title: Potentiation of phagocytosis of Bacteroides fragilis following incubation with clindamycin.
abstract: We studied the effect of clindamycin on phagocytosis of Bacteroides fragilis (MIC = 0.05 mg/l). In the in-vitro test system phagocytosis of Bact. fragilis was less than 11% for the first 30 min of incubation. At 60 min, 25-50% of Bact. fragilis were phagocytosed. At 90 min, phagocytosis increased to 60% of the bacterial inoculum and did not increase thereafter. When clindamycin (0.02 mg/l) was incubated with neutrophils for 2 h prior to exposure to bacteria, there was no increase in phagocytosis. When clindamycin (0.02 mg/l) was incubated with bacteria for 2 h before exposure to neutrophils, phagocytosis increased to 23.1 +/- 5.9 (S.D.) per cent at 30 min compared to 1.1 +/- 15.1% (P less than 0.05) for bacteria not exposed to clindamycin. There was no difference in phagocytosis between the two groups at 60 and 90 min. One-fifth the MIC (0.01 mg/l) but not 0.004 mg/l also led to increased phagocytosis at 30 min but not at 60 min if previously incubated with clindamycin. Thus, clindamycin potentiates phagocytosis of Bact. fragilis. It can act directly on bacteria and promote phagocytosis, although the clinical importance of this last mode of action is not currently known.
mesh_terms: D001441:Bacteroides fragilis / Q000276:immunology*; D002981:Clindamycin / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D010587:Phagocytosis / Q000187:drug effects*; D013268:Stimulation, Chemical
chemical_list: D002981:Clindamycin