Case report: A rare case of pulmonary mucormycosis caused by Lichtheimia ramosa in pediatric acute lymphoblastic leukemia and review of Lichtheimia infections in leukemia

Santiago A, Hallsworth J, Cordeiro T, Voigt K, Kirk P, Crous P, Júnior M, Elsztein C, Lee H. New Mucorales from opposite ends of the world

The Mucorales is a group of ancient fungi with global distribution. In the current study we accessed mucoralean fungi isolated from two countries on opposite sides of the Earth and in different hemispheres: South Korea and Brazil. Mucorales isolates were obtained from freshwater, soil, invertebrates, and fruit seeds and identified using phenotypic techniques combined with the DNA sequence data. These analyses revealed 15 new species including one that we affiliated to a newly proposed genus, Neofennellomyces. Names proposed for these 15 new species are Absidia cheongyangensis, A. fluvii, A. kunryangriensis, A. paracylindrospora, A. tarda, A. variiprojecta, A. variispora, Backusella varians, Mucor albicolonia, M. aurantiacus, M. cryophilus, M. glutinatus, M. paraorantomantidis, M. timomeni, and Neofennellomyces jeongsukae. Of these new species, 12 were isolated from South Korea: A. cheongyangensis, A. fluvii, A. kunryangriensis, A. paracylindrospora, B. varians, M. albicolonia, M. aurantiacus, M. cryophilus, M. glutinatus, M. paraorantomantidis, M. timomeni, and N. jeongsukae, and three from Brazil: A. tarda, A. variiprojecta, and A. variispora. Niche specificity of these fungi is discussed including newly recorded invertebrate hosts and a new geographic distribution for species of Backusella, Circinella, Cunninghamella, and Mucor. Given these findings, we provide an inventory of Mucorales. Taxonomic novelties: New genus: Neofennellomyces Hyang B. Lee & T.T.T. Nguyen. New species: Absidia cheongyangensis Hyang B. Lee & T.T.T. Nguyen, Absidia fluvii Hyang B. Lee, A.L. Santiago, P.M. Kirk, K. Voigt & T.T.T. Nguyen, Absidia kunryangriensis Hyang B. Lee & T.T.T. Nguyen, Absidia paracylindrospora Hyang B. Lee & T.T.T. Nguyen, Absidia tarda T.R.L. Cordeiro, Hyang B. Lee & A.L. Santiago, Absidia variiprojecta T.R.L. Cordeiro & A.L. Santiago, Absidia variispora T.R.L. Cordeiro & A.L. Santiago, Backusella varians Hyang B. Lee & T.T.T. Nguyen, Mucor aurantiacus Hyang B. Lee & T.T.T. Nguyen, Mucor cryophilus Hyang B. Lee & T.T.T. Nguyen, Mucor albicolonia Hyang B. Lee & T.T.T. Nguyen, Mucor glutinatus Hyang B. Lee & T.T.T. Nguyen, Mucor paraorantomantidis Hyang B. Lee & T.T.T. Nguyen, Mucor timomeni Hyang B. Lee & T.T.T. Nguyen, Neofennellomyces jeongsukae Hyang B. Lee & T.T.T. Nguyen. Citation: Nguyen TTT, de A. Santiago ALCM, Hallsworth JE, Cordeiro TRL, Voigt K, Kirk PM, Crous PW, Júnior MAM, Elsztein C, Lee HB (2024). New Mucorales from opposite ends of the world. Studies in Mycology 109: 273-321. doi: 10.3114/sim.2024.109.04.

A rare intestinal mucormycosis caused by Lichtheimia ramosa in a patient with diabetes: a case report

Mucormycosis is an aggressive fungal disease. Gastrointestinal mucormycosis is rare, but its clinical symptoms lack specificity and mortality is high. Here, we report a case of intestinal mucormycosis caused by Lichtheimia ramosa in a 65-year-old woman with diabetes mellitus. The patient exhibited extensive mucosal tissue damage in the colon, with broad, undivided filamentous fungal hyphae present in the intestinal tissue. Therefore, the patient was suspected to have a filamentous fungal infection. Colonic tissue samples were obtained for fungal culture, and the fungus was identified as L. ramosa based on morphology and DNA sequencing. This case highlights the importance of pathologists and microbiologists in identifying pathogenic fungi and the significance of screening for mucormycosis in high-risk patient populations.

