Lack of synergy between phagocytes and antimicrobials against Nocardia asteroides.

Previous observations suggested that synergy between antimicrobials and phagocytes may occur during Nocardia asteroides infection. We incubated N. asteroides with seven antimicrobials, and then exposed the nocardiae to phagocytes. Neutrophils and monocytes killed about half the nocardiae whether or not the nocardiae had been preincubated with antimicrobials. We also determined whether exposure to neutrophils led to increased susceptibility of nocardiae to antimicrobials, and it did not. We found no evidence for synergy between antimicrobials and phagocytes in host defence against this bacterium.