Microbiota signatures associated with invasive Candida albicans infection in the gastrointestinal tract of immunodeficient mice

Gene expression profiling reveals host defense strategies for restricting Candida albicans invasion and gastritis to the limiting ridge of the murine stomach

Candida albicans is a fungal constituent of the human gastrointestinal microbiota that can tolerate acidic environments like the stomach, where it can be associated with ulcers and chronic gastritis. In mice, C. albicans induces gastritis without concurrent intestinal inflammation, suggesting that the stomach is particularly prone to fungal infection. We previously showed that C. albicans invasion in the limiting ridge does not extend to or elicit an inflammatory response in the adjacent glandular region, indicating regionalized gastritis in the murine stomach. However, the molecular pathways involved in the host response to C. albicans specifically in the limiting ridge have not been investigated. Here, we found that gastric dysbiosis was associated with C. albicans limiting ridge colonization and gastritis. We isolated the limiting ridge and evaluated the expression of over 90 genes involved in mucosal responses. C. albicans infection triggered a type 3 immune response marked by elevated Il17a, Il17f, Il1b, Tnf, and Il36g, as well as an upregulation of Il12a, Il4, Il10, and l13. Chemokine gene induction (including Ccl2, Ccl3, Ccl4, Ccl1l, Cxcl1, Cxcl2, Cxcl9, and Cxcl10) coincided with an influx of neutrophils, monocytes/macrophages, and eosinophils. Hyphal invasion caused tissue damage, epithelial remodeling, and upregulation of genes linked to epithelium signaling and antimicrobial responses in the limiting ridge. Our findings support a need for continued exploration into the interactions between the immunological milieu, the host microbiota, and clinical interventions such as the use of antibiotics and immunotherapeutic agents and their collective impact on invasive candidiasis risk.

Multi-omics analysis reveals indicator features of microbe-host interactions during Candida albicans colonization and subsequent infection

Introduction

Candida albicans gastrointestinal (GI) colonization is crucial for the onset of invasive disease. This research encompassed 31 patients diagnosed with Candida spp. bloodstream infections during their admission to a university hospital in China.

Methods

We explored risk factors associated with C. albicans GI colonization and ensuing translocated infection. Animal models were established via gavage with clinical isolates of C. albicans to induce GI tract colonization and subsequent kidney translocation infection. Our analysis is focused on 16S rRNA gene sequencing, metabolomics of colon contents, and transcriptomics of colon tissues, examining the intestinal barrier, inflammatory responses, and immune cell infiltration.

Results

This study observed that down-regulation of programmed cell death 1 (PD-1) in colon tissues is likely linked to the progression from C. albicans colonization to translocated infection. Notably, reductions in Dubosiella abundance and Short-chain fatty acids (SCFA) levels, coupled with increases in Mucispirillum and D-erythro-imidazolylglycerol phosphate, were indicator features during the advancement to translocated invasive infection in hosts with rectal colonization by C. albicans and lower serum protein levels.

Conclusion

Given the similarity in intestinal bacterial communities and metabolome profiles, antifungal treatment may not be necessary for patients with nonpathogenic C. albicans colonization. The reduced expression of PD-1 in colon tissues may contribute to the transition from colonized C. albicans to subsequent translocated infection. The indicator features of decreased Dubosiella abundance and SCFA levels, coupled with increased Mucispirillum and D-erythro-imidazolylglycerol phosphate, are likely linked to the development of translocated invasive infection in hosts colonized rectally by C. albicans with lower serum protein levels.

Importance

Candida albicans invasive infections pose a significant challenge to contemporary medicine, with mortality rates from such fungal infections remaining high despite antifungal treatment. Gastrointestinal colonization by potential pathogens is a critical precursor to the development of translocated infections. Consequently, there is an increasing demand to identify clinical risk factors, multi-omics profiles, and key indicators to prevent the progression to translocated invasive infections in patients colonized rectally by C. albicans.

Essential oils as promising treatments for treating Candida albicans infections: research progress, mechanisms, and clinical applications

Candida albicans: (C. albicans) is a prevalent opportunistic pathogen that can cause severe mucosal and systemic fungal infections, leading to high morbidity and mortality rates. Traditional chemical drug treatments for C. albicans infection have limitations, including the potential for the development of drug resistance. Essential oils, which are secondary metabolites extracted from plants, have gained significant attention due to their antibacterial activity and intestinal regulatory effects. It makes them an ideal focus for eco-friendly antifungal research. This review was aimed to comprehensively evaluate the research progress, mechanisms, and clinical application prospects of essential oils in treating C. albicans infections through their antibacterial and intestinal regulatory effects. We delve into how essential oils exert antibacterial effects against C. albicans infections through these effects and provide a comprehensive analysis of related experimental studies and clinical trials. Additionally, we offer insights into the future application prospects of essential oils in antifungal therapy, aiming to provide new ideas and methods for the development of safer and more effective antifungal drugs. Through a systematic literature review and data analysis, we hope to provide insights supporting the application of essential oils in antifungal therapy while also contributing to the research and development of natural medicines. In the face of increasingly severe fungal infections, essential oils might emerge as a potent method in our arsenal, aiding in the effective protection of human and animal health.

Microbiome Dynamics: A Paradigm Shift in Combatting Infectious Diseases

Infectious diseases have long posed a significant threat to global health and require constant innovation in treatment approaches. However, recent groundbreaking research has shed light on a previously overlooked player in the pathogenesis of disease-the human microbiome. This review article addresses the intricate relationship between the microbiome and infectious diseases and unravels its role as a crucial mediator of host-pathogen interactions. We explore the remarkable potential of harnessing this dynamic ecosystem to develop innovative treatment strategies that could revolutionize the management of infectious diseases. By exploring the latest advances and emerging trends, this review aims to provide a new perspective on combating infectious diseases by targeting the microbiome.