Institute of Food, Nutrition and Human Health, Massey University, Palmerston North 4442, New Zealand
New Zealand (NZ) has a higher rate of reported campylobacteriosis than most of the developed world. One possible reason for the higher rate is that local Campylobacter strains have a greater ability for survival. The objective of this study was to investigate the oxygen tolerance of local isolates. The study will focus on the most implicated isolates (ST-474, ST-48, ST-190) in human cases. These isolates tested: 1) broth culture in a flask exposed to atmospheric oxygen; 2) spread plating on agar and exposed to atmospheric oxygen; (3) plating on Muller Hinton Agar onto which filter discs inoculated with 10 μl of 1mM, 10mM, 100mM, or 1 M hydrogen peroxide (H2O2), after which, the inhibition zone was assessed.
C. jejuni strains exposed to air (for 1 and 2) survived longer at a lower temperature (4°C >10°C >20°C >25°C). At 4°C, the strains could survive for between three weeks to more than four weeks in broth or agar microaerobically (5% O2, 10% CO2 and 85% N2) and for about three weeks aerobically. Whereas, at 10°C the survival was up to two weeks, and at 20°C or 25°C, survival was about a week or less than a week. Exposure to H2O2 revealed that Campylobacter strains tested were sensitive to all concentrations, except the lowest (1 mM). The novelty of this study is that no previous study has disproved the hypothesis of New Zealand Campylobacter strains that they are more oxygen tolerance than most of the other international Campylobacter strains. The higher NZ rate of reported campylobacteriosis compared to other developed countries is possibly due to other factors.
Keywords: Oxidative stress, air tolerance, Campylobacter, low temperature, survival
Arch Lebensmittelhyg 72,
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