EFFECTS OF CIPROFLOXACIN AND VANCOMYCIN ON PHYSICOCHEMICAL SURFACE-PROPERTIES OF STAPHYLOCOCCUS-EPIDERMIDIS, ESCHERICHIA-COLI, LACTOBACILLUS-CASEI AND LACTOBACILLUS-ACIDOPHILUS

Under clinical conditions, during antibiotic treatment, micro-organism s often grow at sub-inhibitory concentrations. This may lead to altere d adhesive cell surface properties and to a disruption of the indigeno us microflora, in addition to the creation of a more pathogenic biofil m. The effects of growing Staphylococcus epidermidis, Escherichia coli and lactobacilli in the presence of sub-inhibitory concentrations of ciprofloxacin and vancomycin were determined. Growing the cells under antibiotic burden sometimes led to altered cell surface hydrophobicity (by adhesion to hexadecane), changes in the pH-dependence of zeta pot entials, and elemental surface compositions or in different SDS-PAGE p rotein profiles. For several isolates only one of the surface properti es was altered by the presence of an antibiotic in the growth medium a nd no systematic effects were observed for all isolates representing a certain species or even strain. The important conclusion to be drawn from the results of this study is that the effects of growing cells un der antibiotic burden on their adhesive cell surface properties can on ly be established when using a variety of techniques.