimental challenge, and the different validation methods of the model. With this work, the investigator will have the keys to choose pivotal experimental parameters and major technical features that are assumed to likely influence the results according to the question asked. As an example, we propose an animal model to explore the immune response during Pneumocystis pneumonia.

Intricate isavuconazole therapy of a subcutaneous nodule caused by Alternaria infectoria in a heart transplant recipient.

Invasive fungal infections have appeared to be increasingly emergent in immunocompromised patients, especially in solid organ transplant (SOT) recipients. The Alternaria genus encompasses more than 80 dematiaceus species. Among them, Alternaria alternata and Alternaria infectoria are the most frequent isolated as responsible for infection in humans. To our knowledge, we report the first case of a heart transplant recipient suffering from subcutaneous nodule caused by Alternaria infectoria and who was treated with isavuconazole. Despite all the promises of this new azole drug, one should keep in mind the potential great variability of the inter-individual responses for such complex patients. We demonstrate herein how it can be challenging to manage Alternaria infection in SOT recipients. More comprehensive studies and recommendations are expected in the context of Alternaria infections.

Health threat caused by fungi of medical interest: where are we in 2021?

No abstract present.

Demonstration of the yeasticidal efficacy of povidone-iodine-based commercial antiseptic solutions against Candida auris.

Candida auris is an emerging yeast pathogen with worldwide distribution and a great propensity for nosocomial spread. Recent reports have warned of the significant emergence of C. auris in several healthcare facilities. In order to stop its nosocomial transmission, use of antiseptics constitutes the first-line lever of action in the fighting against C. auris skin colonization. However, little is known about the efficacy of these products, and moreover no antiseptics are currently registered for use against C. auris. This study investigated the in vitro yeasticidal activity of povidone-iodine against C. auris, and compared the findings to C. albicans and C. glabrata, according to the EN standard 1275:2005. Results support the use of such commercial antiseptics in the context of colonization with this yeast.

Therapeutic Antibodies for the Treatment of Respiratory Tract Infections-Current Overview and Perspectives.

Respiratorytract infections (RTIs) are frequent and life-threatening diseases, accounting for several millions of deaths worldwide. RTIs implicate microorganisms, including viruses (influenza virus, coronavirus, respiratory syncytial virus (RSV)), bacteria (Pseudomonas aeruginosa, Streptococcus pneumoniae, Staphylococcus aureus and Bacillus anthracis) and fungi (Pneumocystis spp., Aspergillus spp. and very occasionally Candida spp.). The emergence of new pathogens, like the coronavirus SARS-CoV-2, and the substantial increase in drug resistance have highlighted the critical necessity to develop novel anti-infective molecules. In this context, antibodies (Abs) are becoming increasingly important in respiratory medicine and may fulfill the unmet medical needs of RTIs. However, development of Abs for treating infectious diseases is less advanced than for cancer and inflammatory diseases. Currently, only three Abs have been marketed for RTIs, namely, against pulmonary anthrax and RSV infection, while several clinical and preclinical studies are in progress. This article gives an overview of the advances in the use of Abs for the treatment of RTIs, based on the analysis of clinical studies in this field. It describes the Ab structure, function and pharmacokinetics, and discusses the opportunities offered by the various Ab formats, Ab engineering and co-treatment strategies. Including the most recent literature, it finally highlights the strengths, weaknesses and likely future trends of a novel anti-RTI Ab armamentarium.

Contribution of a molecular test for the diagnosis of genital infection with Trichomonas vaginalis and Mycoplasma genitalium.

In the present study, we assessed a recently-marketed molecular test, the S-DiaMGTV™ kit (Diagenode), which provides simultaneous detection of Mycoplasma genitalium and Trichomonas vaginalis in urogenital samples. Performance characteristics of the S-DiaMGTV™ kit were compared to an in-house PCR for detection of M. genitalium and, for first time, with direct observation of genital secretions in wet mounting microscopy for T. vaginalis, a routine laboratory method. For M. genitalium, out of 66 samples, two negative with the in-house PCR were found positive with the S-DiaMGTV™ kit and two positive with the in-house PCR were found negative with the kit. For T. vaginalis, four samples were found positive by the molecular test. Among them, two were previously tested by the wet mounting observation and only one was positive. The kit allows an increase of T. vaginalis detection even in a low incidence country. Performances of the kit are in favor of its use in routine laboratory practice.

Combination of ß-(1, 3)-D-glucan testing in serum and qPCR in nasopharyngeal aspirate for facilitated diagnosis of Pneumocystis jirovecii pneumonia.

