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ARS Home » Research » Publications at this Location » Publication #192510


item Chen, Chinyi
item Paoli, George
item Irwin, Peter

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/31/2006
Publication Date: 8/24/2006
Citation: Chen, C., Paoli, G., Irwin, P.L. 2006. Oxygen consumption rate of campylobacter jejuni during growth and survival under various oxygen levels. {Abstract}. International Association of Food Protection. P4-59.

Interpretive Summary:

Technical Abstract: Campylobacter jejuni is an important food-borne pathogen. The microaerophilic nature of this organism has made its isolation and culture in the laboratory problematic. To gain a better understanding of its physiology, we measured the oxygen consumption of C. jejuni strain 81-176 using a Clark-type oxygen electrode at various microaerobic (2-10% oxygen, 10% carbon dioxide, balanced with nitrogen) conditions and at atmospheric oxygen levels (21% oxygen). C. jejuni microaerobic cultures that were grown to different cell densities (up to 72 hours) in Mueller-Hinton (MH) broth were sampled in the microaerobic glove box, sealed with parafilm and placed in an air-tight container and then removed from the glove box. Samples (2.5 ml) were then withdrawn through the parafilm membranes using a syringe fitted with a long blunt needle, and injected into the oxygen electrode chamber to determine the oxygen consumption along with culturable cell counts (colony forming units, CFU) on MH agar. Our results showed that the rate of oxygen consumption was very low (exp 10 (-21) - exp 10(-19) moles/(sec*CFU)) when C. jejuni was grown in MH broth at 42 degree C under microaerobic conditions. The oxygen consumption rate increased almost instantaneously (within 1 minute) after the microaerobic culture was exposed to atmospheric levels of oxygen, and this activity remained relatively constant (ca. 0.6-2.0 x exp 10 (-18) moles/(sec*CFU)) for at least 2 hours, or until culturable cell counts started to decline. After prolonged exposure in air, the gross oxygen consumption (moles/sec) remained steady longer than the culturable cell counts, resulting in an increase in the CFU-normalized oxygen consumption rate (moles/(sec*CFU)). This report provides a direct and real time means for measuring Campylobacter physiological states during growth and survival with minimal manipulation of the test samples, which is pivotal for monitoring such a fast-changing phenomenon.