MORAXELLA-CATARRHALIS IN ACUTE LARYNGITIS - INFECTION OR COLONIZATION

The complement phenotypes of Moraxella catarrhalis isolates obtained f rom adult patients with acute laryngitis were investigated using a mic rotiter serum bactericidal assay and compared with those of other dono r groups. Laryngitis isolates had a higher proportion (57%) of complem ent-resistant strains than did carrier strains from healthy 8- to 13-y ear-old schoolchildren (16%). The difference between these groups was statistically significant (chi(2) [3 x 2 table] = 21.55; P < .001), Th e relatively frequent occurrence of the complement-resistant (virulenc e-associated) phenotype in adults with acute laryngitis supports the t heory of an active role of M. catarrhalis in the pathogenesis of acute laryngitis.