A hypervariable genomic island identified in clinical and environmental Mycobacterium avium subsp. hominissuis isolates from Germany

Int J Med Microbiol. 2016 Nov;306(7):495-503. doi: 10.1016/j.ijmm.2016.07.001. Epub 2016 Jul 18.


Mycobacterium avium subsp. hominissuis (MAH) is an opportunistic human pathogen widespread in the environment. Genomic islands (GI)s represent a part of the accessory genome of bacteria and influence virulence, drug-resistance or fitness and trigger bacterial evolution. We previously identified a novel GI in four MAH genomes. Here, we further explored this GI in a larger collection of MAH isolates from Germany (n=41), including 20 clinical and 21 environmental isolates. Based on comparative whole genome analysis, we detected this GI in 39/41 (95.1%) isolates. Although all these GIs integrated in the same insertion hotspot, there is high variability in the genetic structure of this GI: eight different types of GI have been identified, designated A-H (sized 6.2-73.3kb). These GIs were arranged as single GI (23/41, 56.1%), combination of two different GIs (14/41, 34.1%) or combination of three different GIs (2/41, 4.9%) in the insertion hotspot. Moreover, two GI types shared more than 80% sequence identity with sequences of M. canettii, responsible for Tuberculosis. A total of 253 different genes were identified in all GIs, among which the previously documented virulence-related genes mmpL10 and mce. The diversity of the GI and the sequence similarity with other mycobacteria suggests cross-species transfer, involving also highly pathogenic species. Shuffling of potential virulence genes such as mmpL10 via this GI may create new pathogens that can cause future outbreaks.

Keywords: COG; Clusters of Orthologous Groups; GI; Genomic island; MAH; MCE; MmpL; Mycobacterium avium; Mycobacterium avium subsp. hominissuis; NTM; antibiotic-resistance; genomic islands; horizontal gene transfer; mammalian cell entry; mmpL; mycobacterial membrane protein large; non-tuberculous mycobacteria.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Child
  • Child, Preschool
  • Environmental Microbiology*
  • Gene Transfer, Horizontal
  • Genes, Bacterial
  • Genetic Variation*
  • Genome, Bacterial
  • Genomic Islands*
  • Genotype
  • Germany
  • Humans
  • Mycobacterium avium / classification
  • Mycobacterium avium / genetics*
  • Mycobacterium avium / isolation & purification
  • Sequence Analysis, DNA
  • Sequence Homology, Nucleic Acid
  • Tuberculosis / microbiology*