First case of chromoblastomycosis from Bangladesh

New methylene blue-mediated photodynamic inactivation of multidrug-resistant Fonsecaea nubica infected chromoblastomycosis in vitro

Chromoblastomycosis is a fungal disease presented with local warty papule, plaque, and verrucous nodules. In addition, the incidence and drug resistance of chromoblastomycosis are increasing each year worldwide. Photodynamic therapy is a promising method to treat mycoses. The purpose of this study was to evaluate the effect of new methylene blue (NMB)-induced PDT on multidrug-resistant chromoblastomycosis in vitro. We isolated one wild-type strain pathogen from one clinical patient diagnosed with chromoblastomycosis for over 27 years. The pathogen was identified by histopathology, the morphology of fungal culture, and genetic testing. Drug susceptibility testing was performed on the isolate. It was cultured with logarithmic growth phase spore in vitro and incubated with different concentrations of NMB for 30 min, and received illumination by red light-emitted diode with different light doses. After photodynamic treatment, the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were conducted. The pathogen was Fonsecaea nubica, and it was resistant to itraconazole, terbinafine, amphotericin B, voriconazole andcaspofungin. At the same NMB concentration, the sterilization efficiency of NMB-photodynamic therapy (PDT) on F. nubica increased with increasing light intensity; F. nubica was completely killed at 25 µmol/L NMB with a light dose of 40 J/cm2 or 50 µmol/L NMB and light doses of ≥ 30 J/cm2. SEM and TEM observed ultrastructural changes after PDT. NMB-PDT inactivates the survival of multidrug-resistant F. nubica in vitro; it therefore has the potential to become an alternative or adjuvant treatment for refractory chromoblastomycosis.

The global burden of chromoblastomycosis

BACKGROUND

Chromoblastomycosis (CBM), represents one of the primary implantation mycoses caused by melanized fungi widely found in nature. It is characterized as a Neglected Tropical Disease (NTD) and mainly affects populations living in poverty with significant morbidity, including stigma and discrimination.

METHODS AND FINDINGS

In order to estimate the global burden of CBM, we retrospectively reviewed the published literature from 1914 to 2020. Over the 106-year period, a total of 7,740 patients with CBM were identified on all continents except Antarctica. Most of the cases were reported from South America (2,619 cases), followed by Africa (1,875 cases), Central America and Mexico (1,628 cases), Asia (1,390 cases), Oceania (168 cases), Europe (35 cases), and USA and Canada (25 cases). We described 4,022 (81.7%) male and 896 (18.3%) female patients, with the median age of 52.5 years. The average time between the onset of the first lesion and CBM diagnosis was 9.2 years (range between 1 month to 50 years). The main sites involved were the lower limbs (56.7%), followed by the upper limbs (19.9%), head and neck (2.9%), and trunk (2.4%). Itching and pain were reported by 21.5% and 11%, respectively. Malignant transformation was described in 22 cases. A total of 3,817 fungal isolates were cultured, being 3,089 (80.9%) Fonsecaea spp., 552 (14.5%) Cladophialophora spp., and 56 Phialophora spp. (1.5%).

CONCLUSIONS AND SIGNIFICANCE

This review represents our current knowledge on the burden of CBM world-wide. The global incidence remains unclear and local epidemiological studies are required to improve these data, especially in Africa, Asia, and Latin America. The recognition of CBM as NTD emphasizes the need for public health efforts to promote support for all local governments interested in developing specific policies and actions for preventing, diagnosing and assisting patients.

Chromoblastomycosis in the Amazon region, Brazil, caused by Fonsecaea pedrosoi, Fonsecaea nubica, and Rhinocladiella similis: Clinicopathology, susceptibility, and molecular identification

Chromoblastomycosis is a chronic subcutaneous disease caused by human contact with melanized fungi occurring mainly in tropical and subtropical zones worldwide. This study assessed 12 patients with chromoblastomycosis from Rondônia, Brazil, Amazon region. In sum, 83.3% were men, 41.6% were from Monte Negro city, median age was 52.9 years, and median time to disease progression was 12.2 years. Lesions were located on the lower limbs (75%), and verruciform was prevalent form (66.6%). After 3 years of treatment with itraconazole, two patients were considered cured. The etiological agents were identified by the molecular sequence of the ribosomal internal transcribed spacer ITS1, 5.8S, and ITS2 region and β-tubulin genes. Eight strains were identified as Fonsecaea pedrosoi, two were F. nubica, and two were Rhinocladiella similis. The antifungal activity of five drugs was evaluated, and the most active drug was terbinafine (range minimal inhibitory concentration [MIC] 0.015-0.12 μg/ml), itraconazole (range MIC 0.03-0.5 μg/ml) and voriconazole (range MIC 0.06-0.5 μg/ml). The highest MIC was 5-fluorocytosine (range MIC 2-32 μg/ml), and amphotericin B (range MIC 0.25-2 μg/ml). In conclusion, the present study expanded the epidemiological disease database and described for the first time F. nubica and R. similis as chromoblastomycosis agents in the Brazilian Amazon region. Our results confirmed the importance of using molecular methods to identify the melanized fungi and stimulate the recognition of the disease in other places where no cases have been reported.

