Growth rates and metabolic traits differ by diarrhoeal manifestation in Campylobacter jejuni strains

<b>Introduction</b> <i>. Campylobacter jejuni</i> is the leading cause of bacterial gastroenteritis worldwide. Infections with <i>C. jejuni</i> can result in two different diarrhoeal manifestations in humans: watery diarrhoea or bloody/inflammatory diarrhoea.<b>Hypothesis/Gap Statement.</b> Currently, little is known about <i>C. jejuni</i> and/or host factors associated with the elicitation of these two distinct diarrhoeal manifestations. We hypothesize that these factors may include growth and metabolic trait differences between <i>C. jejuni</i> strains associated with watery diarrhoea and bloody/inflammatory diarrhoea.<b>Aim.</b> Using <i>C. jejuni</i> strains with a defined diarrhoeal manifestation in the neonatal piglet model, we aimed to assess differences in temperature-dependent growth rates, motility, biofilm production and carbon utilization between diarrhoeal manifestation groups.<b>Methodology</b>. Strains were initially assessed for 192 different carbon sources using phenotypic microarrays followed by specific carbon utilization, growth, motility and biofilm assays at 37 and/or 42 °C.<b>Results</b>. We found that at 37 °C, watery diarrhoea-associated <i>C. jejuni</i> strains grew significantly faster compared with bloody/inflammatory diarrhoea-associated <i>C. jejuni</i> strains. However, there was no significant growth difference at 42 °C between the groups, due to bloody/inflammatory diarrhoea-associated strains growing faster at 42 °C compared with 37 °C. Additionally, at 37 °C, we found that l-fucose utilization was significantly higher among watery diarrhoea-associated strains, while l-glutamine utilization was significantly higher among bloody/inflammatory diarrhoea-associated strains.<b>Conclusion</b>. The results indicate there are distinct metabolic adaptations between watery and/or bloody/inflammatory diarrhoea-associated <i>C. jejuni</i> strains particularly at 37 °C, which may be one of the factors associated with differing diarrhoeal manifestations.