Gallibacterium

Abstract

Gal.li.bac.te'ri.um. L. masc. n. gallus chicken; N.L. neut. n. bacterium rod; N.L. neut. n. Gallibacterium bacterium of chicken. Proteobacteria / Gammaproteobacteria / Pasteurellales / Pasteurellaceae / Gallibacterium The genus Gallibacterium was proposed based on the characterization and comparison of 37 strains tentatively classified as biovars of the avian [ Pasteurella ] haemolytica– “ Actinobacillus salpingitidis ” complex or as Pasteurella anatis . PFGE, amplified fragment length polymorphism (AFLP), and plasmid profiling showed that strains representing different biovars were genotypically different. Phylogenetic analysis of 22 strains characterized by 16S rRNA gene sequence comparison showed that strains classified as biovars 5, 8, and 9 were closely related to the suggested type strain of “ A. salpingitidis ” (98.4–99.9% similarity), whereas the remaining strains classified in 12 biovars or as P. anatis were closely related to the type strain of P. anatis (98.1–100% similarity). The two groups were related at 95.7–97.1% similarity. The closest similarity outside this group was 94.6%, between biovar 15 and Bisgaard taxon 3. DNA–DNA hybridization was performed with 34 strains and showed bindings above 85% for strains of biovars 5 and 8, including the suggested type strain of “ A. salpingitidis .” Two strains of P. anatis (F 149 T and F 279) were closely related at 79% DNA binding to 27 strains of biovars 1, 3, 4, 11, 12, 17–20, 22, and 24. A new genus, Gallibacterium, was proposed to include the avian [ P .] haemolytica –“ A. salpingitidis ”– P. anatis complex, since these taxa form a monophyletic unit with similarities above 95% on the basis of 16S rRNA sequence comparison, and they are unrelated to other genera of the family Pasteurellaceae . P. anatis was transferred to the new genus as Gallibacterium anatis gen. nov., comb. nov. Genomospecies 1 of Gallibacterium was proposed to include the former biovars 5 and 8 of the avian [ P .] haemolytica –“ A. salpingitidis ” complex. Subsequently, 23 isolates representing the taxon 2 and 3 complex of Bisgaard and selected based on published data on AFLP of isolates representing all biovars as well as protein profiles were further characterized by polyamine profiling and sequencing of 16S rRNA, infB , rpoB , and recN genes. Comparison of 16S rRNA gene sequences revealed a monophyletic group within the avian 16S rRNA group of Pasteurellaceae . Five monophyletic subgroups, related to G. anatis, were recognized by 16S rRNA, rpoB , infB , and recN sequence comparisons. Whole‐genome similarity between strains of the five subgroups and the type strain of G. anatis calculated from recN sequences allowed classification of all five groups within the genus Gallibacterium . In addition, phenotypic data including biochemical traits, protein profiling, and polyamine patterns clearly indicated that these taxa are related. Major phenotypic diversity was observed for the 16S rRNA gene sequence groups. Furthermore, comparison of whole‐genome similarities, phenotypic data, and published data on AFLP and protein profiling documented that each of the five groups represents unique properties allowing the proposal of three new species of Gallibacterium , for which the names Gallibacterium melopsittaci , Gallibacterium trehalosifermentans , and Gallibacterium salpingitidis were proposed. In addition, a new genomospecies 3 of Gallibacterium and an unnamed taxon (group V) were proposed. The genus meets the phenotypic characteristics of the members of Pasteurellaceae . However, due to its diversity and lack of data for several characteristics for Aggregatibacter and Bisgaardia , these genera cannot be separated from Gallibacterium . The type species of the genus is Gallibacterium anatis . DNA G + C content (mol%) : 39.9. Type species : Gallibacterium anatis Christensen et al. 2003 VP (basonym: Pasteurella anatis Mutters et al. 1985).