Invasive fungal disease in the immunocompromised host: changing epidemiology, new antifungal therapies, and management challenges

Novel benzimidazole hybrids: design, synthesis, mechanistic studies, antifungal potential and molecular dynamics

In this study, two series of benzimidazole hybrids were developed and designed using different strategies. The target compounds were designed through straight chemistry pathways and were screened as possible antimicrobial agents. Twenty new compounds were synthesized, among which compounds 11 and 12 displayed excellent activity against Candida albicans and Cryptococcus neoformans with growth inhibition percentage ranging from 86.42% to 100%. For gaining better insights into the mechanistic ability of the active candidates 11 and 12, their inhibitory activity against lanosterol 14α-demethylase was studied. Results showed IC50 values of 5.6 and 7.1 μM for 11 and 12, respectively, which were comparable to the reference value of fluconazole (2.3 μM), indicating low drug interaction possibilities. Notably, compound 11 displayed excellent inhibition of biofilm metabolic activity. In addition, their synergistic activity against C. neoformans displayed a 2-fold increase compared with fluconazole. Furthermore, it exhibited sustained antifungal activity with time clearance of over 24 h, which was better than the time clearance of fluconazole (6 h). Moreover, compounds 11 and 12 displayed considerable safety profiles, with no cytotoxicity reported against human embryonic kidney cells or hemolysis of red blood cells. Molecular dynamics simulation (MDS) experiments over 100 ns of compound 11 showed its ability to interact with the HEM binding site as the co-crystallized ligand (fluconazole). Finally, in silico ADMET studies predicted its significant oral bioavailability as antifungal candidates.

Efficacy and Safety of Amphotericin B Colloidal Dispersion for Patients with Invasive Fungal Disease and Febrile Neutropenia: A Registry-Based, Multicenter, Retrospective, Real-World Study

Purpose

This study aimed to explore the efficacy and safety of amphotericin B colloidal dispersion (ABCD) in treating patients with invasive fungal disease (IFD) or febrile neutropenia.

Patients and Methods

This study retrospectively included patients diagnosed with IFD or febrile neutropenia who received ABCD treatment from 22 hospitals. The efficacy and safety were evaluated at the end of ABCD treatment. The characteristics of patients diagnosed with possible, probable and proven IFD according to the revised EORTC-MSG criteria were then further analyzed to conduct sensitivity analysis.

Results

A total of 503 patients were enrolled in this study. Of these patients, 391 received ABCD treatment for a minimum of seven days, and the overall efficacy of ABCD was determined to be 71.87% (281/391). 183 patients were diagnosed with possible, probable and proven IFD, the ABCD efficacy of whom was 67.76% (124/183). The efficacy of ABCD in patients with hematologic malignancies, AIDS and diabetes was 70.10% (211/301), 88.24% (30/34), and 83.33% (10/12), respectively. In terms of various fungal species, the efficacy of ABCD in patients with Aspergillus, Mucorales and Candida infections was 62.96% (34/54), 80.49% (33/41) and 66.67% (22/33), respectively. For patients in the targeted therapy, diagnostic-driven therapy, and empirical therapy groups, the efficacy of ABCD was 76.92% (60/78), 70.17% (207/295), and 77.78% (14/18), respectively. The most common adverse events (AEs) were infusion reactions (30.22%, 152/503) and hypokalemia (38.97%, 196/503), with the majority of these AEs classified as grade 1-2. This study was registered with ClinicalTrials.gov, NCT05116059.

Conclusion

ABCD has demonstrated satisfactory therapeutic efficacy and safety in the treatment of IFD or febrile neutropenia.

Voriconazole in the treatment of pediatric patients with hematologic malignancies and invasive fungal infections: a real-world study

PURPOSE

To evaluate the factors influencing voriconazole (VRC) administration, clinical efficacy, and safety in children with hematological malignancies (HM) and invasive fungal infection (IFD).

METHODS

This is a single-center, retrospective real-world study conducted between July 2018 and December 2023. Univariate and multivariate logistic regression analysis were used to analyze the affecting factors.

RESULTS

A total of 167 patients were included in this study. Among them, 13.77% (23/167) of children under 2 years old received off-label use of VRC, with an initial maintenance dose higher than that of other groups (P < 0.001). There were 8 cases (4.79%) of cured, 148 cases (88.62%) of improved, and 11 cases (6.59%) of ineffective. Thirty-eight cases experienced adverse drug reactions (ADR), with a highest incidence (10.2%) of hepatotoxicity. The concomitant proton pump inhibitors (PPIs), days of central venous catheterization and coagulopathy were independent influencing factors of ADR. Sixty-six patients underwent therapeutic drug monitoring (TDM), which increased the probability of achieving the target plasma trough concentration (Cmin). Among children < 2 years old underwent TDM, 88.89% (8/9) achieved therapeutic concentration, and the probability was higher than that of the older groups. Days of VRC treatment had a positive but not statistically significant effect on achievement of target Cmin. Hypoalbuminemia and days of antimicrobials treatment were independent influencing factors of Cmin distribution.

CONCLUSION

Attention to the off-label use of VRC in children < 2 years old, hypoalbuminemia and coagulopathy correction, potential drug interactions with VRC, and ADR monitoring is crucial for clinical efficacy and safety.

Isavuconazole as an optimal treatment option for multiple pathogens induced severe pneumonia in immunocompromised hosts: a case series report

Background

Treating severe pneumonia caused by multiple pathogens in immunocompromised hosts (ICHs) presents significant challenges. Isavuconazole (ISA), a next-generation triazole antifungal agent, has shown promise in managing fungal infections. However, clinical evidence regarding its efficacy in cases of complex infections involving multiple pathogens in ICHs remains limited.

