Adherence of Bacteria to Oral Epithelium in Vivo: Electron Microscopic Observations

Abstract

o highly egrec of specificity seems to exist in the ability of bacteria to adhere to a tooth oi epithelial surface (GIBBONS antI VAN IIOUTF, Infect Imiuiiitili 3: 567-573, 1971) Ultrastructural stu(ics of the relationship of bacteria to in vitio and in vivo epitlielial cells (GIBBONS, VAN Houtr, and LILJEMARK, J Dent Res 51: 424-435, 1972) hlave lemonstratetl that bacterial attachment is mediated by a surface 'fuzz. Additional morphologic evidence fot b)tacterial adherence to epithclium in vivo, an(I sorme news findings ate piesented heteiti. Tissue fhon the tongues of thiee adult C3F mice Nsas fixed fot two houses in Ito-Karnovsky, fixative (ITO and KARNOVSKY, J Cell Biol 39: 168a, 1968) and processed foi election micioscopy. The otitet keratinized epithelial cells fieqtiently were covered with a layet of coccalshaped bacteria, mans of which cotitainecl division planes. WVfsen the epithelial sun face sas notably cons oltited, these hactet ia etc found at the height of the peaks and within the valleys (Fig 1) IJUder higher magnifications, the bactet ia wsetre fountl to possess a filamentoits stitface coating that wsas in intimate association wv'ith the otitet leaflet of the epithelial cell's plasma membrane (Fig 2) Frequently, tdiece was oii filamentous coat on the bacterial surfaces that were not apposed to the epitlielium. More striking was the almost iiniversal finding of an uneveIt dlist ibuttion of clucttosn-luiccnt gtanuls within the bacteria. These grantiles weie similar morphologically to glscogCn grantiles previously described in Streptococcl.s stitiiS (BERM N, GIBBONs, and NALBANDIAN, Archi Oral Biol 12: 1133-1138, 1967). It seemedl as though a cotrelation existed between the presence of the granules andcl a well-developed sits face coat. In addition, individual bacteria wete sutiounded by a clear region outlined 1)) a mote clectron-lensc material, which was thought to lie of salivary origin (Figs 1, 2). The sparsity of filamentous coating on the exposetd scirfaces of adhering lactetia in vivo may l)e due to proteolysis of the coating by salivars etizymes. The uneven distribution of glycogenlike particles described herein ha's not been Yeportedc previously, and is unusual in vicew of past studies, which have shown a more unifoinm distribution of glycogen throughout in vitto cultivatedl sti-eptococcal cells. Uneven dists ihiution of intracellular particles may be significant in tein-ms of bacterial adhsetence in situ and suggests that thesc adhering organisms have tliscrete tegiotis it) which specific metabolic events Occuit.