Abstract
Polymorphonuclear leukocytes [rabbit] selectively inhibited the incorporation of 14C-uridine by intracellular staphylococci. Within specified limits, the amount of radiolabel incorporated by extracellular staphylococci was related to bacterial concentration. Incorporation of labeled uridine can be exploited to assay the extent to which association between staphylococci and polymorphonuclear leukocytes reflects surface adherence as opposed to ingestion. A comparison of the new method with a conventional viable-count determination of leukocyte-associated bacteria shows it is comparable in efficiency when non-immune serum is used as opsonin and superior when specific opsonin is used.