Case presentation

This study describes a case series of three ICHs diagnosed with severe pneumonia, including invasive aspergillosis (IA). All three patients received ISA-based personalized antimicrobial regimens. Alleviation of symptoms was observed in all patients following antimicrobial treatment, with notable absorption of pulmonary lesions and no significant hepatorenal toxic side effects, with no recurrence observed.

Conclusion

ICHs are highly susceptible to fungal infections, and the severity of their condition can escalate dramatically, with a significant risk of mortality, when severe pneumonia caused by multiple pathogens occurs concurrently. A stepwise treatment strategy, which balances the use between immunosuppressant and effective antimicrobial treatment, is crucial. The selection of appropriate drugs should account for potential adverse drug reactions (ADRs). In this case series, ISA exhibited robust efficacy in treating IA with minimal ADRs. Therefore, ISA represents a valuable option for managing severe pneumonia in ICHs, particularly in the context of IA and co-infections caused by multiple pathogens.

Promising antifungal properties of the orally active autophagy inhibitor SBP-7455 against fluconazole-resistant Candida clinical isolates

Candida species, the single most common cause of fungal infections, are major opportunistic pathogens. Novel antifungal agents are needed to address the threat of Candida infections resistant to first-line antifungal agents and those that are multi-drug resistant, both being increasingly reported. Here, we explore the antifungal properties of the novel autophagy inhibitor SBP-7455, whose anticancer effects have been recently described. Using broth microdilution, SBP-7455 inhibited the fluconazole-resistant standard C. albicans strain with minimum inhibitory concentration (MIC) values of 43.91 and 21.95 µM in the presence and absence of d-glucose, respectively. SBP-7455 inhibited the growth of six fluconazole-resistant Candida clinical isolates (MIC range 5.48-87.82 µM). Using the checkerboard assay, the fluconazole-resistant standard strain (MIC > 250 µg/ml) was rendered sensitive (MIC = 3.9 µg/ml) to fluconazole when combined with SBP-7455, but combining SBP-7455 with chloroquine was antagonistic. Compared with control, SBP-7455 treated cell membranes showed disrupted integrity and bulging on SEM images. Treatment with SBP-7455 significantly (P < 0.01) increased reduced glutathione levels with no significant change in nitric oxide levels, possibly adapting to oxidative stress induced by autophagy inhibition. Taken together, our results report for the first time the promising antifungal effects of the dual autophagy inhibitor SBP-7455 against fluconazole-resistant Candida, worthy of further investigation.

Biofilm-Associated Candidiasis: Pathogenesis, Prevalence, Challenges and Therapeutic Options

The rising prevalence of fungal infections, especially those caused by Candida species, presents a major risk to global health. With approximately 1.5 million deaths annually, the urgency for effective treatment options has never been greater. Candida spp. are the leading cause of invasive infections, significantly impacting immunocompromised patients and those in healthcare settings. C. albicans, C. parapsilosis and the emerging species C. auris are categorized as highly dangerous species because of their pathogenic potential and increasing drug resistance. This review comparatively describes the formation of microbial biofilms of both bacterial and fungal origin, including major pathogens, thereby creating a novel focus. Biofilms can further complicate treatment, as these structures provide enhanced resistance to antifungal therapies. Traditional antifungal agents, including polyenes, azoles and echinocandins, have shown effectiveness, yet resistance development continues to rise, necessitating the exploration of novel therapeutic approaches. Antimicrobial peptides (AMPs) such as the anti-biofilm peptides Pom-1 and Cm-p5 originally isolated from snails represent promising candidates due to their unique mechanisms of action and neglectable cytotoxicity. This review article discusses the challenges posed by Candida infections, the characteristics of important species, the role of biofilms in virulence and the potential of new therapeutic options like AMPs.

Emergence of invasive candidiasis with multiple Candida species exhibiting azole and echinocandin resistance

Background

Invasive candidiasis (IC) is an increasingly common, expensive, and potentially fatal infection. However, IC caused by multiple Candida species is rarely reported in China. Herein, we revealed a complex IC caused by multiple Candida species, comprising the rare C. norvegensis, C. albicans, C. glabrata, and C. tropicalis. The resistance mechanism of azole and echinocandin resistance were explored further.

Methods

The isolates were confirmed using internal transcribed spacer (ITS) sequencing. The resistance mechanisms were investigated using PCR-based sequencing, quantitative real-time reverse transcription PCR, and rhodamine 6G efflux quantification.

Results

Antifungal susceptibility testing showed this complex infection was associated with cross-resistance to azole and echinocandin drugs. For C. glabrata, the acquired echinocandin resistance was likely caused by a novel mutational pattern (1,3-beta-D-glucan synthase subunits FKS1-S629P and FKS2-W1497stop) while the acquired azole resistance in C. glabrata RJ05 was related to complex mechanisms including enhanced efflux activity, pleiotropic drug resistance 1 (PDR1) mutation, and increased expression of Candida drug resistance 1 (CDR1) and CDR2. Additionally, the azole resistance of C. tropicalis was caused by two lanosterol 14-alpha demethylase (ERG11) mutations: Y132F and S154F.

Conclusion

Our study revealed a case of clinically complex, multiple Candida invasive infections, further uncovering the resistance mechanisms to azoles and echinocandins. These findings provide valuable references for the diagnosis and treatment of invasive candidiasis (IC) in clinical practice.

New Strategies to Combat Human Fungal Infections

Over the past few decades, numerous reports have highlighted the significant rise in fungal infections worldwide, contributing to considerable morbidity, mortality, and escalating healthcare costs [...].