Evaluating 3 gas-delivery systems for culturing Campylobacter jejuni in a microaerophilic environment

Campylobacter spp. require a microaerophilic environment (80% N(2), 10% CO(2), 5% H(2), and 5% O(2)) for growth. Since the late 1800s, several systems for creating and maintaining specific microbial atmospheres have been developed and applied. The objective of this study was to evaluate Campylobacter jejuni growth by means of 3 commonly used gas-delivery systems for generating a microaerophilic environment: automated, gas-generating sachet, and plastic storage bag. Pure culture C. jejuni cells were suspended in Brucella broth and spread onto campy cefex agar plates. For the automated gas-delivery system, plates were positioned in a Mart anaerobic jar and flushed with a microaerophilic gas mixture using an Anoxomat Mart II system (Mart Microbiology B. V., Netherlands). For the sachet samples, plates were placed in a Mart anaerobic jar and 3 Gaspak EZ campy sachets (Becton Dickinson and Company, Franklin Lakes, NJ) were activated to induce a microaerophilic gas environment. The plates placed in plastic storage bags were flushed with a microaerophilic gas mixture from a premixed tank. For all 3 systems, plates were placed in a low-temperature incubator at 42°C for 24 h. After 24 h, plates were removed from the incubator and colonies were counted. The entire experiment was repeated 5 times. Results indicated no significant difference in colony counts among the gas-delivery systems tested, but colonies grown under the sachet-generated environment were smaller than colonies in the other 2 methods. Smaller colonies could have resulted from the type of media used or the length of time the plates were incubated. In conclusion, all 3 gas-delivery methods were able to produce similar Campylobacter growth results. Initial and long-term costs of equipment, as well as laboratory space availability, may be influential when choosing a gas-delivery method for generating a microaerophilic environment.