New Approaches for Cryptococcosis Treatment

Untargeted metabolomics-based identification of bioactive compounds from Mangifera indica L. seed extracts in drug discovery through molecular docking and assessment of their anticancer potential

BACKGROUND

Mangifera indica L. (mango), a medicinal plant rich in biologically active compounds, has potential to be used in disease-preventing and health-promoting products. The present investigation reveals and uncovers bioactive metabolites with remarkable therapeutic efficiency from mango (family: Anacardiaceae) seeds.

RESULTS

Biological activity was determined by antimicrobial, antioxidant and anticancer assays, and metabolite profiling was performed on gas chromatography coupled to quadrupole time-of-flight mass spectrometry (GC-QTOF-MS) and liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) platforms. Validation of active metabolites was carried out by in silico molecular docking (Molinspiration Cheminformatics Server and PASS). Extracted and identified metabolites were screened; 54 compounds associated with various groups were selected for the in silico interaction study.

CONCLUSIONS

Molecular docking revealed lead molecules with a potential binding energy score, efficacy and stable modulation with a selected protein domain. Investigation, directed by in vitro and in silico analysis, confirms mango seeds as an excellent source of potential metabolites as a therapeutic agent. © 2024 Society of Chemical Industry.

Novel combinatorial approach: Harnessing HIV protease inhibitors to enhance amphotericin B's antifungal efficacy in cryptococcosis

Cryptococcosis is a fungal infection that is becoming increasingly prevalent worldwide, particularly among individuals with compromised immune systems, such as HIV patients. Amphotericin B (AmB) is the first-line treatment mainly combined with flucytosine. The scarcity and the prohibitive cost of this regimen urge the use of fluconazole as an alternative, leading to increased rates of treatment failure and relapses. Therefore, there is a critical need for efficient and cost-effective therapy to enhance the efficacy of AmB. In this study, we evaluated the efficacy of the HIV protease inhibitors (PIs) to synergize the activity of AmB in the treatment of cryptococcosis. Five PIs (ritonavir, atazanavir, saquinavir, lopinavir, and nelfinavir) were found to synergistically potentiate the killing activity of AmB against Cryptococcus strains with ƩFICI ranging between 0.09 and 0.5 against 20 clinical isolates. This synergistic activity was further confirmed in a time-kill assay, where different AmB/PIs combinations exhibited fungicidal activity within 24 hrs. Additionally, PIs in combination with AmB exhibited an extended post-antifungal effect on treated cryptococcal cells for approximately 10 hrs compared to 4 hours with AmB alone. This promising activity against cryptococcal cells did not exhibit increased cytotoxicity towards treated kidney cells, ruling out the risk of drug combination-induced nephrotoxicity. Finally, we evaluated the efficacy of AmB/PIs combinations in the Caenorhabditis elegans model of cryptococcosis, where these combinations significantly reduced the fungal burden of the treated nematodes by approximately 2.44 Log10 CFU (92.4%) compared to the untreated worms and 1.40 Log10 ((39.4%) compared to AmB alone. The cost-effectiveness and accessibility of PIs in resource-limited geographical areas compared to other antifungal agents, such as flucytosine, make them an appealing choice for combination therapy.

Elucidation of furanone as ergosterol pathway inhibitor in Cryptococcus neoformans

In the era of antiretroviral therapy, the prevalence of Cryptococcal infection among HIV patients in developed countries has decreased considerably. However, C. neoformans ranks top among the critical priority pathogen that affects a wide range of immunocompromised individuals. The threat of C. neoformans is because of its incredibly multifaceted intracellular survival capabilities. Cell membrane sterols especially ergosterol and enzymes of its biosynthetic pathway are considered fascinating drug targets because of their structural stability. In this study, the ergosterol biosynthetic enzymes were modeled and docked with furanone derivatives. Among the tested ligands Compound 6 has shown a potential interaction with Lanosterol 14 α-demethylase. This best-docked protein-ligand complex was taken further to molecular dynamics simulation. In addition, Compound 6 was synthesized and an in vitro study was conducted to quantify the ergosterol in Compound 6 treated cells. Altogether the computational and in vitro study demonstrates that Compound 6 has anticryptococcal activity by targeting the biosynthetic pathway of ergosterol.Communicated by Ramaswamy H. Sarma.

Enhancing oral bioavailability of an antifungal thiazolylhydrazone derivative: Development and characterization of a self-emulsifying drug delivery system

RN104 (2-[2-(cyclohexylmethylene)hydrazinyl)]-4-phenylthiazole) is a thiazolylhydrazone derivative with prominent antifungal activity. This work aimed to develop a self-emulsifying drug delivery system (SEDDS) loaded with RN104 to improve its biopharmaceutical properties and enhance its oral bioavailability. Medium chain triglycerides, sorbitan monooleate, and polysorbate 80 were selected as components for the SEDDS formulation based on solubility determination and a pseudo-ternary phase diagram. The formulation was optimized using the central composite design in response surface methodology. The optimized condition consisted of medium chain triglycerides, sorbitan monooleate, and polysorbate 80 in a mass ratio of 65.5:23.0:11.5, achieving maximum drug loading (10 mg/mL) and minimum particle size (118.4 ± 0.7 nm). The developed RN104-SEDDS was fully characterized using dynamic light scattering, in vitro release studies, stability assessments, polarized light microscopy, and transmission electron microscopy. In vivo pharmacokinetic studies in mice demonstrated that RN104-SEDDS significantly improved oral bioavailability compared to free RN104 (the relative bioavailability was 2133 %). These results clearly indicated the successful application of SEDDS to improve the pharmacokinetic profile and to enhance the oral bioavailability of RN104, substantiating its potential as a promising antifungal drug candidate.