Co-occurrence of rhino-orbital mucormycosis and acute lymphoblastic leukemia post-COVID-19 infection in a young adolescent male: A case report from a low middle-income country

Key Clinical Message

Immunosuppression from B-acute lymphoblastic leukemia (B-ALL) chemotherapy and a preceding COVID-19 infection may predispose patients to rare complications such as rhino-orbital mucormycosis. Hence, a high index of suspicion should be maintained by physicians (and oncologists) if patients undergoing B-ALL treatment present with orofacial symptoms and ophthalmological manifestations such as peri-orbital swelling, ophthalmoplegia, and loss of vision, suggestive of infection.

Abstract

Mucormycosis is a severe fungal infection that poses significant mortality and morbidity risks, particularly in immunocompromised individuals. We present a rare case of a 16-year-old patient with rhino-orbital mucormycosis following B-acute lymphoblastic leukemia (B-ALL) treatment and concurrent COVID-19 infection. We describe the clinical presentation, diagnosis, treatment, and outcome of this patient, and discuss the possible interactions and implications of these three conditions. A young 16-year-old male patient without significant clinical history was admitted with complaints of low-grade intermittent fever, fatigue, malaise, restlessness, and unexplained weight loss for the past 2 months. A bone marrow biopsy confirmed the diagnosis of B-ALL. Following the diagnosis of B-ALL, the patient underwent initiation of chemotherapy. Following the initial two cycles of chemotherapy, the patient experienced fever and cough and tested positive for COVID-19 infection. Nearly a week later, the patient presented to the chemotherapy emergency department with a clinical picture characterized by a fever up to 39°C associated with left facial swelling, severe headache, purulent rhinorrhea, and foreign body sensation in the ipsilateral nostril. The following day, erythema and left eyelid edema were observed, with ocular opening limitation. The diagnosis was confirmed based on the positive result of polymerase chain reaction for left-sided mucormycosis. Initial administration of liposomal and lipid amphotericin B at 1-1.5 mg/kg/d doses for 4-6 weeks was followed by surgical debridement of necrotic tissue on the left side of the face and nose. Subsequent ophthalmological examinations showed normal conditions of the left eye. The case underscores the importance of heightened clinical suspicion, early diagnosis through imaging and molecular techniques, aggressive multimodal therapy, and close interdisciplinary collaboration for improved outcomes in such rare and challenging clinical scenarios.

Prophylactic treatment with Bacteroides uniformis and Bifidobacterium bifidum counteracts hepatic NK cell immune tolerance in nonalcoholic steatohepatitis induced by high fat diet

Hepatic immunity is one of the driving forces for the development of nonalcoholic steatohepatitis (NASH), and targeting gut microbiota is believed to affect the hepatic immune constitution. Here, we aimed to investigate the hepatic immunological state in NASH, with a specific emphasis on natural killer (NK) cells. In addition, we aimed to identify the contributing species that target hepatic immunity to provide new directions and support the feasibility of immunotherapy for NASH. A possible NASH population was determined by combination of long-term severe fatty liver, metabolic disorders and increased serum CK18 to detect serum immune factors and gut microbiota. NASH was induced in mice fed a high-fat diet to verify the prophylactic effect of the functional species on the immunopathology and development of NASH. Hepatic immunologic state was examined, and the effector functions of NK cells were detected. Hepatic transcriptome, proteomic, and fecal metagenome were performed. We observed a statistical increase in serum IL-10 (p < 0.001) and non-statistical decrease in interferon-γ and IL-6 in NASH population, hinting at the possibility of immune tolerance. Fecal Bacteroides uniformis and Bifidobacterium bifidum were abundant in healthy population but depleted in NASH patients. In NASH mice, hepatic CD8+T cells, macrophages, and dendritic cells were increased (p < 0.01), and NK cells were inhibited, which were identified with decreased granzyme B (p < 0.05). Bacteroides uniformis and Bifidobacterium bifidum improved hepatic pathological and metabolic cues, increased hepatic NK cells and reduced macrophages (p < 0.05). Bacteroides uniformis also restored hepatic NK cell function, which was identified as increased CD107a (p < 0.05). Transcriptional and translational profiling revealed that the functional species might restore the function of hepatic NK cells through multiple pathways, such as reduction of inhibitory molecules in NK cells. Bacteroides uniformis and Bifidobacterium bifidum are novel prophylactics for NASH that restore the impaired function of hepatic NK cells.

