Mycetomas in northern Yemen: identification of causative organisms and epidemiologic considerations

An updated list of eumycetoma causative agents and their differences in grain formation and treatment response

SUMMARYIn 2023, the World Health Organization designated eumycetoma causative agents as high-priority pathogens on its list of fungal priority pathogens. Despite this recognition, a comprehensive understanding of these causative agents is lacking, and potential variations in clinical manifestations or therapeutic responses remain unclear. In this review, 12,379 eumycetoma cases were reviewed. In total, 69 different fungal species were identified as causative agents. However, some were only identified once, and there was no supporting evidence that they were indeed present in the grain. Madurella mycetomatis was by far the most commonly reported fungal causative agent. In most studies, identification of the fungus at the species level was based on culture or histology, which was prone to misidentifications. The newly used molecular identification tools identified new causative agents. Clinically, no differences were reported in the appearance of the lesion, but variations in mycetoma grain formation and antifungal susceptibility were observed. Although attempts were made to explore the differences in clinical outcomes based on antifungal susceptibility, the lack of large clinical trials and the inclusion of surgery as standard treatment posed challenges in drawing definitive conclusions. Limited case series suggested that eumycetoma cases caused by Fusarium species were less responsive to treatment than those caused by Madurella mycetomatis. However, further research is imperative for a comprehensive understanding.

Mycetoma in north-western Yemen: Clinico-epidemiological and histopathological study

BACKGROUND

Mycetoma is widespread in Yemen; however, there are only a few documented reports on the entity from this geographical area.

METHODS

A prospective study of 184 cases of mycetoma (male 145 and female 39) from different regions of north-western Yemen was conducted between July 2000 and May 2014. Clinical profile was recorded in a standardized protocol. The diagnosis was based on clinical features, X-ray studies, examination of grains, and histopathology.

RESULTS

Eumycetoma was diagnosed in 129, caused by Madurella mycetomatis in 124, Leptosphaeria senegalensis in one and pale grain fungus in four, whereas actinomycetoma occurred in 55, caused by Streptomyces somaliensis in 29, Actinomadura madurai in nine, Actinomadura pelletieri in one, and Nocardia in sixteen. Eumycetoma cases were treated with prolonged course of antifungal drugs, mostly ketoconazole, with itraconazole being used in four patients, along with excision or debulking. Results were better when antifungal drugs were given two to three months before surgery and in those who received itraconazole. Actinomycetoma cases were initially treated with co-trimoxazole monotherapy; later streptomycin was added in 30 cases. Six patients who did not show adequate improvement and two others from the start were treated with modified Welsh regimen and with good results.

LIMITATIONS

Identification of different causative agents was done by histopathology and could not be reconfirmed by culture.

CONCLUSION

Mycetoma is widespread in north-western Yemen with a higher incidence of eumycetoma and a majority of the cases were caused by Madurella mycetomatis. Modified Welsh regimen in actinomycetoma and itraconazole with excision in eumycetoma showed the best results.

Mycetoma (Madura Foot) in Israel: Recent Cases and a Systematic Review of the Literature

AbstractMycetoma is a chronic soft tissue infection caused by fungal or bacterial pathogens, and is endemic in tropical and subtropical regions. Cases in developed countries outside the mycetoma belt are rare and usually imported by immigrants. Sporadic cases have been reported in Israel. Unpublished cases in the participating medical centers are reported. In addition, a systematic review of the literature was performed. All published mycetoma cases diagnosed in Israel were included with relevant variables collected. Twenty-one cases of mycetoma were diagnosed in Israel between 1942 and 2015, including four unpublished cases and 17 published cases. The mean age at diagnosis was 42 years (range 23-73), and 16 of the patients were male. The foot was the primary involved organ. Fifteen patients were immigrants from Yemen, Ethiopia, and Sudan. Five cases were autochthonous. One case was travel related. Among patients who developed symptoms after immigration, the mean time from exposure to symptom onset was 5.6 years (range 1-10 years). The mean time from symptom onset to diagnosis was 6.6 years (range 0.2-35 years). The autochthonous cases demonstrate that Israel is endemic of mycetoma. The immigrant population represents two distinct waves of immigration to Israel in the past century. Two unpublished cases of Ethiopian immigrants are the first reported cases of mycetoma acquired in Ethiopia. The diagnostic and therapeutic challenges along with the epidemiological data emphasize the need of raising the awareness of physicians to this devastating condition even in developed countries.

Global burden of human mycetoma: a systematic review and meta-analysis

Mycetoma is a chronic infectious disease of the subcutaneous tissue with a high morbidity. This disease has been reported from countries between 30°N and 15°S since 1840 but the exact burden of disease is not known. It is currently unknown what the incidence, prevalence and the number of reported cases per year per country is. In order to estimate what the global burden of mycetoma is, a meta-analysis was performed. In total 50 studies were included, which resulted in a total of 8763 mycetoma cases. Most cases were found in men between 11 and 40 years of age. The foot was most commonly affected. Most cases were reported from Mexico, Sudan and India. Madurella mycetomatis was the most prevalent causative agent world-wide, followed by Actinomadura madurae, Streptomyces somaliensis, Actinomadura pelletieri, Nocardia brasiliensis and Nocardia asteroides. Although this study represents a first indication of the global burden on mycetoma, the actual burden is probably much higher. In this study only cases reported to literature could be used and most of these cases were found by searching archives from a single hospital in a single city of that country. By erecting (inter)national surveillance programs a more accurate estimation of the global burden on mycetoma can be obtained.

Madura foot: atypical finding and case presentation

Mycetomas are chronic, subcutaneous infections characterized by a clinical triad of chronic induration, draining sinuses, and discharge of granules. The granules are composed of colonies of either actinomycotic bacteria or eumycotic fungi. The infection develops after traumatic inoculation with contaminated soil and progresses to adjacent tissues or bone. The foot, hand, and lower-leg regions are the most commonly affected areas. Treatment can be difficult and includes surgical debridement with prolonged antibiotic or antifungal treatment. Mycetomas are primarily found in tropical and subtropical areas of the world and are relatively rare in the United States. A case of indigenously obtained actinomycoses that was successfully treated with surgical resection and long-term antibiotic therapy is presented. This case is unique because of the rarity of contracting this type of infection in the United States. Mycetomas have been reported in southern states, but there are no reported cases of obtaining this pathogen in Michigan. This case stresses the need for clinical suspicion of this rare dermatosis, especially considering the increase in immigration to the United States.

Case report of Streptomyces endocarditis of a prosthetic aortic valve

We describe the first case of prosthetic valve endocarditis due to a Streptomyces sp. The patient presented with fever, cutaneous embolic lesions, and bacteremia 3 months after aortic valve replacement. Treatment required valve replacement and a long course of parenteral imipenem.