Effects of group-A streptolysin O on neonatal and adult red blood cell deformability and haemolysis.
Neonates are more susceptible than adults to many Gram-positive and Gram-negative bacterial infections. Whereas group B streptococcus causes life-threatening infections in neonates, group A beta-haemolytic streptococcus infections rarely occur in neonates. To test the hypothesis that group A streptococcus may have different effects on neonatal and adult red blood cells (RBCs), haemolysis and deformability (rheoscope) of RBCs from adults, full-term and pre-term neonates were studied during 60 min incubation with 1 haemolytic unit (HU) mL-1 group A streptolysin O (SLO). SLO incubation of adult RBCs resulted in almost linearly increasing time-dependent haemolysis reaching 82%, whereas haemolysis of neonatal RBCs was below 60% after 1 h. After 60 min SLO incubation, RBC deformation was significantly (P < 0.05) more reduced in adults than in full-term and preterm neonates. An inverse overall relationship (r = 0.68) between SLO-induced haemolysis and RBC deformation was found after 60 min of SLO incubation. We conclude that SLO causes less haemolysis and less impairment of RBC deformation in neonates than in adults. The decreased RBC deformation of unhaemolysed RBC indicates that, before lysis, mechanical RBC membrane properties are altered by SLO.
Pöschl
J M
JM
Department of Pediatrics, University of Heidelberg, Germany.
Ruef
P
P
Schnauffer
M
M
Linderkamp
O
O
D000328:Adult; D001426:Bacterial Proteins; D004907:Erythrocyte Deformability / Q000187:drug effects*; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology*; D006461:Hemolysis / Q000187:drug effects*; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D013301:Streptolysins / Q000494:pharmacology*
D001426:Bacterial Proteins; D013301:Streptolysins; C025964:streptolysin O