Genome analysis of a clinical isolate of Shewanella sp. uncovered an active hybrid integrative and conjugative element carrying an integron platform inserted in a novel genomic locus

Microbiology (Reading). 2016 Aug;162(8):1335-1345. doi: 10.1099/mic.0.000310. Epub 2016 May 23.

Abstract

Shewanella spp. are currently considered to be emerging pathogens that can code for a blaOXA carbapenemase in their chromosome. Complete genome analysis of the clinical isolate Shewanella sp. Sh95 revealed that this strain is a novel species, which shares a lineage with marine isolates. Characterization of its resistome showed that it codes for genes drfA15, qacH and blaOXA-48. We propose that Shewanella sp. Sh95 acts as reservoir of blaOXA-48. Moreover, analysis of mobilome showed that it contains a novel integrative and conjugative element (ICE), named ICESh95. Comparative analysis between the close relatives ICESpuPO1 from Shewanella sp. W3-18-1 and ICE SXTMO10 from Vibrio cholerae showed that ICESh95 encompassed two new regions, a type III restriction modification system and a multidrug resistance integron. The integron platform contained a novel arrangement formed by gene cassettes drfA15 and qacH, and a class C-attC group II intron. Furthermore, insertion of ICESh95 occurred at a unique target site, which correlated with the presence of a different xis/int module. Mobility of ICESh95 was assessed and demonstrated its ability to self-transfer with high efficiency to different species of bacteria. Our results show that ICESh95 is a self-transmissible, mobile element, which can contribute to the dissemination of antimicrobial resistance; this is clearly a threat when natural bacteria from water ecosystems, such as Shewanella, act as vectors in its propagation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics*
  • Base Sequence
  • DNA, Bacterial / genetics
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Gene Transfer, Horizontal / genetics*
  • Genome, Bacterial / genetics
  • Humans
  • Integrons / genetics*
  • Membrane Transport Proteins / genetics*
  • Sequence Analysis, DNA
  • Shewanella / genetics*
  • Shewanella / isolation & purification
  • beta-Lactamases / genetics*

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • Membrane Transport Proteins
  • beta-Lactamases
  • carbapenemase