Microscopy and Microanalysis


Cytochemical Differences in Bacterial Glycocalyx

Wolf Dietrich  Krautgartner  a1 , Ljubomir  Vitkov  a1 a2 c1 , Matthias  Hannig  a2 , Klaus  Pelz  a3 and Walter  Stoiber  a1
a1 Department of Electron Microscopy, Light Microscopy and Digital Image Acquisition, Institute of Zoology, University of Salzburg, Hellbrunnerstraße 34, 5020 Salzburg, Austria
a2 Department of Operative Dentistry and Periodontology, Saarland University, D-66421 Homburg/Saar, Germany
a3 Institute of Medical Microbiology and Hygiene, University of Freiburg, D-79104 Freiburg, Germany

Article author query
krautgartner wd   [PubMed][Google Scholar] 
vitkov l   [PubMed][Google Scholar] 
hannig m   [PubMed][Google Scholar] 
pelz k   [PubMed][Google Scholar] 
stoiber w   [PubMed][Google Scholar] 


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.

(Received November 10 2003)
(Accepted March 12 2004)

Key Words: fimbriae; ruthenium red; cupromeronic blue; critical electrolytic concentrations; tannic acid–metal salt technique; Staphylococcus aureus; Streptococcus sanguis.

c1 Corresponding author. E-mail: lvitkov@yahoo.com