Invasive Fungal Infections Among Immunocompromised Patients in Critical Care Settings: Infection Prevention Risk Mitigation

Fluconazole and levofloxacin prophylaxis are ineffective strategies for preventing infections in acute myeloid leukemia patients undergoing chemotherapy

INTRODUCTION

Acute myeloid leukemia patients are at high risk for infections, which contribute to increased mortality rates of up to 70%. The use of antimicrobial prophylaxis has been shown to significantly lower rates of infection. Therefore, this retrospective study aimed to evaluate the effect of two agents that showed effective results in the literature, levofloxacin and fluconazole, as prophylaxis strategies in AML patients.

METHODOLOGY

A total of 85 AML patients' medical records treated with a 7+3 induction chemotherapy protocol in the Cancer Hospital of Uberlândia from 2017 to 2021 were screened and their data was collected. Within these patients, groups for analysis were created based on whether the acting physician included an antibacterial or antifungal prophylaxis protocol during induction. Contingency tables with χ² and odds ratio tests were realized to verify associations between prophylaxis and infection. Additionally, Kaplan-Meier curves with Cox regression were developed to analyze survival.

RESULTS

The use of prophylaxis with either fluconazole or levofloxacin did not lower rates of infection, as those who with prophylaxis did not demonstrate significant differences when compared to those without (20.3-29.7%, and 12.3-23.3%, respectively). Patients who suffered a bacterial infection during induction were shown to have lower overall survival, with a similar trend seen in fungal infections.

CONCLUSION

Bacterial and fungal infections were associated with higher rates of induction mortality and lower overall survival, and prophylaxis using fluconazole and levofloxacin did not present any significant difference in preventing these infections in this study, contrasting results found in the literature. The individuality of each treatment center should be taken into consideration and future studies should be realized to better determine the most effective methods and agents for prophylaxis.

Deciphering antifungal and antibiofilm mechanisms of isobavachalcone against Cryptococcus neoformans through RNA-seq and functional analyses

Cryptococcus neoformans has been designated as critical fungal pathogens by the World Health Organization, mainly due to limited treatment options and the prevalence of antifungal resistance. Consequently, the utilization of novel antifungal agents is crucial for the effective treatment of C. neoformans infections. This study exposed that the minimum inhibitory concentration (MIC) of isobavachalcone (IBC) against C. neoformans H99 was 8 µg/mL, and IBC dispersed 48-h mature biofilms by affecting cell viability at 16 µg/mL. The antifungal efficacy of IBC was further validated through microscopic observations using specific dyes and in vitro assays, which confirmed the disruption of cell wall/membrane integrity. RNA-Seq analysis was employed to decipher the effect of IBC on the C. neoformans H99 transcriptomic profiles. Real-time quantitative reverse transcription PCR (RT-qPCR) analysis was performed to validate the transcriptomic data and identify the differentially expressed genes. The results showed that IBC exhibited various mechanisms to impede the growth, biofilm formation, and virulence of C. neoformans H99 by modulating multiple dysregulated pathways related to cell wall/membrane, drug resistance, apoptosis, and mitochondrial homeostasis. The transcriptomic findings were corroborated by the antioxidant analyses, antifungal drug sensitivity, molecular docking, capsule, and melanin assays. In vivo antifungal activity analysis demonstrated that IBC extended the lifespan of C. neoformans-infected Caenorhabditis elegans. Overall, the current study unveiled that IBC targeted multiple pathways simultaneously to inhibit growth significantly, biofilm formation, and virulence, as well as to disperse mature biofilms of C. neoformans H99 and induce cell death.

Targeting Fks1 proteins for novel antifungal drug discovery

Fungal infections are a major threat to human health. The limited availability of antifungal drugs, the emergence of drug resistance, and a growing susceptible population highlight the critical need for novel antifungal agents. The enzymes involved in fungal cell wall synthesis offer potential targets for antifungal drug development. Recent studies have enhanced our focus on the enzyme Fks1, which synthesizes β-1,3-glucan, a critical component of the cell wall. These studies provide a deeper understanding of Fks1's function in cell wall biosynthesis, pathogenicity, structural biology, evolutionary conservation across fungi, and interaction with current antifungal drugs. Here, we discuss the role of Fks1 in the survival and adaptation of fungi, guided by insights from evolutionary and structural analyses. Furthermore, we delve into the dynamics of Fks1 modulation with novel antifungal strategies and assess its potential as an antifungal drug target.

Pan-Indian Clinical Registry of Invasive Fungal Infections Among Patients in the Intensive Care Unit: Protocol for a Multicentric Prospective Study

BACKGROUND

Fungal infections are now a great public health threat, especially in those with underlying risk factors such as neutropenia, diabetes, high-dose steroid treatment, cancer chemotherapy, prolonged intensive care unit stay, and so on, which can lead to mycoses with higher mortality rates. The rates of these infections have been steadily increasing over the past 2 decades due to the increasing population of patients who are immunocompromised. However, the data regarding the exact burden of such infection are still not available from India. Therefore, this registry was initiated to collate systematic data on invasive fungal infections (IFIs) across the country.

