Comparison of ribotyping and restriction enzyme analysis for inter- and intraspecies discrimination of Bordetella avium and Bordetella hinzii

Abstract

Bordetella avium is an avian respiratory disease pathogen responsible for substantial economic losses to the turkey industry. The inability to distinguish isolates has hampered outbreak investigations and prevents a complete understanding of transmission mechanisms. Isolates of Bordetella hinzii, often referred to as B. avium-like or as Alcaligenes faecalis type II prior to 1995, have also been acquired from the respiratory tracts of diseased poultry but are not believed to be pathogenic for birds. Therefore, differentiating between B. avium and B. hinzii is of importance for veterinary diagnostic laboratories. It was recently reported that both PvuII ribotyping and HinfI/DdeI restriction endonuclease analysis (REA) show promise for distinguishing isolates of B. avium and B. hinzii. Here we compare the ability of these techniques to discern inter- and intraspecies differences. While both approaches distinguished numerous types within a species, only REA was sufficiently discriminatory for routine use as an epidemiologic tool. Both techniques clearly distinguish between B. avium and B. hinzii, although the results of ribotyping are more easily interpreted. Ribotyping and REA identified numerous, previously unrecognized B. hinzii strains from a collection of bordetella isolates, including one acquired from a rabbit. This is the first report of B. hinzii isolation from a nonhuman mammalian species. At least some of the newly recognized B. hinzii isolates have been previously reported to cause disease in poults, suggesting that the pathogenicity of this agent for poultry should be more rigorously examined.

FIG. 1.

Ribotype patterns observed following digestion of B. avium (A) or B. hinzii (B) genomic DNA with PvuII. Lane numbers correspond to the assigned ribotype profile.

FIG. 2.

Dendrogram and cluster analysis of the B. avium and B. hinzii PvuII ribotype patterns identified from isolates in Table 1 (tolerance, 0.5%). B. avium patterns are assigned the prefix BA; B. hinzii patterns are assigned the prefix BH. The number of isolates identified for each ribotype is indicated in parentheses to its right.

FIG. 3.

Dendrogram and cluster analysis of the B. avium and B. hinzii HinfI (A) or DdeI (B) REA patterns identified from isolates in Table 1 (tolerance, 1%). Individual REA patterns are represented graphically to the right of each dendrogram. B. avium patterns are assigned the prefix BA; B. hinzii patterns are assigned the prefix BH. The number of isolates identified for each REA pattern is indicated in parentheses to its right.