Effects of the Campylobacter jejuniCJIE1 prophage homologs on adherence and invasion in culture, patient symptoms, and source of infection

Clifford G Clark,Jason Moses,Barbara Marshall,Christopher Cr Grant,Matthew W Gilmour,Dobryan M Tracz,Frank Pollari

doi:10.1186/1471-2180-12-269

Clifford G Clark, Jason Moses + Show 5 more

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https://doi.org/10.1186/1471-2180-12-269

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Abstract

BackgroundProphages of enteric bacteria are frequently of key importance for the biology, virulence, or host adaptation of their host. Some C. jejuni isolates carry homologs of the CJIE1 (CMLP 1) prophage that carry cargo genes potentially involved in virulence. Possible role(s) of CJIE1 homologs in the biology and virulence of C. jejuni were therefore investigated by using in vitro cell culture assays and by assessing the association of C. jejuni isolates with and without these prophages with patients’ symptoms, with source, and with clonal lineages within the C. jejuni population.ResultsFour C. jejuni isolates, three carrying the CJIE1-like prophage and one without, were tested in cell culture assays for adherence and invasion. Both adherence and invasion of C. jejuni to cells in culture were increased by the presence of the CJIE1-family prophage. Differences in motility and growth rate did not appear to be responsible. The CJIE1 prophage was present in 23% of isolates from human and non-human sources combined that were obtained through sentinel-site surveillance, and the distribution of CJIE1 in this population showed modest clonal associations. There was no correlation between the presence of the CJIE1 prophage in C. jejuni and patient symptoms, although there was some statistical support for lower rates of abdominal pain and fever when the prophage was present. Little evidence was found for a role of the prophage in host adaptation or host specificity.ConclusionThese biological effects suggest that the presence of the prophage may be a marker for differential virulence of some C. jejuni isolates. Ongoing research into the effects of the prophage on protein expression may provide additional insights into the roles the prophage may play in the biology of its host bacterium.

Highlights

Prophages of enteric bacteria are frequently of key importance for the biology, virulence, or host adaptation of their host
Results from Southern blotting using CMLP1 genes as probes showed that this phage appeared to be capable of loss and insertion or re-insertion into different parts of the C. jejuni genome, producing changes in pulsed-field gel electrophoresis (PFGE) patterns [3], and induction of prophages was found to be responsible for extensive genomic rearrangements in bacteria subject to predation by lytic bacteriophages [4]
Strain characteristics The set of isolates used consisted of three C. jejuni isolates (00–2425, 00–2538, 00–2544) that carried a prophage homologous with, and closely related to, CJIE1 from strain RM1221 [1,6]

Summary

Introduction

Prophages of enteric bacteria are frequently of key importance for the biology, virulence, or host adaptation of their host. Some C. jejuni isolates carry homologs of the CJIE1 (CMLP 1) prophage that carry cargo genes potentially involved in virulence. The recent demonstration of three distinct bacteriophages integrated into the genome of Campylobacter jejuni chicken isolate RM1221 suggested that such phages may be common and important for the biology of C. jejuni [1]. At least one of these three C. jejuni integrated elements (CJIEs) [2] was a Mu-like phage inducible with mitomycin C designated CJIE1 (or Campylobacter Mulike phage 1, CMLP1). Elements similar to these CJIEs were found quite frequently when a large panel of isolates was tested using a DNA microarray, and CMLP1 appeared to integrate essentially randomly in the genome [2]. Proteomics experiments verified that this protein was expressed when isolates were grown on normal laboratory medium and upregulated in the presence of bile salts (unpublished results)

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