Conjugative transfer of ICESde3396 between three β-hemolytic streptococcal species

Smyth, D. J. , Shera, J., Bauer, M. J., Cameron, A., McNeilly, C. L., Sriprakash, K. S. and McMillan, D. J. (2014) Conjugative transfer of ICESde3396 between three β-hemolytic streptococcal species. BMC Research Notes, 7(1), 521. (doi: 10.1186/1756-0500-7-521)

Abstract

Background: Integrative conjugative elements (ICEs) are mobile genetic elements (MGEs) that possess all genes necessary for excision, transfer and integration into recipient genome. They also carry accessory genes that impart new phenotypic features to recipient strains. ICEs therefore play an important role in genomic plasticity and population structure. We previously characterised ICESde 3396, the first ICE identified in the β-hemolytic Streptococcus dysgalactiae subsp equisimilis (SDSE) and demonstrated its transfer to single isolates of Streptococcus pyogenes (group A streptococcus, GAS) and Streptococcus agalactiae (group B streptococcus, GBS). While molecular studies found the ICE in multiple SDSE and GBS isolates, it was absent in all GAS isolates examined. Results: Here we demonstrate that ICESde 3396:km is transferable from SDSE to multiple SDSE, GAS and GBS isolates. However not all strains of these species were successful recipients under the same growth conditions. To address the role that host factors may have in conjugation we also undertook conjugation experiments in the presence of A549 epithelial cells and DMEM. While Horizontal Gene Transfer (HGT) occurred, conjugation efficiencies were no greater than when similar experiments were conducted in DMEM. Additionally transfer to GAS NS235 was successful in the presence of DMEM but not in Todd Hewitt Broth suggesting that nutritional factors may also influence HGT. The GAS and GBS transconjugants produced in this study are also able to act as donors of the ICE. Conclusion: We conclude that ICEs are major sources of interspecies HGT between β-hemolytic streptococci, and by introducing accessory genes imparting novel phenotypic characteristics, have the potential to alter the population structure of these species.

• Item Type: Articles
• Additional Information: The authors thank Henry McSorley for assistance with tissue culture. This work was funded the Australian Government National Health and Medical Research (NHMRC) Project Grant (GNT496655) and NHMRC Program grants.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Smyth, Dr Danielle
• Authors: Smyth, D. J., Shera, J., Bauer, M. J., Cameron, A., McNeilly, C. L., Sriprakash, K. S., and McMillan, D. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity
• Journal Name: BMC Research Notes
• Publisher: BioMed Central
• ISSN: 1756-0500
• ISSN (Online): 1756-0500
• Copyright Holders: Copyright © 2014 Smyth et al.; licensee BioMed Central Ltd.
• First Published: First published in BMC Research Notes 7(1):521
• Publisher Policy: Reproduced under a Creative Commons License