Once-Weekly Liposomal Amphotericin B Use for Maintenance and Consolidation Phase Treatment of Cryptococcal Meningitis in Patients With AIDS

Cryptococcal meningitis should be considered in individuals diagnosed with human immunodeficiency virus (HIV) infection and presenting with a cluster of differentiation 4 (CD4)-helper T cell count below 100 cells/ml. The 2022 guidelines from the World Health Organization (WHO) advocate for initiating treatment with a high dose (10 mg/kg) of liposomal amphotericin B, followed by flucytosine and fluconazole for a two-week duration. Additionally, alternative treatment options involving a combination of flucytosine and fluconazole are recommended. Consolidation therapy, as per the WHO guidelines, involves an eight-week course of fluconazole (800 mg), initiated after the induction phase. The dosage is then reduced to 200 mg/day, maintaining this level until the CD4 count exceeds 200 cells/mm3. Notably, the 2022 WHO guidelines prioritize a single dose of liposomal amphotericin B (LampB) over amphotericin B deoxycholate (AmpB-D) at 1 mg/kg due to its association with fewer side effects, including decreased mortality, kidney damage, and anemia. These recommendations are founded on the outcomes of the Ambisome Therapy Induction Optimization (AMBITION-CM), a multicenter, open-label, randomized controlled trial. This case report details the outpatient management of cryptococcal meningitis in a 47-year-old male with acquired immunodeficiency syndrome (AIDS) who exhibited intolerance to fluconazole. In this scenario, the decision to employ liposomal amphotericin B (LampB) as the sole agent for treatment during the outpatient phase was driven by challenges in tolerating fluconazole. Despite the absence of specific research on LampB's standalone use during the maintenance and consolidation phases, concerns regarding the patient's adverse reaction to fluconazole influenced the choice. Notably, LampB's once-weekly infusion schedule, although more expensive than AmpB-D, contributes to enhanced patient compliance. Exploring alternatives to traditional medications, such as interferon-gamma (INF-γ), Mycograb, 18B7, APX001, and T2307, holds promise in targeting novel antigens or complementing existing treatment regimens. Post-discharge, the patient received weekly LampB infusions alongside antiretroviral therapy (ART), resulting in an undetectable viral load and an increased CD4 count. A subsequent cerebrospinal fluid analysis post-discharge revealed a positive India ink stain but negative cultures for Cryptococcus, underscoring the necessity for a comprehensive and adaptable approach in managing cryptococcal meningitis.

Murine Models of Cryptococcus Infection

Cryptococcus is recognized as one of the emerging fungal pathogens that have major impact on diverse populations worldwide. Because of the high mortality rate and limited antifungal therapy options, there is an urgent need to understand the impact of dynamic processes between fungal pathogens and hosts that influence cryptococcal pathogenesis and disease outcomes. With known common limitations in human studies, experimental murine cryptococcosis models that can recapitulate human disease provide a valuable tool for studying fungal virulence and the host interaction, leading to development of better treatment strategies. Infection with Cryptococcus in mice via intranasal inhalation is mostly used because it is noninvasive and considered to be the most common mode of infection, strongly correlating with cryptococcal disease in humans. The protocols described in this article provide the procedures of establishing a murine model of Cryptococcus infection by intranasal inhalation and assessing the host immune response and disease progression during Cryptococcus infection. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Murine model of pulmonary cryptococcal infection via intranasal inhalation Basic Protocol 2: Assessment of the pulmonary immune response during Cryptococcus infection Support Protocol: Evaluation of pulmonary gene expression by real-time PCR Basic Protocol 3: Enumeration of survival rate and organ fungal burden.

Interplay between acetylation and ubiquitination of imitation switch chromatin remodeler Isw1 confers multidrug resistance in Cryptococcus neoformans

Cryptococcus neoformans poses a threat to human health, but anticryptococcal therapy is hampered by the emergence of drug resistance, whose underlying mechanisms remain poorly understood. Herein, we discovered that Isw1, an imitation switch chromatin remodeling ATPase, functions as a master modulator of genes responsible for in vivo and in vitro multidrug resistance in C. neoformans. Cells with the disrupted ISW1 gene exhibited profound resistance to multiple antifungal drugs. Mass spectrometry analysis revealed that Isw1 is both acetylated and ubiquitinated, suggesting that an interplay between these two modification events exists to govern Isw1 function. Mutagenesis studies of acetylation and ubiquitination sites revealed that the acetylation status of Isw1K97 coordinates with its ubiquitination processes at Isw1K113 and Isw1K441 through modulating the interaction between Isw1 and Cdc4, an E3 ligase. Additionally, clinical isolates of C. neoformans overexpressing the degradation-resistant ISW1K97Q allele showed impaired drug-resistant phenotypes. Collectively, our studies revealed a sophisticated acetylation-Isw1-ubiquitination regulation axis that controls multidrug resistance in C. neoformans.

Topical delivery of seriniquinone for treatment of skin cancer and fungal infections is enabled by a liquid crystalline lamellar phase

Seriniquinone (SQ) was initially described by our group as an antimelanoma drug candidate and now also as an antifungal drug candidate. Despite its promising in vitro effects, SQ translation has been hindered by poor water-solubility. In this paper, we described the challenging nanoformulation process of SQ, which culminated in the selection of a phosphatidylcholine-based lamellar phase (PLP1). Liposomes and nanostructured lipid carriers were also evaluated but failed to encapsulate the compound. SQ-loaded PLP1 (PLP1-SQ) was characterized for the presence of sedimented or non-dissolved SQ, rheological and thermal behavior, and irritation potential with hen's egg test on the chorioallantoic membrane (HET-CAM). PLP1 influence on transepidermal water loss (TEWL) and skin penetration of SQ was assessed in a porcine ear skin model, while biological activity was evaluated against melanoma cell lines (SK-MEL-28 and SK-MEL-147) and C. albicans SC5314. Despite the presence of few particles of non-dissolved SQ (observed under the microscope 2 days after formulation obtainment), PLP1 tripled SQ retention in viable skin layers compared to SQ solution at 12 h. This effect did not seem to relate to formulation-induced changes on the barrier function, as no increases in TEWL were observed. No sign of vascular toxicity in the HET-CAM model was observed after cutaneous treatment with PLP1. SQ activity was maintained on melanoma cells after 48 h-treatment (IC50 values of 0.59-0.98 µM) whereas the minimum inhibitory concentration (MIC) against C. albicans after 24 h-treatment was 32-fold higher. These results suggest that a safe formulation for SQ topical administration was developed, enabling further in vivo studies.

