Entomophthoromycosis: a challenging emerging disease

Masquerading fungal bowel mass in an adolescent: a clinicopathological challenge

Abdominal masses clubbed with weight loss in the paediatric age group can raise hairs, especially since malignancy is a differential. We present the case of an early adolescent male who presented with abdominal pain and was found to have a mass mimicking a malignancy. The resected surgical specimen revealed entomophthoromycosis of the jejunum and he made a complete recovery following surgery and adjuvant itraconazole. The diagnosis of a fungal aetiology in these cases requires a high index of suspicion and background knowledge of the risk factors, disease occurrence and mode of presentation. Gastrointestinal entomophthoromycosis has an impressive potential for cure if promptly diagnosed and treated.

Clinical characteristics of 5 adult patients with rhinofacial entomophthoromycosis in Thailand

Five patients [mean age: 36 years (range: 22-65)] were diagnosed with rhinofacial entomophthoromycosis at our center during the study period. All patients presented with painless cheek and nasal dorsum swelling with nasal obstruction. All pathology reports confirmed rhinofacial entomophthoromycosis, which is characterized by the Splendore-Hoeppli phenomenon. Conidiobolus coronatus was identified from fungal culture in all patients. All patients were successfully treated with various antifungals.

Disseminated Basidiobolomycosis Caused by Basidiobolus omanensis in a Child with Acute Lymphoblastic Leukemia (ALL). Case Report and Literature Review

Basidiobolomycosis is an uncommon fungal infection caused by the genus Basidiobolus. In immunocompetent children, it usually causes cutaneous infection and rarely affects the gastrointestinal tract, and it is extremely rare for the disease to spread. The present study reports the first case of disseminated basidiobolomycosis caused by Basidiobolus omanensis in a child with acute lymphoblastic leukemia who died as a result of uncontrolled infection and multi-organ failure despite surgical and antifungal therapy with L-AMB and voriconazole. A review of the literature yielded 76 cases, including the current case with the majority of which were reported as invasive gastrointestinal infection. The median age was 4 years (61 male and 15 female) and the majority of these children were from the Middle East (80%), specifically Saudi Arabia (45%). Most patients were treated with systemic antifungal agents (mostly itraconazole and amphotericin B). Surgical intervention was done in 25% of these patients and the death rate was 12%.

Basidiobolomycosis caused by a rare species - Basidiobolus meristosporus

A five-year girl was referred to our centre with swelling over the right lower back. The child was evaluated to rule out chronic cutaneous tuberculosis, lymphoma and soft tissue tumor. Biopsy of the lesion on culture yielded Basidiobolus species. Whole genome sequencing of the isolate identified it as Basidiobolus meristosporus. Sequencing of fungi pathogenic to humans which cannot be differentiated by conventional methods of speciation becomes essential to assign pathogenicity, understand epidemiology and resolve the nuances in the ever-evolving taxonomical classification.

Subcutaneous entomophthoromycosis in an immunocompetent individual: a localised forearm swelling

A man in his 80s with no known comorbidities presented with diffuse swelling on the dorsal aspect of his right forearm for 3 months. Clinical features were suggestive of soft tissue sarcoma of the right forearm. A high resolution CT scan of the thorax showed allergic bronchopulmonary aspergillosis associated with mild mediastinal lymphadenopathy. MRI of the right upper limb showed a suspicious neoplastic/infective aetiology. A core biopsy of the right arm swelling found a granuloma with no malignancy features so an incisional biopsy of the lesion was carried out. This indicated granulomatous inflammation with excessive giant cell reaction and focal panniculitis with the possibility of a mycotic lesion. Bronchoalveolar lavage was negative for tuberculosis and fungal infection. After a multidisciplinary team discussion, the patient was started on antifungal medication. There was a marked reduction in both the size and consistency of the swelling after several weeks of oral itraconazole and potassium iodide solution. The purpose of this report is to increase the awareness of this uncommon treatable condition which, if misdiagnosed, could result in an inappropriate intervention.

