title: Successful treatment of refractory cutaneous infection caused by Mycobacterium marinum with a combined regimen containing amikacin.
abstract: BACKGROUND
  The incidence of Mycobacterium marinum infection has been increasing. First-line antituberculous drugs and other common antibiotics are effective for most cutaneous M. marinum infections; however, treatment failure still occurs in some rare cases. We report a case of a 70-year-old man with refractory cutaneous infection caused by M. marinum. Reasons for delayed diagnosis and related factors of the refractory infection are also discussed.
  
  
  METHODS
  Samples of lesional skin were inoculated on Löwenstein-Jensen medium for acid-fast bacilli. Species of mycobacterium were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. We then carried out genotyping by using mycobacterial interspersed repetitive units and sequencing of heat shock protein 65 (hsp65) and 16S rDNA genes.
  
  
  RESULTS
  Tissue cultures for acid-fast bacilli were positive. PCR-RFLP analysis and sequencing of hsp65 and 16S rDNA genes confirmed the isolated organisms to be M. marinum. Systemic therapy with rifampicin, clarithromycin, and amikacin empirically over 6 months led to complete resolution of skin lesions leaving only some residual scars.
  
  
  CONCLUSIONS
  Key diagnostic elements for M. marinum infections include a high index of suspicion raised by chronic lesions, poor response to conventional treatments, and a history of fish-related exposure. Strong clinical suggestion of M. marinum infection warrants initial empirical treatment. The duration of therapy is usually several months or even longer, especially for elderly patients. Amikacin can be considered in multidrug therapy for treatment of some refractory M. marinum infections.
authors.affiliation: Key Laboratory of Molecular Biology for Skin Diseases, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China.
authors.forename: Yingxue
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiulian
authors.initials: X
authors.lastname: Xu
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: Kan
authors.initials: K
authors.lastname: Wu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Pai
authors.initials: P
authors.lastname: Liu
authors.forename: Xuesi
authors.initials: X
authors.lastname: Zeng
authors.forename: Jianfang
authors.initials: J
authors.lastname: Sun
authors.forename: Yiqun
authors.initials: Y
authors.lastname: Jiang
authors.forename: Hongsheng
authors.initials: H
authors.lastname: Wang
mesh_terms: D000368:Aged; D000583:Amikacin / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D001426:Bacterial Proteins; D018834:Chaperonin 60; D005838:Genotype; D006801:Humans; D008297:Male; D009165:Mycobacterium Infections, Nontuberculous / Q000175:diagnosis* / Q000188:drug therapy*; D019910:Mycobacterium marinum / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018834:Chaperonin 60; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S; C074119:heat-shock protein 65, Mycobacterium; D000583:Amikacin