Antifungal activity of selective serotonin reuptake inhibitors against Cryptococcus spp. and their possible mechanism of action

Fungal infections caused by Cryptococcus spp. pose a threat to health, especially in immunocompromised individuals. The available arsenal of drugs against cryptococcosis is limited, due to their toxicity and/or lack of accessibility in low-income countries, requiring more therapeutic alternatives. Selective serotonin reuptake inhibitors (SSRIs), through drug repositioning, are a promising alternative to broaden the range of new antifungals against Cryptococcus spp. This study evaluates the antifungal activity of three SSRIs, sertraline, paroxetine, and fluoxetine, against Cryptococcus spp. strains, as well as assesses their possible mechanism of action. Seven strains of Cryptococcus spp. were used. Sensitivity to SSRIs, fluconazole, and itraconazole was evaluated using the broth microdilution assay. The interactions resulting from combinations of SSRIs and azoles were investigated using the checkerboard assay. The possible action mechanism of SSRIs against Cryptococcus spp. was evaluated through flow cytometry assays. The SSRIs exhibited in vitro antifungal activity against Cryptococcus spp. strains, with minimum inhibitory concentrations ranging from 2 to 32 μg/mL, and had synergistic and additive interactions with azoles. The mechanism of action of SSRIs against Cryptococcus spp. involved damage to the mitochondrial membrane and increasing the production of reactive oxygen species, resulting in loss of cellular viability and apoptotic cell death. Fluoxetine also was able to cause significant damage to yeast DNA. These findings demonstrate the in vitro antifungal potential of SSRIs against Cryptococcus spp. strains.

Clinical and mycological implications of cryptococcal meningitis in Iran

Cryptococcal meningitis (CM) is an uncommon and severe infection that tends to affect both immunocompromised and immunocompetent hosts. To gain insights into the clinical and epidemiological characteristics of CM in Iran, this study evaluated patients with subacute or chronic meningitis referred to 15 Iranian hospitals. Relevant clinical and epidemiological characteristics of the patients were analyzed. Diagnosis of CM cases was performed by microscopic examination, culture, latex agglutination assay, lateral flow assay, and multiplex PCR on cerebrospinal fluid (CSF) samples. The isolates were processed and subjected to molecular identification and in vitro susceptibility antifungal profile. Among the 272 evaluated patients, 7 (2.6 %) CM cases were diagnosed. Out of seven CM cases, 6 (86 %) were male with a median age of 36 years. The most common neurological signs were headache (100 %), followed by nausea and vomiting (71.4 %). All CSF samples from CM patients exhibited positive results across all mycological tests conducted. The isolates were identified as Cryptococcus neoformans (86 %) and Cryptococcus gattii (14 %). All isolates were susceptible to voriconazole and fluconazole, while resistance was observed with itraconazole (MIC value of 0.5 μg/mL) and amphotericin B (MIC values of 4 and 1 μg/mL). The highest mortality (6/7, 86 %) was observed among patients. While a comprehensive study on this subject is currently lacking in Iran, the data acquired through this research play a crucial role in enhancing the clinical and epidemiological understanding of this infection, particularly within low-income countries. Moreover, these findings will serve as a cornerstone for future international comparative studies in this field.

Screening and Synthesis of Tetrazole Derivatives that Inhibit the Growth of Cryptococcus Species

Cryptococcosis has become a major health problem worldwide and caused morbidity and mortality in immunocompromised patients, especially those infected with human immunodeficiency virus (HIV). Despite the global distribution of cryptococcosis, the number and types of the available antifungals are limited, and the treatment outcomes in HIV patients are generally poor. In this study, we screened a compound library and identified one tetrazole derivative as an efficient inhibitor of Cryptococcus neoformans and Cryptococcus gattii. We further designed and synthesized a series of tetrazole derivatives and determined their structure-activity relationship, demonstrating that tetrazole backbone-containing compounds could be developed as novel antifungal drugs with distinct mechanisms against Cryptococcus spp. Our findings provide a starting point for novel target identification and structural optimization to develop a distinct class of therapeutics for patients with cryptococcosis.

Adaptive immunology of Cryptococcus neoformans infections-an update

The fungal genus Cryptococcus comprises a group of pathogens with considerable phenotypic and genotypic diversity that can lead to cryptococcosis in both healthy and immunocompromised individuals. With the emergence of the HIV pandemic, cryptococcosis, mainly meningoencephalitis, afflicts HIV-infected patients with severe dysfunction of T cells. It has also been reported in recipients of solid organ transplantation and in patients with autoimmune diseases who take immunosuppressive agents long-term, as well as in those with unidentified immunodeficiency. The clinical outcome of the disease is primarily determined by the immune response resulting from the interplay between the host immune system and the pathogen. Most human infections are caused by Cryptococcus neoformans, and nearly all immunological studies have focused on C. neoformans. This review provides an updated understanding of the role of adaptive immunity during infection with C. neoformans in human and animal models over the past half-decade.

Oral delivery of brain-targeted miltefosine-loaded alginate nanoparticles functionalized with polysorbate 80 for the treatment of cryptococcal meningitis

OBJECTIVES

To develop alginate nanoparticles functionalized with polysorbate 80 (P80) as miltefosine carriers for brain targeting in the oral treatment of cryptococcal meningitis.

METHODS

Miltefosine-loaded alginate nanoparticles functionalized or not with P80 were produced by an emulsification/external gelation method and the physicochemical characteristics were determined. The haemolytic activity and cytotoxic and antifungal effects of nanoparticles were assessed in an in vitro model of the blood-brain barrier (BBB). A murine model of disseminated cryptococcosis was used for testing the efficacy of oral treatment with the nanoparticles. In addition, serum biomarkers were measured for toxicity evaluation and the nanoparticle biodistribution was analysed.

RESULTS

P80-functionalized nanoparticles had a mean size of ∼300 nm, a polydispersity index of ∼0.4 and zeta potential around -50 mV, and they promoted a sustained drug release. Both nanoparticles were effective in decreasing the infection process across the BBB model and reduced drug cytotoxicity and haemolysis. In in vivo cryptococcosis, the oral treatment with two doses of P80 nanoparticles reduced the fungal burden in the brain and lungs, while the non-functionalized nanoparticles reduced fungal amount only in the lungs, and the free miltefosine was not effective. In addition, the P80-functionalization improved the nanoparticle distribution in several organs, especially in the brain. Finally, treatment with nanoparticles did not cause any toxicity in animals.

