[Opsonin requirements for phagocytosis of Enterococcus spp. by human polymorphonuclear leukocytes].
BACKGROUND
Interaction of Enterococcus spp. and host defense mechanisms is not well known. Opsonic requirements of Enterococcus faecalis and Enterococcus faecium to be phagocyted by human polymorphonuclear leukocytes (PMN) were evaluated.


METHODS
Twenty strains (10 E. faecalis and 10 E. faecium) were studied. Phagocytosis was determined by a radiometric assay. Bacterial cells were labelled with 3H-adenine and opsonized with: a) 10% of human pool sera (HPS); b) 10% of decomplemented HPS, and c) albumin and fibronectin.


RESULTS
Phagocytosis of Enterococcus spp. by PMN in the presence of HPS was significantly higher than that in the absence of opsonins. The phagocytosis of E. faecium was higher than that of E. faecalis. A strain-dependent effect of complement in the phagocytosis of Enterococcus spp. was observed. Neither albumin nor fibronectin showed an opsonic activity on Enterococcus spp.


CONCLUSIONS
A great heterogeneity in the opsonic requirements of Enterococcus spp. was observed. Serum opsonins show a critical role in the phagocytosis of E. faecalis and E. faecium by PMN, this effect being more relevant with E. faecium. A strain-dependent opsonic activity of complement was observed.
García
I
I
Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla.
Joyanes
P
P
Pascual
A
A
Martínez-Martínez
L
L
Perea
E J
EJ
D000328:Adult; D001769:Blood / Q000276:immunology; D002478:Cells, Cultured; D013293:Enterococcus faecalis / Q000276:immunology*; D016984:Enterococcus faecium / Q000276:immunology*; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D009504:Neutrophils / Q000502:physiology*; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis; D012709:Serum Albumin / Q000494:pharmacology
D005353:Fibronectins; D009895:Opsonin Proteins; D012709:Serum Albumin