Bacterial growth and virulence factors production by different Bordetella pertussis strains

The aim of this study was to compare bacteria growth and pertussis antigens (pertussis toxin-PT, filamentous haemagglutinin-FHA and endotoxin-LPS) production by 11 Bordetella pertussis strains. A synthetic Stainer-Scholte culture medium supplemented with (2,6-0-dimethyl) beta-cyclodextrin (heptakis) or methylcellulose (for greater PT and FHA production) and solid modified Cohen-Wheeler medium (for LPS isolation) were used. Our results demonstrated that heptakis and methylcellulose were more effective for antigens production than for bacterial growth. It was interesting that these stimulated substances supported the bacterial growth from small inocula. The investigated strains differed in PT, FHA and LPS production. The best PT producer was the B. pertussis 134 strain, the worst B. pertussis 2897. The differences in FHA production are not as big as in PT production, but the B. pertussis 2897 was also the worst FHA producer. Isolated LPS consists of dry bacteria pellet ranging from 1,9% (B.p. Tohama) to 5,6% (B.p. 3803 strain). No great differences in serological activity of LPS isolated from different strains were observed. In the haemagglutination inhibition test the endotoxin isolated from B.p. 509 and B.p. Tohama strains showed the highest activity.