Complete Genome Sequence and Comparative Genomic Analysis of <i>Mycobacterium massiliense</i> JCM 15300 in the <i>Mycobacterium abscessus</i> Group Reveal a Conserved Genomic Island MmGI-1 Related to Putative Lipid Metabolism

<div><p><i>Mycobacterium abscessus</i> group subsp., such as <i>M. massiliense, M. abscessus sensu stricto</i> and <i>M. bolletii</i>, are an environmental organism found in soil, water and other ecological niches, and have been isolated from respiratory tract infection, skin and soft tissue infection, postoperative infection of cosmetic surgery. To determine the unique genetic feature of <i>M. massiliense</i>, we sequenced the complete genome of <i>M. massiliense</i> type strain JCM 15300 (corresponding to CCUG 48898). Comparative genomic analysis was performed among <i>Mycobacterium</i> spp. and among <i>M. abscessus</i> group subspp., showing that additional ß-oxidation-related genes and, notably, the mammalian cell entry (<i>mce</i>) operon were located on a genomic island, <i>M. massiliense</i> Genomic Island 1 (MmGI-1), in <i>M. massiliense</i>. In addition, putative anaerobic respiration system-related genes and additional mycolic acid cyclopropane synthetase-related genes were found uniquely in <i>M. massiliense</i>. Japanese isolates of <i>M. massiliense</i> also frequently possess the MmGI-1 (14/44, approximately 32%) and three unique conserved regions (26/44; approximately 60%, 34/44; approximately 77% and 40/44; approximately 91%), as well as isolates of other countries (Malaysia, France, United Kingdom and United States). The well-conserved genomic island MmGI-1 may play an important role in high growth potential with additional lipid metabolism, extra factors for survival in the environment or synthesis of complex membrane-associated lipids. ORFs on MmGI-1 showed similarities to ORFs of phylogenetically distant <i>M. avium</i> complex (MAC), suggesting that horizontal gene transfer or genetic recombination events might have occurred within MmGI-1 among <i>M. massiliense</i> and MAC.</p>