[Long-pulsed 1064 nm Nd: YAG laser combined with terbinafine against chromoblastomycosis caused by Fonsecaea nubica and the effect of laser therapy in a Wistar rat model]

We report a case of chromoblastomycosis caused by Fonsecaea nubica, which was successfully treated by long-pulsed 1064 nm Nd: YAG laser combined with terbinafine. A 60-year-old man was admitted for the presence of a 30 mm×40 mm erythematous plaque on the dorsum of his right hand for about 10 months without any subjective symptoms. Both microscopic examination and tissue biopsy of the lesion showed characteristic sclerotic bodies of chromoblastomycosis. Lesion tissue culture on SDA at 26 ℃ for 2 weeks resulted in a black colony, and slide culture identified the isolate as Fonsecaea species. ITS sequence analysis of the isolate showed a 99% homology with F. nubica strain KX078407. The in vitro susceptibility of the isolate to 9 antifungal agents was determined using the microdilution method according to the guidelines of CLSI M38-A2 protocol, and terbinafine showed the lowest MIC (0.125 μg/ml). We subsequently established a Wistar rat model of chromoblastomycosis using the clinical isolate F. nubica and treated the rats with long-pulsed 1064 nm Nd: YAG laser (pulse width of 3.0 ms, fluence of 24 J/cm², spot size of 3 mm, frequency of 4 Hz, repeated 3 times at an interval of 30 s) twice a week for a total of 8 sessions. Although the laser treatment alone was not able to eliminate the fungi, histopathological examination showed the aggregation of numerous lymphocytes in the local affected tissue, indicating an immune response that consequently facilitate the regression of the lesion. The patient was successfully treated by long-pulsed 1064 nm Nd: YAG laser once a week combined with terbinafine (0.25 /bid) for 8 weeks, and follow-up for 20 months did not reveal any signs of recurrence.

Chromoblastomycosis Caused by Fonsecaea nubica: First Report in Northern China and Literature Review

Chromoblastomycosis is found worldwide with higher incidence in tropical and subtropical regions. Fonsecaea spp. is one of the major causative agents of this disease. First case of chromoblastomycosis due to Fonsecaea nubica in Northern China is reported in a 75-year-old Chinese male. We firstly summarized molecular identification methods of Fonsecaea spp. and all the strains of F. nubica reported in the literature. Sequencing of internal transcribed spacer alone and/or combined with actin (ACT1), partial cell division cycle (CDC42) and partial beta-tubulin (BT2) were most commonly used to identify species, while lactase (Lac), homogentisate (HmgA) and polyketide synthase (PKS1) were also used in some cases. Most strains were isolated from South America and Eastern China. Five clinical cases of chromoblastomycosis due to F. nubica from Asia and Europe were also reviewed. All the five patients were male, over 30 years old, and their lesions occurred after trauma.

Case Report: A Case of Chromoblastomycosis Caused by Fonsecaea pedrosoi in Vietnam

BACKGROUND

Chromoblastomycosis is a chronic fungal infection of the skin and subcutaneous tissues caused by different melanized fungi. The disease occurs worldwide, particularly in tropical and subtropical regions but not reported in Vietnam. A 47-year-old women was admitted to hospital 103, Hanoi, Vietnam, with a 10-year lasting lesion on backside of her right shank. Diagnosis of chromoblastomycosis was made after discovery of a muriform cell in histopathological examination. A black, slow-growth fungus was isolated and identified as Fonsecaea pedrosoi after molecular analysis. After 1-month treatment with itraconazole, the lesion has significant improvement.

CONCLUSION

This is the first case of chromoblastomycosis caused by Fonsecaea pedrosoi reported in Vietnam.

Successful treatment of chromoblastomycosis of 10-year duration due to Fonsecaea nubica

We report a case of chromoblastomycosis due to the presence of large plaque and verrucous hyperplasia lesions on the left upper limb, with elbow abnormal activities, in a 56-year-old male. The diagnosis of chromoblastomycosis was based on gross and microscopic morphologies, histopathological examination and clinical manifestation. Molecular tools were applied to identifying the causative agent Fonsecaea nubica, which is rarely reported to be associated with chromoblastomycosis. The patient was initially treated orally with terbinafine (250 mg/day) and itraconazole (200 mg/day), subsequently patient received thermotherapy (45-50°C, 3 h/day) for 1 month. The patient was successfully cured. A literature review was performed to assess general features, treatment and outcome of chromoblastomycosis due to F.  nubica. All the 5 reviewed patients were male, over 30 years old and their lesions occurred after traumatic inoculation.