Merits and Pitfalls of Currently Used Diagnostic Tools in Mycetoma

Abstract

Treatment of mycetoma depends on the causative organism and since many organisms, both actinomycetes (actinomycetoma) and fungi (eumycetoma), are capable of producing mycetoma, an accurate diagnosis is crucial. Currently, multiple diagnostic tools are used to determine the extent of infections and to identify the causative agents of mycetoma. These include various imaging, cytological, histopathological, serological, and culture techniques; phenotypic characterisation; and molecular diagnostics. In this review, we summarize these techniques and identify their merits and pitfalls in the identification of the causative agents of mycetoma and the extent of the disease. We also emphasize the fact that there is no ideal diagnostic tool available to identify the causative agents and that future research should focus on the development of new and reliable diagnostic tools.

A young boy with unusual foot lump (madura foot)

“…They can be identified by haematoxylin and eosin (H&E) staining and can aid at identification of organism. A Gram stain is useful for detecting actinomycetoma and Periodic acid-Schiff (PAS) staining is useful to detect eumycetoma [3]. …”

Histopathological Approach in Diagnosis of Mycetoma Causative Agents: A Mini Review

“…Several histochemical stains are essential for in-depth identification of the causative organisms [11][12][13][14]. Gram stains, such as Gram Weigert, play a critical role in differentiating between bacterial and fungal agents of mycetoma the fine filamentous agent with in the grains of actinomycetoma were gram positive whereas eumycetoma are gram negative (Figure 7).…”

“…Other special stains like Periodic acid-Schiff (PAS), Gomori methanamine silver, and Gridley are the most useful stains for detecting hyphae and chlamydospores in eumycetoma grains [12][13][14].…”

Chronic swelling of the foot

“…Mycetoma, first described in the Madura district of India in 1842 [1][2][3], is a clinical entity referring to a chronic, debilitating, granulomatous disease of soft tissues, usually of the foot, resulting from infection either with filamentous bacteria (actinomycetoma) or true fungi (eumycetoma) [1,2,[4][5][6]. It is endemic in equatorial, tropical, and subtropical regions, including the Middle East [1,4,5], but is not well known in the USA and Europe [5], except in migrant populations [7].…”

“…Isolation of the fungal grains may be performed either via a deep-seated biopsy or aspiration cytology [2], necessitating the use of special stains for thorough identification of the causative organism [2]. Microbiological culture provides definitive diagnosis, but may take several weeks to months [2,6,9], with the potential for inadvertent contamination, and additional, more extensive biopsies [8,10].…”