Joichi Yumiko, Chijimatsu Ikue, Yarita Kyoko, Kamei Katsuhiko, Miki Mizuka, Onodera Makoto, Harada Masako, Yokozaki Michiya, Kobayashi Masao, Ohge Hiroki
Section of Infection Diseases, Laboratory Division of Clinical Support, Hiroshima University Hospital.
Med Mycol J. 2014;55(2):E43-8. doi: 10.3314/mmj.55.e43.
Filamentous fungi were detected in the blood culture of a one-year-old boy after autologous peripheral blood stem cell transplantation. The patient was suspected to have aspergillosis and received micafungin. Fungi were isolated on potato dextrose agar medium and incubated at 37℃ for 2-5 days. Grayish, cottony colonies formed. A slide culture showed a spherical sporangium at the tips of the sporangiophores. The fungus could have been a zygomycete. The zygomycete was isolated from three blood cultures. The antifungal drug was changed from micafungin to liposomal amphotericin B, which resulted in an improvement in the patient's symptoms. Growth was observed at 37℃, but not 42℃ in a growth temperature test. Gene sequence analysis identified the fungus as Mucor velutinosus. To the best of our knowledge, this is the first time M. velutinosus has been detected in Japan, and this case is very rare. Zygomycetes are known to be pathogens that cause fungal infections in immunodeficient patients such as those with leukemia. They are difficult to identify by culture and are identified at autopsy in many cases. Therefore, culture examinations should be performed for immunodeficient patients with the consideration of zygomycetes.
在一名一岁男孩自体外周血干细胞移植后的血培养中检测到丝状真菌。该患者疑似患有曲霉病并接受了米卡芬净治疗。真菌在马铃薯葡萄糖琼脂培养基上分离，并在37℃下培养2 - 5天。形成了灰白色、棉絮状菌落。玻片培养显示在孢囊梗顶端有球形孢子囊。该真菌可能是接合菌。从三份血培养物中分离出了接合菌。抗真菌药物从米卡芬净换成了脂质体两性霉素B，这使患者症状有所改善。在生长温度测试中，该真菌在37℃生长，但在42℃不生长。基因序列分析确定该真菌为绒毛状毛霉。据我们所知，这是日本首次检测到绒毛状毛霉，且该病例非常罕见。接合菌是已知的可在免疫缺陷患者（如白血病患者）中引起真菌感染的病原体。它们很难通过培养来鉴定，在很多情况下是在尸检时才得以鉴定。因此，对于免疫缺陷患者应考虑接合菌进行培养检查。
