Abstract: ZHANG Zhong-kui *, WANG Chun-mei, LIU Tai-hua, CHEN Yi-hua, ZENG Ping, WANG Jun, ZHOU Zhou, HE Si-xian, TANG Li-jun, KANG Dao-xian, RAN Yu-ping. *Department of Dermatology, Chengdu Military General Hospital, Chengdu 610083, China Corresponding author: ZHANG Zhong-kui, Email: malelion13@sina.com 【Abstract】 A 69-year-old female presented with erythematous swelling, tender nodules and ulcer in the right leg for five months, which had been aggravated for one month. Dermatological examination revealed a mild swelling of the right lower extremity, and more than ten dull red, elevated, tender and soft ulcerative nodules with bloody fluid exudates below the right knee. Culture of the bloody exudate on Sabouraud′s dextrose agar grew smooth, wet and non-color-producing white colony, which was confirmed as an acid-fast bacillus. There was a 100% homology in the sequence of 16S rRNA between the bacillus isolate and Mycobacterium chelonae type strain （Genebank accession number AB548610.1）. Pathological study revealed a chronic purulent inflammation of subcutaneous tissue, which was positive for acid-fast staining, but negative for periodic acid-Schiff staining. A diagnosis of cutaneous Mycobacterium chelonae infection was made. The condition was improved and the patient was discharged after treatment with imipenem-cilastatin 500 mg thrice daily and compound sulphamethoxazole four tablets thrice daily.

Key words: Mycobacterium chelonae