CONCLUSIONS

These results support the potential use of P80-functionalized alginate nanoparticles as miltefosine carriers for non-toxic and effective alternative oral treatment, enabling BBB translocation and reduction of fungal infection in the brain.

Disseminated Cryptococcosis in an HIV-Negative Patient With Liver Cirrhosis and Asplenia: A Rare but Dreadful Disease

Cryptococcosis (cryptococcal infection) is a severe life-threatening fungal infection. It is seen worldwide, specifically in immunocompromised, mainly in human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS)-infected individuals. Cryptococcal infection can present with meningitis, pneumonia, peritonitis, disseminated cryptococcosis, and cryptococcal fungemia. Here, we report the case of an HIV-negative Caucasian male in his early 50s with liver cirrhosis and asplenia who presented to our hospital with bilateral foot cellulitis and pneumonia. He was eventually diagnosed with disseminated cryptococcosis. Even with appropriate treatment, he developed multiorgan failure and finally expired. The disseminated cryptococcal infection has a very high mortality rate in patients with liver cirrhosis and asplenia. Liver cirrhosis is an independent risk factor, and asplenia is a comorbid condition for cryptococcal infection in HIV-negative patients. Healthcare providers should have a high suspicion of cryptococcosis in these patients. Early testing with cryptococcal antigen assay and initiation of an appropriate antimicrobial regimen can help minimize bad outcomes.

Functional Analysis of the P-Type ATPases Apt2-4 from Cryptococcus neoformans by Heterologous Expression in Saccharomyces cerevisiae

Lipid flippases of the P4-ATPase family actively transport phospholipids across cell membranes, an activity essential for key cellular processes such as vesicle budding and membrane trafficking. Members of this transporter family have also been implicated in the development of drug resistance in fungi. The encapsulated fungal pathogen Cryptococcus neoformans contains four P4-ATPases, among which Apt2-4p are poorly characterized. Using heterologous expression in the flippase-deficient S. cerevisiae strain dnf1Δdnf2Δdrs2Δ, we tested their lipid flippase activity in comparison to Apt1p using complementation tests and fluorescent lipid uptake assays. Apt2p and Apt3p required the co-expression of the C. neoformans Cdc50 protein for activity. Apt2p/Cdc50p displayed a narrow substrate specificity, limited to phosphatidylethanolamine and -choline. Despite its inability to transport fluorescent lipids, the Apt3p/Cdc50p complex still rescued the cold-sensitive phenotype of dnf1Δdnf2Δdrs2Δ, suggesting a functional role for the flippase in the secretory pathway. Apt4p, the closest homolog to Saccharomyces Neo1p, which does not require a Cdc50 protein, was unable to complement several flippase-deficient mutant phenotypes, neither in the presence nor absence of a β-subunit. These results identify C. neoformans Cdc50 as an essential subunit for Apt1-3p and provide a first insight into the molecular mechanisms underlying their physiological functions.

Nanotechnology-Based Approaches for Voriconazole Delivery Applied to Invasive Fungal Infections

Invasive fungal infections increase mortality and morbidity rates worldwide. The treatment of these infections is still limited due to the low bioavailability and toxicity, requiring therapeutic monitoring, especially in the most severe cases. Voriconazole is an azole widely used to treat invasive aspergillosis, other hyaline molds, many dematiaceous molds, Candida spp., including those resistant to fluconazole, and for infections caused by endemic mycoses, in addition to those that occur in the central nervous system. However, despite its broad activity, using voriconazole has limitations related to its non-linear pharmacokinetics, leading to supratherapeutic doses and increased toxicity according to individual polymorphisms during its metabolism. In this sense, nanotechnology-based drug delivery systems have successfully improved the physicochemical and biological aspects of different classes of drugs, including antifungals. In this review, we highlighted recent work that has applied nanotechnology to deliver voriconazole. These systems allowed increased permeation and deposition of voriconazole in target tissues from a controlled and sustained release in different routes of administration such as ocular, pulmonary, oral, topical, and parenteral. Thus, nanotechnology application aiming to delivery voriconazole becomes a more effective and safer therapeutic alternative in the treatment of fungal infections.

Bioactive metabolites of Streptomyces misakiensis display broad-spectrum antimicrobial activity against multidrug-resistant bacteria and fungi

Background

Antimicrobial resistance is a serious threat to public health globally. It is a slower-moving pandemic than COVID-19, so we are fast running out of treatment options.

Purpose

Thus, this study was designed to search for an alternative biomaterial with broad-spectrum activity for the treatment of multidrug-resistant (MDR) bacterial and fungal pathogen-related infections.

Methods

We isolated Streptomyces species from soil samples and identified the most active strains with antimicrobial activity. The culture filtrates of active species were purified, and the bioactive metabolite extracts were identified by thin-layer chromatography (TLC), preparative high-performance liquid chromatography (HPLC), nuclear magnetic resonance (NMR) spectroscopy, and gas chromatography-mass spectrometry (GC-MS). The minimum inhibitory concentrations (MICs) of the bioactive metabolites against MDR bacteria and fungi were determined using the broth microdilution method.

