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Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)
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Site-specific Bacterial Chromosome Engineering: ΦC31 Integrase Mediated Cassette Exchange (IMCE)

Published on: March 16, 2012

ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and

Eleonora Giovanetti1, Andrea Brenciani, Erika Tiberi

  • 1Department of Biomedical Sciences, Section of Microbiology, Marche Polytechnic University, Ancona, Italy.

Antimicrobial Agents and Chemotherapy
|October 12, 2011
PubMed

Insights

A genetic element in Streptococcus pyogenes, ICESp2905, carries erm(TR) and tet(O) resistance genes. It was found to be composed of two smaller integrative and conjugative elements (ICEs), demonstrating complex gene transfer mechanisms in bacteria.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Streptococcus pyogenes harbors mobile genetic elements that contribute to antibiotic resistance.
  • Integrative and conjugative elements (ICEs) are key mediators of horizontal gene transfer in bacteria.
  • The erm(TR) and tet(O) genes confer resistance to macrolide-lincosamide-streptogramin B and tetracycline antibiotics, respectively.

Purpose of the Study:

  • To characterize the structure and transferability of the genetic element ICESp2905 in Streptococcus pyogenes.
  • To elucidate the composition of ICESp2905, specifically its erm(TR) and tet(O) resistance determinants.
  • To determine the relationship between ICESp2905 and other integrative and conjugative elements.

Main Methods:

  • Genomic analysis of ICESp2905 to determine its size and genetic content.
  • Conjugation experiments to assess the transferability of ICESp2905 in its intact and defective forms.
  • Identification and characterization of individual genetic fragments within ICESp2905.

Main Results:

  • ICESp2905 (approximately 65.6 kb) contains erm(TR) and tet(O) resistance determinants on separate fragments within a clostridial-derived scaffold.
  • ICESp2905 was transferable in both its regular form and a defective form (ICESp2906, approximately 53.0 kb) lacking the erm(TR) fragment.
  • The erm(TR) fragment constitutes an independent integrative and conjugative element (ICESp2907, approximately 12.6 kb).

Conclusions:

  • ICESp2905 is a composite genetic element formed by the integration of ICESp2907 into ICESp2906.
  • The modular nature of ICESp2905 facilitates the dissemination of antibiotic resistance genes erm(TR) and tet(O) in Streptococcus pyogenes.
  • Understanding the structure and transfer of such elements is crucial for combating antibiotic resistance.

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