In this study, we compared three human isolates (F5380, Scott A, and Murray B) and one laboratory strain (EGD) of Listeria monocytogenes for their resistance to ingestion and killing by human neutrophils. We observed no substantial difference in killing among these strains when they were grown at 37°C. Because it is likely that listerial growth occurs at lower temperatures during food-borne outbreaks of listeriosis, we also compared these strains after they were grown at 22 and 4°C. A general reduction in the ability of human neutrophils to kili L. monocytogenes was observed as the temperature at which the listeriae were grown decreased. Growth at 4°C significantly decreased the killing of ail four strains of L. monocytogenes by human neutrophils; two strains (EGD and F5380) were more resistant to killing than were the other two strains (Scott A and Murray B). No obvious relationship was noted between the chemiluminescence response of neutrophils to opsonized listeriae and the ability of the neutrophils to kill listeriae in vitro. Growth at 4°C, however, significantly increased the resistance of L. monocytogenes to killing by hydrogen peroxide.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.