Afshari Mohammad Ali, Shams-Ghahfarokhi Masoomeh, Razzaghi-Abyaneh Mehdi
Department of Mycology, Faculty of Medical Sciences, Tarbiat Modares University, 14115-331 Tehran, Iran.
Department of Mycology, Pasteur Institute of Iran, 13164 Tehran, Iran; Microbiology Research Center, Pasteur Institute of Iran, 13164 Tehran, Iran.
Iran J Microbiol. 2016 Feb;8(1):36-46.
Dermatophytes possess a wide array of virulence factors and various antifungal susceptibility patterns which influence their pathogenesis in humans and animals. The aim of this study was to evaluate antifungal susceptibility and keratinase and proteinase activity of 49 dermatophyte strains from the genera Microsporum, Trichophyton and Epidermophyton which were isolated from human cases of dermatophytosis.
Forty-nine dermatophyte strains isolated from clinical samples were cultured on general and specific culture media. Keratinase and proteinase activity was screened on solid mineral media and confirmed in liquid cultures. Drug susceptibility toward azoles (fluconazole, ketoconazole and itraconazole), griseofulvin and terbinafine was evaluated using disk diffusion method on Mueller-Hinton agar and minimum inhibitory concentrations (MICs) were determined using microbroth dilution assay according to the Clinical and Laboratory Standards Institute (CLSI) guidelines.
Our results indicated that clinically isolated dermatophytes from 7 major species produced keratinase and proteinase at different extents. The mean keratinase and proteinase activity was reported as 6.69 ± 0.31 (U/ml) and 2.10 ± 0.22 (U/ml) respectively. Disk diffusion and microbroth dilution (MIC) results of antifungal susceptibility testing showed that ketoconazole was the most effective drug against Epidermophyton floccosum and Trichophyton mentagrophytes, itraconazole against T. rubrum and E. floccosum, and griseofulvin and terbinafine against Trichophyton verrucosum. Our results showed that all dermatophyte isolates were resistant to fluconazole. Overall, ketoconazole and itraconazole were the most effective drugs for all dermatophyte species tested.
Our results showed that antifungal susceptibility testing is an urgent need to select drugs of choice for treatment of different types of dermatophytosis and further indicated the importance of keratinase and proteinase in pathogenesis of dermatophyte species.
皮肤癣菌具有多种毒力因子以及不同的抗真菌药敏模式，这些因素会影响其在人和动物体内的致病机制。本研究的目的是评估从人类皮肤癣菌病病例中分离出的49株来自小孢子菌属、毛癣菌属和表皮癣菌属的皮肤癣菌的抗真菌药敏性以及角蛋白酶和蛋白酶活性。
将从临床样本中分离出的49株皮肤癣菌接种于普通和特殊培养基上培养。在固体矿物培养基上筛选角蛋白酶和蛋白酶活性，并在液体培养中进行确认。采用纸片扩散法在Mueller-Hinton琼脂上评估对唑类药物（氟康唑、酮康唑和伊曲康唑）、灰黄霉素和特比萘芬的药敏性，并根据临床和实验室标准协会（CLSI）指南使用微量肉汤稀释法测定最低抑菌浓度（MIC）。
我们的结果表明，从7个主要菌种临床分离出的皮肤癣菌在不同程度上产生角蛋白酶和蛋白酶。角蛋白酶和蛋白酶的平均活性分别报告为6.69±0.31（U/ml）和2.10±0.22（U/ml）。抗真菌药敏试验的纸片扩散法和微量肉汤稀释法（MIC）结果显示，酮康唑是对抗絮状表皮癣菌和须癣毛癣菌最有效的药物，伊曲康唑对抗红色毛癣菌和絮状表皮癣菌，灰黄霉素和特比萘芬对抗疣状毛癣菌。我们的结果显示所有皮肤癣菌分离株对氟康唑耐药。总体而言，酮康唑和伊曲康唑是所有受试皮肤癣菌种类最有效的药物。
我们的结果表明，抗真菌药敏试验对于选择治疗不同类型皮肤癣菌病的首选药物至关重要，进一步表明角蛋白酶和蛋白酶在皮肤癣菌致病机制中的重要性。
