Department of Pathology, Bacteriology and Avian Diseases, Ghent University, Merelbeke, Belgium.
BMC Vet Res. 2012 Sep 25;8:175. doi: 10.1186/1746-6148-8-175.
The establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. In this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated.
Florfenicol, sulfamethoxazole, sulfadiazine and the combination of trimethoprim and sulfonamides were active in vitro against cultures of five Batrachochytrium dendrobatidis strains containing sporangia and zoospores, with minimum inhibitory concentrations (MIC) of 0.5-1.0 μg/ml for florfenicol and 8.0 μg/ml for the sulfonamides. Trimethoprim was not capable of inhibiting growth but, combined with sulfonamides, reduced the time to visible growth inhibition by the sulfonamides. Growth inhibition of B. dendrobatidis was not observed after exposure to clindamycin, doxycycline, enrofloxacin, paromomycin, polymyxin E and tylosin. Cultures of sporangia and zoospores of B. dendrobatidis strains JEL423 and IA042 were killed completely after 14 days of exposure to 100 μg/ml florfenicol or 16 μg/ml trimethoprim combined with 80 μg/ml sulfadiazine. These concentrations were, however, not capable of efficiently killing zoospores within 4 days after exposure as assessed using flow cytometry. Florfenicol concentrations remained stable in a bathing solution during a ten day period. Exposure of Discoglossus scovazzi tadpoles for ten days to 100 μg/ml but not to 10 μg florfenicol /ml water resulted in toxicity. In an in vivo trial, post metamorphic Alytes muletensis, experimentally inoculated with B. dendrobatidis, were treated topically with a solution containing 10 μg/ml of florfenicol during 14 days. Although a significant reduction of the B. dendrobatidis load was obtained, none of the treated animals cleared the infection.
We thus conclude that, despite marked anti B. dendrobatidis activity in vitro, the florfenicol treatment used is not capable of eliminating B. dendrobatidis infections from amphibians.
迫切需要建立安全有效的方案来治疗两栖动物的壶菌病。在这项研究中，评估了抗菌剂清除感染的两栖动物中的壶菌病的有用性。
氟苯尼考、磺胺甲恶唑、磺胺嘧啶和甲氧苄啶与磺胺类药物的组合对含有孢子囊和游动孢子的五种蛙壶菌菌株的培养物具有活性，氟苯尼考的最小抑菌浓度（MIC）为 0.5-1.0μg/ml，磺胺类药物的 MIC 为 8.0μg/ml。甲氧苄啶不能抑制生长，但与磺胺类药物联合使用时，可缩短磺胺类药物可见生长抑制的时间。克林霉素、多西环素、恩诺沙星、巴龙霉素、黏菌素 E 和泰乐菌素对蛙壶菌无抑制作用。暴露于 100μg/ml 氟苯尼考或 16μg/ml 甲氧苄啶联合 80μg/ml 磺胺嘧啶 14 天后，JEL423 和 IA042 菌株的孢子囊和游动孢子培养物完全死亡。然而，在暴露后 4 天内，使用流式细胞术评估时，这些浓度并不能有效地杀死游动孢子。在十天的时间里，氟苯尼考在洗浴溶液中的浓度保持稳定。Discoglossus scovazzi 蝌蚪暴露于 100μg/ml 氟苯尼考但不暴露于 10μg/ml 氟苯尼考/水 10 天导致毒性。在体内试验中，实验性接种蛙壶菌的成年 Alytes muletensis 用含有 10μg/ml 氟苯尼考的溶液进行了 14 天的局部治疗。尽管获得了 B. dendrobatidis 负荷的显著降低，但没有一只治疗动物清除了感染。
因此，尽管氟苯尼考在体外具有明显的抗 B. dendrobatidis 活性，但所用的氟苯尼考治疗方法不能从两栖动物中消除 B. dendrobatidis 感染。