BACKGROUND: Currently, the biological diagnosis of Pneumocystis jirovecii pneumonia (PjP infection) usually relies on microbiological investigations in bronchial-alveolar lavage fluid (BALF) by conventional staining methods and/or molecular biology. However, bronchial-alveolar lavage is sometimes complicated to manage, especially in weakened patients. Therefore, alternative clinical samples-easier to collect-are warranted in such specific contexts. OBJECTIVE: Over a four-year period, diagnostic performance of an original method based on combination of quantitative real-time polymerase chain reaction (qPCR) in nasopharyngeal aspirate (NPA) with measurement of ß-(1, 3)-D-glucan antigen (BDG) in serum was prospectively assessed in a single centre. PATIENTS/METHODS: Results were compared with those obtained in BALF through direct staining methods and qPCR. True positives were defined by an independent committee based on clinical, radiological and biological data. Overall, 48 individuals with a definitive diagnosis of PjP infection were included, and 48 controls were selected upon matching for age, sex and underlying disease(s). RESULTS: qPCR results were strongly correlated between BALF and NPA (P < .0001). Altogether, greater diagnostic performance was achieved when establishing the positive cut-off of BDG antigen at 143 pg/mL. In such conditions, sensitivity of the testing based on either positive BDG measurement or positive qPCR in NPA was then calculated at 93.75%, 95% CI [82.37%-98.40%], and specificity at 97.87%, 95% CI [87.66%-100.00%]. CONCLUSIONS: Further validation through multicentre studies is now required, especially for establishing clear cut-offs. However, one could already state that combination of qPCR in the NPA with BDG measurement in serum may be a valuable substitute for BALF examination.

Targeting Aspergillus fumigatus Crf Transglycosylases With Neutralizing Antibody Is Relevant but Not Sufficient to Erase Fungal Burden in a Neutropenic Rat Model.

Aspergillus fumigatus is an airborne opportunistic fungal pathogen responsible for severe infections. Among them, invasive pulmonary aspergillosis has become a major concern as mortality rates exceed 50% in immunocompromised hosts. In parallel, allergic bronchopulmonary aspergillosis frequently encountered in cystic fibrosis patients, is also a comorbidity factor. Current treatments suffer from high toxicity which prevents their use in weakened subjects, resulting in impaired prognostic. Because of their low toxicity and high specificity, anti-infectious therapeutic antibodies could be a new alternative to conventional therapeutics. In this study, we investigated the potential of Chitin Ring Formation cell wall transglycosylases of A. fumigatus to be therapeutic targets for therapeutic antibodies. We demonstrated that the Crf target was highly conserved, regardless of the pathophysiological context; whereas the CRF1 gene was found to be 100% conserved in 92% of the isolates studied, Crf proteins were expressed in 98% of the strains. In addition, we highlighted the role of Crf proteins in fungal growth, using a deletion mutant for CRF1 gene, for which a growth decrease of 23.6% was observed after 48 h. It was demonstrated that anti-Crf antibodies neutralized the enzymatic activity of recombinant Crf protein, and delayed fungal growth by 12.3% in vitro when added to spores. In a neutropenic rat model of invasive pulmonary aspergillosis, anti-Crf antibodies elicited a significant recruitment of neutrophils, macrophages and T CD4 lymphocytes but it was not correlated with a decrease of fungal burden in lungs and improvement in survival. Overall, our study highlighted the potential relevance of targeting Crf cell wall protein (CWP) with therapeutic antibodies.

Discordance in the minimal inhibitory concentrations of ertapenem for Enterobacter cloacae: Vitek 2 system versus Etest and agar dilution methods.

Our objective was to compare the ertapenem minimal inhibitory concentrations (MICs) for Enterobacter cloacae isolates categorized intermediate or resistant to ertapenem when measured with the Vitek 2 system, with the MICs for these isolates when measured by two methods performed in agar medium: the Etest and agar plate dilution method (APDM). Overall, 50 E. cloacae isolates were included in the study. The mean MIC of ertapenem was 2.92±1.77µg/ml according to the Vitek 2 system, 0.94±0.84µg/ml according to the Etest strips, and 0.93±0.62µg/ml according to the APDM. Furthermore, the MICs determined by the Vitek 2 system were higher than the MICs determined by the two other methods for 96% of strains. Lastly, according to the Etest strips and APDM, 42% of E. cloacae were susceptible to ertapenem. No carbapenemase was identified by the screening method used. Using the Vitek 2 system to determine ertapenem MICs for E. cloacae can have potential consequences in terms of additional carbapenemase-detecting tests and antimicrobial therapy. It would be interesting to determine if the Vitek 2 system is more effective for the detection of carbapenemase producers with low-level carbapenem resistance than the two methods performed in agar medium.