Mycobacterium chelonae is a species of the phylum actinobacteria (Gram-positive bacteria with high guanine and cytosine content, one of the dominant phyla of all bacteria), belonging to the genus mycobacterium.

• Mycobacterium chelonae is a rapidly growing mycobacterium, that is found all throughout the environment including sewage and tap water.
• It can occasionally cause opportunistic infections of humans. It is grouped in Runyon group IV.
• Type strain: strain CM 6388 = ATCC 35752 = CCUG 47445 = CIP 104535 = DSM 43804 = JCM 6388 = NCTC 946.

• On average, 2 cases of nonpulmonary M. chelonae infection are reported in South Australia each year.^[1]

• 1. Localized infections ^[2]

• Preferred regimen: Clarithromycin 500 mg PO BID
• Alternative regimen: Azithromycin

• 2. Disseminated or extensive disease

• 2.1 monotherapy

• Preferred regimen: Clarithromycin 500 mg PO BID

• 2.2 multidrug therapy

• Preferred regimen: Clarithromycin 500 mg PO BID AND Tobramycin 5 mg IV/kg/day PO OR Imipenem 0.5-1 g IV q6h OR Linezolid 600 mg IV/PO BID for 4-8 weeks
• Alternative regimen: Moxifloxacin 400 mg PO qd AND Linezolid 600 mg PO BID
• Note (1): During initial treatment, multidrug therapy may prevent development of acquired resistance
• Note (2): Total treatment duration is 6 months

• 3. Keratitis (LASIK-related)

• Preferred regimen: Clarithromycin 500 mg PO BID AND topicals (Tobramycin 0.3%, 2 gtts q4h AND Gatifloxacin 0.3%, 1 gtt q4h OR Moxifloxacin 0.5%, 1 gtt q4h