Characterization of Mono- and Mixed-Culture Campylobacter jejuni Biofilms
ABSTRACTCampylobacter jejuni, one of the most common causes of human gastroenteritis, is a thermophilic and microaerophilic bacterium. These characteristics make it a fastidious organism, which limits its ability to survive outside animal hosts. Nevertheless,C. jejunican be transmitted to both humans and animals via environmental pathways, especially through contaminated water. Biofilms may play a crucial role in the survival of the bacterium under unfavorable environmental conditions. The goal of this study was to investigate survival strategies ofC. jejuniin mono- and mixed-culture biofilms. We grew monoculture biofilms ofC. jejuniand mixed-culture biofilms ofC. jejuniwithPseudomonas aeruginosa. We found that mono- and mixed-culture biofilms had significantly different structures and activities. MonocultureC. jejunibiofilms did not consume a measurable quantity of oxygen. Using a confocal laser scanning microscope (CLSM), we found that cells from monoculture biofilms were alive according to live/dead staining but that these cells were not culturable. In contrast, in mixed-culture biofilms,C. jejuniremained in a culturable physiological state. MonocultureC. jejunibiofilms could persist under lower flow rates (0.75 ml/min) but were unable to persist at higher flow rates (1 to 2.5 ml/min). In sharp contrast, mixed-culture biofilms were more robust and were unaffected by higher flow rates (2.5 ml/min). Our results indicate that biofilms provide an environmental refuge that is conducive to the survival ofC. jejuni.