Hariu Maya, Watanabe Yuji, Shimada Daishi, Imai Haruka, Takano Kauki, Kamioka Yasuhiro, Seki Masafumi
Division of Infectious Diseases and Infection Control, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan.
Laboratory for Clinical Microbiology, Tohoku Medical and Pharmaceutical University Hospital, Sendai City, Miyagi, Japan.
Am J Case Rep. 2021 Apr 4;22:e930713. doi: 10.12659/AJCR.930713.
BACKGROUND Microsporum canis is a pathogenic dermatophyte that usually colonizes animals, and secondary infection of humans comes from pets. The infected patients show hair loss with erythema and are diagnosed as having dermatophytosis, but the transmission routes of M. canis from animals to others are sometimes unclear, although they are critical to the treatment of patients and infection control. To identify the pathogens and the transmission routes, morphological observations by microscopes and conventional polymerase chain reaction (PCR) have been used; however, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has recently become a useful tool. CASE REPORT A 4-year-old girl presented with pruritic, erythematous lesions on the head with alopecia. The dermatologists diagnosed dermatophytosis caused by fungal infection, and M. canis was suspected as the pathogen because of the morphologic characteristics. All of her family members subsequently showed similar hair findings and symptoms. The growth of M. canis was also observed in serial cultures, and all strains were confirmed to be identical, but different from the standard strain on MALDI-TOF MS. In this household infection case, abandoned cats were considered to be the origin of M. canis transmission, and the family members finally improved following oral administration of antifungal agents. CONCLUSIONS M. canis should be carefully investigated as the causative pathogen of dermatophytosis secondary to household infection. MALDI-TOF MS appears to be an excellent tool to confirm the transmission routes of the fungal pathogens among infected patients.
犬小孢子菌是一种致病性皮肤真菌，通常寄生于动物，人类的继发性感染源于宠物。受感染患者表现为脱发伴红斑，被诊断为皮肤癣菌病，但犬小孢子菌从动物传播给其他宿主的途径有时并不明确，尽管这些途径对患者治疗和感染控制至关重要。为了识别病原体及其传播途径，已采用显微镜形态学观察和传统聚合酶链反应（PCR）；然而，基质辅助激光解吸/电离飞行时间质谱（MALDI-TOF MS）最近已成为一种有用的工具。病例报告：一名4岁女孩头部出现瘙痒性红斑性皮损并伴有脱发。皮肤科医生诊断为由真菌感染引起的皮肤癣菌病，由于形态学特征怀疑病原体为犬小孢子菌。随后她的所有家庭成员均出现了类似的毛发表现和症状。在连续培养中也观察到了犬小孢子菌的生长，所有菌株经确认均相同，但在MALDI-TOF MS上与标准菌株不同。在这起家庭感染病例中，流浪猫被认为是犬小孢子菌传播的源头，家庭成员在口服抗真菌药物后最终病情好转。结论：对于家庭感染继发的皮肤癣菌病，应仔细调查犬小孢子菌作为致病病原体的情况。MALDI-TOF MS似乎是确认真菌病原体在受感染患者之间传播途径的一种出色工具。
