Clinical improvement of chromoblastomycosis refractory to itraconazole successfully treated with high dose of terbinafine

Chromoblastomycosis Caused by Fonsecaea monophora Mimicking Lichen Planus

Chromoblastomycosis is a rare fungal infection acquired by traumatic inoculation of pigmented fungi from an environmental source. The polymorphic presentation of chromoblastomycosis may mimic other dermatologic conditions, leading to delays in diagnosis. Thus, histopathology is critical in identifying the presence of fungi and confirming the diagnosis. We present a case of chromoblastomycosis caused by the organism Fonsecaea monophora mimicking a lesion of lichen planus to highlight the importance of histopathology in the diagnosis of this condition.

Does DHN-Melanin Always Protect Fungi against Antifungal Drugs? The Fonsecaea/Micafungin Paradigm

Several human pathogenic fungi produce melanin. One of its properties during parasitism is the protection against antifungal drugs. This occurs with the agents of chromoblastomycosis, in which DHN-melanin reduces antifungal susceptibility to terbinafine and itraconazole. Since these agents are resistant to some antifungal drugs, we investigated the role of DHN-melanin on the Fonsecaea susceptibility to amphotericin B, micafungin, fluconazole, and flucytosine, drugs that usually present high minimal inhibitory concentrations (MIC) to this genus. Seven strains from three Fonsecaea human pathogenic species were treated with tricyclazole, a DHN-melanin inhibitor, and the MIC of the treated and untreated cells were compared. A survival assay was performed to confirm the alterations in the susceptibility of strains with reduced melanization, and the chitin levels of the strains were estimated by fluorescence. Tricyclazole did not affect fluconazole and flucytosine MIC, while melanin inhibition increased susceptibility to amphotericin B. Surprisingly, DHN-melanin inhibition decreased the susceptibility to micafungin. Survival assays confirmed this result on five strains. Cell wall chitin levels of the strains were not associated with the decrease in micafungin susceptibility. The results show that DHN-melanin does not have a role in the intrinsic resistance of Fonseacaea spp. to amphotericin B, fluconazole, and flucytosine, and its inhibition may promote micafungin resistance.

Synergistic effect of terbinafine and amphotericin B in killing Fonsecaea nubica in vitro and in vivo

Chromoblastomycosis is a chronic fungal infection. Itraconazole and terbinafine are the most recommended antifungal drugs for chromoblastomycosis, while amphotericin B is not usually recommended. A patient with chromoblastomycosis in our hospital showed poor clinical responses to itraconazole and terbinafine. The fungus isolated from the lesions of this patient was identified as Fonsecaea nubica and numbered zssy0803. In vitro antifungal susceptibilities of F. nubica zssy0803 to terbinafine, amphotericin B, itraconazole, voriconazole and caspofungin were evaluated, as well as the combinations of terbinafine with the other four antifungals. The combined effect of terbinafine and amphotericin B on other 20 clinical F. nubica strains was also evaluated. The minimal inhibitory concentrations of terbinafine, amphotericin B, itraconazole, voriconazole and caspofungin on F. nubica zssy0803 were 0.25 μg/mL, 2 μg/mL, 1 μg/mL, 4 μg/mL and 8 μg/mL, respectively. The combination of terbinafine and amphotericin B showed the lowest fractional inhibitory concentration index of 0.28 to F. nubica zssy0803 in comparison with combinations of terbinafine and the other four antifungal drugs. The combination of terbinafine and amphotericin B was also synergistic for all the other 20 F. nubica strains. Then, the combination of oral terbinafine (500 mg/day) and intralesional injections of amphotericin B (1 mg/mL) was used to treat this patient. After this combined therapy for 25 weeks and terbinafine monotherapy for additional 12 weeks, the patient was cured. These findings indicate for the first time that terbinafine and amphotericin B are synergistic in killing F. nubica both in vitro and in vivo.

Successful Treatment of Canine Sporotrichosis with Terbinafine: Case Reports and Literature Review

Sporotrichosis occurs worldwide, and the metropolitan region of Rio de Janeiro, Brazil, is a main endemic area, with a large number of human and animal cases in the last 19 years. This mycosis is more frequently described in cats rather than in dogs. There are a limited number of oral antifungal agents for the treatment of sporotrichosis in animals. In this context, the effectiveness of terbinafine in the treatment of sporotrichosis in humans, as well as the promising results of in vitro susceptibility tests, inspired us to use this drug in the therapy of this mycosis in dogs. We reported for the first time the use of terbinafine in the treatment of two dogs with sporotrichosis caused by Sporothrix brasiliensis. Moreover, we provided an overview of therapeutic features of canine sporotrichosis cases reported since the 1960s. One of the dogs presented the fixed cutaneous form of the disease, while the other patient presented hyperemia of the nasal mucosa and respiratory signs only. Terbinafine showed high antifungal activity in vitro against the canine Sporothrix isolates. The dogs were successfully treated with terbinafine, with remission of all clinical signs initially presented. The current reports indicate that this drug can emerge as a therapeutic option for canine sporotrichosis.

Chromoblastomycosis

Chromoblastomycosis (CBM), also known as chromomycosis, is one of the most prevalent implantation fungal infections, being the most common of the gamut of mycoses caused by melanized or brown-pigmented fungi. CBM is mainly a tropical or subtropical disease that may affect individuals with certain risk factors around the world. The following characteristics are associated with this disease: (i) traumatic inoculation by implantation from an environmental source, leading to an initial cutaneous lesion at the inoculation site; (ii) chronic and progressive cutaneous and subcutaneous tissular involvement associated with fibrotic and granulomatous reactions associated with microabscesses and often with tissue proliferation; (iii) a nonprotective T helper type 2 (Th2) immune response with ineffective humoral involvement; and (iv) the presence of muriform (sclerotic) cells embedded in the affected tissue. CBM lesions are clinically polymorphic and are commonly misdiagnosed as various other infectious and noninfectious diseases. In its more severe clinical forms, CBM may cause an incapacity for labor due to fibrotic sequelae and also due to a series of clinical complications, and if not recognized at an early stage, this disease can be refractory to antifungal therapy.

Arthrocladium fulminans Arthritis and Osteomyelitis

Arthrocladium fulminans is the only species in the Arthrocladium genus that has been involved in a previous human infection. To date, only one case of A. fulminans infection in a patient with GATA-2 immunodeficiency has been reported. We here report the second human case and the first case of septic arthritis and osteomyelitis due to A. fulminans in an immunocompetent patient, living in Mayotte, a French island in western Indian Ocean. He was successfully treated with surgical debridement and 6 months of antifungal treatment. This second observation of human invasive disease caused by A. fulminans is an additional argument for the pathogenicity of this rare species.