The
pathogen Campylobacter jejuni is considered a
microaerophile yet has been shown to grow in vitro in atmospheres with partial oxygen tension of 21%. To achieve a better understanding of its microaerophily, the oxygen requirement and tolerance of
four C. jejuni strains were investigated by measuring their growth under different conditions, by performing
bioinformatic analyses and by determining their
metronidazole resistance. At high cell
densities,
C. jejuni showed similar growth under microaerobic and fully aerobic oxygen tensions, but did not grow under oxygen-depleted conditions. At low cell
densities, the
bacteria grew only under microaerobic conditions. Eighteen genes were identified bioinformatically as potential contributors to the differences in oxygen tolerance between strains. Among them, cj0203, cj0264c, cj0415, cj0425, cj0628, cj0629 and cj0864 were considered the top potential contributors. The oxygen tolerance of the
four C. jejuni strains was different, and this tolerance positively
correlated with their resistance to
metronidazole. This study provided evidence that
C. jejuni was an obligate
microaerophile. The data indicated that the strains had different oxygen tolerances; it suggested that they could result in
phenotypic and physiological differences between strains grown under the same conditions. These differences could modulate the outcome of experiments, and may explain discrepancies in the results between strains.
