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Histopathological appearance of mycetoma causative agents. The histopathological appearance of A. madurae (A), S. somaliensis (B), A. pelletierii (C) and M. mycetomatis (D) in HE stained sections (Magnification 10x). https://doi.org/10.1371/journal.pntd.0007056.g003
Source publication
Mycetoma is a devastating neglected tropical disease, caused by various fungal and bacterial pathogens. Correct diagnosis to the species level is mandatory for proper treatment. In endemic areas, various diagnostic tests and techniques are in use to achieve that, and that includes grain culture, surgical biopsy histopathological examination, fine n...
Contexts in source publication
Context 1
... mycetomatis has two different types of grains, and these are the filamentous and vesicular. The filamentous type, is the most common type and consists of brown septated and branched hyphae that may be slightly more swollen towards the edges (Fig 3D). ...
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... appear faint yellow in unstained sections, and the grains are not well stained with H&E. Moreover, as a result of sectioning they may show longitudinal cracks, the filaments are fine (measured between 0.5-2 μm in diameter), closely packaged and embedded in cement matrix (Fig 3B). ...
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... filamentous structures are pretty difficult to be detected. However, a careful and meticulous examination of the periphery of the grains may show some of them. A. pelletierii grains stain deep violet with H&E, which is very characteristic and allows the definitive diagnosis without a need for culturing techniques (Fig 3C). ...
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... periphery of the grain is opaque, homogenous and deep purple when stained with H&E stain, while the centre is less densely stained. Additionally, the periphery of the grains shows an eosinophilic material (Fig 3A). ...
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... mycetomatis has two different types of grains, and these are the filamentous and vesicular. The filamentous type, is the most common type and consists of brown septated and branched hyphae that may be slightly more swollen towards the edges (Fig 3D). ...
Context 6
... appear faint yellow in unstained sections, and the grains are not well stained with H&E. Moreover, as a result of sectioning they may show longitudinal cracks, the filaments are fine (measured between 0.5-2 μm in diameter), closely packaged and embedded in cement matrix (Fig 3B). ...
Context 7
... filamentous structures are pretty difficult to be detected. However, a careful and meticulous examination of the periphery of the grains may show some of them. A. pelletierii grains stain deep violet with H&E, which is very characteristic and allows the definitive diagnosis without a need for culturing techniques (Fig 3C). ...
Context 8
... periphery of the grain is opaque, homogenous and deep purple when stained with H&E stain, while the centre is less densely stained. Additionally, the periphery of the grains shows an eosinophilic material (Fig 3A). ...
Context 9
... mycetomatis has two different types of grains, and these are the filamentous and vesicular. The filamentous type, is the most common type and consists of brown septated and branched hyphae that may be slightly more swollen towards the edges (Fig 3D). ...
Context 10
... appear faint yellow in unstained sections, and the grains are not well stained with H&E. Moreover, as a result of sectioning they may show longitudinal cracks, the filaments are fine (measured between 0.5-2 μm in diameter), closely packaged and embedded in cement matrix (Fig 3B). ...
Context 11
... filamentous structures are pretty difficult to be detected. However, a careful and meticulous examination of the periphery of the grains may show some of them. A. pelletierii grains stain deep violet with H&E, which is very characteristic and allows the definitive diagnosis without a need for culturing techniques (Fig 3C). ...
Citations
... Individuals in the initial phase of the disease do not show any obvious external symptoms; consequently, a diagnosis of the infection is difficult (9). When symptoms are noticeable, proper diagnosis requires complex histopathology and imaging techniques (10). Such methods are rapid and highly accurate but require surgical biopsies and expensive equipment. ...
... Simpler and cheaper culturing techniques to identify the causative species, which use grains from patients, also have limitations. Many bacterial species are challenging to grow in labs, so such methods take roughly four times longer to yield a diagnostic result than histological examinations (10). Identification of pathogens cultured from grains can also easily be erroneous, leading to incorrect drug choices for treatment and for alleviating the patients' suffering (11). ...
