[Environmental scanning electron microscopy for biofilm detection in tonsils]

To describe an environmental scanning electron microscopic method for the study of biofilms in clinical samples. A comparison with standard scanning electron microscopy is performed.

Nine patients with a past history of recurrent tonsillitis underwent tonsillectomy. Samples from each patient were obtained for both conventional and environmental scanning electron microscopy. The tonsils removed from 2 patients with sleep apnoea syndrome were used as controls.

Eight of nine tonsils had biofilms on their surface. Scanning electron microscopy showed accumulations of bacteria covered by fibrillar structures resulting from the sample dehydration process. Environmental scanning electron microscopy provided a view of bacteria embedded in a homogeneous, amorphous substance that was preserved during the examination.

Environmental scanning electron microscopy permits the imaging of wet systems at different degrees of dehydration. It therefore allows researchers to observe biofilms in their natural hydrated state.