To examine new cytochemical aspects of the bacterial adhesion, a
strain 41452/01 of the oral commensal Streptococcus
sanguis and a wild strain of Staphylococcus aureus were
grown with and without sucrose supplementation for 6 days.
Osmiumtetraoxyde (OsO4), uranyl acetate (UA), ruthenium red
(RR), cupromeronic blue (CB) staining with critical electrolytic
concentrations (CECs), and the tannic acid–metal salt technique
(TAMST) were applied for electron microscopy. Cytochemically, only
RR-positive fimbriae in S. sanguis were visualized. By
contrast, some types of fimbriae staining were observed in S.
aureus glycocalyx: RR-positive, OsO4-positive,
tannophilic and CB-positive with ceasing point at 0.3 M
MgCl2. The CB staining with CEC, used for the first time for
visualization of glycoproteins of bacterial glycocalyx, also reveals
intacellular CB-positive substances—probably the monomeric
molecules, that is, subunits forming the fimbriae via extracellular
assembly. Thus, glycosylated components of the biofilm matrix can be
reliably related to single cells. The visualization of intracellular
components by CB with CEC enables clear distinction between S.
aureus and other bacteria, which do not produce CB-positive
substances. The small quantities of tannophilic substances found in
S. aureus makes the use of TAMST for the same purpose
difficult. The present work protocol enables, for the first time, a
partial cytochemical differentiation of the bacterial glycocalyx.