Adhesion of lactobacilli to polymer surfaces in vivo and in vitro

The ability of bacteria to attach to surfaces has been recognized as an important phenomenon, particularly for pathogenic organisms that utilize this capacity to initiate disease. The present investigation was undertaken to determine whether indigenous urogenital bacteria, lactobacilli, colonized prosthetic devices in vivo and in vitro and attached to specific polymer surfaces in vitro. Polyethylene intrauterine devices (IUDs) in place for 2 years were removed from six women who were asymptomatic and free of signs of cervical or uterine infection. Lactobacilli were found attached to the IUDs, as determined by culture, and fluorescent antibody and acridine orange staining techniques. This demonstrated that bacterial biofilms consisting of indigenous bacteria can occur on prosthetic devices without inducing a symptomatic infection. In vitro studies were then undertaken with well-documented lactobacilli strains L. acidophilus T-13, L. casei GR-1, GR-2, and RC-17, and L. fermentum A-60. These organisms were found to adhere to IUDs and urinary catheters within 24 hours. A quantitative assay was designed to examine the mechanisms of adhesion of L. acidophilus T-13 to specific polymer surfaces that are commonly used as prosthetic devices. The lactobacilli adhered optimally to fluorinated ethylene propylene when 10⁸ bacteria were incubated for 9 hours at 37°C in phosphate buffered saline, pH 7.1. Additional experiments verified that the lactobacilli adhered to polyethyleneterephthalate, polystyrene, and sulfonated polystyrene and to silkolatex catheter material. There was a linear relationship found between polymer hydrophobicity and bacterial adherence. These results demonstrate that lactobacilli bind to various surfaces in vivo and in vitro, and that the nature of the substratum can affect the colonization.