A Systematic Review of the Therapeutic Outcome of Mucormycosis

Background

Mucormycosis is a potentially lethal mycosis. We reviewed peer-reviewed publications on mucormycosis to assess therapeutic outcomes.

Methods

A systematic literature search using the Ovid MEDLINE and EMBASE databases identified manuscripts describing human mucormycosis diagnosed according to European Organization for Research and Treatment of Cancer and the Mycoses Study Group criteria with therapeutic outcomes published from 2000 to 2022.

Results

In 126 articles, 10 335 patients were described, most from Asia (n = 6632, 66%). Diabetes was the most frequent underlying disease (n = 6188, 60%); 222 (2.1%) patients had no underlying diseases. The dominant clinical form was rhino-orbitocerebral (n = 7159, 69.3%), followed by pulmonary (n = 1062, 10.3%). Of 5364 patients with outcome data, amphotericin B monotherapy (n = 3749, mortality 31.5%) was most frequent, followed by amphotericin B + azole (n = 843, mortality 6.6%; P < .0001), amphotericin B followed by azole (n = 357, mortality 13.7%; P < .0001), posaconazole only (n = 250, mortality 17.2%; P < .0001), and isavuconazole only (n = 65, mortality 24.6%; P = .24). Duration and dose of antifungals varied widely. Documented outcomes from surgical resections in 149 patients found that 47 of 125 died (37.6%), compared with 16 of 24 (66.7%) patients who did not undergo surgery (P = .008).

Conclusions

Mucormycosis is more frequently reported in Asia than in Europe and is often linked to diabetes. Antifungal therapy, usually with surgery, is frequently effective for mucormycosis.

Mucormycosis in Human Immunodeficiency Virus-Infected Individuals: A Systematic Review of Case Reports

Mucormycosis in human immunodeficiency virus (HIV) infection is uncommon; notably, many cases have additional predisposing factors. Whether mucormycosis differs in HIV-affected individuals with and without additional risk factors (e.g., neutropenia, diabetes mellitus, and transplantation) remains unclear. In this systematic review, we identified 94 cases of HIV and mucormycosis classifiable into three groups: (1) HIV with additional risk factors (n = 50), (2) intravenous drug users (IVDU, n = 24), and (3) no other risk factor (n = 19) for mucormycosis. The most common presentation in IVDU was renal (41.7%) and cerebral mucormycosis (39.2%), whereas rhino-orbital mucormycosis (ROM, 4.2%) was uncommon. In the other two groups, ROM was the most common presentation. Rhizopus was the most frequently isolated Mucorales; however, in IVDU, Lichtheimia was the most common. The overall mortality was 53% and not significantly different in the three groups. Mucormycosis in HIV-infected individuals is rare without additional risk factors or IVDU.

Widespread Lichtheimia Infection in a Patient with Extensive Burns: Opportunities for Novel Antifungal Agents

The Mucorales fungi-formerly classified as the zygomycetes-are environmentally ubiquitous fungi, but generally rare causes of clinical infections. In the immunocompromised host, however, they can cause invasive, rapidly spreading infections that confer a high risk of morbidity and mortality, often despite surgical and antifungal therapy. Patients with extensive burn injuries are particularly susceptible to skin and soft-tissue infections with these organisms. Here, we present a case of Lichtheimia infection in a patient with extensive full-thickness burns that required significant and repeated surgical debridement successfully treated with isavuconazole and adjunctive topical amphotericin B washes. We also review the available literature on contemporary antifungal treatment for Lichtheimia species and related Mucorales fungi.

Five new species of the obligate mycoparasite Syncephalis (Zoopagales, Zoopagomycotina) from soil

More than 520 soil samples were surveyed for species of the mycoparasitic zygomycete genus Syncephalis using a culture-based approach. These fungi are relatively common in soil using the optimal conditions for growing both the host and parasite. Five species obtained in dual culture are unknown to science and are described here: (i) S. digitata with sporangiophores short, merosporangia separate at the apices, simple, 3-5 spored; (ii) S. floridana, which forms galls in the host and has sporangiophores up to 170 µm long with unbranched merosporangia that contain 2-4 spores; (iii) S. pseudoplumigaleta, with an abrupt apical bend in the sporophore; (iv) S. pyriformis with fertile vesicles that are long-pyriform; and (v) S. unispora with unispored merosporangia. To facilitate future molecular comparisons between species of Syncephalis and to allow identification of these fungi from environmental sampling datasets, we used Syncephalis-specific PCR primers to generate internal transcribed spacer (ITS) sequences for all five new species.

Mucormycoses caused by Lichtheimia species

Mucormycoses are life-threatening infections with fungi from the order Mucorales (Mucoromycotina). Although mucormycoses are uncommon compared to other fungal infections, e.g. aspergillosis and candidiasis, the number of cases is increasing especially in immunocompromised patients. Lichtheimia (formerly Absidia) species represent the second to third most common cause of mucormycoses in Europe. This mini review presents current knowledge about taxonomy and clinical relevance of Lichtheimia species. In addition, clinical presentation and risk factors will be discussed. Proper animal infection models are essential for the understanding of the pathogenesis and the identification of virulence factors of fungal pathogens. To date, several animal models have been used to study Lichtheimia infection. A brief overview of the different models and the main conclusions from the infection experiments is summarised in this review.