An old confusion: Entomophthoromycosis versus mucormycosis and their main differences

Fungal diseases were underestimated for many years. And the global burden of fungal infections is substantial and has increased in recent years. Invasive fungal infections have been linked to several risk factors in humans which basically depend on the individual homeostasis of the patients. However, many fungi can infect even apparently healthy people. Knowledge of these pathogens is critical in reducing or stopping morbidity and/or mortality statistics due to fungal pathogens. Successful therapeutic strategies rely on rapid diagnosis of the causative fungal agent and the underlying disease. However, the terminology of the diseases was updated to existing phylogenetic classifications and led to confusion in the definition of mucormycosis, conidiobolomycosis, and basidiobolomycosis, which were previously grouped under the now-uncommon term zygomycosis. Therefore, the ecological, taxonomic, clinical, and diagnostic differences are addressed to optimize the understanding and definition of these diseases. The term "coenocytic hyphomycosis" is proposed to summarize all fungal infections caused by Mucorales and species of Basidiobolus and Conidiobolus.

Long-Term Monitoring of the Seasonal Abundance of Basidiobolus spp. in Gecko Feces in KwaZulu-Natal (South Africa)

The fungal genus Basidiobolus is typically associated with ectothermic animals such as amphibians and reptiles. In rare cases, it can cause infections in humans, which are often misdiagnosed. Although usually restricted to tropical and subtropical countries, infections have recently been more frequently reported in hot-dry regions such as Arizona and Saudi Arabia. Reptiles such as geckos are known to shed Basidiobolus spp. via feces and frequently live in close proximity to humans. To establish the frequency and burden of Basidiobolus spp. released by geckos in a suburban location, we regularly quantified viable Basidiobolus units per gram of feces from indoors and outdoors over 3.5 years between 2018 and 2022 using a selective medium. Geckos were shedding Basidiobolus spp. in all seasons, with most counts established ranging between 5.0 and 6.5 log₁₀ cfu per gram. Statistically significant seasonal differences per location were only observed for the outside winter counts and, apparently, correlated to lower temperatures, while inside counts showed no seasonal difference. Overall, counts for droppings collected outdoors were significantly higher than counts for droppings collected indoors. Our data confirm that geckos, which frequently enter homes and are global invaders, are a regular source of this fungus.

Phylogenetic Revision and Patterns of Host Specificity in the Fungal Subphylum Entomophthoromycotina

The Entomophthoromycotina, a subphylum close to the root of terrestrial fungi with a bias toward insects as their primary hosts, has been notoriously difficult to categorize taxonomically for decades. Here, we reassess the phylogeny of this group based on conserved genes encoding ribosomal RNA and RNA polymerase II subunits, confirming their general monophyly, but challenging previously assumed taxonomic relationships within and between particular clades. Furthermore, for the prominent, partially human-pathogenic taxon Conidiobolus, a new type species C. coronatus is proposed in order to compensate for the unclear, presumably lost previous type species C. utriculosus Brefeld 1884. We also performed an exhaustive survey of the broad host spectrum of the Entomophthoromycotina, which is not restricted to insects alone, and investigated potential patterns of co-evolution across their megadiverse host range. Our results suggest multiple independent origins of parasitism within this subphylum and no apparent co-evolutionary events with any particular host lineage. However, Pterygota (i.e., winged insects) clearly constitute the most dominantly parasitized superordinate host group. This appears to be in accordance with an increased dispersal capacity mediated by the radiation of the Pterygota during insect evolution, which has likely greatly facilitated the spread, infection opportunities, and evolutionary divergence of the Entomophthoromycotina as well.

