Detection of villous conidia of Conidiobolus coronatus in a blood sample by scanning electron microscopy investigation

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.

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.

Blooming of Unusual Cytochrome P450s by Tandem Duplication in the Pathogenic Fungus Conidiobolus coronatus

While the Zygomycete fungus Conidiobolus coronatus primarily infects insects, it can be pathogenic to mammals as well, including humans. High variability in the treatment of this fungal infection with currently available drugs, including azole drugs is a very common phenomenon. Azoles bind to the cytochrome P450 monooxygenases (P450s/CYP) including CYP51, a sterol 14-α-demethylase, inhibiting the synthesis of cell membrane ergosterol and thus leading to the elimination of infecting fungi. Despite P450’s role as a drug target, to date, no information on C. coronatus P450s has been reported. Genome-wide data mining has revealed the presence of 142 P450s grouped into 12 families and 21 subfamilies in C. coronatus. Except for CYP51, the remaining 11 P450 families are new (CYP5854-CYP5864). Despite having a large number of P450s among entomopathogenic fungi, C. coronatus has the lowest number of P450 families, which suggests blooming P450s. Further analysis has revealed that 79% of the same family P450s is tandemly positioned, suggesting that P450 tandem duplication led to the blooming of P450s. The results of this study; i.e., unravelling the C. coronatus P450 content, will certainly help in designing experiments to understand P450s’ role in C. coronatus physiology, including a highly variable response to azole drugs with respect to P450s.

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.

Rhinofacial conidiobolomycosis (entomophthoramycosis)

Conidiobolomycosis is a tropical rhinofacial subcutaneous mycosis caused by Conidiobolus coronatus. It is characterized histopathologically by the presence of hyphae surrounded by an eosinophilic halo, the so-called Splendore-Hoeppli phenomenon. There is no standard treatment, but itraconazole is an effective option.

Rhinoentomophthoromycosis due to Conidiobolus coronatus. A case report and an overview of the disease in India

Rhinoentomophthoromycosis due to Conidiobolus coronatus is a rare, chronic, granulomatous disease, occurring mainly in tropical Africa, South and Central America and south-east Asia, including India. We report a case of rhinoentomophthoromycosis in a 30-year-old male farmer, a resident of Gorakhpur city in Uttar Pradesh, which was diagnosed by histopathology and isolation C. coronatus in culture. The patient presented with a swollen nose with obstruction that had progressed slowly over one year. His nasal swelling was bilateral, diffuse, mildly tender, erythematous, non-pitting, with mucosal crusting and hypertrophy of inferior turbinates but no regional lympha-denopathy. A contrast-enhanced computed tomography (CECT) scan revealed bilateral pan-sinusitis with nasoethmoid polyposis. Culture of tissue from the nasal biopsy on Sabouraud glucose agar yielded multiple colonies of a mold with satellite smaller colonies at periphery. The isolate demonstrated the macroscopic and microscopic morphologic characteristics of C. coronatus. Its identity was further confirmed by direct DNA sequencing of internal transcribed spacer (ITS) and D1/D2 regions of rDNA. Haemotoxylin and eosin stained tissue sections of the skin biopsy revealed irregular epidermal acanthosis, marked inflammatory and granulomatous reaction with sparse, non-septate hyphae. The patient was treated successfully with a combination therapy of oral saturated potassium iodide solution, itraconazole, and intravenous infusion of amphotericin B. An overview of rhinoentomophthoromycosis cases reported to-date in India is presented.