HAEMOPHIHUS INFLUENZAE TYPE-B EXOPRODUCTS INDUCE CHEMOTAXIS AND MACROLIDE ANTIBIOTIC RELEASE BY HUMAN POLYMORPHONUCLEAR LEUKOCYTES

The capacity of phagocytes to concentrate macrolide antibiotics was su ggested by previous reports. In this study, we evaluated the capacity of Haemophilus influenzae type b culture supernatants (HICS) to induce polymorphonuclear leukocyte (PMNL) migration and macrolide antibiotic delivery. Using a Boyden multiwell chamber and a chemotaxis assay und er agarose combined with a bioassay to measure antibiotic levels in ag ar, we demonstrated the chemotactic activity of HICS. Preincubation of PMNL with either erythromycin or azithromycin did not affect PMNL che motaxis. By the agar diffusion test, we established that HICS increase d the release of antibiotic from PMNL when compared with spontaneous r elease. Furthermore, we determined that the antibiotics remain bioacti ve after release. These results suggest that HICS may have a modulator y effect on transport and delivery of macrolide antibiotics by PMNL at the infection site.