Case Report: Pulmonary Conidiobolomycosis in a Vietnamese Pot-Bellied Pig

An adult castrated male Vietnamese pot-bellied pig had a 1-week history of acute dyspnea and lethargy. Minimal diagnostic testing was authorized by the owner, resulting in treatment with a third-generation cephalosporin and a non-steroidal anti-inflammatory drug. Partial improvement was observed after a week; however, the pig died 2 weeks after the initial onset of clinical signs. Macroscopically, ~90% of the left lung was effaced by large masses with a caseonecrotic center. Histologic examination revealed eosinophilic granulomas with myriad, intralesional, negatively staining hyphae highlighted by "sleeves" of hypereosinophilic material (Splendore-Hoeppli material). Infection with an oomycete or "zygomycete" (i.e., organisms of the order Entomophthorales or Mucorales) was initially considered. Pan-fungal PCR and sequencing performed on formalin-fixed, paraffin-embedded lung tissue identified Conidiobolus spp., consistent with a diagnosis of primary pulmonary conidiobolomycosis. There are only a few reports of infections with Conidiobolus spp. (and other members of the order Entomophthorales) in swine. Unlike humans and other animal species, conidiobolomycosis in pigs presents more commonly as a primary pulmonary disease rather than rhinofacial or nasopharyngeal disease.

Basidiobolus omanensis sp. nov. Causing Angioinvasive Abdominal Basidiobolomycosis

Human infectious fungal diseases are increasing, despite improved hygienic conditions. We present a case of gastrointestinal basidiobolomycosis (GIB) in a 20-year-old male with a history of progressively worsening abdominal pain. The causative agent was identified as a novel Basidiobolus species. Validation of its novelty was established by analysis of the partial ribosomal operon of two isolates from different organs. Phylogeny of ITS and LSU rRNA showed that these isolates belonged to the genus Basidiobolus, positioned closely to B. heterosporus and B. minor. Morphological and physiological data supported the identity of the species, which was named Basidiobolus omanensis, with CBS 146281 as the holotype. The strains showed high minimum inhibitory concentrations (MICs) to fluconazole (>64 µg/mL), itraconazole and voriconazole (>16 µg/mL), anidulafungin and micafungin (>16 µg/mL), but had a low MIC to amphotericin B (1 µg/mL). The pathogenic role of B. omanensis in gastrointestinal disease is discussed. We highlight the crucial role of molecular identification of these rarely encountered opportunistic fungi.

Differentiation of Basidiobolus spp. Isolates: RFLP of a Diagnostic PCR Amplicon Matches Sequence-Based Classification and Growth Temperature Preferences

The genus Basidiobolus, known since 1886, is primarily associated with reptiles and amphibians. Although globally distributed, rare infections caused by members of this genus mainly occur in tropical and subtropical regions. Morphological and physiological characteristics were used in the past for the description of species. However, some of these characteristics vary depending on culture conditions. Therefore, most species names are regarded as synonyms of B. ranarum as the only pathogenic species. Yet, not all environmental isolates are necessarily pathogenic. This study aimed to analyze if environmental Basidiobolus isolates can be distinguished reliably based on morpho-physiological and molecular characteristics. Eleven isolates originally obtained from feces of south African reptiles and one type strain, Basidiobolus microsporus DSM 3120, were examined morpho-physiologically. Sequence analysis of the 18S and partial 28S rRNA gene and restriction analysis of a diagnostic amplicon (restriction fragment length polymorphism, RFLP) were performed for all 12 strains. Based on the results obtained, morphological features and the 18S rRNA sequence proved insufficient for the reliable differentiation of isolates. However, isolates were distinguishable by growth temperature profiles, which matched isolate clusters established by partial 28S rRNA gene sequence and restriction analysis of a Basidiobolus specific diagnostic PCR amplicon. Our results indicate that RFLP analysis can be used as a fast screening method to identify Basidiobolus isolates with similar physiological characteristics.

Entomophthoramycosis: A diagnostically challenging presentation of liver space-occupying lesion

Entomophthoramycosis, a rare fungal infection, can mimic various clinical entities. We present a case of entomophthoramycosis affecting a 3-year-old male masquerading as liver tumour, diagnosed on stereotactic biopsy and later on resected specimen. He improved following partial hepatectomy and antifungal therapy. A high index of suspicion and heightened awareness regarding its unique morphological characteristics are required for appropriate management.

