Emerging therapeutic regimes for the management of mycetomas

Subcutaneous mycoses in coastal Karnataka in south India

BACKGROUND

Subcutaneous mycoses are chronic, localized infections of the skin and subcutaneous tissue which occur following traumatic implantation of the etiological agent. The causative organisms are soil saprophytes of regional epidemiology with varying ability to adapt to the tissue environment and elicit disease.

OBJECTIVES

This study was conducted to evaluate the various types of subcutaneous mycoses, including actinomycotic mycetomas, in south coastal Karnataka, India.

METHODS

Between January 2005 and January 2013, a total of 25 patients were diagnosed with subcutaneous mycoses based on a detailed clinical history and presentation, histopathology, and culture of organisms.

RESULTS

Chromoblastomycosis was the infection most commonly seen (n = 16 patients, 64%), followed by mycetoma (n = 4, 16%), sporotrichosis (n = 4, 16%), and rhinoentomophthoromycosis (n = 1, 4%). The extremities were the most common site of involvement, with the lower limb being most affected (64%). Males were more commonly afflicted (64%) than females (36%). Most patients were agricultural workers, although preceding trauma was noted in only three patients. The majority of patients responded well to therapy and were disease-free on follow-up.

CONCLUSIONS

Subcutaneous mycoses are a rare group of disorders. Chromoblastomycosis is the most frequent subcutaneous fungal infection in south India. Morphologically, chromomoblastomycoses present as verrucous, ulcerative, nodular, or eczematous lesions. Clinical diagnosis is important as culture is often negative. The incidence of infection is higher among rubber tappers. It is important to clinically differentiate chromoblastomycosis from tuberculosis verrucosa cutis. Most of the subcutaneous mycoses respond well to treatment, with the exception of rhinoentomophthoromycosis, which is a rare form of deep mycosis with associated mutilation. Eumycetomas are not observed in this part of India.

Management of mycetomas in France

OBJECTIVE OF THE STUDY

Mycetomas are chronic sub-cutaneous tropical infections in which exogenous causative agents, fungal (eumycetes) or bacterial (actinomycetes), generate grains. The typical presentation is multi-fistulized pseudotumors. This disease, particularly eumycetoma, is difficult to treat. It is a major health problem in tropical and subtropical countries. In France, the disease is rare, but patients have access to a broader range of treatments. The authors had for objective to present the cases of mycetomas diagnosed in developed country and their management.

PATIENTS AND METHODS

A retrospective study was made on the clinical presentation and management of mycetomas from 1995 to 2011, in the Bobigny Avicenne teaching hospital.

RESULTS

Six patient files were studied. The patients were men with a median age of 31 years (16-70). Five patients were from Sub Saharan Africa, one from Sri Lanka. The etiologies were one actinomycetoma and five eumycetomas. There was bone involvement in five cases. There was one atypical presentation: a primary intra-osseous mycetoma. Three patients were cured including two by surgical management and one by medical treatment (actinomycetoma). Antifungal therapy failed (four patients) in every case (voriconazole, itraconazole, ketoconazole, terbinafine, caspofungin).

CONCLUSION

The results of this study made in a non-epidemic zone revealed that despite a typical clinical presentation, the diagnosis and management were delayed because this imported disease is rare in France. The patients received new broad-spectrum triazole and caspofungin, but none were cured with antifungal therapy alone.

Mycetoma caused by Madurella mycetomatis: a completely neglected medico-social dilemma

Mycetoma is a debilitating disease with a highly particular geographical distribution. The mycetoma belt circles the entire world just above the equator and defines the region with the highest prevalence and incidence. Although the disease is seen in Central America, India and all across Africa, Sudan seems to be the homeland of mycetoma. Mycetoma is an infectious disease caused either by bacteria (actinomycetoma) or true fungi (eumycetoma). In Sudan most cases are caused by the fungal species Madurella mycetomatis. The precise natural habitat of this fungus is still an enigma, but its DNA can easily be found in soil and plant samples in endemic areas. Although the entire human population in these areas are in regular contact with the fungus, most individuals are unaffected. Thus mycetoma is an ideal clinical and experimental model system for the study of host-pathogen interactions. Also, given its relative importance locally, improvements in clinical and laboratory diagnostics and knowledge of the epidemiology of the disease are badly needed. This chapter describes the current state of affairs in the field of eumycetoma caused by M. mycetomatis. The value of laboratory research on this disease and future perspective for control and prevention of the infection are discussed.

Treatment of actinomycetoma foot--our experience with ten patients

BACKGROUND

Mycetoma is a chronic granulomatous inflammation of the subcutaneous tissue and usually results due to traumatic implantation of soil organisms. Mycetoma can be eumycotic or acinomycotic in origin. Actinomycetoma is susceptible to a large number of chemotherapeutic agents, but the response is variable and affected by various factors such as extent of involvement, duration of disease, presence or absence of bony involvement and drugs used for treatment.

AIMS AND OBJECTIVES

To describe our experience of various treatment regimens used for actinomycetoma.

MATERIAL AND METHODS

It was a prospective, open label study of actinomycetoma. Ten patients who were diagnosed clinically as mycetoma were included in this study. All patients were completely evaluated and investigated including skin biopsy, Gram staining of grains and discharge, Ziehl-Nielson stain, KOH preparation, fungal and bacterial cultures and CT scan/Magnetic resonance imaging (MRI), if required. Patients were treated with different treatment regimens, for example, Ramam regimen, modified Ramam regimen, Welsh regimen and its modification.

