Background: Perflubron® (PFB, Alliance Pharm. Corp.San Diego,CA) decreases macrophage oxidative burst and cytokine production. Despite these inhibitory effects on macrophages, we previously demonstrated a 10-fold decrease in viable bacteria from lungs of rabbits with experimental pneumonia during treatment with PFB. We hypothesize that this finding may be due to inhibition of bacterial adhesion to respiratory epithelial cells by PFB. Materials and Methods: E.coli (type 1-fimbriated strain CAB1) was labelled by growth in tryptic soy broth containing3 H-adenine. Labelled cells were then exposed to buffer or to one of three perfluorochemicals 1) PFB 2) Rimar or 3) FC-77, with gentle rocking for 2.5 h. The perfluorochemical-exposed (PFC-E) bacterial suspensions were then adjusted to a standard cell density and incubated with either rabbit bronchoalveolar lavage fluid (BAL) or human submandibular-sublingual saliva(HSMSL) immobilized as standardized dots on nitrocellulose membranes. The membranes were first blocked in buffer containing 3% skim milk before exposure to bacteria, and all experimental points were performed in triplicate. Following washing, the number of bacteria bound to each dot was quantitated by liquid scintillation chromatography. To determine the effects of PFC-E on bacterial viability, bacterial cells exposed for 2.5 hrs to each of the three perfluorochemicals were serially diluted, plated and cultured on agar, and the resulting colonies ennumerated. Results: The Table illustrates the percentage of PFC-E bacteria adherent to immobilized substrate as compared to untreated bacteria. These results indicate that PFC-E- bacteria are generally less adherent than untreated bacteria. Bacterial viability was not effected by direct exposure to PFC. Conclusions: 1) PFB and FC-77 significantly reduced bacterial adhesion to BAL and HSMSL. Rimar may increase bacterial adhesion to HSMSL. 2) Loss of bacterial viability does not account for the differences obtained. These findings suggest that perfluorochemicals may limit bacterial pneumonia by inhibiting microbial adhesion.

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