Haemagglutination properties of Moraxella (Branhamella) catarrhalis
Fitzgerald, M.; Murphy, S.; Mulcahy, R.; Keane, C.; Coakley, D.; Scott, T.
British Journal of Biomedical Science 53(4): 257-262
1996
ISSN/ISBN: 0967-4845 PMID: 9069102 Document Number: 461069
The ability of 30 isolates of Moraxella (Branhamella) catarrhalis to haemagglutinate erythrocytes of five species was examined. Two haemagglutination phenotypes of M. catarrhalis were observed: phenotype I isolates (n=10) agglutinated human erythrocytes, while phenotype II isolates (n=7) agglutinated both human and rabbit erythrocytes. No haemagglutination was observed with chick, sheep or horse erythrocytes. Haemagglutination by both phenotype I and II isolates was abolished following treatment of these isolates with pronase and trypsin, while heat treatment at 70 degree C markedly reduced the level of haemagglutination by both sets of isolates. Haemagglutination by phenotype II isolates was inhibited by galactose, whereas haemagglutination by phenotype I isolates was not inhibited by this carbohydrate. Transmission electron microscopy (TEM) studies showed that very close cell-surface interactions occurred when both phenotypes of M. catarrhalis adhered to the human erythrocyte. Fimbrial attachment was not apparent. Haemagglutinating isolates of both phenotypes had a trypsin-sensitive outer fibrillar coat when examined by TEM.