Mycetoma is a devastating neglected tropical infection of the subcutaneous tissues. It is caused by fungal and bacterial pathogens recognized as eumycetoma and actinomycetoma, respectively. Mycetoma treatment involves diagnosing the causative microorganism as a prerequisite to prescribing a proper medication. Current therapy of fungal eumycetoma causative agents, such as Madurella mycetomatis, consists of long-term antifungal medication with itraconazole followed by surgery, yet with usually unsatisfactory clinical outcomes. Actinomycetoma, on the contrary, usually responds to treatment with co-trimoxazole and amikacin. Therefore, there is a pressing need to discover novel broad-spectrum antimicrobial agents to circumvent the time-consuming and costly diagnosis. Using the resazurin assay, a series of 23 naphthylisoquinoline (NIQ) alkaloids and related naphthoquinones were subjected to in vitro screening against two fungal strains of M. mycetomatis and three bacterial strains of Actinomadura madurae and A. syzygii. Seven NIQs, mostly dimers, showed promising in vitro activities against at least one strain of the mycetoma-causative pathogens, while the naphthoquinones did not show any activity. A synthetic NIQ dimer, 8,8'''-O,O-dimethylmichellamine A (18), inhibited all tested fungal and bacterial strains (IC50 = 2.81–12.07 µg/mL). One of the dimeric NIQs, michellamine B (14), inhibited a strain of M. mycetomatis and significantly enhanced the survival rate of Galleria mellonella larvae infected with M. mycetomatis at concentrations of 1 and 4 µg/mL, without being toxic to the uninfected larvae. As a result, broad-spectrum dimeric NIQs like 14 and 18 with antimicrobial activity are considered hit compounds that could be worth further optimization to develop novel lead antimycetomal agents.
... FNA specimens can be either imprinted on slides for further DME or processed for cell blocks and further processed as biopsy specimens for histopathological assessment. 8 Treatment of mycetoma depends mainly on causative organisms, fungi or bacteria. 9 Usually, actinomycetoma is treated by using anti-bacterial treatments such as cotrimoxazole, whereas eumycetoma is treated by using anti-fungal treatments before and after surgical excision. ...
... 2 The infection is commonly manifested at the feet and hands. 3 Eumycetoma typically presents with a classical triad of painless swelling, sinuses (abnormal openings), and discharge-containing grains. 4 However, due to the severe neglection of operational research in mycetoma, detection and diagnosis of mycetoma cases are challenging particularly when they are presented atypically. ...
Key Clinical Message
Atypical presentations of eumycetoma can pose a challenge in the diagnosis and treatment of the disease. Healthcare providers thorough in their differential diagnosis and investigations, even in the absence of classic symptoms, in order to improve early detection and the case management for such a neglected tropical disease.
Abstract
In this communication, we present a case study of an unusual presentation of eumycetoma; a fungal infection that is considered a neglected tropical disease. The patient, a 28‐year‐old male from Sudan, presented with a recurrent mass in the abdominal wall. Despite two surgeries to remove the mass, it continued to recur. Unlike typical cases of eumycetoma, this patient did not exhibit common symptoms such as painless swelling, sinuses, or grain‐containing discharge. The diagnosis was made incidentally after surgical excision of the mass. The abstract highlights the importance of recognizing uncommon presentations and maintaining a high suspicion for rare diagnoses, even in the absence of classic symptoms. Further research is needed to better understand atypical presentations of eumycetoma and improve early detection.
... The grains are identifiable as small, black, or colored structures containing the causative organisms. 4 While mycetoma presents with distinctive clinical features, it shares similarities with other conditions, making a differential diagnosis crucial. 3 Some of the differential diagnoses for mycetoma include bacterial abscesses, 5 subcutaneous nodules of tuberculosis, 6 syphilis gummas, neoplasms, and deep fungal infections. ...
