pH manipulation as a novel strategy for treating mucormycosis

Disseminated Cutaneous Mucormycosis Developing in Peristomal Pyoderma Gangrenosum

A patient on long-term glucocorticoid therapy for peristomal pyoderma gangrenosum (PPG) who developed mucormycosis (MM) of the wound with dissemination was presented. The importance of skin biopsy, together with clinical evaluation in patients with PPG who are resistant to conventional therapy or who develop new symptoms related to their PPG is stressed. The risk and pathogenesis of invasive fungal infections with long-term corticosteroid therapy were explored. The epidemiology and detection of mucormycosis is discussed in this article.

Local Administration of Sodium Bicarbonate for Preventing COVID-19 Associated Mucormycosis

Background

One important complication of the coronavirus disease 2019 (COVID-19) is COVID Associated Mucormycosis (CAM), especially in patients with conditions such as diabetes and in immunosuppressed patients. Systemic acidosis, hyperglycemia, and other biochemical factors such as free iron and β-hydroxybutyrate (BHB) can play a role in this complication.

Materials and Methods

Rhizopus oryzae was isolated from a patient at Masih Daneshvari Hospital microbiology laboratory and sub-cultured on the Potato Dextrose Agar (PDA) for 48 hours at 37 °C. Subsequently, Roswell Park Memorial Institute (RPMI) 1640 Broth medium buffered to pH 7.0 with 3-N-morpholino-propane sulfonic acid. Macrodilution and microdilution methods were performed with 8.4% sodium bicarbonate. After 24 hours of incubation at 35°C, the minimum inhibitory concentration (MIC) and the minimum fungicidal concentrations (MFC) were evaluated.

Results

We found that the minimum inhibitory and fungicidal concentrations are at 1.05 % and 2.1 % respectively. Therefore, the minimum concentration is 2% sodium bicarbonate, which requires achieving the desired environmental pH for fungal inhibition and fungicidal effects.

Conclusion

Regulation of systemic acidosis by sodium bicarbonate could be used to decrease the chance of mucormycosis. In addition, According to our study and some others, an alkaline environment can prevent fungal growth. We found that a minimum concentration of 2% sodium bicarbonate is required to achieve the desired mucosal pH to inhibit the fungus. Therefore, sodium bicarbonate inhalation, as a cost-effective and well-tolerated medicine, is a good candidate for the prevention of mucormycosis. In this regard, extensive clinical and laboratory research is needed to achieve more accurate doses and appropriate administration intervals.

Mucormycosis in burns: a review

Mucormycosis is a rare fungal infection with a high mortality rate. It presents with scattered black/necrotic ulcers, white fungal elements, and progression of wounds despite seemingly adequate debridement. Diagnosis is confirmed on wound histology, however this is often delayed. There is currently no comprehensive review of burn related mucormycosis within the literature, making this the first paper to provide evidence-based treatment guidance. We performed a review of publications from 1946 - present. There were 151 cases of mucormycosis complicating burns. The mortality rate was 54.5%, and there was a significant increase in mortality with axial body site involvement compared with isolated peripheral involvement. The standard treatment was prompt and radical debridement. Utilisation of frozen section to guide debridement aided in clinical decision making. No systemic treatment reached statistical significance, however amphotericin B trended towards significance. Although there is no strong evidence for topical amphotericin B or hyperbaric oxygen, there may be benefit in some cases. This study recommends early radical debridement in conjunction with the European Confederation of Medical Mycology guidelines of IV liposomal/lipid complex amphotericin B >5mg/kg/day, with posaconazole 800mg daily in divided doses as a salvage or oral step-down 1.

Antagonistic Interaction of Staphylococcus aureus and Staphylococcus epidermidis with Rhizopus arrhizus Mediated by Phenol Soluble Modulins and Organic Acids

Rhizopus arrhizus (R. arrhizus) is a common causative agent of mucormycosis that usually enters the human body through the respiratory tract and skin. Both these sites harbor staphylococci as a part of the normal microflora, indicating the possibility of interspecies interactions. We aimed to elucidate this interaction and identify the molecular mechanisms involved. Both Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) substantially hindered R. arrhizus radial growth, spore germination, and liquid culture biomass. Secreted components in the stationary-phase supernatant were responsible for this activity. The active components, based on molecular weight-based fractionation, mass spectrometry, and ion exclusion chromatography, were identified as a truncated version of phenol soluble modulin α2 (Δ1Δ2PSMα2) and PSMα3 in S. aureus, PSMδ in S. epidermidis, and organic acids in both the species. Exposure to the phenol soluble modulins (PSMs) extensively damaged the fungal spores and pre-existing hyphae, leading to bleb formation, shriveling, hyphal shrinkage, and cell distortion.

