Comparative genomic analysis of Mycobacterium iranicum UM_TJL against representative mycobacterial species suggests its environmental origin

Abstract

Mycobacterium iranicum is a newly reported mycobacterial species. We present the first comparative study of M. iranicum UM_TJL and other mycobacteria. We found M. iranicum to have a close genetic association with environmental mycobacteria infrequently associated with human infections. Nonetheless, UM_TJL is also equipped with many virulence genes (some of which appear to be the consequence of transduction-related gene transfer) that have been identified in established human pathogens. Taken all together, our data suggest that M. iranicum is an environmental bacterium adapted for pathogenicity in the human host. This comparative study provides important clues and forms the basis for future functional studies on this mycobacterium.

Mycobacterium iranicum septic arthritis and tenosynovitis

“…M. iranicum has been isolated in various regions including Iran; the Mediterranean (Italy, Greece); Northern Europe (the Netherlands, Sweden); the United States; and Asia (Malaysia, Japan). [7], [8], [9] It is a newly discovered species, with the first documented case reports dating back to 2005[3]. Prior to the publication of this current report, M. iranicum was isolated in both immunocompetent patients and those with immunocompromising conditions, including renal transplantation, cancer, diabetes mellitus, Crohn's disease, and human immunodeficiency virus (HIV) infection (Table 1).…”

“…In a comparative genome analysis, M. iranicum was found to have a close genetic association with other environmental mycobacteria. [8] Based on phylogenetic analysis, M. iranicum may be closely related to another rapid grower M. gilvum . [9] It may have acquired virulence genes via horizontal transfer with other mycobacteria, Gram-positive bacteria ( Rhodococcus, Corynebacterium, Nocardia ), and Gram-negative bacteria ( Achromobacter ).…”

“…[9] It may have acquired virulence genes via horizontal transfer with other mycobacteria, Gram-positive bacteria ( Rhodococcus, Corynebacterium, Nocardia ), and Gram-negative bacteria ( Achromobacter ). [8]…”

“…Prior to the publication of this current report, M. iranicum was isolated in both immunocompetent patients and those with immunocompromising conditions, including renal transplantation, cancer, diabetes mellitus, Crohn's disease, and human immunodeficiency virus (HIV) infection (Table 1). [3], [7], [8]…”

Draft genome sequences of eight bacteria isolated from the indoor environment: Staphylococcus capitis strain H36, S. capitis strain H65, S. cohnii strain H62, S. hominis strain H69, Microbacterium sp. strain H83, Mycobacterium iranicum strain H39, Plantibacter sp. strain H53, and Pseudomonas oryzihabitans strain H72

“…CoNS are typically benign inhabitants of the human skin and mucous membranes, but they are associated with infections and can be pathogenic to humans with compromised immune systems [ 10 ]. Mycobacterium iranicum is a newly described species which has been isolated from clinical specimens originating in diverse countries including Iran , Greece , the Netherlands , Sweden and the USA [ 11 ], although genomic comparison indicated that this is likely an environmental bacterium [ 12 ]. Pseudomonas oryzihabitans (synonym Flavimonas oryzihabitans ) has been isolated from water and damp environments such as rice paddies and sink drains [ 13 ].…”