RT Journal Article SR Electronic T1 Campylobacter jejuni transcriptome changes during loss of culturability in water JF bioRxiv FD Cold Spring Harbor Laboratory SP 150383 DO 10.1101/150383 A1 Christina Bronowski A1 Kasem Mustafa A1 Ian B. Goodhead A1 Chloe E. James A1 Charlotte Nelson A1 Anita Lucaci A1 Paul Wigley A1 Tom J. Humphrey A1 Nicola J. Williams A1 Craig Winstanley A1 for the ENIGMA Consortium. YR 2017 UL http://biorxiv.org/content/early/2017/06/15/150383.abstract AB Background The natural environment serves as a potential reservoir for Campylobacter, the leading cause of bacterial gastroenteritis in humans. However, little is understood about the mechanisms underlying variations in survival characteristics between different strains of C. jejuni in natural environments, including water.Results We identified three Campylobacter jejuni strains that exhibited variability in their ability to retain culturability after suspension in water at two different temperatures (4°C and 25°C). Of the three, strains C. jejuni M1 exhibited the most rapid loss of culturability whilst retaining viability. Using RNAseq transcriptomics, we characterised C. jejuni M1 gene expression in response to suspension in water by analyzing bacterial suspensions recovered immediately after introduction into water (Time 0), and from two sampling time/temperature combinations where considerable loss of culturability was evident, namely (i) after 24 h at 25°C, and (ii) after 72 h at 4°C. Transcript data were compared with a culture-grown control. Some gene expression characteristics were shared amongst the three populations recovered from water, with more genes being up-regulated than down. Many of the up-regulated genes were identified in the Time 0 sample, whereas the majority of down-regulated genes occurred in the 25°C (24 h) sample.Conclusions Variations in expression were found amongst genes associated with oxygen tolerance, starvation and osmotic stress. However, we also found upregulation of flagellar assembly genes, accompanied by down-regulation of genes involved in chemotaxis. Our data also suggested a switch from secretion via the sec system to via the tat system, and that the quorum sensing gene luxS may be implicated in the survival of strain M1 in water. Variations in gene expression also occurred in accessory genome regions. Our data suggest that despite the loss of culturability, C. jejuni M1 remains viable and adapts via specific changes in gene expression.