ANTIBODY-RESPONSE TO PREVOTELLA SPP IN PATIENTS WITH VENTILATOR-ASSOCIATED PNEUMONIA

Although anaerobic bacteria are frequently isolated from the oropharyn geal flora, their potential pathogenic role in ventilator-associated p neumonia (VAP) has been poorly investigated, In order to evaluate the pathogenic role of Prevotella spp, isolated from protected specimen br ushes, we investigated the systemic humoral response with the enzyme-l inked immunosorbent assay (ELISA) and Western blot (immunoblot) in 13 patients who developed a VAP associated with Prevotella species (group I), The antigen used was a mixture of whole-cell proteins taken from four reference Prevotella strains, We compared the antibody levels obs erved in these patients with those measured in 30 patients who develop ed a VAP unrelated to anaerobic bacteria (group II), in 27 patients wi th dental stumps (group III), and in 30 healthy patients (group IV) wh o had Prevotella species on dental plaque. The ELISA levels obtained i n the four groups showed significant differences between group I and e ach of the three control groups (P < 0.05). The antibody profiles obta ined by Western blot showed an intensity of response roughly superposa ble over levels obtained by ELISA and a species specificity. These fin dings suggested that colonization of these patients with Prevotella sp ecies may have been associated with an infectious process leading to a systemic humoral response and that these bacteria could play a role i n VAP.