In vitro evaluation of the type of interaction obtained by the combination of terbinafine and itraconazole, voriconazole, or amphotericin B against dematiaceous molds

In Vitro Combination of Terbinafine with Ketoconazole Against Aspergillus Species with Terbinafine High MIC Values Isolated From Otomycosis

Otomycosis is a common mycotic infection of the external auditory canal, and Aspergillus species are one of the most frequent causative agents worldwide. The limited antifungal arsenal, the high toxicity and side effects of antifungal agents, and the growing resistance to the currently available antifungals underscore the need for new therapeutic strategies. The present study aimed to evaluate the combined in vitro efficacy of terbinafine and ketoconazole against Aspergillus species with terbinafine high MIC values isolated from patients with otomycosis.84 Aspergillus species with high MIC values to terbinafine (≥ 4 µg/ml), consisting of A. flavus, A. tubingensis, A. niger, and A. terreus, were included in this study. The checkerboard microdilution method evaluated the in vitro interactions using the CLSI reference technique. Synergistic effects were observed for 66.67% (56/84) of all isolates (FICI ranging from 0.19 to 0.5). However, the interactions of terbinafine and ketoconazole exhibited indifference in 33.33% (28/84) of the isolates, and no antagonism was observed for any combination. The interaction of terbinafine and ketoconazole showed synergistic activity against Aspergillus species with high MIC values, suggesting that this is an alternative and promising approach for treating otomycosis.

New possibilities for chromoblastomycosis and phaeohyphomycosis treatment: identification of two compounds from the MMV Pathogen Box® that present synergism with itraconazole

BACKGROUND

Black fungi of the Herpotrichiellaceae family are agents of chromoblastomycosis and phaeohyphomycosis. There are few therapeutic options for these infections and it is common to associate antifungal drugs in their treatment.

OBJECTIVES

To investigate the Medicines for Malaria Venture (MMV) Pathogen Box^® for possible compounds presenting synergism with antifungal drugs used to treat black fungal infections.

METHODS

An initial screening of the Pathogen Box^® compounds was performed in combination with itraconazole or terbinafine at sub-inhibitory concentrations against Fonsecaea pedrosoi. Hits were further tested against eight Herpotrichiellaceae using the checkerboard method.

FINDINGS

No synergism was observed with terbinafine. MMV687273 (SQ109) and MMV688415 showed synergism with itraconazole against F. pedrosoi. Synergism of these compounds was confirmed with some black fungi by the checkerboard method. SQ109 and itraconazole presented synergism for Exophiala dermatitidis, F. pedrosoi, F. monophora and F. nubica, with fungicidal activity for F. pedrosoi and F. monophora. MMV688415 presented synergism with itraconazole only for F. pedrosoi, with fungicidal activity. The synergic compounds had high selectivity index values when combined with itraconazole.

MAIN CONCLUSIONS

These compounds in combination, particularly SQ109, are promising candidates to treat Fonsecaea spp. and E. dermatitidis infections, which account for most cases of chromoblastomycosis and phaeohyphomycosis.

Empiric antifungal therapy in patients with cutaneous and subcutaneous phaeohyphomycosis

We encountered two cases of phaeohyphomycosis caused by Exophiala jeanselmei and E. oligosperma that were treated with fosravuconazole and terbinafine, respectively. Our cases were successfully treated with empiric therapy before the pathogen's species or antifungal sensitivity had been determined. We summarized 32 cases of cutaneous and subcutaneous phaeohyphomycosis caused by Exophiala species in Japan. The patients received antifungals, including itraconazole, terbinafine, voriconazole, and fosravuconazole, and the treatment success rates of these monotherapies were 77% (17/22), 67% (8/12), 100% (5/5), and 50% (1/2), respectively. Although the broad-spectrum azole antifungal itraconazole is the first choice for treatment, terbinafine at 125 mg/day might exert the same efficacy. Fosravuconazole is a novel broad-spectrum azole and a moderate inhibitor of Cyp3A4 that causes fewer drug interactions than itraconazole and voriconazole, indicating a promising drug for this disease.

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.