OBJECTIVE

The primary aim of this study is to create a multicenter digital clinical registry and monitor trends of IFIs and emerging fungal diseases, as well as early signals of any potential fungal outbreak in any region. The registry will also capture information on the antifungal resistance patterns and the contribution of fungal infections on overall morbidity and inpatient mortality across various conditions.

METHODS

This multicenter, prospective, noninterventional observational study will be conducted by the Indian Council of Medical Research through a web-based data collection method from 8 Advanced Mycology Diagnostic and Research Centers across the country. Data on age, gender, clinical signs and symptoms, date of admission, date of discharge or death, diagnostic tests performed, identified pathogen details, antifungal susceptibility testing, outcome, and so on will be obtained from hospital records. Descriptive and multivariate statistical methods will be applied to investigate clinical manifestations, risk variables, and treatment outcomes.

RESULTS

These Advanced Mycology Diagnostic and Research Centers are expected to find the hidden cases of fungal infections in the intensive care unit setting. The study will facilitate the enhancement of the precision of fungal infection diagnosis and prompt treatment modalities in response to antifungal drug sensitivity tests. This registry will improve our understanding of IFIs, support evidence-based clinical decision-making ability, and encourage public health policies and actions.

CONCLUSIONS

Fungal diseases are a neglected public health problem. Fewer diagnostic facilities, scanty published data, and increased vulnerable patient groups make the situation worse. This is the first systematic clinical registry of IFIs in India. Data generated from this registry will increase our understanding related to the diagnosis, treatment, and prevention of fungal diseases in India by addressing pertinent gaps in mycology. This initiative will ensure a visible impact on public health in the country.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/54672.

Recent developments in membrane targeting antifungal agents to mitigate antifungal resistance

Fungal infections cause severe and life-threatening complications especially in immunocompromised individuals. Antifungals targeting cellular machinery and cell membranes including azoles are used in clinical practice to manage topical to systemic fungal infections. However, continuous exposure to clinically used antifungal agents in managing the fungal infections results in the development of multi-drug resistance via adapting different kinds of intrinsic and extrinsic mechanisms. The unique chemical composition of fungal membranes presents attractive targets for antifungal drug discovery as it is difficult for fungal cells to modify the membrane targets for emergence of drug resistance. Here, we discussed available antifungal drugs with their detailed mechanism of action and described different antifungal resistance mechanisms. We further emphasized structure-activity relationship studies of membrane-targeting antifungal agents, and classified membrane-targeting antifungal agents on the basis of their core scaffold with detailed pharmacological properties. This review aims to pique the interest of potential researchers who could explore this interesting and intricate fungal realm.

Monocyte distribution width (MDW) in sepsis

Sepsis is a life-threatening syndrome due to a dysregulated host response to infection, which can be caused by bacterial, viral, or fungal infection. Thus, it is crucial to know how the different microorganisms influence the levels of a biomarker. In the last decade, monocyte distribution width (MDW) has emerged as a promising sepsis biomarker, especially in acute settings, such as the Emergency Department and Intensive Care Unit. In this article, we explore the relationship between MDW and the different pathogens causing infection. Noteworthy, MDW is not a biological molecule, but it is calculated by a mathematical formula based on monocyte characteristics. Monocytes represent the first line defence against microorganisms and undergo activation upon infection, independently from the invading pathogen. According to the knowledge on the biomarker biology and the few literatures evidence, MDW may be considered a biomarker of sepsis, independent of the causative pathogen. However, further investigations are warranted before drawing definite conclusion.

Discovery and development of novel substituted monohydrazides as potent antifungal agents

Novel substituted monohydrazides synthesized for this study displayed broad-spectrum activity against various fungal strains, including a panel of clinically relevant Candida auris strains. The activity of these compounds was either comparable or superior to amphotericin B against most of the fungal strains tested. These compounds possessed fungistatic activity in a time-kill assay and exhibited no mammalian cell toxicity. In addition, they prevented the formation of fungal biofilms. Even after repeated exposures, the Candida albicans ATCC 10231 (strain A) fungal strain did not develop resistance to these monohydrazides.

Intradural Candida Albicans infection that presented as epidural abscess: A case report

INTRODUCTION

Intradural Candida Albicans infections are rare with limited number of reports on the pathological condition. Among these reports, patients with these infections had radiographic evidence supporting an intradural infection diagnosis. In this case, the patient displayed radiographic imaging suggestive of an epidural infection, but surgery revealed the infection to be intradural. This case exemplifies the importance of considering intradural infections in future cases of suspected epidural abscesses and highlights antibiotic management of intradural C. albicans infections.

