Characterization of a Novel Plasmid, pMAH135, from Mycobacterium avium Subsp. hominissuis

Abstract

Mycobacterium avium complex (MAC) causes mainly two types of disease. The first is disseminated disease in immunocompromised hosts, such as individuals infected by human immunodeficiency virus (HIV). The second is pulmonary disease in individuals without systemic immunosuppression, and the incidence of this type is increasing worldwide. M. avium subsp. hominissuis, a component of MAC, causes infection in pigs as well as in humans. Many aspects of the different modes of M. avium infection and its host specificity remain unclear. Here, we report the characteristics and complete sequence of a novel plasmid, designated pMAH135, derived from M. avium strain TH135 in an HIV-negative patient with pulmonary MAC disease. The pMAH135 plasmid consists of 194,711 nucleotides with an average G + C content of 66.5% and encodes 164 coding sequences (CDSs). This plasmid was unique in terms of its homology to other mycobacterial plasmids. Interestingly, it contains CDSs with sequence homology to mycobactin biosynthesis proteins and type VII secretion system-related proteins, which are involved in the pathogenicity of mycobacteria. It also contains putative conserved domains of the multidrug efflux transporter. Screening of isolates from humans and pigs for genes located on pMAH135 revealed that the detection rate of these genes was higher in clinical isolates from pulmonary MAC disease patients than in those from HIV-positive patients, whereas the genes were almost entirely absent in isolates from pigs. Moreover, variable number tandem repeats typing analysis showed that isolates carrying pMAH135 genes are grouped in a specific cluster. Collectively, the pMAH135 plasmid contains genes associated with M. avium’s pathogenicity and resistance to antimicrobial agents. The results of this study suggest that pMAH135 influence not only the pathological manifestations of MAC disease, but also the host specificity of MAC infection.

Comparative Genomic and Transcriptomic Analyses of Mycobacterium kansasii Subtypes Provide New Insights Into Their Pathogenicity and Taxonomy

“…The new plasmid pMKIII01 (Supplementary Figure 1) harbors a locus encoding a putative Type IV secretion system and a putative Type VII secretion system. This plasmid resembles the conjugative mycobacterial plasmids that have been discovered previously, such as the type-plasmid pRAW in M. marinum (Ummels et al, 2014), pMAH135 (Uchiya et al, 2015), and pMA100 (da Silva Rabello et al, 2012) of Mycobacterium avium, pMyong1 from Mycobacterium yongonense (Kim et al, 2013), pMK12478 (Veyrier et al, 2009) from M. kansasii 12478 and several plasmids from Mycobacterium chimera (van Ingen et al, 2017). The presence of a pRAW-like plasmid in M. kansasii subtype III confirms that these plasmids are widespread in the Mycobacterium genus, which seems to be logical, as they were shown to be conjugative (Ummels et al, 2014).…”

Comparative genome analyses of Mycobacterium avium reveal genomic features of its subspecies and strains that cause progression of pulmonary disease

“…Plasmid DNA analysis was performed using S1-pulsed-field gel electrophoresis (PFGE) and Southern hybridization using a specific probe, as described previously25. Bacteria in agarose gel plugs were treated with lysozyme and proteinase K, before digestion of the total DNA in the plugs by 10 U S1 nuclease (Takara Bio, Shiga, Japan) for 10 min at 37 °C.…”

“…In our previous study, we determined the complete genome sequence of strain TH135 isolated from a serious case with worsening pulmonary MAH disease24, and further demonstrated the presence of a circular plasmid, pMAH13525. This novel plasmid consists of 194,711 nucleotides and has 164 coding sequences (CDSs), some of which encode proteins involved in the pathogenicity of mycobacteria and their resistance to antimicrobial agents.…”

Explored a cryptic plasmid pSXM33 from Shewanella xiamenensis BC01 and construction as the shuttle vector

“…Genes on plasmid DNA have been found to encode one or more special functional proteins, which play crucial roles in the evolution of bacterial pathogenicity. For example, plasmid pMAH135 derived from Mycobacterium avium contains genes that encode mycobactin biosynthesis proteins and type VII secretion system-related proteins, which are involved in the pathogenicity of mycobacteria [13]. As aforementioned, plasmid exploration is a crucial task in the study of the Shewanella genus.…”