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FEMS Immunol Med Microbiol. 1995 Jun;11(3):207-11.

Complement resistance is a virulence factor of Branhamella (Moraxella) catarrhalis.

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Eijkman-Winkler Institute for Medical and Clinical Microbiology, University Hospital, Utrecht, The Netherlands.


The purpose of this study was to investigate complement resistance in Branhamella (Moraxella) catarrhalis isolated from healthy schoolchildren or sputum-producing adult patients. Two techniques were used: a serum bactericidal assay as the gold standard and an easier 'culture and spot' test. Children (age 4-13; n = 303) and patients (n = 1047) showed high colonization/infection rates with B. catarrhalis (31% and 19%, respectively). Complement resistance or intermediate sensitivity occurred frequently in patient isolates (62% and 27%, respectively) and less often in children (33% and 8.5%, respectively; P << 0.0001). In young children (age 4-5 years), the proportion of complement-resistant strains was around 50%. Complement resistance in B. catarrhalis is associated with illness and may hence be considered a virulence factor.

[Indexed for MEDLINE]

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