Evaluation of the CampyPak II gas generator system for isolation of Campylobacter fetus subsp. jejuni.

The CampyPak II (BBL Microbiology Systems, Cockeysville, Md.) method for isolating Campylobacter fetus subsp. jejuni was evaluated with clinical specimens by comparison with an evacuation replacement procedure. Of 757 specimens, 26 (3.4%) were positive for C. fetus subsp. jejuni. All 26 were recovered by both systems. No difference was found in the time necessary for isolation, except with one isolate that required 3 days for isolation with CampyPak II and 2 days with the established procedure. Although the average colony size was slightly smaller for colonies incubated in the CampyPak II system (P less than 0.02 by a paired t test), this is probably of no practical consequence. In terms of technical performance, therefore, the CampyPak II system appears to be an excellent alternative method for establishing microaerophilic conditions necessary for isolating C. fetus subsp. jejuni. The only difference between the two systems was the cost of using the CampyPak II envelopes. Excluding the initial equipment costs, CampyPak II envelopes cost approximately $0.74 per specimen, whereas the standard Torbal jar technique cost about $0.10 per specimen.