Optimization of Diverse Carbon Sources and Cultivation Conditions for Enhanced Growth and Lipid and Medium-Chain Fatty Acid (MCFA) Production by Mucor circinelloides

Keywords: Mucor circinelloides; microbial lipids; medium-chain fatty acids; culture optimization

Spore Germination of Pathogenic Filamentous Fungi

Fungi, algae, plants, protozoa, and bacteria are all known to form spores, especially hardy and ubiquitous propagation structures that are also often the infectious agents of diseases. Spores can survive for thousands of years, frozen in the permafrost (Kochkina et al., 2012), with the oldest viable spores extracted after 250 million years from salt crystals (Vreeland, Rosenzweig, & Powers, 2000). Their resistance to high levels of UV, desiccation, pressure, heat, and cold enables the survival of spores in the harshest conditions (Setlow, 2016). For example, Bacillus subtilis spores can survive and remain viable after experiencing conditions similar to those on Mars (Horneck et al., 2012). Spores are disseminated through environmental factors. Wind, water, or animal carriage allow spores to be spread ubiquitously throughout the environment. Spores will break dormancy and begin to germinate once exposed to favorable conditions. Germination is the mechanism that converts the spore from a dormant biological organism to one that grows vegetatively and is capable of either sexual or asexual reproduction. The process of germination has been well studied in plants, moss, bacteria, and many fungi (Hohe & Reski, 2005; Huang & Hull, 2017; Vesty et al., 2016). Unfortunately, information on the complex signaling involved in the regulation of germination, particularly in fungi remains lacking. This chapter will discuss germination of fungal spores covering our current understanding of the regulation, signaling, outcomes, and implications of germination of pathogenic fungal spores. Owing to the morphological similarities between the spore-hyphal and yeast-hyphal transition and their relevance for disease progression, relevant aspects of fungal dimorphism will be discussed alongside spore germination in this chapter.

Invasive Fungal Infections Secondary to Traumatic Injury

Invasive fungal infection (IFI) is a rare but serious complication of traumatic injury. The purpose of this article is to review the epidemiology, natural history, mycology, risk factors, diagnosis, treatment, and outcomes associated with post-traumatic IFI in military and civilian populations. The epidemiology of post-traumatic IFI is poorly characterized, but incidence appears to be rising. Patients often suffer from severe injuries and require extensive medical interventions. Fungi belonging to the order Mucorales are responsible for most post-traumatic IFI in both civilian and military populations. Risk factors differ between these cohorts but include specific injury patterns and comorbidities. Diagnosis of post-traumatic IFI typically follows positive laboratory results in the appropriate clinical context. The gold standard of treatment is surgical debridement in addition to systemic antifungal therapy. Patients with post-traumatic IFI may be at greater risk of amputation, delays in wound healing, hospital complications, and death as compared to trauma patients who do not develop IFI. More research is needed to understand the factors surrounding the development and management of post-traumatic IFI to reduce the significant morbidity and mortality associated with this disease.

Cutaneous mucormycosis secondary to penetrative trauma

INTRODUCTION

Mucormycosis is a rare but serious sequelae of penetrating trauma [1-5]. In spite of aggressive management, mortality remains high due to dissemination of infection. We completed a review of literature to determine the most optimal treatment of cutaneous mucormycosis which occurs secondary to penetrating trauma.

METHODS

We completed a review regarding the management of mucormycosis in trauma patients. We selected a total of 36 reports, of which 18 were case-based, for review.

RESULTS

Surgical debridement is a primary predictor of improved outcomes in the treatment of mucormycosis [3,6,7]. Anti-fungal therapy, especially lipid soluble formulation of Amphotericin B, is helpful as an adjunct or when surgical debridement has been maximally achieved. Further research is needed to fully evaluate the impact of topical dressings; negative pressure wound therapy is helpful.

CONCLUSION

An aggressive and early surgical approach, even at the expense of disfigurement, is necessary to reduce mortality in the setting of cutaneous mucormycosis that results from penetrating trauma [4,8,9]. Anti-fungal therapy and negative pressure wound therapy are formidable adjuncts.