Actinomycetoma laboratory-based diagnosis: a mini-review

A Longstanding Case of Black Grain Mycetoma in a Somalian Male Patient: A Case Report

Mycetoma is a chronic granulomatous infection predominantly affecting young individuals, characterized by painless swelling and often misdiagnosed due to its resemblance to other conditions. This case report presents the first documented instance of eumycetoma located in the buttock of a 44-year-old male patient from Somalia, a region with limited literature on this disease. The patient exhibited a 10-year history of indurated swelling, which progressed to the discharge of dark granules, leading to the diagnosis of black grain eumycetoma. Comprehensive diagnostic methods, including imaging and histopathological analysis, were used, confirming the fungal etiology. Surgical excision followed, alongside antifungal therapy, resulting in significant improvement. This case emphasizes the necessity for increased awareness and consideration of mycetoma in clinical practice, especially in atypical presentations and underreported geographical areas.

Comprehensive management of actinomycetoma in a young male: A case report from Somalia

Mycetoma is a neglected tropical disease that predominantly affects individuals in low socioeconomic strata, primarily in tropical and subtropical regions. This case report describes a 20-year-old male student from Bahdo City, Somalia, who presented with a persistent cervical mass following a history of trauma. The patient exhibited vital signs within normal limits, and imaging studies, including ultrasound and computed tomography, revealed well-defined cystic masses. A Fine Needle Aspiration cytology confirmed the diagnosis of actinomycetoma by revealing sheets of neutrophils, multinucleated giant cells, and branching filamentous bacteria structures. The patient was treated with co-trimoxazole and amikacin, resulting in significant improvement after three months, highlighting the critical role of early diagnosis and appropriate medical management in enhancing patient outcomes. This report emphasizes the importance of thorough clinical evaluation and the use of cytological methods, particularly in resource-limited settings, to expedite the diagnosis and treatment of actinomycetoma.

First report on mycetoma in Turkana County-North-western Kenya

Mycetoma is one of the six Neglected Tropical Diseases that are prevalent in Turkana County (northwest Kenya). The aim of the study was to estimate the prevalence of mycetoma in the county, as well as to describe the main causative agents involved in the disease using methods affordable locally. Based on the data collected by the team of cooperative medicine Cirugia en Turkana (Surgery in Turkana), a specific study for mycetoma was started during the 16th humanitarian medicine campaign in February 2019. Patients with suspected mycetoma were studied at the Lodwar County Referral Hospital (LCRH). After informing the patient and getting their consent, the lesions were examined and sampled (mainly by biopsy) and clinical data were recorded. Samples were washed in sterile saline solution and cut in fragments. Some of these were inoculated on Sabouraud Dextrose Agar, Malt Extract Agar, and diluted Nutrient Agar plates. One fragment of each sample was used for DNA extraction. The DNA and the rest of the fragments of samples were kept at -20°C. All cultures were incubated at room temperature at the LCRH laboratory. The DNA obtained from clinical samples was submitted to PCR amplification of the ITS-5.8S and the V4-V5 16S rRNA gene region, for the detection and identification of fungi and bacteria respectively. From February 2019 till February 2022, 60 patients were studied. Most of them were men (43, 74,1%) between 13 and 78 y.o. (mean age 37). Half of the patients were herdsmen but, among women 40% (6) were housewives and 26.7% (4) charcoal burners. Lesions were mainly located at the feet (87.9%) and most of the patients (54; 93.1%) reported discharge of grains in the exudate, being 27 (46.6%) yellow or pale colored and 19 (32.8%) of them dark grains. Culture of clinical samples yielded 35 fungal and bacterial putative causative agents. Culture and molecular methods allowed the identification of a total of 21 causative agents of mycetoma (39.6% of cases studied). Most of them (17) corresponded to fungi causing eumycetoma (80.9%) being the most prevalent the genus Madurella (7; 41.2%), with two species involved (M. mycetomatis and M. fahalii), followed by Aspergillus (2; 11.8%). Other minority genera detected were Cladosporium, Fusarium, Acremonium, Penicillium, and Trichophyton (5.9% each of them). Actinobacteria were detected in 19.1% of samples, but only Streptomyces somaliensis was identified as a known agent of mycetoma, the rest being actinobacteria not previously described as causative agents of the disease, such as Cellulosimicrobium cellulans detected in two of the patients. Although Kenya is geographically located in the mycetoma belt, to our knowledge this is the first report on mycetoma in this country from 1973, and the first one for Turkana County.