Results

Preliminary screening revealed that Streptomyces misakiensis and S. coeruleorubidus exhibited antimicrobial potential. The MIC₅₀ and MIC₉₀ of S. misakiensis antibacterial bioactive metabolite (ursolic acid methyl ester) and antifungal metabolite (tetradecamethylcycloheptasiloxane) against all tested bacteria and fungi were 0.5 μg/ml and 1 μg/mL, respectively, versus S. coeruleorubidus metabolites: thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester against bacteria (MIC₅₀: 2 μg/ml and MIC₉₀: 4 μg/mL) and fungi (MIC₅₀: 4 μg/ml and MIC₉₀: 8 μg/mL). Ursolic acid methyl ester was active against ciprofloxacin-resistant strains of Streptococcus pyogenes, S. agalactiae, Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica serovars, colistin-resistant Aeromonas hydrophila and K. pneumoniae, and vancomycin-resistant Staphylococcus aureus. Tetradecamethylcycloheptasiloxane was active against azole- and amphotericin B-resistant Candida albicans, Cryptococcus neoformans, C. gattii, Aspergillus flavus, A. niger, and A. fumigatus. Ursolic acid methyl ester was applied in vivo for treating S. aureus septicemia and K. pneumoniae pneumonia models in mice. In the septicemia model, the ursolic acid methyl ester-treated group had a significant 4.00 and 3.98 log CFU/g decrease (P < 0.05) in liver and spleen tissue compared to the infected, untreated control group. Lung tissue in the pneumonia model showed a 2.20 log CFU/g significant decrease in the ursolic acid methyl ester-treated group in comparison to the control group. The haematological and biochemical markers in the ursolic acid methyl ester-treated group did not change in a statistically significant way. Moreover, no abnormalities were found in the histopathology of the liver, kidneys, lungs, and spleen of ursolic acid methyl ester-treated mice in comparison with the control group.

Conclusion

S. misakiensis metabolite extracts are broad-spectrum antimicrobial biomaterials that can be further investigated for the potential against MDR pathogen infections. Hence, it opens up new horizons for exploring alternative drugs for current and reemerging diseases.

Semi-Synthetic Ecdysteroid 6-Oxime Derivatives of 20-Hydroxyecdysone Possess Anti-Cryptococcal Activity

Cryptococcosis, a life-threatening fungal infection, frequently occurs in patients suffering from AIDS. The treatment of the disease is hampered by the limited number of the effective drugs and the increasing resistance; therefore, to find new active substances is needed. As meningitis is the most serious infection affecting the AIDS patients, effective drugs have to be capable of entering to the central nervous system. Ecdysteroids are natural bioactive molecules with considerable anabolic activity and without toxic side effects on humans. The aim of this work was to study the anti-cryptococcal activity of a natural ecdysteroid, 20E, and its three semi-synthetic derivatives obtained by structural modification of the original molecule. We established the minimum inhibitory concentration of the compounds with microdilution method and demonstrated their fungicidal activity by flow cytometry and cultivation of the drug-treated cells. The interaction of the compounds with each other and efflux transporter inhibitors was assessed by checkerboard titration method. Two derivatives, 20E-EOx and 20E-ZOx, inhibited the growth of Cryptococcus neoformans with minimum inhibitory concentration 2 mg/mL and 1 mg/mL, respectively; both compounds possess fungicidal effect. A combination of the ecdysteroids with each other and verapamil resulted in additive interaction. This study confirmed that structural modification of an originally non-antimicrobial molecule can enhance its effectiveness.

Primary Cutaneous Cryptococcosis Caused by Cryptococcus gatti in an Elderly Patient

According to the spread of Cryptococcus sp., fungal infections can be classified as primary or secondary. In primary cutaneous cryptococcosis, the fungi are restricted to the skin of the patients, without systemic involvement. The incidence of primary cutaneous cryptococcosis is high in patients with immunosuppression, and this type of infection is rarely observed in patients who are immunocompetent. In the present case report, a patient who is immunocompetent and has systemic comorbidity reported that, after skin trauma, ulcerovegetative lesions appeared in the right upper arm; the etiologic agent was identified as Cryptococcus gatti, serotype B. The cutaneous lesions healed completely after 5 months of fluconazole treatment.

Cryptococcal Pneumonia: An Unusual Complication in a COVID-19 Patient

Cryptococcal superinfection is a rare but potentially fatal complication, especially if its detection and subsequent treatment are delayed. Histopathological findings of pulmonary parenchyma from a deceased patient with these complications were acquired. Quite interestingly, only a minimal inflammatory reaction could be seen in an individual with no previously known immune suppression, indicating a disturbance of the immune system. This finding was well in concordance with the described changes in cellular immunity in COVID-19. We report the case of a 60 year old male with critical coronavirus disease 2019 (COVID-19) complicated by cryptococcal pneumonia and multiorgan failure. Both X-ray and CT scans revealed lung infiltrates corresponding with COVID-19 infection early after the onset of symptoms. Despite receiving standard treatment, the patient progressed into multiple organ failure, requiring mechanical ventilation, circulatory support, and haemodialysis. Cryptococcus neoformans was detected by subsequent BAL, and specific antifungal treatment was instituted. His clinical status deteriorated despite all treatment, and he died of refractory circulatory failure after 21 days from hospital admission. Histopathological findings confirmed severe diffuse alveolar damage (DAD) caused by COVID-19 and cryptococcal pneumonia. Timely diagnosis of cryptococcal superinfection may be challenging; therefore, PCR panels detecting even uncommon pathogens should be implemented while taking care of critical COVID-19 patients.

The Antidepressant Sertraline Induces the Formation of Supersized Lipid Droplets in the Human Pathogen Cryptococcus neoformans

The prevalence and increasing incidence of fungal infections globally is a significant worldwide health problem. Cryptococcosis, primarily caused by the pathogenic yeast Cryptococcus neoformans, is responsible for approximately 181,000 estimated deaths annually. The scarcity of treatments and the increasing resistance to current therapeutics highlight the need for the development of antifungal agents which have novel mechanisms of action and are suitable for clinical use. Repurposing existing FDA-approved compounds as antimycotic therapeutics is a promising strategy for the rapid development of such new treatments. Sertraline (SRT), a commonly prescribed antidepressant, is a broad-spectrum antifungal agent with particular efficacy against C. neoformans. However, the effect of SRT on fungal physiology is not understood. Here, we report that SRT induces the formation of supersized lipid droplets (SLDs) in C. neoformans, and in Candida albicans, Saccharomyces cerevisiae, and Aspergillus fumigatus. SLDs were not induced in C. neoformans by treatment with the antifungal fluconazole (FLC), consistent with SRT and FLC acting differently to perturb C. neoformans physiology. The formation of SLDs in response to SRT indicates that this compound alters the lipid metabolism of C. neoformans. Moreover, the SRT-induced enlargement of LDs in other fungal species may indicate a common fungal response to SRT.

