一例由本哈米（benhamiae）毛癣菌引起的犬皮肤癣菌病

王帆

Dermatophytosis caused by Trichophyton benhamiae in a dog

一例由本哈米（benhamiae）毛癣菌引起的犬皮肤癣菌病

作者：Miguel Angel Scarpa等人

翻译：王佳妮

Trichophyton benhamiae was diagnosed in a 9-year-old female dog by histopathological evaluation, fungal culture and confirmation by sequencing of the internal transcribed spacer region of ribosomal DNA. Successful therapy was achieved with itraconazole, bathing with miconazole and chlorhexidine shampoo, and topical application of sodium hypochlorite as a rinse.

通过组织病理学鉴定、真菌培养、核糖体DNA内转录间隔区测序，确诊一只9岁的雌性犬感染本哈米（benhamiae）毛癣菌。使用伊曲康唑、咪康唑和氯己定香波洗澡，以及外用次氯酸钠浸泡，成功治愈。

Introduction

介绍

Dermatophytoses are superficial mycoses that affect the skin and other keratinised structures (nails or hair) and are caused by dermatophytic fungi.Guinea pigs are considered the primary host of Trichophyton benhamiae, yet this species also has been isolated from rabbits and other rodents, which can be carriers.The present study is a case report of dermatophytosis caused by T. benhamiae in a dog.

皮肤癣菌病是影响皮肤和其他角化结构（指甲或毛发）的浅表真菌病，由皮肤癣菌引起。豚鼠被认为是本哈米（benhamiae）毛癣菌的主要宿主，但该菌种也已从兔子和其他啮齿动物中分离出来，这些动物可能是携带者。本研究是一例由本哈米（benhamiae）毛癣菌感染导致的犬皮肤癣菌病的病例报告。

Case description

病例说明

A 9-year-old spayed female cross-bred dog from Buenos Aires, Argentina, was presented with progressive alopecia, erythema and erosions with sero-haemorrorhagic crusts, affecting the limbs, axillae and chest (Figure 1a). Skin impression smear cytological examination revealed pyogranulomatous inflammation and intracellular coccoid bacteria within neutrophils. A skin biopsy was acquired for histopathological examination, and hairs and scale from lesions on the ventral thoracic area were collected for fungal culture. Histopathological evaluation revealed folliculitis and severe, diffuse, pyogranulomatous furunculosis and intralesional endothrix arthrospores. Periodic acid Schiff staining highlighted the presence of fungal hyphae around the hair follicle (Figure 2). Mycological culture in Lactrimel Borelli agar and potato dextrose agar produced fungal colony growth after seven days of incubation. Microscopic examination of the colonies showed a septate, hyaline mycelial fungus with cigarshaped macroconidia containing eight to 12 transverse septa and globose-to-pyriform microconidia grouped in clusters. This morphology is characteristic of the T. mentagrophytes complex. DNA was extracted from the mycelium for PCR and sequencing of the internal transcribed spacer (ITS) fragment (ITS1-5.8S-ITS2) of the rDNA. The sequence showed 99.70% similarity with T. benhamiae (accession no. KP132805.1), using the BLAST algorithm from NCBI GenBank (MV292805). Treatment included itraconazole 10 mg/kg/day (Sporanox, CIMA; Latina, Italy), bathing every five days with a 2% miconazole/2% chlorhexidine shampoo (MacDonald Gel Shampoo; Buenos Aires, Argentina) and daily topical spray application of 0.025% sodium hypochlorite solution for 120 days until complete remission of the lesions was achieved (Figure 1b).

来自阿根廷布宜诺斯艾利斯的一只9岁绝育雌性混血犬出现了进行性脱毛、红斑、糜烂和血清性结痂，病变位于四肢、腋下和胸部(图1a)。皮肤压片细胞学检查显示化脓性肉芽肿性炎症和中性粒细胞内的胞内球菌。取皮肤活检进行组织病理学检查，取胸腹侧病变部位的毛发和皮屑进行真菌培养。组织病理学检查显示毛囊炎和严重的弥漫性脓性肉芽肿性疖病和病灶内毛发内分节孢子。过碘酸希夫染色剂染色突出了毛囊周围真菌菌丝的存在(图2)。在Lactrimel Borelli琼脂和马铃薯葡萄糖琼脂中进行真菌培养，培养7天后真菌菌落生长。菌落显微镜检查显示一个有隔膜的透明菌丝体，有8 - 12个横隔膜的雪茄状大分生孢子和球形到梨状的小分生孢子。这种形态是须毛癣菌复合体的特征。从菌丝体中提取DNA进行PCR检测，并对其rDNA的ITS片段(ITS1-5.8S-ITS2)进行测序。该序列与本哈米（benhamiae）毛癣菌 (登记号.KP132805.1)，使用美国国家生物技术信息中心基因库(MV292805)中的BLAST算法。治疗包括伊曲康唑10 mg/kg/day ，每五天一次使用2%咪康唑/2%洗必泰香波洗澡。每日外涂0.025%次氯酸钠溶液，持续120天，直到病变完全缓解(图1b)。

Figure 1. Lateral view of a dog with Trichophyton benhamiae dermatophytosis.(a) Clinical presentation showing alopecia, erythema and erosions with crusts. (b) Hair regrowth with resolution of most lesions posttreatment. Residual erythema and a self-induced erosive lesion (arrow) were thought to be due to persistent atopic dermatitis .

