Higher In vitro Proliferation Rate of Rhizopus oryzae in Blood of Diabetic Individuals in Chronic Glycaemic Control Compared with Non-diabetic Individuals

The cross-talk between mucormycosis, steroids and diabetes mellitus amidst the global contagion of COVID-19

Mucormycosis is an opportunistic fungal disease that targets individuals having an impaired immune system due to a wide array of risk factors including HIV-AIDS, immunosuppressive therapy, diabetes mellitus, etc. The current explosive outbreak of coronavirus disease 2019 (COVID-19) has become the latest threat to such patients who are already susceptible to secondary infections. Physiological outcomes of COVID-19 end up in a cascade of grave alterations to the immunological profile and irreparable harm to their respiratory passage, heart and kidneys. Corticosteroidal treatment facilitates faster recovery and alleviates the adverse pathological effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). But clinical reports lend this approach a darker perspective especially if these patients have pre-existing diabetes mellitus. The mucormycotic fungal genera belonging to the order Mucorales not only survive but thrive under the comorbidity of COVID-19 and diabetes, often staying undetected until they have inflicted irreversible damage. Steroidal usage has been noted to be a common thread in the sudden spurt in secondary fungal infections among COVID-19 cases. Once considered a rare occurrence, mucormycosis has now acquired a notoriously lethal status in mainstream medical hierarchy. We set out to investigate whether corticosteroidal therapy against COVID-19 emboldens the development of mucormycosis. We also assess the conditions brought forth by steroidal usage and uncontrolled progression of diabetes in COVID-19 cases and their effect on the susceptibility towards mucormycosis.

Host-Pathogen Molecular Factors Contribute to the Pathogenesis of Rhizopus spp. in Diabetes Mellitus

Purpose of Review

Infectious diseases represent up to 12% of all deaths in people with diabetes mellitus (DM). The development and progression of DM generate a chronic inflammatory state with unique characteristics that have been exploited by some pathogens; one of them is Rhizopus spp., a fungus considered the causative agent of mucormycosis. This disease has a poor prognosis with high mortality rates, and the apparition of resistant isolates each year has become a worrying concern. DM is an actual and continuing health problem, and for that reason, it is of foremost importance to study the pathogenesis of mucormycosis to generate new prevention and treatment strategies.

Recent Findings

The worldwide incidence of mucormycosis has increased in recent years. The pathogenic mechanisms and factors identified in Rhizopus spp. are the cell wall, spore germination, proteins, and enzymes related to iron sequestration, CotH fungal protein, positive regulation of the GRP78 cell receptor, and immune evasion due to survival within phagocytes, among others. The physiopathology of DM offers favorable conditions for the successful replication of Rhizopus spp.

Summary

The main reason for increase of incidence of mucormycosis caused by Rhizopus spp. has been associated with the rise of worldwide prevalence of DM. Knowing the fungal pathogenic mechanisms as well as the relationships between Rhizopus with the microenvironment found in the human body will undoubtedly help generate better antifungals to enhance treatment outcomes. Nowadays, some strategies to combat the fungus are based on the knowledge of its proteins, cellular interactions, and iron metabolism.

Successful posaconazole salvage therapy for rhinocerebral mucormycosis in a child with leukemia. Review of the literature

BACKGROUND

Mucormycosis is a fungal infection caused by species of the Mucorales order. These microorganisms are angioinvasive, with rapid disease progression and potentially lethal in its rhinocerebral form.

CASE REPORT

We present the case of a 12-year-old female with trisomy 21, acute lymphoblastic leukemia and diabetes, with fever and neutropenia who developed rhinocerebral mucormicosis. After treatment with amphotericin B lipid complex and extensive surgery, disease progressed and posaconazole was added as salvage treatment with full remission of the infection. Four years after diagnosis the patient continues without relapse of mucormycosis or leukemia.

CONCLUSIONS

This case highlights the use of posaconazole as either monotherapy or combined therapy. Although it is still debated, it can be considered an option for salvage treatment in children with non-responding mucormycosis, despite lack of standard dosage in pediatric patients.