To our knowledge this is the second report of chromoblastomycosis associated with a leech bite. Platelet microbiocidal proteins and konocidins have shown to exert strong efficacy against bacteria and fungi. The coagulation system overlaps with the immune system and many acute-phase proteins of inflammation are also involved in the coagulation process. The injection of platelet inhibitors during leech bites might impair the local skin immunity increasing the risk for fungal infections. It is possible that the patient acquired the infection via the leech bite or subsequently through the wound. from biopsy material compared to ITS primers, however, PCR diagnosis of Fonsecaea spp. PCR with 18S primers may have a higher sensitivity for the detection of Fonsecaea spp. The finding that only one sample was positive with 18S primers might be due to a very low fungal load or an alteration during the sample processing and transport from remote northern Laos. The gene sequence analysis using 18S primers, in contrast to ITS primers, which have been used for Fonsecaea species identification in pure cultures, cannot distinguish between Fonsecaea pedrosoi, F. Which species of Fonsecaea was responsible remains unclear in our patient. pedrosoi, even in imidazole-refractory cases and dual therapy with itraconazole and terbinafin is recommended. However, terbinafin has shown high tolerability and efficacy especially against F. pedrosoi appears to be less sensitive to antifungal therapy than either C. Despite being the most common aetiological agent, F. Antifungals needed to be given for at least 6-12 months, often combined with physical treatments such as surgery, cryotherapy and thermotherapy. Treatment remains challenging, especially in financially-poor countries. Direct microscopic identification of muriform/sclerotic cells is diagnostic but doctors have to be aware of this differential diagnosis. Its slow growth and variable appearance may result in confusion with skin cancer, eczema, psoriasis, or leprosy, as in our patient. The patient's left lower leg and foot healed without lesions but with some residual swelling (Figure 6).Ĭhromoblastomycosis has been reported from neighbouring Thailand and China, and it is likely to be endemic in Laos. Local terbinafin ointment was also applied for 6 months. The sequence was published in GenBank (accession number HQ616145).Īfter 4 months, oral terbinafin (500 mg/day, later 750 mg/day) for 9 months was added. Subsequent sequencing revealed 100% similarity with Fonsecaea pedrosoi, monophora, and F. PCR using ITS primers remained negative in all 3 samples, whereas 18S rRNA-PCR was positive in one of the 3 samples. PCR-products were subsequently sequenced as described and compared with Basic Local Alignment Search Tool (BLAST). Fungal DNA was amplified with two different PCR-protocols, using primers of the internal transcribed spacer (ITS) 1 and 4 region and the conserved 18S subunit of the rRNA gene with 2.5 μl of DNA-extract applied in each PCR reaction. DNA extraction was performed from each of three tissue samples of about 3 mm in diameter from the patient's lower leg. In order to confirm the diagnosis, and as fungal cultures were not available in Laos, identification by PCR was attempted at Tübingen from heated and ethanol-treated tissue. Due to the pathognomonic microscopic findings of sclerotic cells he was diagnosed with chromoblastomycosis and started on itraconazole 400 mg/d monthly pulse therapy on day 18 and a surgical debridement of all skin lesions was performed on day 21.Īdditional file 1: Videoclip showing perpendicular scraping movements of maggots in the patient's very tender heel that initially were overlooked. During wound dressing on day 3, 22 maggots (fly larvae) were discovered in the heel wound (Figure 5, Additional file 1) and identified as third instar larvae of the Old World screwworm fly, Chrysomya bezziana (Diptera: Calliphoridae). Bacterial culture of wound discharge grew Escherichia coli susceptible to co-trimoxazole by disc diffusion testing (according to CLSI guidelines ). He was treated with oral cloxacillin and metronidazole for 1 week, followed by co-trimoxazole, and local iodine-based antiseptics. Left lower leg and foot radiographs showed no evidence of bone involvement. He was thought initially to have leprosy or skin cancer, but skin scrapings from the left lower leg lesions revealed typical brownish, round, thick-walled, multiseptate sclerotic cells in a wet film, confirmed with the 10% potassium hydroxide technique (Figure 3 and 4).
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