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Biofilm production by different strains of Salmonella typhimurium: genetics, morphology and role of surface and nutrient content of medium

Abstract number: p840

Romanova  J.M., Alekseeva  N., Andreev  A.L., Smirnova  T.A., Stepanova  T.V., Gintsburg  A.L.

Objectives: 

To investigate the ability of biofilm production by 14 different strains of Salmonella typhimurium in depending on genotype and culture conditions in artificial systems: in 96-well plastic microtitre plates, plastic and glass tubes, plastic Petri dishes and on microscope glasses.

Methods: 

Quantitative biofilm growth was monitored by using an assay based on crystal violet staining, while planctonic growth in the same cultures was monitored by absorbance in iEMS Reader MF, and qualitative biofilm growth—by digital photo and visually. Morphology of the planktonic cells and cells in the biofilm was investigated by methods of transmission microscopy of ultra-thin cessions.

Results and conclusions: 

Optimal rate between growth and biofilm indications for all strains was determined at initial cell concentration 106-7 KOE/ml and T°= 28 °C culture incubation. The nutrient content of the medium significantly influenced the quantity of produced biofilm. The nutrient broth LB without NACl was the most effective in promoting biofilm formation, than LB itself. The least quantity of biofilm was formed in water. The chemical content of plastic and glass also influenced biofilm formation. The ability to induce biofilm on the walls of plastic tubes is very suitable for visual screening of a number of strains. We used this property for the testing of influence of some proteins on the biofilm production intensity. Plastic tubes were treated before incubation by 1% BSA or milk proteins and sterilized by ethanol. It seems to be, that protein pretreatment of plastic surfaces increased adhesion and biofilm production. It is possible to conclude the more effective biofilm production on surfaces, contacting to blood proteins or food products. The genotype of the strains also critically influenced the quantity of produced biofilm. Nonmotile mutants cells reduced ability to form biofilm. RpoS mutant cells produced significantly less biofilm as compared with cells of isogenic parent strains. The morphology of S. typhimurium grown as biofilm or as planctonic cells was also different.

Session Details

Date: 01/08/2007
Time: 00:00-00:00
Session name: XXIst ISTH Congress
Subject:
Location: Oxford, UK
Presentation type:
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