Bacteriophage treatment of Campylobacter biofilms : formation of the carrier state life cycle
Siringan, Patcharin (2013) Bacteriophage treatment of Campylobacter biofilms : formation of the carrier state life cycle. PhD thesis, University of Nottingham.
Campylobacter jejuni is a gram-negative thermotolerant microaerobic pathogen that causes human gastroenteritis worldwide. The production of extracellular polymeric substances to create a biofilm is a mechanism by which C. jejuni can protect itself from unfavourable environments, and is a contributory factor to the survival and transmission of the organism to farms animals and into the human food chain. Bacteriophages are natural predators of bacteria that have the potential for use as targeted biocontrol agents with the advantage that they can penetrate and affect bacteria embedded in biofilms. The effects of virulent Campylobacter-specific bacteriophages CP8 and CP30 on C. jejuni biofilms formed on glass by strains NCTC 11168, PT14 and HPC5 at 37 °C under microaerobic conditions were investigated. Independent bacteriophage treatment led to 1 to 3 Log10 CFU/cm2 reductions in the viable count 24 h postinfection compared with control levels. In contrast, bacteriophage applied under these conditions effected a reduction of less than 1 Log10 CFU/ml in planktonic cells. Resistance to bacteriophage in bacteria surviving bacteriphage treatment of C. jejuni NCTC 11168 biofilms was >80%, whereas bacteriophage resistance was not found in similarly recovered C. jejuni PT14 cells. Concomitant dispersal of the biofilm matrix by bacteriophage was demonstrated by crystal violet staining and transmission electron microscopy (TEM).
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