中毒性表皮坏死松解症伴发林生地霉感染一例

A case report of toxic epidermal necrolysis associated with geotrichosis due to Geotrichum silvicola

目的报道中毒性表皮坏死松解症伴发林生地霉引起的地霉病1例。方法多次取患者体表分泌物、血、尿液做真菌直接镜检,同时接种于沙氏培养基做真菌培养。对阳性分离株进行光学显做镜观察,同时应用PCR扩增其26S rDNA D1／D2区域,在DNA自动测序仪上对扩增产物进行测序,在基因库核酸序列数据库中进行同源序列搜索,并通过系统树显示亲缘关系。结果患者左手背脓液直接镜检,可见大量孢子和少量透明菌丝。连续3次血、尿真菌培养,均有形态一致的白色菌落生长,皮损分泌物培养阴性,联用伊曲康唑和大蒜素治疗1周后均转为阴性。阳性分离株光学显微镜下可见链状排列的关节孢子、芽生孢子及少量菌丝。DNA序列分析显示阳性分离株(Hebei-1)的26S rDNA D1／D2区序列与脓癣样皮损分离株(Changzheng-1)比较有1个碱基的差异,与林生地霉模式菌株比较有4个碱基的差异,基于26S rDNA D1／D2区序列分析的系统发育树显示,其与Changzheng-1的亲缘关系最近。结论该中毒性表皮坏死松解症患者伴发林生地霉感染。

Objective To report a case of toxic epidermal necrolysis associated with geotrichosis due to Geotrichum silvicola. Methods The exudates from the body surface, blood and urine of the patient were examined by microscopy and simultaneously inoculated onto the Sabouraud dextrose agar （SDA） medium. The isolate was examined by microscopy, PCR which amplified the D1/D2 domain of 26S rDNA, and gene sequencing. Homologous sequences were searched in the GenBank/EMBL/DDBJ/PD nucleotide sequence library, and the genetic relationship was analyzed with the genealogical tree. Results Microscopy of pus from the abscess on the dorsa of left hand revealed a lot of spores and a few hyphae, which were not observed in the blood or urine specimens. Meanwhile, whitish colonies were grown in all the three successive cultures of blood and urine specimens, rather than the exudates on the body surface. After itraconazole and garlicin were administered for one week, both microscopic exam and fungus culture were negative. Mi- croscopic exam of the isolate showed arthrospores arranged in chains, budding spores and a few of hyphae. It was found that there was a one-base difference between our isolate （ Hebei-1 ） and the isolate from kerion-like eruptions （Changzheng-1）, and a four-base difference between our isolate and the reference Geotrichum silvicola strain as well, in the D1/D2 domain of 26S rDNA. This isolate was identified to be most close to Changzheng-1 in the phylogenetic tree. Conclusion The patient with toxic epidermal necrolysis is associated with geotrichosis due to Geotrichum silvicola.