... Culture techniques were used to isolate and grow the microorganism in a laboratory setting. 4 Fine needle aspiration cytology (FNAC) was utilized to collect samples from the affected area for microscopic examination and assessment. 4,12 Treatment for Streptomyces somaliensis actinomycetoma typically involves a combination of antibiotherapy, F I G U R E 2 Photography showing the presence of two cyst. ...
... 4 Fine needle aspiration cytology (FNAC) was utilized to collect samples from the affected area for microscopic examination and assessment. 4,12 Treatment for Streptomyces somaliensis actinomycetoma typically involves a combination of antibiotherapy, F I G U R E 2 Photography showing the presence of two cyst. ...
Key Clinical Message
This case presents an atypical cystic presentation of mycetoma without sinuses or discharge. Awareness of these variations is crucial for accurate diagnosis and timely intervention, highlighting the need for healthcare professionals to consider diverse manifestations of mycetoma.
Abstract
Mycetoma is a chronic and debilitating infectious disease characterized by localized swellings and granulomatous lesions. It primarily affects individuals in tropical and subtropical regions and is caused by certain fungi or bacteria. While mycetoma typically presents with sinuses and discharge, this case report presents a unique cystic presentation without these features. The patient, a 12‐year‐old female from Sudan, presented with a painless swelling on the dorsum of her right foot. Physical examination revealed a round, non‐tender, and fluctuant mass. Histopathological examination confirmed actinomycetoma caused by Streptomyces somaliensis. The patient was successfully treated with a combination of antibiotherapy. This atypical presentation underscores the need for healthcare professionals to consider uncommon variations of mycetoma for accurate diagnosis and management.
... Additionally, the disease usually starts as a small lesion on the affected site, which is usually the foot, after the inoculation of the causative agents. However, inside the body of the host, the pathogen population clusters into granule-like structures called grains of various colours depending to the causative agents [1][2][3][4]. Therefore, the structure and colour of the grains are commonly used by healthcare providers as diagnostic features. ...
... Among the black-grained eumycetoma causative agents, the most prevalent species is Madurella mycetomatis, followed by Falciformispora senegalensis and Trematosphaeria grisea, while the most prevalent pale-grained eumycetoma agents are Scedosporium boydii, Acremonium falciforme, Neotestudina rosatii, and Fusarium spp. [1][2][3]. ...
... Recent advances in molecular techniques, especially those based on sequencing, show promise for the accurate and rapid diagnosis and characterization of mycetoma causative agents at the species level. Sequencing the ITS region is particularly useful when traditional techniques such as culture-based and histopathology techniques fail in identifying the causative agents at the species level [1][2][3]. ...
Eumycetoma is an infectious disease caused by various fungal pathogens. The disease is characterised by black and pale-yellowish grain discharge. In this communication, we report a case of eumycetoma with a pale grain foot-eumycetoma caused by Fusarium falciforme. The patient presented at the outpatient clinic of the Mycetoma Research Centre in Sudan. The causative agent was initially misidentified as Aspergillus nidulans based on its seemingly similar histopathological appearance. However, sequencing the internally transcribed spacer region of the extracted grain confirmed infection with Fusarium falciforme. Although the patient received Itraconazole and underwent surgical excision, the disease was recurrent. To our knowledge, this is the first report on Fusarium falciforme causing eumycetoma in Sudan, indicating the expansion of the geographical distribution of this pathogen. This calls for raising the awareness of healthcare providers and improving the diagnostic and surveillance systems in at-risk areas to improve the case management and reduce the threat of further spread. Considering the potential impacts of F. falciforme infection including threatening the global health, food security, and ecosystem balance, as well as loss of biodiversity and negative socioeconomic changes in endemic countries, we recommend the implementation of an integrated transdisciplinary One Health strategy for the prevention and control of emerging infectious diseases including F. falciforme.
