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

Turonova H, Briandet R, Rodrigues R, Hernould M, Hayek N, Stintzi A, Pazlarova J, Tresse O - Front Microbiol (2015)

Bottom Line: 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.These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

View Article: PubMed Central - PubMed

Affiliation: SECALIM UMR1014, Institut National de la Recherche Agronomique Nantes, France ; LUNAM Université, Oniris, Université de Nantes Nantes, France ; Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Czech Republic.

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 well-described 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.

No MeSH data available.


Related in: MedlinePlus

Oxygen enhances biofilm development ofC. jejuniNCTC 11168 and 81-176 after incubation for 24 and 48 h. (A) The CLSM images represent an aerial view of the biofilm structures in OEC (19% O2, 10% CO2, 71% N2) with the shadow projection at the bottom. (B) The effect of cultivation time (24 h white bars, 48 h black bars) and OEC on biofilm formation of the two C. jejuni strains as expressed by maximum height and biomass volume. Results show the means and standard deviations of three replicates. Statistical data are presented in Supplementary Table 1.
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Figure 2: Oxygen enhances biofilm development ofC. jejuniNCTC 11168 and 81-176 after incubation for 24 and 48 h. (A) The CLSM images represent an aerial view of the biofilm structures in OEC (19% O2, 10% CO2, 71% N2) with the shadow projection at the bottom. (B) The effect of cultivation time (24 h white bars, 48 h black bars) and OEC on biofilm formation of the two C. jejuni strains as expressed by maximum height and biomass volume. Results show the means and standard deviations of three replicates. Statistical data are presented in Supplementary Table 1.

Mentions: Two different approaches were used to evaluate the effect of subinhibitory oxygen concentration on biofilm formation of two strains with different biofilm forming ability (NCTC 11168 and 81-176). Firstly, biofilms were cultivated under controlled oxygen-enriched conditions (OECc) as described previously by Sulaeman et al. (2012). In OEC, the same concentration of CO2 (10%) as in MAC was maintained, while the O2 concentration was increased to a sublethal level (19% O2 in OEC vs. 5% in MAC). This enabled the evaluation of the effect of increased O2 concentration on biofilm development of C. jejuni regardless of its capnophilic nature requiring increased concentration of CO2. Biofilm volume of both strains was significantly increased (P < 0.01) when cultivated in OECc (Figure 2 and Supplementary Table 1). Incubation time and O2 concentration had a significant effect (P < 0.01) on increased biomass production in OECc when compared to MACc. Interestingly, some significant differences in both maximum height and biomass volume (P < 0.01) remained between the two strains even after cultivation in OEC, with a greater biofilm development for 81-176 than for NCTC 11168, indicating that strain biology impacts biofilm formation (Supplementary Table 1). This was confirmed by formation of a denser compact biomass for NCTC 11168 biofilm while 81-176 induced more voids and open water channels across the biofilm.


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

Turonova H, Briandet R, Rodrigues R, Hernould M, Hayek N, Stintzi A, Pazlarova J, Tresse O - Front Microbiol (2015)

Oxygen enhances biofilm development ofC. jejuniNCTC 11168 and 81-176 after incubation for 24 and 48 h. (A) The CLSM images represent an aerial view of the biofilm structures in OEC (19% O2, 10% CO2, 71% N2) with the shadow projection at the bottom. (B) The effect of cultivation time (24 h white bars, 48 h black bars) and OEC on biofilm formation of the two C. jejuni strains as expressed by maximum height and biomass volume. Results show the means and standard deviations of three replicates. Statistical data are presented in Supplementary Table 1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4499754&req=5

Figure 2: Oxygen enhances biofilm development ofC. jejuniNCTC 11168 and 81-176 after incubation for 24 and 48 h. (A) The CLSM images represent an aerial view of the biofilm structures in OEC (19% O2, 10% CO2, 71% N2) with the shadow projection at the bottom. (B) The effect of cultivation time (24 h white bars, 48 h black bars) and OEC on biofilm formation of the two C. jejuni strains as expressed by maximum height and biomass volume. Results show the means and standard deviations of three replicates. Statistical data are presented in Supplementary Table 1.
Mentions: Two different approaches were used to evaluate the effect of subinhibitory oxygen concentration on biofilm formation of two strains with different biofilm forming ability (NCTC 11168 and 81-176). Firstly, biofilms were cultivated under controlled oxygen-enriched conditions (OECc) as described previously by Sulaeman et al. (2012). In OEC, the same concentration of CO2 (10%) as in MAC was maintained, while the O2 concentration was increased to a sublethal level (19% O2 in OEC vs. 5% in MAC). This enabled the evaluation of the effect of increased O2 concentration on biofilm development of C. jejuni regardless of its capnophilic nature requiring increased concentration of CO2. Biofilm volume of both strains was significantly increased (P < 0.01) when cultivated in OECc (Figure 2 and Supplementary Table 1). Incubation time and O2 concentration had a significant effect (P < 0.01) on increased biomass production in OECc when compared to MACc. Interestingly, some significant differences in both maximum height and biomass volume (P < 0.01) remained between the two strains even after cultivation in OEC, with a greater biofilm development for 81-176 than for NCTC 11168, indicating that strain biology impacts biofilm formation (Supplementary Table 1). This was confirmed by formation of a denser compact biomass for NCTC 11168 biofilm while 81-176 induced more voids and open water channels across the biofilm.

Bottom Line: 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.These findings constitute a clear example of a survival strategy used by this emerging human pathogen.

View Article: PubMed Central - PubMed

Affiliation: SECALIM UMR1014, Institut National de la Recherche Agronomique Nantes, France ; LUNAM Université, Oniris, Université de Nantes Nantes, France ; Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology Prague, Czech Republic.

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 well-described 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.

No MeSH data available.


Related in: MedlinePlus