Phagocytosed Bordetella pertussis fails to survive in human neutrophils

Previous studies have reported that phagocytosed Bordetella pertussis sun i ves in human neutrophils. This issue has been reexamined. Opsonized or unop sonized bacteria expressing green fluorescent protein (GFP) were incubated with adherent human neutrophils. Phagocytosis was quantified by fluorescenc e microscopy, and the viability of phagocytosed bacteria was determined by colony counts following treatment with polymyxin B to kill extracellular ba cteria. Only 1 to 2% of the phagocytosed bacteria remained viable. Opsoniza tion with heat-inactivated immune serum reduced the amount of attachment an d phagocytosis of the bacteria but did not alter survival rates. In contras t to previous reports, these data suggest that phagocytosed B, pertussis ba cteria are killed by human neutrophils.