Location: Produce Safety and Microbiology Research
Title: Oxygen requirement and tolerance of Campylobacter jejuni. Authors
|Kaakoush, Nadeem - UNIV. NEW SOUTH WALES, AS|
|DE Reuse, Hilde - INSTIUT PASTEUR, FRANCE|
|Mendz, George - UNIV. NEW SOUTH WALES, AS|
Submitted to: Research in Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 24, 2007
Publication Date: November 1, 2007
Citation: Kaakoush, N.O., Miller, W.G., De Reuse, H., Mendz, G.L. 2007. Oxygen requirement and tolerance of Campylobacter jejuni. Research in Microbiology. 158(8-9):644-650. Interpretive Summary: Campylobacter jejuni is a major causal agent of gastroenteritis world-wide. Unlike other food-borne bacterial pathogens, such as Salmonella, Campylobacter cannot grow in normal atmospheric concentrations of oxygen but requires much lower oxygen concentrations for growth. A better understanding of the oxygen requirement and tolerance of Campylobacter is important, as this might be expected to be an important consideration when devising novel strategies to minimize or eliminate Campylobacter contamination of foods. This study showed a direct correlation with oxygen tolerance and resistance to the antibiotic metronidazole. Also, eighteen genes in the C. jejuni chromosome, involved potentially in oxygen tolerance, were identified.
Technical Abstract: The human pathogen Campylobacter jejuni is considered a microaerophile, yet it has been shown to grow in vitro under atmospheres with elevated oxygen tensions. Hence, a better understanding of the oxygen requirement and tolerance of C. jejuni is required. Bacterial growth was measured under various conditions employing classical solid and liquid culture techniques. At high cell densities, C. jejuni showed similar growth under microaerobic or fully aerobic oxygen tensions, and did not grow under oxygen-depleted conditions. At low cell densities, the bacteria were able to grow only under microaerobic conditions. The oxygen tolerance of several C. jejuni strains was different, and this tolerance positively correlated with their resistance to metronidazole. Eighteen genes were identified as potential contributors to the differences in oxygen tolerance of strains. Among these genes were cj0203, cj0264c, cj0415, cj0425, cj0628, cj0629 and cj0864 which ranked among the top potential contributors. The study demonstrated significant physiological differences between strains with respect to their oxygen sensitivity. It also identified potential causes of the differences since they may affect the survival of C. jejuni under various experimental conditions, and they result in different phenotypes, for example their drug resistance.