Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions

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Turonova, Hana | Briandet, Romain | Rodrigues, Ramila | Hernould, Mathieu | Hayek, Nabil | Stintzi, Alain | Pazlarova, Jarmila | Tresse, Odile

Edité par CCSD ; Frontiers Media -

International audience. During the last years, Campylobacter has emerged as the leading cause of bacterialfoodborne infections in developed countries. Described as an obligate microaerophile,Campylobacter has puzzled scientists by surviving a wide range of environmentaloxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidativedamage from macrophages to cause human infection. In this study, confocal laserscanning microscopy (CLSM) was used to explore the biofilm development of two welldescribed Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or duringcultivation under oxygen-enriched conditions. Quantitative and qualitative appraisalindicated that C. jejuni formed finger-like biofilm structures with an open ultrastructurefor 81-176 and a multilayer-like structure for NCTC 11168 under microaerobic conditions(MAC). The presence of motile cells within the biofilm confirmed the maturation of the C.jejuni 81-176 biofilm. Acclimation of cells to oxygen-enriched conditions led to significantenhancement of biofilm formation during the early stages of the process. Exposure tothese conditions during biofilm cultivation induced an even greater biofilm developmentfor both strains, indicating that oxygen demand for biofilm formation is higher than forplanktonic growth counterparts. Overexpression of cosR in the poorer biofilm-formingstrain, NCTC 11168, enhanced biofilm development dramatically by promoting an openultrastructure similar to that observed for 81-176. Consequently, the regulator CosRis likely to be a key protein in the maturation of C. jejuni biofilm, although it is notlinked to oxygen stimulation. These unexpected data advocate challenging studiesby reconsidering the paradigm of fastidious requirements for C. jejuni growth whenvarious subpopulations (from quiescent to motile cells) coexist in biofilms. These findingsconstitute a clear example of a survival strategy used by this emerging human pathogen.

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