... Deep-seated excisional biopsies are invasive and need to be performed under anesthesia, either general or regional, depending on the site of infection. Furthermore, deep-seated biopsies are taken in a surgical theatre to reduce the risk of complications [5]. Fine needle aspirations (FNA) are less-invasive, as only a thin, hollow needle is inserted into the lesion. ...
... For the diagnosis of mycetoma, FNA material has been used for cytological examination; however, the sensitivity and specificity were relatively low. This because grains within the pockets were often missed, and misidentifications due to the lack of clear differential features in the stained grains were common [5]. This made it impossible to identify the grains to the species level. ...
... mycetomatis-specific PCR instead of cytology on FNA material increased the sensitivity further from 64.5% to 96.8%. The sensitivity for US-FNA cytology found in this study was a bit lower than found in our previous studies in which we found a sensitivity for FNA cytology ranging between 80.5% and 100% [5,6]. Furthermore, with cytology it is also possible that the cytologist might have interpreted a grain as a contamination. ...
Background:
Eumycetoma is a chronic subcutaneous inflammatory fungal infection most often caused by Madurella mycetomatis. Using a species-specific PCR on DNA directly isolated from grains is currently the most reliable method for species identification. However, so far, PCR has been performed on grains obtained through deep-seated surgical biopsies, which are invasive procedures. Grains can also be obtained via ultrasound-guided fine needle aspiration (US-FNA). Here we determined the diagnostic performance of species-specific PCRs performed on samples obtained through US-FNA.
Methods:
From 63 patients, US-FNA was performed to obtain eumycetoma grains; 34 patients also underwent a deep-seated biopsy. From the grains, DNA was isolated, and one pan-fungal and two M. mycetomatis-specific PCRs were performed. The sensitivity and specificity were determined.
Results:
Of the 63 patients who underwent US-FNA, 78% (49/63) had evidence of eumycetoma based on cytology and 93.7% (59/63) based on species-specific PCRs. In the 34 patients for whom surgical biopsies were performed as well, 31 patients had a positive PCR for M. mycetomatis when DNA was isolated from the deep-seated biopsy, and 30 had a positive PCR when DNA was obtained from US-FNA material. This resulted in a 96.8% sensitivity, and 100% specificity with 97.1% diagnostic accuracy for PCR performed on US-FNA.
Conclusion:
PCR performed on US-FNA material has a similar sensitivity and specificity as PCR performed on deep-seated biopsies. Therefore when using PCR, a deep-seated biopsy may not be necessary to obtain grains.
... At present, the diagnosis of mycetoma is often made clinically. The causative agent is usually identified through a combination of histology and culturing (6). For this a deep-seated biopsy is recommended, as the grains secreted from open sinuses are often non-viable (4). ...
... Histopathological findings, with the identification of fungi characterized by the pigmentation of the wall, allowed us to classify the lesions as a eumycetoma with melaninproducing fungi. Hematoxylin and eosin (HE) staining is generally sufficient to achieve a diagnosis [16]. However, when present only in a small amount, pigmentation can be overlooked by routine HE staining. ...
A captive-kept adult male tiger presented with a large cutaneous and subcutaneous mass on the thigh with a fistula. During sedation, multiple nodules were detected and samples for a histopathological exam were collected. Histologically, granulomatous panniculitis and dermatitis were seen around dense aggregates of pigmented fungal hyphae, and a diagnosis of phaeohyphomycosis was made; considering the clinical features, it was classified as a eumycotic mycetoma. This is a rarely reported subcutaneous fungal infection in humans and animals, caused by dematiaceous fungi. Clinically, it is characterized by tumefaction, fistulous sinus tracts, and the formation of macroscopically visible grains. In the literature, only a few infections in wild felids have been reported. In this case, Fontana–Masson staining better showed pigmentation and panfungal PCR and sequencing identified Madurella pseudomyectomatis (OP623507) as the causative agent. Systemic therapy with oral administration of itraconazole was planned, but the patient died during the first period of treatment. The animal was not submitted for post-mortem examination. Visceral dissemination of the agent cannot be excluded. To the authors’ knowledge, this is the first report of eumycotic mycetoma by Madurella pseudomycetomatis in a captive tiger.
