Skip to main content
. 2005 Jun;73(6):3210–3218. doi: 10.1128/IAI.73.6.3210-3218.2005

FIG. 4.

FIG. 4.

Confocal microscopy images of whole-mount sections of chinchilla inferior bulla (white arrows indicate bone of the inferior bulla in each panel) stained with LIVE/DEAD bacterial stain 5 days after direct challenge with NTHI. The parent strain, 2019 (panel A) induced the formation of a large biofilm (white bracket) with long finger-like projections that appear to be separated by water channels that do not contain bacteria. These projections extend well into the middle ear space. Strain 2019pgm (panel B) formed a very small biofilm with what also appears to be water channels; however, this biofilm appeared to be less organized. Strains 2019lsgB (panel C) and 2019siaA (panel D) formed very dense biofilms with no apparent water channels. A much larger population of dead NTHI (red stain, panel C) was observed in the biofilm induced by strain 2019lsgB than seen in that produced by the parental isolate at this time point postchallenge of themiddle ear. Strain 2019wecA induced the formation of a biomass in only two of the six challenged middle ears (panel E). These biomasses lacked architecture and were predominantly nonviable (bone of inferior bulla was viable; however, it appears black in this image because it was below the plane that was optimal for imaging the fluorescent bacterial biomass). In the majority of middle ears challenged with 2019wecA, there were no detectable biofilms; however, there were focal areas of bright fluorescence on the mucosal surface and the bone of the inferior bulla appears to be considerably thickened (panel F), suggesting the presence of viable bacteria and demonstrating that an inflammatory response, with new bone formation, had occurred following challenge of the depicted middle ear with strain 2019wecA. Strain 2019siaB (panel G) did not form detectable biofilms in the chinchilla middle ear 5 days after direct inoculation. A similarly stained naïve bulla is presented in panel H to demonstrate the normal thickness of the bone of the inferior bulla in an unchallenged chinchilla middle ear.