The present study was undertaken to investigate bacterial adhesion to biomaterial surfaces, with a long term goal of lowering the incidence of urinary sepsis related to catheter colonization. The main thrust of our investigations has been to use lactobacilli to interfere with uropathogenic infection. The latest experiments demonstrated that L. acidophilus T-13 adhered well to polymer surfaces, with a negative linear correlation with substratum surface tension (determined by the equation of state approach). The organisms adhered well to commercially manufactured silkolatex urinary catheter material (94% coverage within 9 has measured by image analysis). The adhesion of S. epidermidis strain 1938 did not relate to polymer surface tension and these organisms adhered best to sulfonated polystyrene (72% coverage) and fluorinated ethylene propylene (48% coverage). Time course experiments demonstrated that the adhesion of the staphylococci increased dramatically within 1 to 3 h (48% coverage of sulfonated polystyrene after 3 h), reaching a plateau around 9 h. A pyelonephritogenic strain of E. coli adhered very poorly to all polymers tested. Contact angle measurements indicated that lactobacilli surface hydrophobicity was altered by growth conditions and that there were large differences between strains. The net surface charge was negative for all specimens tested and there was a significant difference between the electrophoretic mobilities for lactobacilli grown in urine compared to urine plus sugars. These studies indicate that bacterial, substratum and fluid components can influence bacterial surface charge and hydrophobicity, leading to alteration of bacterial adhesion to biomaterials.
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