A highly conserved complete accessory Escherichia coli type III secretion system 2 is widespread in bloodstream isolates of the ST69 lineage

Fox, S., Goswami, C. , Holden, M., Connolly, J. P.R., Mordue, J., O'Boyle, N., Roe, A. , Connor, M., Leanord, A. and Evans, T. J. (2020) A highly conserved complete accessory Escherichia coli type III secretion system 2 is widespread in bloodstream isolates of the ST69 lineage. Scientific Reports, 10, 4135. (doi: 10.1038/s41598-020-61026-x) (PMID:32139768) (PMCID:PMC7058095)

Abstract

Bacterial type III secretion systems (T3SSs) play an important role in pathogenesis of Gram-negative infections. Enteropathogenic and enterohemorrhagic Escherichia coli contain a well-defined T3SS but in addition a second T3SS termed E. coli T3SS 2 (ETT2) has been described in a number of strains of E. coli. The majority of pathogenic E. coli contain elements of a genetic locus encoding ETT2, but which has undergone significant mutational attrition rendering it without predicted function. Only a very few strains have been reported to contain an intact ETT2 locus. To investigate the occurrence of the ETT2 locus in strains of human pathogenic E. coli, we carried out genomic sequencing of 162 isolates obtained from patient blood cultures in Scotland. We found that 22 of 26 sequence type (ST) 69 isolates from this collection contained an intact ETT2 together with an associated eip locus which encodes putative secreted ETT2 effectors as well as eilA, a gene encoding a putative transcriptional regulator of ETT2 associated genes. Using a reporter gene for eilA activation, we defined conditions under which this gene was differentially activated. Analysis of published E. coli genomes with worldwide representation showed that ST69 contained an intact ETT2 in these strains as well. The conservation of the genes encoding ETT2 in human pathogenic ST69 strains strongly suggests it has importance in infection, although its exact functional role remains obscure.

• Item Type: Articles
• Additional Information: The work was funded by the Scottish Executive via the Chief Scientists Office through the provision of a grant to establish the Scottish Healthcare Associated Infection Prevention Institute (SHAIPI).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Connolly, Dr James and Goswami, Dr Cosmika and Leanord, Professor Alistair and Evans, Professor Tom and Roe, Professor Andrew and Mordue, Mr James and O Boyle, Dr Nicky and Fox, Dr Stephen
• Authors: Fox, S., Goswami, C., Holden, M., Connolly, J. P.R., Mordue, J., O'Boyle, N., Roe, A., Connor, M., Leanord, A., and Evans, T. J.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Life Sciences
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Scientific Reports 10:4135
• Publisher Policy: Reproduced under a Creative Commons License