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ABSTRACT: This work aimed to characterize the surface properties of Staphylococcus carnosus and the influence of different media on their ability to adhere and grow on industrial supports. As their colonization could be dependant of the strain, the genetic diversity of the strains was studied. The diversity of 13 strains analysed by pulsed-field gel electrophoresis revealed that the S. carnosus strains formed a homogeneous genetic group. Their surface properties, characterized by studying their affinity to solvents, were hydrophilic with a strong negative surface charge. The S. carnosus strain CIT 833 hardly adhered to polytetrafluoroethylene (PTFE) and stainless steel chips. Tryptic soy broth (TSB) was the most favourable medium for growth on stainless steel support while TSB/NaCl was better for growth on PTFE. Scanning electron microscopy (sem) showed that this strain weakly colonized both supports and did not form cell aggregates. Indeed, the strain did not synthesize polysaccharides. These results showed that S. carnosus adhered on different abiotic surfaces which are used in food factories but was not able to accumulate on these surfaces. The inability of S. carnosus to form biofilm could explain why S. carnosus is rarely isolated in meat processing environment.
Food Microbiology 03/2007; 24(1):44-51. · 3.28 Impact Factor
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ABSTRACT: The ability of 12 Staphylococcus xylosus strains to form biofilm was determined through the study of different criteria. Eleven out of the 12 strains were able to form biofilm, 10 preferentially on hydrophilic support (glass) and one, S. xylosus C2a, on both hydrophilic and hydrophobic (polystyrene) supports. The determination of bacterial surface properties showed that all strains were negatively charged with five strains moderately hydrophobic and seven hydrophilic. The bap and icaA genes, important for biofilm formation of some staphylococci, were searched. All strains were bap positive but icaA negative. Furthermore, S. xylosus strain C2a was studied on two supports widely used in the food industry, polytetrafluoroethylene (PTFE, hydrophobic) and stainless steel (hydrophilic) and appeared to adhere preferentially on stainless steel. Addition of 20 g/l of NaCl to Tryptic Soy Broth medium (TSB) did not improve significantly its adhesion but enhanced both bacterial growth and cell survival, which were optimum in this medium. Environmental scanning electron microscopy showed that S. xylosus C2a colonized the surface of stainless steel chips with intercellular spaces. The strain formed cell aggregates embedded in an amorphous polysaccharidic matrix. Indeed, synthesis of polysaccharides increased during growth on stainless steel chips in TSB.
International Journal of Food Microbiology 06/2006; 109(1-2):88-96. · 3.33 Impact Factor
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ABSTRACT: This work aimed to characterize the surface properties of Staphylococcus carnosus and the influence of different media on their ability to adhere and grow on industrial supports. As their colonization could be dependant of the strain, the genetic diversity of the strains was studied. The diversity of 13 strains analysed by pulsed-field gel electrophoresis revealed that the S. carnosus strains formed a homogeneous genetic group. Their surface properties, characterized by studying their affinity to solvents, were hydrophilic with a strong negative surface charge. The S. carnosus strain CIT 833 hardly adhered to polytetrafluoroethylene (PTFE) and stainless steel chips. Tryptic soy broth (TSB) was the most favourable medium for growth on stainless steel support while TSB/NaCl was better for growth on PTFE. Scanning electron microscopy (sem) showed that this strain weakly colonized both supports and did not form cell aggregates. Indeed, the strain did not synthesize polysaccharides. These results showed that S. carnosus adhered on different abiotic surfaces which are used in food factories but was not able to accumulate on these surfaces. The inability of S. carnosus to form biofilm could explain why S. carnosus is rarely isolated in meat processing environment.
Food Microbiology.
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[show abstract]
[hide abstract]
ABSTRACT: The ability of 12 Staphylococcus xylosus strains to form biofilm was determined through the study of different criteria. Eleven out of the 12 strains were able to form biofilm, 10 preferentially on hydrophilic support (glass) and one, S. xylosus C2a, on both hydrophilic and hydrophobic (polystyrene) supports. The determination of bacterial surface properties showed that all strains were negatively charged with five strains moderately hydrophobic and seven hydrophilic. The bap and icaA genes, important for biofilm formation of some staphylococci, were searched. All strains were bap positive but icaA negative. Furthermore, S. xylosus strain C2a was studied on two supports widely used in the food industry, polytetrafluoroethylene (PTFE, hydrophobic) and stainless steel (hydrophilic) and appeared to adhere preferentially on stainless steel. Addition of 20 g/l of NaCl to Tryptic Soy Broth medium (TSB) did not improve significantly its adhesion but enhanced both bacterial growth and cell survival, which were optimum in this medium. Environmental scanning electron microscopy showed that S. xylosus C2a colonized the surface of stainless steel chips with intercellular spaces. The strain formed cell aggregates embedded in an amorphous polysaccharidic matrix. Indeed, synthesis of polysaccharides increased during growth on stainless steel chips in TSB.
International Journal of Food Microbiology.
