Linking Plaque and Endotrach Biofilm/Matrix by Structure and Composition

OBJECTIVE: Evidence continues to accumulate that the biofilm composition on the lumen of the endotrach (ETT) is of dental plaque origin. In this study, we wanted to further link the ETT luminal biofilm with dental plaque utilizing SEM, by determining: 1) the similarity in 3D architecture and 2) elemental analysis in a 20 patient ICU study. Our hypothesis was that the endotracheal origin could explain the recalcitrant ETT biofilms and focus on oral preventative intervention for ventilator associated pneumonia (VAP).

METHODS: This study incorporated three corresponding phases: 1) control patient plaque, 2) inoculated cultured plaque organisms into the endotrach and 3) analysis of ETT biological material as part a 20 patient study at Cardiff University Hospital of Wales, Cardiff, UK. Plaque samples were harvested by curetting. ETT of inoculated control organisms or mechanically ventilated patients were transversally sectioned and 1 cm of material placed into 10% formaldehyde. Structure was analyzed by JOEL SEM with gold shadowing and elemental composition by x-ray microanalysis after carbon coating.

RESULTS: Two signatures were developed. The first was based on three-dimensional structure and showed significant similarity in spacing, organization and integrity of the matrix 3-D architecture, including bacteria X-ray microanalysis occurred between 0 and 20 Kev, but similar profiles of elements were clustered between 0 and 5 Kev. X-ray analysis detected a mean of 14 elements, of which elements 12-32, were commonly found in plaque and endotrach biofilm. This included: Ca, Fe, Na, P, S, Ka, and Ni. Semi-quantification ratios of elements helped highlight similarities between dental plaque and endotrach matrix.

CONCLUSION: Dental plaque and ETT biologic matrix as a biofilm have similar structure and identifiable elements. This ETT “Bio-Plaque” originates in great part from the oral cavity.