In vitro susceptibility of chromoblastomycosis agents to antifungal drugs: A systematic review

Chromoblastomycosis (CBM) is a chronic granulomatous mycosis caused by dematiaceous fungi that affects cutaneous and subcutaneous tissues. The standard antifungal drug for treatment is itraconazole, followed by terbinafine. However, cure rates vary from 15% to 80% when these drugs are used as monotherapy. A systematic review of the in vitro susceptibility of CBM agents to antifungal drugs, alone and in combination, was conducted using the Cochrane methodology. Forty-seven search terms were included in the PICOS method of searching electronic databases. The search resulted in 35 studies, of which 8 evaluated antifungal drugs in combination. Based on minimum inhibitory concentrations (MICs), posaconazole, terbinafine, itraconazole and voriconazole were, in descending order, the most effective antifungal drugs against CBM agents in vitro. In drug combination studies, only terbinafine-voriconazole and itraconazole-caspofungin showed 100% synergy for Fonsecaea pedrosoi, Exophiala jeanselmei and Phialophora verrucosa. However, none of the combinations studied showed antagonism.

Combination of Amphotericin B and Terbinafine against Melanized Fungi Associated with Chromoblastomycosis

Our in vitro studies showed that a combination of amphotericin B and terbinafine had synergistic effects against the majority of melanized fungi associated with chromoblastomycosis (CBM) and similar infections, including those with Cladophialophora carrionii, Cladophialophora arxii, Exophialadermatitidis, Exophialaspinifera, Fonsecaea monophora, Fonsecaea nubica, Fonsecaea pedrosoi, and Phialophora verrucosa. This drug combination could provide an option for the treatment of severe or unresponsive cases of CBM, particularly in cases due to species of Fonsecaea and Cladophialophora.

In Vitro Antifungal Activities against Moulds Isolated from Dermatological Specimens

BACKGROUND

This study aimed to determine the minimum inhibitory concentrations (MICs) of various antifungal agents against moulds isolated from dermatological specimens.

METHODS

We identified 29 moulds from dermatological specimens between October 2012 and March 2013 by conventional methods. We performed antifungal susceptibility testing on six antifungal agents, amphotericin B, clotrimazole, itraconazole, ketoconazole, miconazole and terbinafine, according to the Clinical and Laboratory Standards Institute guidelines contained in the M38-A2 document.

RESULTS

Most antifungal agents were active against the dermatophytes, except for terbinafine against Trichophyton rubrum (geometric mean MIC, MICGM 3.17 μg/mL). The dematiaceous moulds were relatively susceptible to amphotericin B and azoles (MICGM 0.17-0.34 μg/mL), but not to terbinafine (MICGM 3.62 μg/mL). Septate hyaline moulds showed variable results between the relatively more susceptible Aspergillus spp. (MICGM 0.25-4 μg/mL) and the more resistant Fusarium spp. (MICGM 5.66-32 μg/mL). The zygomycetes were susceptible to amphotericin B (MICGM 0.5 μg/mL) and clotrimazole (MICGM 0.08 μg/mL), but not to other azoles (MICGM 2.52-4 μg/mL).

CONCLUSION

Amphotericin B and clotrimazole were the most effective antifungal agents against all moulds excepting Fusarium spp., while terbinafine was useful against dermatophytes (except T. rubrum) and Aspergillus spp. However, a larger study is required to draw more solid conclusions.

Systematic review of severe acute liver injury caused by terbinafine

BACKGROUND

Terbinafine is an effective antimicrobial agent against dermatophytes, cryptococcus and other fungi. It is the preferred drug to treat onychomycosis. However, severe acute hepatitis from oral terbinafine administration has been recently reported.

AIM

To describe a representative case, and review the literature regarding the best evidence on treatment and prognosis of severe acute hepatitis caused by oral terbinafine.

METHODS

The literature was searched for publications on severe hepatitis caused by terbinafine using MEDLINE, China Biology Medicine Disc, and the VIP Medical Information Resource System. Related references were searched manually.

RESULTS

Seventeen English and three Chinese references of case reports were included after eliminating duplicate publications. No randomized control studies were found. Liver enzyme levels were found to have been increased significantly. Abdominal ultrasound demonstrated cholestasis.

CONCLUSIONS

Severe acute liver injury is a known, but unusual complication of terbinafine exposure. The prognosis is often good with appropriate treatment. Liver function assessment before treatment and periodic monitoring 4-6 weeks after initiation of treatment is recommended.