Rapidly enlarging pulmonary mass due to immune reconstitution inflammatory syndrome (IRIS) in an immunocompetent host with pulmonary Cryptococcus neoformans

An immunocompetent man presented with Cryptococcus neoformans disease manifesting as a large pulmonary mass (cryptococcoma). Despite an initial induction course of 4 weeks of liposomal amphotericin B (LAmB), followed by 8 weeks of fluconazole, the cryptococcoma enlarged in size. Ten days into a second course of induction therapy with LAmB and flucytosine, the cryptococcoma markedly increased in size with encroachment on critical vascular structures. Due to concern for immune reconstitution inflammatory syndrome (IRIS), prednisone was added with significant decrease in the size of the mass. To our knowledge, this is the first reported case of pulmonary cryptococcal-IRIS in an immunocompetent host.

COVID-19-associated opportunistic infections: a snapshot on the current reports

Treatment of the novel Coronavirus Disease 2019 (COVID-19) remains a complicated challenge, especially among patients with severe disease. In recent studies, immunosuppressive therapy has shown promising results for control of the cytokine storm syndrome (CSS) in severe cases of COVID-19. However, it is well documented that immunosuppressive agents (e.g., corticosteroids and cytokine blockers) increase the risk of opportunistic infections. On the other hand, several opportunistic infections were reported in COVID-19 patients, including Aspergillus spp., Candida spp., Cryptococcus neoformans, Pneumocystis jiroveci (carinii), mucormycosis, Cytomegalovirus (CMV), Herpes simplex virus (HSV), Strongyloides stercoralis, Mycobacterium tuberculosis, and Toxoplasma gondii. This review is a snapshot about the main opportunistic infections that reported among COVID-19 patients. As such, we summarized information about the main immunosuppressive agents that were used in recent clinical trials for COVID-19 patients and the risk of opportunistic infections following these treatments. We also discussed about the main challenges regarding diagnosis and treatment of COVID-19-associated opportunistic infections (CAOIs).

Clinical Profile of 24 AIDS Patients with Cryptococcal Meningitis in the HAART Era: A Report from an Infectious Diseases Tertiary Hospital in Western Romania

Management of cryptococcal infections among patients suffering from acquired immunodeficiency syndrome (AIDS) represents a medical challenge. This retrospective study aims to describe the disease management and outcomes among 24 AIDS patients who suffered from Cryptococcus neoformans meningitis. The parameters evaluated from our patients’ database records include epidemiological data, clinical manifestations, biochemical and microbiological analysis of patients’ cerebrospinal fluid (CSF), treatment profiles, and disease outcomes. All patients included in the study had a lymphocyte count of less than 200 CD4/mm³. Of the 24 patients included in this study, five had been diagnosed with HIV infection since childhood, after receiving HIV-infected blood transfusions. The most prominent symptom was fatigue in 62.5% of patients, followed by nausea/vomiting and headache. Seven patients had liver cirrhosis due to hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, while Kaposi sarcoma and cerebral toxoplasmosis were found in two patients. Six out of 24 patients died due to bacterial sepsis and acute respiratory distress syndrome (ARDS). High intracranial pressure was the strongest predictive factor for mortality (OR = 2.9), followed by ARDS (OR = 1.8), seizures at disease onset (OR = 1.4), and diabetes mellitus (OR = 1.2). Interestingly, patients younger than 40 years old had a significantly lower survival rate than that of the older patients. Before developing Cryptococcal meningitis, all patients had low adherence to the early ART treatment scheme and skipped the follow-up visits. All patients received a combination of amphotericin B and flucytosine as induction therapy, adding fluconazole for maintenance. Simultaneously, AIDS HAART was initiated at diagnosis of the cryptococcal infection. A combined regimen of antifungals and highly active antiretroviral therapy showed improved patient recovery with minor side effects.

Imaging of cryptococcus neoformans infection in breasts: A case report

There have been few reports on the imaging characteristics of cryptococcus neoformans (C. neoformans) infection of the breast. Herein, we reported the imaging features of C. neoformans infection of the breast in a 41-year-old woman with immune thrombocytopenic purpura. Bilateral, diffuse, hyperechoic, and well-defined margin lesions were observed on breast ultrasounds. In addition, a global asymmetry in the left breast, and a focal asymmetry in the right breast were observed on mammograms. Breast fine needle aspiration and biopsy results revealed a C. neoformans infection. After 5 months of treatment with oral fluconazole and amphotericin B, the lesion on the right breast disappeared on repeated-breast ultrasounds.

Docusate-Based Ionic Liquids of Anthelmintic Benzimidazoles Show Improved Pharmaceutical Processability, Lipid Solubility, and in Vitro Activity against Cryptococcus neoformans

As the existing therapeutic modalities for the treatment of cryptococcal meningitis (CM) have suboptimal efficacy, repurposing existing drugs for the treatment of CM is of great interest. The FDA-approved anthelmintic benzimidazoles, albendazole, mebendazole, and flubendazole, have demonstrated potent but variable in vitro activity against Cryptococcus neoformans, the predominant fungal species responsible for CM. We performed molecular docking studies to ascertain the interaction of albendazole, mebendazole, and flubendazole with a C. neoformans β-tubulin structure, which revealed differential binding interactions and explained the different in vitro efficacies reported previously and observed in this investigation. Despite their promising in vitro efficacy, the repurposing of anthelmintic benzimidazoles for oral CM therapy is significantly hampered due to their high crystallinity, poor pharmaceutical processability, low and pH-dependent solubility, and drug precipitation upon entering the intestine, all of which result in low and variable oral bioavailability. Here, we demonstrate that the anthelmintic benzimidazoles can be transformed into partially amorphous low-melting ionic liquids (ILs) with a simple metathesis reaction using amphiphilic sodium docusate as a counterion. In vitro efficacy studies on a laboratory reference and a clinical isolate of C. neoformans showed 2- to 4-fold lower IC₉₀ values for docusate-based ILs compared to the pure anthelmintic benzimidazoles. Furthermore, using a C. neoformans strain with green fluorescent protein (GFP)-tagged β-tubulin and albendazole and its docusate IL as model candidates, we showed that the benzimidazoles and their ILs reduce the viability of C. neoformans by interfering with its microtubule assembly. Unlike pure anthelmintic benzimidazoles, the docusate-based ILs showed excellent solubility in organic solvents and >30-fold higher solubility in bioavailability-enhancing lipid vehicles. Finally, the docusate ILs were successfully incorporated into SoluPlus, a self-assembling biodegradable polymer, which upon dilution with water formed polymeric micelles with a size of <100 nm. Thus, the development of docusate-based ILs represents an effective approach to improve the physicochemical properties and potency of anthelmintic benzimidazoles to facilitate their repurposing and preclinical development for CM therapy.

