CHARACTERIZATION OF MICROBIAL ADHERENCE TO EPITHELIAL-CELLS FOLLOWINGBIOCIDE TREATMENT BY ANALYSIS OF AREA UNDER THE FREQUENCY-DISTRIBUTION CURVE

The aim of this study was to further characterise the anti-adherence e ffects of certain antimicrobial agents by evaluating their effects on the frequency distribution of Candida albicans blastospores (MEN strai n) to buccal epithelial cells (BEC). A light microscopic assay was emp loyed to evaluate the effects of super- and sub-minimal inhibitory con centrations of chlorhexidine gluconate, dequalinium chloride, cetrimid e and cetylpyridinium chloride on candidal adherence in vitro. Frequen cy distributions were plotted to describe the adherence profile of eac h treatment and mathematical descriptions of these distributions were performed by calculating the areas under the frequency distribution cu rves (AUC). Comparison of the AUC of each treatment and control (steri le water treatment) was performed using a one-way analysis of variance . Each concentration of all antimicrobial agents significantly reduced the AUC. These reductions were due to greater percentages of BEC show ing lower numbers (zero, one, two) of adherent blastospores and also l ower percentages of BEC showing higher numbers of adherent blastospore s in comparison to control. Generally, the anti-adherence effects of t hese antimicrobial agents (as measured using AUC determinations) were greater following treatment of blastospores and were observed with bot h super- and sub-minimal inhibitory concentrations. These findings sug gest a greater affinity of the antimicrobial agents for the blastospor e surface and also a greater ability to block, either directly or indi rectly via steric hinderance, adhesins on the blastospore surface than receptors on the surface of BEC. It is suggested that to fully apprec iate the anti-adherence potential of antimicrobial agents, the frequen cy distribution of microbial adherence data should be considered, as t his will provide information on specific adherence population shifts, in conjunction with their effects on the mean number of adherent micro organisms per epithelial cell. In addition, the anti-adherence activit y observed for the antimicrobial agents examined indicates their poten tial use in the prophylaxis of superficial candidal infections in the oral cavity.