Abstract: | The comparative biochemical and serological characterization of 424 H. influenzae strains isolated from healthy children and patients with acute and chronic bronchopulmonary diseases is presented. As the result of biotyping H. influenzae strains, 82.3-90.9% of the strains isolated from both healthy children and patients with acute and chronic bronchopulmonary diseases were found to belong to the first three biotypes according to M. Kilian's classification. Among H. influenzae strains isolated from healthy children no capsular variants were detected in the coagglutination test. From patients with acute and chronic diseases of respiratory organs, as a rule, the capsular variants of H. influenzae were isolated (94.4% and 98.1%, respectively). In patients with chronic pneumonia biotypes I, II and III, more seldom biotype V, proved to be mo st invasive. In the determination of the minimum inhibiting concentration of ampicillin, no H. influenzae strains resistant to this antibiotic were detected. |