Fluorescence assay to monitor phagocytosis by blood-clot derived polymorphonuclear leucocytes. 1. Study of patients with diabetes and phagocytosis of different staphylococcal species.

A recently developed simple and rapid fluorescence assay of phagocytosis by polymorphonuclear leucocytes (PMNs) was used to compare the phagocytic activity of PMNs from diabetic patients and healthy people. Differences in phagocytosis have been described in these systems. Different bacterial strains were used to challenge the phagocytic capabilities of bacterial ingestion and killing for both patient and control groups. Staphylococcus epidermidis derived from clinical isolates was prone to faster ingestion and more rapid killing once the bacteria were intracellular, compared with S. epidermidis derived from normal skin. The pathogen, S. aureus, though ingested rapidly, was not so easily killed. PMNs from diabetics appeared to ingest S. aureus and kill ingested pathogenic bacteria not as effectively as PMNs from healthy volunteers. These difference were not found for non-pathogenic skin isolates of S. epidermidis.