A case of COVID-19-associated mucormycosis due to Lichtheimia ramosa

BACKGROUND

Mucormycosis is a life-threatening invasive fungal infection in immunocompromised and COVID-19 patients.

CASE REPORT

Here, we report a fatal rhino-orbito-cerebral mucormycosis caused by Lichtheimia ramosa, in a 79-year-old diabetic female. She was initially admitted to the hospital for COVID-19 infection and received broad-spectrum antibiotics and corticosteroids. After 1 month, she was admitted again because of persistent headaches and decreased right eye movement when the computed tomography scan showed mucosal thickening and opacification of paranasal sinuses. Microbiological investigations, including culture and direct microscopy, and histopathological findings confirmed the diagnosis of proven mucormycosis. The isolated causal agent was identified as Lichtheimia ramosa by sequencing the entire ITS region of nuclear ribosomal DNA. Despite surgical debridement and administration of liposomal amphotericin B 5 mg/kg/day, the patient's level of consciousness suddenly deteriorated; she was intubated and mechanically ventilated in the ICU and died on the same day.

CONCLUSION

To our knowledge, this is the first worldwide case of COVID-19-associated rhino-orbito-cerebral mucormycosis due to Lichtheimia ramosa.

The application of metagenomic next-generation sequencing in patients with infection or colonization caused by Lichtheimia species

BACKGROUND

Mucormycosis is considered the fourth most common invasive fungal disease after candidiasis, aspergillosis and cryptococcosis. Lichtheimia species accounted for 5%-29% of all mucormycosis. However, available data on species-specific analysis of Lichtheimia infections are limited.

METHODS

This study included nine patients hospitalized in five hospitals in two cities in south China with mucormycosis or colonization caused by Lichtheimia species, diagnosed mainly by metagenomic next-generation sequencing (mNGS). The corresponding medical records were reviewed, and the clinical data analyzed included demographic characteristics, site of infection, host factors and type of underlying disease, diagnosis, clinical course, management, and prognosis.

RESULTS

In this study, nine patients with Lichtheimia infections or colonization had a recent history of haematological malignancy (33.3%), solid organ transplants (33.3%), pulmonary disease (22.2%), and trauma (11.1%) and were categorized as 11.1% (one case) proven, 66.7% (six cases) probable mucormycosis and 22.2% (two cases) colonization. Pulmonary mucormycosis or colonization was the predominant presentation in 77.8% of cases and mucormycosis caused by Lichtheimia resulted in death in four out of seven patients (57.1%).

CONCLUSION

These cases highlight the importance of early diagnosis and combined therapy for these sporadic yet life-threatening infections. Further studies on the diagnosis and control of Lichtheimia infection in China are required.

Discovery of a New Lichtheimia (Lichtheimiaceae, Mucorales) from Invertebrate Niche and Its Phylogenetic Status and Physiological Characteristics

Species of Lichtheimia are important opportunistic fungal pathogens in the order Mucorales that are isolated from various sources such as soil, indoor air, food products, feces, and decaying vegetables. In recent years, species of Lichtheimia have become an emerging causative agent of invasive mucormycosis. In Europe and USA, Lichtheimia are the second and third most common causal fungus of mucormycosis, respectively. Thus, the aim of this study was to survey the diversity of species of Lichtheimia hidden in poorly studied hosts, such as invertebrates, in Korea. Eight Lichtheimia strains were isolated from invertebrate samples. Based on morphology, physiology, and phylogenetic analyses of ITS and LSU rDNA sequence data, the strains were identified as L. hyalospora, L. ornata, L. ramosa, and a novel species, L. koreana sp. nov. Lichtheimia koreana is characterized by a variable columellae, sporangiophores arising solitarily or up to three at one place from stolons, and slow growth on MEA and PDA at all temperatures tested. The new species grows best at 30 and 35 °C and has a maximum growth temperature of 40 °C. Detailed descriptions, illustrations, and a phylogenetic tree are provided.