Correlation between genetic, physico-chemical surface characteristics and adhesion of four strains of Lactobacillus

A genetic and surface physico-chemical examination of four human urogenital isolates of Lactobacillus rhamnosus showed very similar whole-chromosome DNA and identical ribosomal DNA restriction fragment length polymorphism patterns. Plasmids were absent from less adherent strains 76 and 81, and present in highly adherent strains GR-1 and 36. The strains GR-1 and 36 had similar formamide, diiodomethane and α-bromonaphthalene contact angles to strains 76 and 81, but were significantly more hydrophilic as judged by water contact angles. Also, these more hydrophilic strains had higher oxygen to carbon surface concentration ratios than the more hydrophobic strains as measured by X-ray photoelectron spectroscopy. Only strain 81 adhered to hexadecane, albeit exclusively below pH 4.0. This is probably due to the absence of electrostatic repulsion between hexadecane and strain 81 in this pH range, as the zeta potentials show an isoelectric point at pH 2.9. The presence of plasmids, detected in strains GR-1 and 36, correlated with expression of hydrophilic surface properties and adhesion to uroepithelial cells.