Phaeoacremonium parasiticum phaeohyphomycosis in a patient with systemic lupus erythematosus treated successfully with surgical debridement and voriconazole: A case report and review of the literature

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Purulent drainage, woody induration and sinus tract formation suggest mycetoma.

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Phaeohyphomycosis management may require debridement and prolonged antifungal therapy.

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Microbiological identification is needed for optimal medical management.

A 26-year old woman presented for evaluation of extensive edema, erythema, sinus tract formation and purulent drainage from the left lower extremity after trauma from a wooden object approximately three months prior. Skin biopsies and blood cultures revealed Phaeoacremonium parasiticum consistent with a diagnosis of phaeohyphomycosis. Despite hospitalization and initial treatment with several antifungals, including voriconazole, her infection progressed. Surgical debridement with split thickness skin grafting was performed. Subsequent clinical improvement allowed a transition from intravenous to oral voriconazole and discharge home. Seven months post presentation she remained on oral voriconazole with significant improvement and no clinical evidence of recurrence. This case illustrates an approach to management where aggressive debridement with split-thickness skin grafting and a prolonged course of intravenous and oral antifungals resulted in a good long-term outcome for the patient.

Terbinafine in combination with other antifungal agents for treatment of resistant or refractory mycoses: investigating optimal dosing regimens using a physiologically based pharmacokinetic model

Terbinafine is increasingly used in combination with other antifungal agents to treat resistant or refractory mycoses due to synergistic in vitro antifungal activity; high doses are commonly used, but limited data are available on systemic exposure, and no assessment of pharmacodynamic target attainment has been made. Using a physiologically based pharmacokinetic (PBPK) model for terbinafine, this study aimed to predict total and unbound terbinafine concentrations in plasma with a range of high-dose regimens and also calculate predicted pharmacodynamic parameters for terbinafine. Predicted terbinafine concentrations accumulated significantly during the first 28 days of treatment; the area under the concentration-time curve (AUC)/MIC ratios and AUC for the free, unbound fraction (fAUC)/MIC ratios increased by 54 to 62% on day 7 of treatment and by 80 to 92% on day 28 compared to day 1, depending on the dose regimen. Of the high-dose regimens investigated, 500 mg of terbinafine taken every 12 h provided the highest systemic exposure; on day 7 of treatment, the predicted AUC, maximum concentration (Cmax), and minimum concentration (Cmin) were approximately 4-fold, 1.9-fold, and 4.4-fold higher than with a standard-dose regimen of 250 mg once daily. Close agreement was seen between the concentrations predicted by the PBPK model and the observed concentrations, indicating good predictive performance. This study provides the first report of predicted terbinafine exposure in plasma with a range of high-dose regimens.

Drug combinations against Mucor irregularis in vitro

Combinations of terbinafine or caspofungin with amphotericin B, posaconazole, or itraconazole were studied as potential treatments against 18 isolates of Mucor irregularis in vitro. Synergism of the combinations of terbinafine with amphotericin B, posaconazole, and itraconazole against 38.9, 33.3, and 44.4% of the strains studied was observed. In contrast, synergism of the combinations of caspofungin with amphotericin B, posaconazole, and itraconazole against 99.4, 66.7, and 99.4% of the strains studied was observed. Furthermore, no antagonism was observed.

In vitro susceptibility of environmental isolates of Exophiala dermatitidis to five antifungal drugs

Several dematiaceous fungi frequently isolated from nature are involved in cases of superficial lesions to lethal cerebral infections. Antifungal susceptibility data on environmental and clinical isolates are still sparse despite the advances in testing methods. The objective of this study was to examine the activities of 5-flucytosine, amphotericin B, itraconazole, voriconazole and terbinafine against environmental isolates of Exophiala strains by minimum inhibition concentration (MIC) determination. The strains were obtained from hydrocarbon-contaminated soil, ant cuticle and fungal pellets from the infrabuccal pocket of attine gynes. Broth microdilution assay using M38-A2 reference methodology for the five antifungal drugs and DNA sequencing for fungal identification were applied. Terbinafine was the most active drug against the tested strains. It was observed that amphotericin B was less effective, notably against Exophiala spinifera, also studied. High MICs of 5-flucytosine against Exophiala dermatitidis occurred. This finding highlights the relevance of studies on the antifungal resistance of these potential opportunistic species. Our results also contribute to a future improvement of the standard methods to access the drug efficacy currently applied to black fungi.