title: Adherence of Haemophilus influenzae to human buccal and pharyngeal epithelial cells: relationship to pilation.
abstract: An improved understanding of the role of pili in adherence of Haemophilus influenzae type b to human epithelial cells (EC) would enhance knowledge of the pathogenesis of H. influenzae b infections. In this study a highly sensitive in-vitro assay allowed the quantitative assessment of H. influenzae b adherence to EC. The degree of adherence was influenced by incubation time, temperature, bacteria/EC ratio, EC type and the growth phase of the bacteria. Most serially subcultured (SC) capsular type-b strains originally isolated from cerebrospinal fluid, blood, nasopharynx or throat gave similar low degrees of adherence, as did representative single strains of capsular types a, c, d, e and f. SC non-capsulated H. influenzae strains adhered in significantly greater numbers than most SC capsulated strains (p less than 0.001). One SC type-b strain isolated from a throat, with stable piliation, adhered in very high numbers despite capsulation. Piliated subpopulations selected from type-b capsulated strains adhered in greater numbers than did their parent strains. These data suggest that capsulation of H. influenzae is a deterrent to adherence of the bacteria to EC. However, the presence of pili may allow type-b organisms to overcome the effects of capsulation.
mesh_terms: D000268:Adhesiveness; D000328:Adult; D002610:Cheek; D004848:Epithelium / Q000382:microbiology; D004912:Erythrocytes / Q000382:microbiology; D005260:Female; D010861:Fimbriae, Bacterial / Q000502:physiology*; D006193:Haemophilus influenzae / Q000502:physiology* / Q000648:ultrastructure; D006801:Humans; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D009061:Mouth Mucosa / Q000382:microbiology*; D010614:Pharynx / Q000382:microbiology*; D013696:Temperature; D013997:Time Factors