Measurement of bacterial adhesion-in vitro evaluation of different methods.
The adhesion of bacteria to host tissue is the first step in pathogenesis. Similarly, bacterial adhesion to inanimate surfaces is the first step in formation of biofilms-a real problem in industrial processes and medical devices. Various agents capable of blocking the adhesion of bacteria to surfaces have been identified, such as probiotics, which are supposed to prevent the adhesion of pathogenic bacteria to the intestinal mucosa. Although measurement of bacterial adhesion is important itself, especially when agents used to prevent adhesion are developed, a relative small number of techniques can be used in the measurement of adhesion. These techniques are not well validated and there is lack of studies where those methods are compared to each other. Here we have compared different commonly used methods to measure adhesion of bacteria; radioactive labelling, fluorescence tagging, and staining of bacteria. The methods were used to measure the adhesion of Escherichia coli and Salmonella enterica serovar Typhimurium to intestinal mucus. Moreover, selected probiotic strains were used to study whether probiotics or the adhesion method used affected the results. As a result, we show that the best reproducibility and sensitivity were obtained using radioactive labelling. With other methods, the sensitivity was too low due to poorly adhering bacteria and low signal-to-background ratio.
Vesterlund
Satu
S
Department of Biochemistry and Food Chemistry, University of Turku, Itäinen Pitkäkatu 4A, 20014 Turku, Finland. satu.vesterlund@utu.fi
Paltta
Johanna
J
Karp
Matti
M
Ouwehand
Arthur C
AC
D001422:Bacterial Adhesion / Q000502:physiology*; D015169:Colony Count, Microbial; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology*; D005470:Fluorometry; D005840:Gentian Violet / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000502:physiology; D006801:Humans; D007211:Indoles / Q000378:metabolism; D007413:Intestinal Mucosa / Q000382:microbiology*; D019936:Probiotics / Q000378:metabolism; D011851:Radioactivity; D015203:Reproducibility of Results; D012486:Salmonella typhimurium / Q000235:genetics / Q000502:physiology*; D012680:Sensitivity and Specificity; D014170:Transformation, Genetic; D014316:Tritium / Q000378:metabolism
D007211:Indoles; D014316:Tritium; D049452:Green Fluorescent Proteins; C007293:DAPI; D005840:Gentian Violet