... [16][17][18] The diagnosis of the causative organisms is based on their identification on histopathological sections from surgical biopsies or cytological smears and the classical grains culture. [19][20][21] Other useful molecular techniques, such as DNA sequencing, are presently in use. 22,23 Various imaging techniques such as conventional radiology, ultrasound, and magnetic resonance can be used for disease extension determination. ...
Background Mycetoma is a common medical and health problem endemic in many tropical and subtropical regions and is characterised by devastating deformities, disability, and high morbidity. It has serious negative medical, health, and socio-economic impacts on patients, families, communities, and health authorities in endemic regions. Yet, it enjoys scanty attention across the globe, culminating in massive knowledge gaps in various aspects of mycetoma. Hence, this study was set out to assess the knowledge of pharmacists in a highly mycetoma endemic area in Sudan.
Method This descriptive cross-sectional, community-based study was conducted in Sennar State using a validated web-based self-administrated questionnaire that included important and basic knowledge of mycetoma; 217 pharmacists were invited to participate, and 153 responded. The data were managed and analysed by appropriate statistical tests, and the overall knowledge scores were calculated.
Results The study population included 76 males (49.7%) and 77 females (50.3%). Their ages ranged from 20 to 50 years, with a mean of 31.7 years. Most of them (n= 134, 87.6%) were holders of bachelor’s degrees in pharmacy, while 19 (12.4%) had higher degrees; 98 (64.1%) were community pharmacists; 38 (24.8%) were hospital pharmacists and their practice experience ranged from less than five years to more than 20 years. The majority of the participants (92.2%) had insufficient knowledge of mycetoma, and only 7.8% had good knowledge. There was no significant association between knowledge score and the participants’ demographic characteristics.
Conclusion Mycetoma is a common problem in Sennar State, and despite that, most of the study
participants had insufficient knowledge of the disease. A well-structured continuing professional development programme for pharmacists together with implementation of clinical pharmacy services in mycetoma endemic regions are badly needed
... Causative agents and their species can be identified by their microscopic appearance and morphological properties. 26,28,29 In many instances, misdiagnosis and difficulty in distinguishing the different microorganisms based on morphological features are frequent. 20,26,29,30 In conclusion, grain culture is the core tool for organism identification, but it is time-consuming and requires expert microbiologists to obtain accurate results. ...
... 26,28,29 In many instances, misdiagnosis and difficulty in distinguishing the different microorganisms based on morphological features are frequent. 20,26,29,30 In conclusion, grain culture is the core tool for organism identification, but it is time-consuming and requires expert microbiologists to obtain accurate results. Also, this method is vulnerable to false-positive results because of contamination. ...
... The histopathological examination of the surgical biopsies is useful for confirming the clinical diagnosis, but it remains ineffective for definitive species identification, particularly for eumycetoma species. 10,11,20,29 Primarily Haematoxylin and Eosin (H&E) stain is used for the mycetoma diagnosis based on histology, while special stains are crucial for species differentiation and inconclusive identification of grains by H&E staining. 11,20,26,32 These special staining includes Gram, Periodic acid-Schiff (PAS) stains, and others. ...
In 1842, the missionary John Gill reported the first clinical case of mycetoma in an Indian city named “Madurai”.1 Vandyke Carter first described the fungus form of mycetoma in 1860; thus, he proposed the name “mycetoma”, which is driven from the Greek terms “mykes” and “oma”, which means fungus and tumour, respectively.2 Mycetoma is also known as “Madura Foot”, referring to the first reported case, but this name is inappropriate as it is neither confided to the Madurai nor the foot. Chalmers and Archibald from Sudan formally classified mycetoma into two main groups, fungal and bacterial mycetoma,3 after a suggestion made in 1913 to classify mycetoma based on the causative organisms
