Phylogeny of the genus Haemophilus as determined by comparison of partial infB sequences The GenBank accession numbers for the sequences reported in this paper are AJ289629 through AJ289694, AJ290742 through AJ290767, and AJ295746.

Abstract

A 453 bp fragment of infB, the gene encoding translation initiation factor 2, was sequenced and compared from 66 clinical isolates and type strains of Haemophilus species and related bacteria. Analysis of the partial infB sequences obtained suggested that the human isolates dependent on X and V factor, H. influenzae, H. haemolyticus, H. aegyptius and some cryptic genospecies of H. influenzae, were closely related to each other. H. parainfluenzae constituted a heterogeneous group within the boundaries of the genus, whereas H. aphrophilus/paraphrophilus and Actinobacillus actinomycetemcomitans were only remotely related to the type species of the genus Haemophilus. H. parahaemolyticus and H. paraphrohaemolyticus took up an intermediary position and may not belong in the genus Haemophilus sensu stricto. Ambiguous results were obtained with seven isolates tentatively identified as H. segnis, which fell into two discrete clusters. The delineation of ' Haemophilus sensu stricto ' as suggested by infB analysis supports previous results obtained by DNA hybridization, in contrast to the delineation inferred from 16S rRNA sequence comparison.

Multilocus sequence phylogenetic study of the genus Haemophilus with description of Haemophilus pittmaniae sp. nov.

“…DNA-DNA hybridization also indicates that the parahaemolyticus group takes up an intermediate position between 'Haemophilus sensu stricto' and other parts of the family Pasteurellaceae (Burbach, 1987). By investigating 66 isolates of Haemophilus and related bacteria, it has been shown previously that partial infB sequencing supports delineation of the genus Haemophilus obtained by DNA-DNA hybridization (Hedegaard et al, 2001). …”

“…DNA was released from cells as previously described (Hedegaard et al, 2001) and 1 ml was amplified in Ready-to-go vials (Pharmacia) with 15 pmol forward and 15 pmol reverse primers in a total volume of 25 ml. After an initial denaturation step at 94 uC for 5 min, 30 cycles (94 uC for 1 min, 50 uC for 1 min and 72 uC for 2 min) were run.…”

“…Relationships based on infB sequences from our previous investigation (Hedegaard et al, 2001) are shown (Fig. 1a) for comparison with those for the other housekeeping genes.…”

“…2(b) shows the phylogenetic comparison based on near-full-length 16S rRNA gene sequences. The 16S rRNA gene sequence of the type strain of H. parahaemolyticus, available in databases as M75073, is based on an incorrect strain (Hedegaard et al, 2001) and therefore both the type strain (HK 385 T ) and H. parahaemolyticus strain HIM 570-6 (sequence accession nos AJ295746 and AJ290758, respectively) were sequenced. The 1466 nt 16S rRNA gene sequence of HK 385 T determined by us showed 96 % similarity with the deposited sequence of the type strain of H. paraphrohaemolyticus (M75076).…”

“…T and HK 1651 (=CCUG 49496), and Pasteurella multocida P801 T and Pm70. Strains were selected from our previous study of infB sequences (Hedegaard et al, 2001) and supplemented with the type strain of A. lignieresii, the additional H. aphrophilus isolate (RH01) and Pm70, a fully sequenced isolate of P. multocida (May et al, 2001). …”