Biofilm spatial organization by the emerging pathogen Campylobacter jejuni: comparison between NCTC 11168 and 81-176 strains under microaerobic and oxygen-enriched conditions
Abstract
During the last years, Campylobacter has emerged as the leading cause of bacterial
foodborne infections in developed countries. Described as an obligate microaerophile,
Campylobacter has puzzled scientists by surviving a wide range of environmental
oxidative stresses on foods farm to retail, and thereafter intestinal transit and oxidative
damage from macrophages to cause human infection. In this study, confocal laser
scanning microscopy (CLSM) was used to explore the biofilm development of two welldescribed Campylobacter jejuni strains (NCTC 11168 and 81-176) prior to or during
cultivation under oxygen-enriched conditions. Quantitative and qualitative appraisal
indicated that C. jejuni formed finger-like biofilm structures with an open ultrastructure
for 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 significant
enhancement of biofilm formation during the early stages of the process. Exposure to
these conditions during biofilm cultivation induced an even greater biofilm development
for both strains, indicating that oxygen demand for biofilm formation is higher than for
planktonic growth counterparts. Overexpression of cosR in the poorer biofilm-forming
strain, NCTC 11168, enhanced biofilm development dramatically by promoting an open
ultrastructure similar to that observed for 81-176. Consequently, the regulator CosR
is likely to be a key protein in the maturation of C. jejuni biofilm, although it is not
linked to oxygen stimulation. These unexpected data advocate challenging studies
by reconsidering the paradigm of fastidious requirements for C. jejuni growth when
various subpopulations (from quiescent to motile cells) coexist in biofilms. These findings
constitute a clear example of a survival strategy used by this emerging human pathogen.
Domains
Life Sciences [q-bio]Origin | Files produced by the author(s) |
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