Abstract：
A 35-year-old immunocompetent woman from southern China went to the hand surgery clinic with a six-month history of progressive swelling in her right index finger. She had been pinched by a lobster and had received several treatments without any improvement. Pus specimens were taken from the swollen parts of her finger, and the pathology showed granulomatous inflammation. Ziehl-Neelsen staining revealed positive bacillus in the pus specimens. The bacteria grew well on Columbia blood agar. However, the MALDI-TOF MS and 16S rRNA gene sequencing were not able to distinguish between Mycobacterium marinum and Mycobacterium ulcerans because of their close genetic relationship. Photochromogenicity testing can help differentiate between these species based on the alteration in colony color after light exposure. For our patient, the colonies turned yellow after 18h of incubation in the sun, identifying the species as M. marinum. Besides surgical drainage, the patient received rifampicin and clarithromycin for three months, and her symptoms resolved without relapse after six months of follow-up.
摘要：
一名来自中国南方的35岁有免疫能力的妇女去了手外科诊所，她的右手食指有六个月的进行性肿胀史。她被龙虾捏了一下，接受了几次治疗，没有任何改善。从她手指肿胀的部位采集脓液样本，病理显示肉芽肿性炎症。Ziehl-Neelsen染色显示脓液标本中呈阳性杆菌。这种细菌在哥伦比亚血琼脂上生长良好。然而,MALDI-TOFMS和16SrRNA基因测序由于遗传亲缘关系密切，无法区分marinum分枝杆菌和溃疡分枝杆菌。光致显色性测试可以根据光照后菌落颜色的改变来帮助区分这些物种。对我们的病人来说,在阳光下孵化18小时后，菌落变成黄色，鉴定该物种为M.marinum。除了手术引流,患者接受了三个月的利福平和克拉霉素，经过六个月的随访，她的症状没有复发。