Drug Repurposing in Medical Mycology: Identification of Compounds as Potential Antifungals to Overcome the Emergence of Multidrug-Resistant Fungi

Immunodepression, whether due to HIV infection or organ transplantation, has increased human vulnerability to fungal infections. These conditions have created an optimal environment for the emergence of opportunistic infections, which is concomitant to the increase in antifungal resistance. The use of conventional antifungal drugs as azoles and polyenes can lead to clinical failure, particularly in immunocompromised individuals. Difficulties related to treating fungal infections combined with the time required to develop new drugs, require urgent consideration of other therapeutic alternatives. Drug repurposing is one of the most promising and rapid solutions that the scientific and medical community can turn to, with low costs and safety advantages. To treat life-threatening resistant fungal infections, drug repurposing has led to the consideration of well-known and potential molecules as a last-line therapy. The aim of this review is to provide a summary of current antifungal compounds and their main resistance mechanisms, following by an overview of the antifungal activity of non-traditional antimicrobial drugs. We provide their eventual mechanisms of action and the synergistic combinations that improve the activity of current antifungal treatments. Finally, we discuss drug repurposing for the main emerging multidrug resistant (MDR) fungus, including the Candida auris, Aspergillus or Cryptococcus species.

Pneumococcal Bacteremia and Cryptococcal Meningitis Dual Infection in a Patient With Multiple Myeloma

Infections remain one of the major complications in patients with multiple myeloma, having a significant impact on morbidity and mortality. The increased risk of infection in these patients are a result of various factors contributing to the impairment of immune system caused by the disease and the chemotherapy regimens given during the treatment phases. Here we report a rare case of pneumococcal bacteraemia and cryptococcal meningitis dual infection in a patient with underlying multiple myeloma who had a favourable clinical outcome. This case also serves to highlight the importance of adult vaccinations especially in patients with underlying comorbidities.

Production of Secreted Carbohydrates that Present Immunologic Similarities with the Cryptococcus Glucuronoxylomannan by Members of the Trichosporonaceae Family: A Comparative Study Among Species of Clinical Interest

Glucuronoxylomannan (GXM) participates in several immunoregulatory mechanisms, which makes it an important Cryptococcus virulence factor that is essential for the disease. Trichosporon asahii and Trichosporon mucoides share with Cryptococcus species the ability to produce GXM. To check whether other opportunistic species in the Trichosporonaceae family produce GXM-like polysaccharides, extracts from 28 strains were produced from solid cultures and their carbohydrate content evaluated by the sulfuric acid / phenol method. Moreover, extracts were assessed for cryptococcal GXM cross-reactivity through latex agglutination and lateral flow assay methods. Cryptococcus neoformans and Saccharomyces cerevisiae were used as positive and negative controls, respectively. In addition to T. asahii, the species Trichosporon inkin, Apiotrichum montevideense, Trichosporon japonicum, Trichosporon faecale, Trichosporon ovoides, Cutaneotrichosporon debeurmannianum, and Cutaneotrichosporon arboriformis are also producers of a polysaccharide immunologically similar to the GXM produced by human pathogenic Cryptococcus species. The carbohydrate concentration of the extracts presented a positive correlation with the GXM contents determined by titration of both methodologies. These results add several species to the list of fungal pathogens that produce glycans of the GXM type and bring information about the origin of potential false-positive results on immunological tests for diagnosis of cryptococcosis based on GXM detection.

Evaluating Infectious, Neoplastic, Immunological, and Degenerative Diseases of the Central Nervous System with Cerebrospinal Fluid-Based Next-Generation Sequencing

Cerebrospinal fluid (CSF) is a clear and paucicellular fluid that circulates within the ventricular system and the subarachnoid space of the central nervous system (CNS), and diverse CNS disorders can impact its composition, volume, and flow. As conventional CSF testing suffers from suboptimal sensitivity, this review aimed to evaluate the role of next-generation sequencing (NGS) in the work-up of infectious, neoplastic, neuroimmunological, and neurodegenerative CNS diseases. Metagenomic NGS showed improved sensitivity—compared to traditional methods—to detect bacterial, viral, parasitic, and fungal infections, while the overall performance was maximized in some studies when all diagnostic modalities were used. In patients with primary CNS cancer, NGS findings in the CSF were largely concordant with the molecular signatures derived from tissue-based molecular analysis; of interest, additional mutations were identified in the CSF in some glioma studies, reflecting intratumoral heterogeneity. In patients with metastasis to the CNS, NGS facilitated diagnosis, prognosis, therapeutic management, and monitoring, exhibiting higher sensitivity than neuroimaging, cytology, and plasma-based molecular analysis. Although evidence is still rudimentary, NGS could enhance the diagnosis and pathogenetic understanding of multiple sclerosis in addition to Alzheimer and Parkinson disease. To conclude, NGS has shown potential to aid the research, facilitate the diagnostic approach, and improve the management outcomes of all the aforementioned CNS diseases. However, to establish its role in clinical practice, the clinical validity and utility of each NGS protocol should be determined. Lastly, as most evidence has been derived from small and retrospective studies, results from randomized control trials could be of significant value.