RESULTS

Ten patients (eight males, two females) age ranging from 9 to 55 years (mean 29.6 years) were included in this study. Six patients were successfully treated with Ramam regimen, three patients were treated with our modified Welsh regimen (one of these three patients (case 7) initially failed to respond to Ramam regimen), and one patient was treated with modified Ramam regimen.

CONCLUSION

Ramam regimen was found to be quite effective in treating patients of actinomycetoma with only minimal bony involvement, while Welsh regimen and its modification should be used in case of severe disease due to amikacin being more sensitive than gentamicin in treating resistant organisms. Intensive phase of Modified Welsh regimen can be extended to five cycles in case of extensive bony involvement.

Subcutaneous fungal infections

Subcutaneous mycoses are common in tropical and subtropical regions of the world. These infections have multiple features in common, including similar epidemiology, mode of transmission, indolent chronic presentation with low potential for dissemination in immunocompetent hosts, and pyogranulomatous lesions on histopathology. Herein, we provide up-to-date epidemiologic, clinical, diagnostic, and therapeutic data for three important subcutaneous mycoses: chromoblastomycosis, mycetoma, and sporotrichosis.

The Madura Foot

“Mycetoma” means a fungal tumor. Mycetoma is a chronic, granulomatous, subcutaneous tissue infection caused by both bacteria (actinomycetoma) and fungi (eumycetoma). This chronic infection was termed Madura foot and eventually mycetoma, owing to its etiology. Inoculation commonly follows minor trauma, predominantly to the foot and hence is seen more among the barefoot-walking populations, common among adult males aged 20 to 50 years. The hallmark triad of the disease includes tumefaction, fistulization of the abscess, and extrusion of colored grains. The color of these extruded grains in the active phase of the disease offers a clue to diagnosis. Radiology, ultrasonology, cytology, histology, immunodiagnosis, and culture are tools used in diagnosis. Recently, DNA sequencing has also been used successfully. Though both infections manifest with similar clinical findings, Actinomycetoma has a rapid course and can lead to amputation or death secondary to systemic spread. However, actinomycetomas are more responsive to antibiotics, whereas eumycetomas require surgical excision in addition to antifungals. Complications include secondary bacterial infections that can progress to full-blown bacteremia or septicemia, resulting in death. With extremely disfiguring sequelae, following the breakdown of the nodules and formation of discharging sinuses, it poses a therapeutic challenge.

Variable antibiotic susceptibility patterns among Streptomyces species causing actinomycetoma in man and animals

BACKGROUND

Drug therapy is recommended in conjunction with surgery in treatment of actinomycetoma. The specific prescription depends on the type of bacteria (actinomycetoma) or fungi (eumycetoma) causing the disease and their in vitro antimicrobial susceptibility.

OBJECTIVES

To investigate the antimicrobial susceptibility among isolates of Streptomyces spp. isolated from cases of actinomycetoma in man and animals in Sudan.

METHODS

Streptomyces strains (n = 18) isolated from cases of actinomycetoma were tested in vitro against 15 commonly prescribed antibacterial agents using MIC agar dilution method as per standard guidelines.

RESULTS

Streptomyces strains isolated from actinomycetoma fall into various phenotypic groups. All of the strains were inhibited by novobiocin (8 μg/mL), gentamycin (8, 32 μg/mL) and doxycycline (32 μg/mL). Fusidic acid (64 μg/mL) inhibited 94.4% of the strains; bacitracin, streptomycin, cephaloridine, clindamycin, ampicillin, rifampicin and tetracycline (64 μg/mL) inhibited between 61.1 and 77.8% of the strains. All strains were found resistant to amphotericin B (64 μg/mL), penicillin (20 μg/mL) and sulphamethoxazole (64 μg/mL).

CONCLUSIONS

Saprophytic Streptomyces spp. cause actinomycetoma in man and animal belong to separate phenotypes and have a wide range of susceptibility patterns to antimicrobial agents, which pose a lot of difficulties in selecting effective in vivo treatment for actinomycetoma.

Mycetoma or synovial sarcoma? A case report with review of the literature

Mycetoma, also commonly referred to as Madura foot, is statistically rare in the United States. However, it is endemic to other parts of the world. It is a pseudotumor characterized by a triad of tumefaction, draining sinuses, and grains. Two types exist, with each caused by different groups of organisms that require different treatment approaches. Therefore, the exact diagnosis and culture of the organism is vital to successful treatment outcomes. Synovial sarcoma, in contrast, is a malignancy much more commonly seen in the United States. It is characterized by a well-circumscribed, often palpable, mass that is usually well delineated on magnetic resonance imaging. It has characteristic histologic and genetic features that help distinguish it from other soft tissue masses. We present a case of a soft tissue mass diagnosed in the United States. The patient had several clinical and radiographic features of synovial sarcoma but the histologic outcome was mycetoma. The case is followed by a review of the published data.

Eumycetoma of the hand caused by Leptosphaeria tompkinsii and refractory to medical therapy with voriconazole

We report on the first case of eumycetoma caused by the organism Leptosphaeria tompkinsii to be diagnosed and possibly acquired within the United Kingdom. Conventional culture of fungal grains and surgical tissue specimens was negative and the diagnosis was achieved using panfungal polymerase chain reaction and sequencing technology. Despite limited surgical resection and prolonged antifungal therapy with voriconazole, the patient developed progressive disease with mycetoma bone involvement. This case highlights the usefulness of molecular diagnostic techniques in eumycetoma where organisms may fail to grow with conventional culture or be difficult to identify morphologically. It also reminds us that eumycetoma is a difficult infection to treat and despite optimism regarding the efficacy of the newer triazole antifungals in this condition, treatment failures may still occur.