Mycetoma management and clinical outcomes: the Mycetoma Research Center experience

BACKGROUND

Mycetoma is a chronic granulomatous inflammatory disease that affects the cutaneous and subcutaneous tissues, leading to gruesome complications if not treated early. As a neglected disease, it has received scant attention in developing curable drugs. Mycetoma treatment is still based on expert opinions in the absence of guidelines.

METHODS

This descriptive, cross-sectional, hospital-based study aimed to determine and assess the disease treatment outcomes observed at Mycetoma Research Center, Sudan.

RESULTS

In this study, 75% of patients had eumycetoma, all of whom were treated with itraconazole and 37.4% underwent surgical excision, while 25% of the patients had actinomycetoma, 99.2% of whom were treated with a combination of cotrimoxazole and amoxicillin-clavulanate. The cure rate was 12.7% and 14.3% for patients with eumycetoma and actinomycetoma, respectively. Only 6.1% of eumycetoma patients underwent amputation. Remarkably, no patient with actinomycetoma underwent an amputation. Small lesions (OR=10.09, p<0.001) and good follow-up (OR=6.81, p=0.002) were positive predictors of complete cure. In terms of amputation, history of surgical recurrence at presentation (OR=3.67, p=0.020) and presence of grains (OR=7.13, p=0.012) were positive predictors, whereas small lesions were negative predictors (OR=0.06, p=0.009).

CONCLUSIONS

Treatment of mycetoma was suboptimal, with a low cure rate despite a long treatment duration. Complete cure has a significant association with small lesions and good follow-up.

Updated Review on Nocardia Species: 2006-2021

This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.

Estimating the burden of mycetoma in Sudan for the period 1991-2018 using a model-based geostatistical approach

Mycetoma is widespread in tropical and subtropical regions favouring arid areas with low humidity and a short rainy season. Sudan is one of the highly endemic countries for mycetoma. Estimating the population at risk and the number of cases is critical for delivering targeted and equitable prevention and treatment services. In this study, we have combined a large dataset of mycetoma cases recorded by the Mycetoma Research Centre (MRC) in Sudan over 28 years (1991-2018) with a collection of environmental and water and hygiene-related datasets in a geostatistical framework to produce estimates of the disease burden across the country. We developed geostatistical models to predict the number of cases of actinomycetoma and eumycetoma in areas considered environmentally suitable for the two mycetoma forms. Then used the raster dataset (gridded map) with the population estimates for 2020 to compute the potentially affected population since 1991. The geostatistical models confirmed this heterogeneous and distinct distribution of the estimated cases of eumycetoma and actinomycetoma across Sudan. For eumycetoma, these higher-risk areas were smaller and scattered across Al Jazirah, Khartoum, White Nile and Sennar states, while for actinomycetoma a higher risk for infection is shown across the rural districts of North and West Kurdufan. Nationally, we estimated 63,825 people (95%CI: 13,693 to 197,369) to have been suffering from mycetoma since 1991 in Sudan,51,541 people (95%CI: 9,893-166,073) with eumycetoma and 12,284 people (95%CI: 3,800-31,296) with actinomycetoma. In conclusion, the risk of mycetoma in Sudan is particularly high in certain restricted areas, but cases are ubiquitous across all states. Both prevention and treatment services are required to address the burden. Such work provides a guide for future control and prevention programs for mycetoma, highly endemic areas are clearly targeted, and resources are directed to areas with high demand.

