BORDETELLA-AVIUM HEMAGGLUTINATION AND MOTILITY MUTANTS - ISOLATION, CHARACTERIZATION, AND PATHOGENICITY

Transposon mutagenesis was used to produce Bordetella avium mutants, w hich were screened for the lack of potential virulence factors, includ ing a hemagglutinin, flagella, pili, and toxins. A mini-Tn 10 transpos on containing a kanamycin-resistance gene was introduced into the chro mosomal DNA of the virulent 002/S isolate by electroporation. A hemagg lutination-negative (HA-) mutant and a motility-negative mutant were o btained. Southern blot analysis showed that only the motility-negative mutant contained the transposon, whereas the HA- mutant was a spontan eous kanamycin-resistant mutant. Both mutants were stable in vitro and in vivo. Following inoculation of 2-week-old poults, the HA- mutant w as determined to be less virulent than the 002/S parent, whereas the m otility-negative mutant was similar in virulence to the 002/S parent. These results indicate that the hemagglutinin of B. avium is a virulen ce factor, but motility does not appear to contribute to virulence.