AIR-WATER-INTERFACE DISPLACES ADSORBED BACTERIA

Video microscopy was employed to observed the spatial distribution of Staphylococcus epidermidis and Pseudomonas aeruginosa adherent to glas s and polymer substrates. During rinsing procedures the bacteria remai ned in their original positions when the surfaces were rinsed with sal ine for 3 min followed by ethanol for 3 min before exposure to air. Wh en the surfaces were rinsed with saline only, the air-liquid interface disrupted the spatial distribution of the bacteria, removing and rede positing the bacteria in clumps. A moving air-liquid interface of a ga s bubble on substrate also displaced bacteria. Such artefacts produced by air-water interfaces should be avoided during bacterial adhesion e xperiments.