Skin and soft tissue infection caused by Basidiobolus spp. in Australia

Fungi from the order Entomophthorales are rare but well recognized cause of tropical fungal infection, typically causing subcutaneous truncal or limb lesions in immunocompetent hosts. They may also mimic malignancy by causing intrabdominal mass, sometimes resulting in obstructive gastrointestinal or renal presentations. A 4-year-old female presented with a progressively growing abdominal wall lesion over several months, developing into acute inflammation of the abdominal wall with systemic symptoms. She underwent surgical debridement and fungal culture of subcutaneous tissue was positive for Basidiobolus spp with characteristic histopathological findings. Treatment with voriconazole followed by itraconazole over a total duration of 6 weeks led to complete resolution.

Basidiobolus spp is an unusual cause of infection with characteristic mycological and histopathological findings. Infection can present in a number of ways ranging from a slow-growing mass in the subcutaneous soft tissue to an invasive mass in the gastrointestinal tract. Identification of its unique beak-like zygospore and Splendore-Hoeppli phenomenon on histopathological specimens can be pathognomonic and could provide the key to early diagnosis. Review of the literature found that timely diagnosis and commencement of antifungal therapy can be curative with or without surgical treatment. Considering the rarity of this tropical infection, this case provides the opportunity for revision of the typical presentations and diagnostic findings of Basidiobolus spp. With early recognition and suitable treatment, outcomes are generally favorable.

Rare indolent zygomycosis caused by subcutaneous Saksenaea vasiformis infection

We report an immunocompetent male child with chronic, indolent subcutaneous limb infection akin to basidiobolomycosis, but was shown by PCR method to be caused by a mucoralean fungus Saksenaea vasiformis. Treatment with oral potassium iodide solution was effective. This finding highlights the consideration of treatment decision according to the phenotypic severity as opposed to species identified.

A Rhinofacial Conidiobolus coronatus Fungal Infection Presenting as an Intranasal Tumour

Conidiobolomycosis is a rare fungal infection that affects adults in tropical regions. We report a 42-year-old male patient who was referred to the Sulaiman Al Habib Hospital, Dubai, United Arab Emirates (UAE), in 2013 with excessive nasal bleeding and a suspected nasal tumour. He reported having briefly visited central India nine months previously. Computed tomography and magnetic resonance imaging showed a highly vascularised mass in the nasal cavity. However, after surgical excision, initial treatment with amphotericin B deoxycholate was unsuccessful and the disease progressed, leading to external and internal nasal deformation and necessitating further excision and facial reconstruction. Histopathological analysis of the second biopsy revealed Splendore-Hoeppli changes consistent with a fungal infection. Microbiological findings subsequently confirmed Conidiobolus coronatus. Subsequently, the patient was successfully treated with a combination of itraconazole and fluconazole. To the best of the authors' knowledge, this is the first report of a case of rhinofacial conidiobolomycosis from the UAE.

An unusual case of gastrointestinal basidiobolomycosis mimicking colon cancer; literature and review

Gastrointestinal basidiobolomycosis (GIB), a rare fungal infection associated with high mortality, has been reported worldwide mainly from tropical and subtropical regions of Asia, USA, and Latin America. The clinical manifestations are highly diverse and non-specific depending on the underlying disease, but fever, abdominal pain, weight loss, diarrhea, constipation and chills have been observed. There are no prominent risk factors for GIB but climatic conditions and life style are related to this infection in arid and semi-arid regions. Therefore timely diagnosis and early treatment is a challenge. Herein, we present an unusual case of gastrointestinal basidiobolomycosis in a 54-year-old male, initially misdiagnosed as colon cancer. After follow-up, no evidence of relapse and the patient was successfully cured by liposomal amphotericin B. In addition, the differential diagnosis and histopathological findings are discussed with a review of the literature.