Systematic whole-genome sequencing reveals an unexpected diversity among actinomycetoma pathogens and provides insights into their antibacterial susceptibilities

Mycetoma is a neglected tropical chronic granulomatous inflammatory disease of the skin and subcutaneous tissues. More than 70 species with a broad taxonomic diversity have been implicated as agents of mycetoma. Understanding the full range of causative organisms and their antibiotic sensitivity profiles are essential for the appropriate treatment of infections. The present study focuses on the analysis of full genome sequences and antibiotic inhibitory concentration profiles of actinomycetoma strains from patients seen at the Mycetoma Research Centre in Sudan with a view to developing rapid diagnostic tests. Seventeen pathogenic isolates obtained by surgical biopsies were sequenced using MinION and Illumina methods, and their antibiotic inhibitory concentration profiles determined. The results highlight an unexpected diversity of actinomycetoma causing pathogens, including three Streptomyces isolates assigned to species not previously associated with human actinomycetoma and one new Streptomyces species. Thus, current approaches for clinical and histopathological classification of mycetoma may need to be updated. The standard treatment for actinomycetoma is a combination of sulfamethoxazole/trimethoprim and amoxicillin/clavulanic acid. Most tested isolates had a high IC (inhibitory concentration) to sulfamethoxazole/trimethoprim or to amoxicillin alone. However, the addition of the β-lactamase inhibitor clavulanic acid to amoxicillin increased susceptibility, particularly for Streptomyces somaliensis and Streptomyces sudanensis. Actinomadura madurae isolates appear to have a particularly high IC under laboratory conditions, suggesting that alternative agents, such as amikacin, could be considered for more effective treatment. The results obtained will inform future diagnostic methods for the identification of actinomycetoma and treatment.

Ultrasound-guided Fine Needle Aspiration Cytology significantly improved mycetoma diagnosis

Background

Ultrasound (US)‐guided fine‐needle aspiration cytology (US‐FNAC) has improved the diagnosis of many malignancies, infections and other diseases as it is safe, simple, quick and accurate. In mycetoma, it is assumed that this technique may have a better diagnostic yield than the conventional FNAC as it can accurately identify the optimal site for the aspiration.

Objective

To compare the diagnostic yield of conventional FNAC with US‐FNAC.

Methods

This descriptive cross‐sectional hospital‐based study included 80 patients with clinically suspected mycetoma.

Results

Of the 80 patients included, 35 proved to have actinomycetoma, and 37 had eumycetoma based on surgical biopsies, histopathological examination and the culture of grains. Eight patients appeared to have no mycetoma. For actinomycetoma diagnosis, the US‐guided FNAC improved sensitivity to 97% and negative predictive value (NPV) to 83% compared to the conventional FNAC, which had 63% sensitivity; and NPV of 28%. No improvement was found for specificity. For eumycetoma, the conventional FNAC had 86.5% sensitivity, 100% specificity, 100% PPV and 37.5% NPV. The US‐FNAC for the diagnosis of eumycetoma had 100% sensitivity and specificity.

Conclusions and relevance

The obtained results showed that US‐FNAC is better than the conventional FNAC with lower false‐negative results. It can accurately distinguish between the two types of mycetoma, allowing rapid initiation of proper treatment. The technique can be used in rural areas with low resources and for epidemiological surveys as a quick screening tool for patients suspected of mycetoma.

Skin Mycetoma in an 11-Year-Old African Boy: Case Presentation with Emphasis on Histopathological Features and Differential Diagnosis

Mycetoma is an uncommon, chronic infective disease of the skin and subcutaneous tissues, characterized by the triad of tumefaction, draining sinuses, and the presence in the exudate of colonial grains. In cases of long-term disease, the presence of colonial grains together with the host's derivative material can lead to the formation of real sinuses. Histological analysis is of fundamental importance to allow an accurate etiological diagnosis and to understand if the basic pathogen is an actinomycete (bacterium) or a real fungus (eumycetic mycetomas) and is also fundamental for therapy, which is quite different. Here, we present a case of Mycetoma in an 11-year-old patient who emigrated from Djibouti, Somalia, and showed the essential histopathological features of this rare and forgotten nosographic entity in the industrialized world and briefly discuss the major and most important differential diagnoses.