Bacterial quantification--a necessary complement for the comprehension of middle ear inflammations.

Quantification of bacteria in various types of middle ear effusion (MEE) obtained during current acute otitis media (AOM), otitis media with effusion (OME) and chronic suppurative otitis media (COM) was performed. The bacteria were stained with acridine orange and their number per ml effusion evaluated under the fluorescence microscope according to a method described in detail elsewhere. During AOM, 53% of the MEE samples were culture-positive and contained 10(6)-10(8) bacteria per ml (median value 10(7) per ml). During OME, serous effusion and 78% of the mucoid effusions contained no bacteria whatsoever, whereas the remaining mucoid effusions contained 10(4)-5 x 10(5) bacteria per ml (median value 10(4) per ml). Mucopurulent effusions contained 6 x 10(5)-10(8) bacteria per ml (median value 5 x 10(6) per ml). During COM, purulent MEE had 6 x 10(6)-10(9) bacteria per ml (median value 10(8) per ml). Quantification of bacteria involved in middle ear diseases provides further information about the etiopathogenesis and appropriate management of various pathological conditions of the middle ear.