Disseminated angioinvasive basidiobolomycosis with a favourable outcome

Basidiobolomycosis, a rare fungal infection, is of worldwide distribution but areas commonly involved include the tropical areas of Africa, USA and South East Asia. 88% of the cases are reported among patients younger than 20 years. Many of the case reports in Saudi Arabia are from Tohama area where our patient lives. The diagnosis tends to be overlooked as the presentation may mimic colonic carcinoma in adults or inflammatory bowel diseases and tuberculosis in both children and adults. Angioinvasion seen in our patient is extremely rare suggesting the diagnosis of mucormycosis and resulting in a delay in choosing the most appropriate treatment. We report this case to remind physicians and surgeons to consider this diagnosis in patients from endemic area presenting with such conditions.

First-time isolation and quantification of Basidiobolus spp. from reptile faeces in KwaZulu-Natal (South Africa) using selective media

Members of the genus Basidiobolus are potentially pathogenic fungi, known to cause mycoses in tropical and subtropical countries. Basidiobolus spp. can be associated with animals, and reptiles and amphibians are candidate vectors for the distribution of this fungus. The presence of Basidiobolus spp. was described for different reptiles in several African countries, although not for South Africa. In addition, quantitative data are scarce. The aim of this study was to analyse faeces of selected South African reptiles for the presence and quantity of "viable Basidiobolus units." Faecal samples of gecko and agama lizards were collected and analysed using spread plating, with confirmation by PCR. The addition of dichloran and benomyl to standard fungal media improved the selectivity and allowed quantification of Basidiobolus spp. in reptile faeces. The amount of Basidiobolus spp. varied between 300 and 1.4 × 10⁶  CFU per gram of pooled gecko faeces, which mostly corresponds to >1000 CFU per outside dropping and <100 CFU per inside dropping. About 60% of analysed agama faeces carried Basidiobolus spp., ranging from 150 to 1.2 × 10⁵  CFU per dropping. Our results show for the first time that faeces of South African reptiles frequently carry Basidiobolus spp., confirming that they can contribute to the distribution of this fungus.

Human Pathogenic Entomophthorales

The pathogenic entomophthoralean fungi cause infection in insects and mammalian hosts. Basidiobolus and Conidiobolus species can be found in soil and insect, reptile, and amphibian droppings in tropical and subtropical areas. The life cycles of these fungi occur in these environments where infecting sticky conidia are developed. The infection is acquired by insect bite or contact with contaminated environments through open skin. Conidiobolus coronatus typically causes chronic rhinofacial disease in immunocompetent hosts, whereas some Conidiobolus species can be found in immunocompromised patients. Basidiobolus ranarum infection is restricted to subcutaneous tissues but may be involved in intestinal and disseminated infections. Its early diagnosis remains challenging due to clinical similarities to other intestinal diseases. Infected tissues characteristically display eosinophilic granulomas with the Splendore-Höeppli phenomenon. However, in immunocompromised patients, the above-mentioned inflammatory reaction is absent. Laboratory diagnosis includes wet mount, culture serological assays, and molecular methodologies. The management of entomophthoralean fungi relies on traditional antifungal therapies, such as potassium iodide (KI), amphotericin B, itraconazole, and ketoconazole, and surgery. These species are intrinsically resistant to some antifungals, prompting physicians to experiment with combinations of therapies. Research is needed to investigate the immunology of entomophthoralean fungi in infected hosts. The absence of an animal model and lack of funding severely limit research on these fungi.