图1。患有本哈米（benhamiae）毛癣菌皮肤癣菌病的犬的侧位图。(a)临床表现为脱毛、红斑和糜烂，伴有结痂。(b)毛发再生，大多数病灶在治疗后消退。残留的红斑和自我损伤性糜烂病变(箭头所示)，考虑是由于特应性皮炎导致。

Figure 2. Histopathological findings in a skin biopsy of a dog with Trichophyton benhamiae dermatophytosis.

Fungal hyphae and arthrospores (arrows) are observed colonizing a hair follicle. Periodic acid Schiff stain, x40.

图2。患有本哈米（benhamiae）毛癣菌皮肤癣菌病的犬的皮肤活检的组织病理学发现。

观察到真菌菌丝和分节孢子(箭头)定植在毛囊中。。过碘酸希夫染色，x40。

Discussion

讨论

Dermatophytes are important pathogens given their contagious nature and zoonotic potential. A rapid and accurate diagnosis, accompanied by adequate treatment,limits the contagion potential to other animals and people. Contagion was not documented in this case. Skin infections by T. benhamiae have been associated with inflammation in immunosuppressed children and adults,where it can lead to severe clinical signs with secondary bacterial infections, scarring and kerion celsi.  Carriage studies conducted in Denmark on guinea pigs, hamsters and rabbits in pet stores have shown a 38% positive rate in guinea pigs, 6% in hamsters and 0% in rabbits. In the case presented here, although the dog had no contact with guinea pigs, it did frequently hunt cavies (Microcavia australis), a wild rodent related to guinea pigs, which may have been the source of the contagion. The fungal species presents two phenotypes: one produces white colonies and the other yellow colonies. In France, all yellow phenotype strains were isolated from human patients with inflammatory dermatophytosis who had had previous contact with guinea pigs. In the case reported here, the isolated strain manifested a white phenotype. Although T. benhamiae colonies may exhibit some variation in colour between strains, their micromorphology is indistinguishable from the T. mentagrophytes complex. However, in the typing and identification of dermatophyte species, the sequence and length of the ITS region in dermatophyte rDNA has shown good interspecific specificity and intraspecific conservation.

考虑到皮肤癣菌的传染性和人畜共患潜力，皮肤癣菌是重要的病原体。快速和准确的诊断，伴随着充分的治疗，限制了传染给其他动物和人的可能性。这个病例没有记录传染的扩散。 本哈米（benhamiae）毛癣菌引起的皮肤感染与儿童的免疫抑制和成人的炎症有关，可导致严重的临床症状，包括继发性细菌感染、瘢痕和脓癣。在丹麦对宠物店的豚鼠、仓鼠和兔子进行的携带研究表明，豚鼠的阳性率为38%、仓鼠为6%、兔子为0%。在本文案例中，虽然本文患犬没有与豚鼠接触，但它确实经常捕食豚鼠（南方小豚鼠），这是一种与豚鼠有关的野生啮齿动物，可能是传染源。真菌菌种呈现两种表型：一种产生白色菌落，另一种产生黄色菌落。在法国，所有黄色表型菌株都是从曾与豚鼠接触过的炎性皮肤癣菌病人类患者中分离出来的。在这里报道的案例中，分离的菌株表现出白色表型。虽然本哈米（benhamiae）毛癣菌菌落可能在菌株之间表现出一些颜色变化，但它们的微形态与须毛癣菌复合体无法区分。但在皮肤癣菌种类的分型和鉴定中，皮肤癣菌rDNA中ITS区的序列和长度表现出良好的种间特异性和种租守恒定律。

Conclusion

结论

Trichophyton benhamiae must be considered as one of the aetiological agents of canine dermatophytosis. It is important to reach an early and definitive diagnosis in order to identify the ecological niche of infectious source,in order to minimise contagion and zoonosis.

本哈米（benhamiae）毛癣菌应被认为是犬皮肤病的病原之一。重要的是要作出早期和明确的诊断，以确定传染源的生态位，以尽量减少传染和人畜共患病。

海绵饱饱

红蓝紫

王超

毛衣

马海军

青春年少