Novel 2-Aryloxazoline Compounds Exhibit an Inhibitory Effect on Candida spp., Including Antifungal-Resistant Isolates

Because of the increased resistance to currently available antifungals, fungal infections represent a significant challenge to human health. Herein, we report the synthesis of 2-aryloxazoline derivatives from the reaction between l-threonine and derivatives of salicylic or naphthoic acid. In total, 26 compounds were obtained and tested against species of Candida, Cryptococcus, and Aspergillus. We found that all of the compounds inhibited the growth of Candida species at low concentrations (<0.25 μg/mL) and exhibited reduced hemolytic and cytotoxic activities. Additionally, compounds 4i and 9i were especially effective against antifungal-resistant isolates and the emerging fungus Candida auris. However, the compounds were less active on Cryptococcus and Aspergillus. Because of the improved in vitro antifungal efficacy and attenuated cytotoxicity, these two 2-aryloxazolines obtained from salicylic and naphthoic acid derivatives, respectively, may be considered lead molecules for the development of novel antifungal drugs.

Hypervirulence and cross-resistance to a clinical antifungal are induced by an environmental fungicide in Cryptococcus gattii

The increasing human population requires ongoing efforts in food production. This is frequently associated with an increased use of agrochemicals, leading to environmental contamination and altering microbial communities, including human fungal pathogens that reside in the environment. Cryptococcus gattii is an environmental yeast and is one of the etiological agents of cryptococcosis. Benomyl (BEN) is a broad-spectrum fungicide used on several crops. To study the effects of agrochemicals on fungal pathogens, we first evaluated the susceptibility of C. gattii to BEN and the interactions with clinical antifungals. Antagonistic interaction between BEN and fluconazole was seen and was strain- and concentration-dependent. We then induced BEN-resistance by culturing strains in increasing drug concentrations. One strain demonstrated to be more resistant and showed increased multidrug efflux pump gene (MDR1) expression and increased rhodamine 6G efflux, leading to cross-resistance between BEN and fluconazole. Morphologically, BEN-adapted cells had a reduced polysaccharide capsule; an increased surface/volume ratio; increased growth rate in vitro and inside macrophages and also higher ability in crossing an in vitro model of blood-brain-barrier. BEN-adapted strain demonstrated to be hypervirulent in mice, leading to severe symptoms of cryptococcosis, early mortality and higher fungal burden in the organs, particularly the brain. The parental strain was avirulent in murine model. In vivo cross-resistance between BEN and fluconazole was observed, with mice infected with the adapted strain unable to present any improvement in survival and behavior when treated with this antifungal. Furthermore, BEN-adapted cells cultured in drug-free media maintained the hypervirulent and cross-resistant phenotype, suggesting a persistent effect of BEN on C. gattii. In conclusion, exposure to BEN induces cross-resistance with fluconazole and increases the virulence of C. gattii. Altogether, our results indicate that agrochemicals may lead to unintended consequences on non-target species and this could result in severe healthy problems worldwide.

Green Synthesis of Antileishmanial and Antifungal Silver Nanoparticles Using Corn Cob Xylan as a Reducing and Stabilizing Agent

Corn cob is an agricultural byproduct that produces an estimated waste burden in the thousands of tons annually, but it is also a good source of xylan, an important bioactive polysaccharide. Silver nanoparticles containing xylan (nanoxylan) were produced using an environmentally friendly synthesis method. To do this, we extracted xylan from corn cobs using an ultrasound technique, which was confirmed by both chemical and NMR analyses. This xylan contained xylose, glucose, arabinose, galactose, mannose, and glucuronic acid in a molar ratio of 50:21:14:9:2.5:2.5, respectively. Nanoxylan synthesis was analyzed using UV-vis spectroscopy at kmax = 469 nm and Fourier transform infrared spectroscopy (FT-IR), which confirmed the presence of both silver and xylan in the nanoxylan product. Dynamic light scattering (DLS) and atomic force microscopy (AFM) revealed that the nanoxylan particles were ~102.0 nm in size and spherical in shape, respectively. DLS also demonstrated that nanoxylan was stable for 12 months and coupled plasma optical emission spectrometry (ICP-OES) showed that the nanoxylan particles were 19% silver. Nanoxylan reduced Leishmania amazonensis promastigote viability with a half maximal inhibitory concentration (IC50) value of 25 μg/mL, while xylan alone showed no effective. Additionally, nanoxylan exhibited antifungal activity against Candida albicans (MIC = 7.5 μg/mL), C. parapsilosis (MIC = 7.5 μg/mL), and Cryptococcus neoformans (MIC = 7.5 μg/mL). Taken together, these data suggest that it is possible to synthesize silver nanoparticles using xylan and that these nanoxylan exert improved antileishmanial and antifungal activities when compared to the untreated polysaccharide or silver nitrate used for their synthesis. Thus, nanoxylan may represent a promising new class of antiparasitic agents for use in the treatment of these microorganisms.

An Overview of the Management of the Most Important Invasive Fungal Infections in Patients with Blood Malignancies

In patients with hematologic malignancies due to immune system disorders, especially persistent febrile neutropenia, invasive fungal infections (IFI) occur with high mortality. Aspergillosis, candidiasis, fusariosis, mucormycosis, cryptococcosis and trichosporonosis are the most important infections reported in patients with hematologic malignancies that undergo hematopoietic stem cell transplantation. These infections are caused by opportunistic fungal pathogens that do not cause severe issues in healthy individuals, but in patients with hematologic malignancies lead to disseminated infection with different clinical manifestations. Prophylaxis and creating a safe environment with proper filters and air pressure for patients to avoid contact with the pathogens in the surrounding environment can prevent IFI. Furthermore, due to the absence of specific symptoms in IFI, rapid and accurate diagnosis reduces the mortality rate of these infections and using molecular techniques along with standard mycological methods will improve the diagnosis of disseminated fungal infection in patients with hematologic disorders. Amphotericin B products, extended-spectrum azoles, and echinocandins are the essential drugs to control invasive fungal infections in patients with hematologic malignancies, and according to various conditions of patients, different results of treatment with these drugs have been reported in different studies. On the other hand, drug resistance in recent years has led to therapeutic failures and deaths in patients with blood malignancies, which indicates the need for antifungal susceptibility tests to use appropriate therapies. Life-threatening fungal infections have become more prevalent in patients with hematologic malignancies in recent years due to the emergence of new risk factors, new species, and increased drug resistance. Therefore, in this review, we discuss the different dimensions of the most critical invasive fungal infections in patients with hematologic malignancies and present a list of these infections with different clinical manifestations, treatment, and outcomes.