Gastro-intestinal basidiobolomycosis in a 2-year-old boy: dramatic response to potassium iodide

Gastro-intestinal basidiobolomycosis (GIB) is a rare fungal infection caused by Basidiobolus ranarum. Treatment includes surgical resection and long-term antifungal therapy. A 2.5-year-old boy presented with a 10-day history of abdominal pain, fever and diarrhoea, and a palpable abdominal mass was detected. Resection was undertaken and histology confirmed basidiobolomycosis. Treatment with amphotericin B and itraconazole was commenced, but the infection progressed and spread to involve the intestines, liver, ribs and lung, and also the abdominal wall after 6 months, requiring four operative procedures. Because of unresponsiveness to amphotericin and itraconazole, oral potassium iodide was added which resulted in complete resolution of the infection. Potassium iodide is an essential component of the treatment of systemic B. ranarum.

Rhinofacialentomophthoromycosis

Entomopthoromycosis is a rare subcutaneous fungal infection caused by onidiobolus coronatus affecting mainly the upper respiratory mucosa in immunocompetent people.The manifestations of this disease masquerades other clinical entities.Hence, high index of suspicion is required for prompt diagnosis.Histopathological examination and culture are the gold standard diagnostic tools, however no standard treatment protocols ha been mentioned in literature.We present a case of rhinofacial entomopthoromycosis in a yearold ma with a leftsided rhinofacial swelling to highlight the presence of this unusual fungal infection and its treatment.

Fungi that Infect Humans

Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides; the Cryptococcus spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients-Candida, Pneumocystis, and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.

Entomophthoramycosis: a neglected tropical mycosis

The term 'entomophthoramycosis' classically refers to infections caused by members of the order Entomophthorales. A new subphylum, Entomophthoramycota, has been created to include Basidiobolomycetes, Neozygitomycetes and Entomophthoramycetes. Basidiobolomycetes encompass Basidiobolus spp., while the Entomophthoramycetes include Conidiobolus spp. Conidiobolus spp. characteristically cause rhinofacial entomophthoramycosis in apparently immunocompetent hosts. Conidiobolus spp. may also cause disseminated infection in immunocompromised patients. Basidiobolus spp. more typically cause subcutaneous entomophthoramycosis of the limbs, buttocks, back and thorax in immunocompetent patients. While once considered to be rare, there is an increasing number of reported cases of gastrointestinal infection caused by Basidiobolus spp. worldwide in countries such as United States, Thailand, Australia, Iran, Egypt and Saudi Arabia. These cases have clinical presentations similar to those of inflammatory bowel diseases, particularly Crohn's disease. Retroperitoneal, pulmonary, nasal and disseminated basidiobolomycosis have also been reported. Histology of entomophthoramycosis may reveal the Splendore-Hoeppli phenomenon. Culture of infected tissue remains the definitive method of laboratory diagnosis. However, molecular methods with specific DNA probes and panfungal primers, as well as real time PCR, are increasingly used to detect and identify these organisms in tissue. Treatment largely consists of therapy with antifungal triazoles. Surgery plays a selective role in the management of entomophthoramycosis, depending upon location, organism and extent of the infection.

Orofacial infection by Conidiobolus coronatus

Entomophtoramycosis is a type of subcutaneous mycosis which includes both basidiobolomycosis and conidiobolomycosis; the latter is caused by Conidiobolus coronatus, a saprophytic fungus which lives in tropical soils. This mycosis characteristically affects the paranasal sinuses and oropharynx, with the potential to deform the face in patients without apparent immunodeficiency. It has a chronic course of infection with a tendency to form granulomas visible using histology. We present the case of a 28 year-old male agricultural worker, with a clinical profile of 6 months' evolution of rhinofacial tumefaction, nasal obstruction and post-nasal drip who was diagnosed with conidiobolomycosis by means of tissue culture after multiple biopsies of the facial area. The patient received antifungal treatment with amphotericin B and subsequently with itraconazol, resulting in a dramatic improvement without the need for surgical treatment; itraconazol was administered for one year and there was no evidence of relapse at the end of this period. Due to the low frequency of this disease there is no established treatment strategy; however, the use of azoles such as itraconazol with or without adjuvant surgical treatment is increasingly seen in case reports. The present report adds to the clinical experience in Colombia of this rare mycosis and also describes the long-term clinical and therapeutic response.