Proposed minimal standards for the description of genera, species and subspecies of the Pasteurellaceae

Abstract

4Rødding Tvaervej 3, 6630 Rødding, DenmarkPrinciples and guidelines are presented to ensure a solid scientific standard of papers dealing with the taxonomy of taxa of Pasteurellaceae Pohl 1981. The classification of the Pasteurellaceae is in principle based on a polyphasic approach. DNA sequencing of certain genes is very important for defining the borders of a taxon. However, the characteristics that are common to all members of the taxon and which might be helpful for separating it from related taxa must also be identified. Descriptions have to be based on as many strains as possible (inclusion of at least five strains is highly desirable), representing different sources with respect to geography and ecology, to allow proper characterization both phenotypically and genotypically, to establish the extent of diversity of the cluster to be named. A genus must be monophyletic based on 16S rRNA gene sequence-based phylogenetic analysis. Only in very rare cases is it acceptable that monophyly can not be achieved by 16S rRNA gene sequence comparison. Recently, the monophyly of genera has been confirmed by sequence comparison of housekeeping genes. In principle, a new genus should be recognized by a distinct phenotype, and characters that separate the new genus from its neighbours should be given clearly. Due to the overall importance of accurate classification of species, at least two genotypic methods are needed to show coherence and for separation at the species level. The main criterion for the classification of a novel species is that it forms a monophyletic group based on 16S rRNA gene sequence-based phylogenetic analysis. However, some groups might also include closely related species. In these cases, more sensitive tools for genetic recognition of species should be applied, such as DNA-DNA hybridizations. The comparison of housekeeping gene sequences has recently been used for genotypic definition of species. In order to separate species, phenotypic characters must also be identified to recognize them, and at least two phenotypic differences from existing species should be identified if possible. We recommend the use of the subspecies category only for subgroups associated with disease or similar biological characteristics. At the subspecies level, the genotypic groups must always be nested within the boundaries of an existing species. Phenotypic cohesion must be documented at the subspecies level and separation between subspecies and related species must be fully documented, as well as association with particular disease and host. An overview of methods previously used to characterize isolates of the Pasteurellaceae has been given. Genotypic and phenotypic methods are separated in relation to tests for investigating diversity and cohesion and to separate taxa at the level of genus as well as species and subspecies. et al., 1992). However, it makes no sense to name a novel taxon without having considered its specific properties and evaluated how it differs from related taxa. To ensure the optimal circumscript...

Multilocus sequence analysis of Pasteurella multocida demonstrates a type species under development

“…Among the 116 isolates sequence typed, the phenotypes of 86 were available based on characterizations described previously (Bisgaard et al, 1991;Christensen et al, 2007). The phenotypes of 48 strains including 36 P. multocida subsp.…”

“…These isolates had been isolated and identified as P. multocida according to Christensen et al (2012) and Mutters et al (1985). Strains investigated were stored frozen as described by Christensen et al (2007). Cultures were plated on blood agar (Blood Agar Base, CM55; Oxoid) containing 5 % sterile bovine blood and incubated at 37 u C for 24 h. Subcultures were made after 24 h. DNA was extracted using Qiagen QIAamp DNA Blood and Tissue kit according to the manufacturer's instructions (Qiagen).…”

Phenotypic and Genetic Characterization of Pasteurella Multocida and Related Isolates from Rabbits in Switzerland

“…The second largest group within the phenotypically delineated P. multocida strains was BT 7, represented by 68 isolates, which were positive for indole, mannitol, and ODC and negative for dulcitol, sorbitol, trehalose, and maltose. The remaining 25 P. multocida strains were distributed among the other BTs (1,(3)(4)(5)(6)(8)(9)(10). Eleven isolates were identified as Pasteurella canis (BT 11), and 8 isolates were unidentifiable based on their phenotypic appearance (BT 12).…”

Observations on the incidence and aetiology of valvular endocarditis in broiler breeders and detection of a newly described taxon ofPasteurellaceae,Avibacterium endocarditidis

“…The rpoB gene, encoding the b-subunit of DNAdependent RNA polymerase, has been recommended for DNA sequence-based identification of Pasteurellaceae by Christensen et al (2007). The rpoB sequences of all four strains stated above were identical or with high similarity to the type strain of A. endocarditidis Table 1.…”