PRESENTATION OF CASE

A incarcerated 26-year-old male presented with a rare Candida Albicans infection. He arrived at the hospital unable to walk, and radiographic imaging was consistent with a thoracic epidural abscess. Due to his severe neurologic deficit and spreading edema, surgical intervention was required and revealed no signs of epidural infection. Incision of the dura revealed a purulent material cultured as C. albicans. After six weeks, the intradural infection returned and the patient required another surgery. This operation helped prevent further motor function loss.

DISCUSSION

When patients present with a progressive neurologic deficit and radiographic evidence indicative of an epidural abscess, it is important for surgeons to be mindful of a possible intradural infection. If no abscess is found in the epidural space during surgery, opening the dura in patients with worsening neurologic symptoms must be considered to rule out an intradural infection.

CONCLUSION

Preoperative suspicion of an epidural abscess can differ from intraoperative diagnosis and looking intradural for an infection can prevent further motor loss.

Successful application of photodynamic therapy for skin infection caused by Corynespora cassiicola in an immunosuppressed patient and literature review

Corynespora cassiicola (C. cassiicola) is a common plant pathogen but occasionally causes infections in human skin. Poor outcome and death in such cases were then often reported even after a long course of antifungal treatment. In the present case, the patient was a 54-year-old farmer who presented with a ten-month history of an ulcerative lesion in the right lower extremity after a minor skin trauma. The patient had been undergoing immunosuppressive treatment for nephrotic syndrome for 2 months before the onset of the skin lesion. The fungal isolate from the lesion was identified as C. cassiicola by morphology and molecular sequencing. The patient was treated with ALA-PDT 5 times at 10 days intervals. The lesion disappeared and has not recurred in the 8-month follow-up. To our knowledge, it is the first time ALA-PDT has been used for treatment of a skin lesion caused by C. cassiicola. A retrospective analysis of the literature found 9 cases of C. cassiicola infection. All 9 patients had a history of immunodeficient conditions and had experienced a long course of antifungal therapy. Despite the rigorous antifungal treatment, 2 patients with CARD9 gene deficiency ultimately died. Our case suggests that photodynamic therapy is a potentially beneficial approach for treatment of fungal infection in immunosuppressed patients who failed to respond to antifungal agents.

Vitamin A Deficiency, COVID-19, and Rhino-Orbital Mucormycosis (Black Fungus): An Analytical Perspective

Mucormycosis is a rare but serious opportunistic fungal disease characterized by rhino-orbito-cerebral and pulmonary involvement. It is mainly seen in people with secondary immunosuppression, isolated vitamin A deficiency, measles, and AIDS patients. It showed a rise during the second wave of the COVID-19 epidemic in the spring of 2021 in India, especially in diabetic COVID-19 patients. Vitamin A deficiency is known to cause nutritional immunodeficiency and hence leading the way to increased opportunistic fungal, bacterial, and viral infections. In the eye, it causes keratitis, night blindness, xerophthalmia, conjunctivitis, Bitot spots, keratomalacia, and retinopathy. It also causes decreased tear secretion and deterioration of the anatomical/physiological defense barrier of the eye. The negative impact of vitamin A deficiency has been previously demonstrated in measles, AIDS, and COVID-19. We think that mucormycosis in COVID-19 might be rendered by vitamin A deficiency and that vitamin A supplementation may have preventive and therapeutic values against mucormycosis and other ocular symptoms associated with COVID-19. However, any vitamin A treatment regimen needs to be based on laboratory and clinical data and supervised by medical professionals.

The nature of the fungal cargo induces significantly different temporal programmes of macrophage phagocytosis

Phagocytosis is an essential component of our immune defence against fungal pathogens. Differences in the dynamics of phagocyte migration, recognition, uptake and phagolysosome maturation are dependent on the characteristics of the fungal cargo, and in particular to differences in cell wall composition and cellular morphology. However, studies that have focused on phagocyte interactions with individual fungal species have not enabled comparisons in the kinetics of these interactions to be made between these different species. We therefore used live cell video microscopy to examine the temporal dynamics of phagocytosis for a range of fungal cargoes by thioglycollate-elicited peritoneal macrophages from C57BL/6 mice. Uniform populations of macrophages were challenged at the same time with yeast cells of Candida albicans, Candida glabrata, Saccharomyces cerevisiae and Cryptococcus neoformans (wild-type and an acapsular mutant, cap59Δ), and spores of Aspergillus fumigatus and Mucor circinelloides to enable standardized comparative interactions to be quantified from different stages of phagocytosis. Differences in the rate of uptake of fungal cells varied by up to 26-fold, whilst differences in time to induce phagosome acidification varied by as much as 29-fold. Heat-killing or opsonizing the fungal targets markedly affected the kinetics of the interaction in a species-specific manner. Fungal and macrophage killing assays further revealed cargo-specific differences in phagocytosis and diversity in fungal evasion mechanisms. Therefore, simultaneous assessment of the interaction of macrophages with different fungal pathogens highlighted major differences in the kinetics and growth responses during fungus-phagocyte interactions that are likely to impact on pathogenesis and virulence.