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At least 19 recordsLinked to original sources

PubMed1999

Growth medium affects the cellular fatty acid composition of Pasteurellaceae.

We studied the cellular fatty acid composition of 10 Actinobacillus (A.) and Pasteurella (P.) reference strains grown on 2 types of agar by the MIDI Microbial Identification System (MIS). A. capsulatus, A. equuli, A. lignieresii, A. ureae, A. dagmatis, P. gallinarum, P. haemolytica, P. multocida, P. pneumotropica biotypes Heyl and Jawetz were grown on GC agar supplemented with ascitic fluid and X and V factor (Levinthal's agar = LA agar) or GC agar supplemented with vitox and hemoglobin (VH agar) on 3 to 7 and 7 to 16 occasions respectively and fatty acid methylester (FAME) profiles were submitted to principal component analysis (PCA). All Pasteurellaceae strains showed FAME profiles typical for the family. Maximum coefficients of variation of the percentage of the 3 major FAMEs 14:0, 16:0, and 16:1 cis were 0.03, 0.03 and 0.03 for Pasteurellaceae strains grown on VH agar and 0.09, 0.17 and 0.09 respectively for strains grown on LA agar. PCA of FAME profiles obtained with growth from LA agar generally did not allow species separation of the Pasteurellaceae but most species were clearly discriminated by PCA when they were grown on VH agar. Our findings indicate that the growth medium had a significant effect on the reproducibility of fatty acid profiling in Pasteurellaceae and that PCA of fatty acid data obtained under standardized growth conditions may discriminate Pasteurellaceae species.

Animals↗

PubMed2002

RTX toxins in Pasteurellaceae.

RTX toxins (repeats in the structural toxin) are pore-forming protein toxins produced by a broad range of pathogenic Gram-negative bacteria. In vitro, RTX toxins mostly exhibit a cytotoxic and often also a hemolytic activity. They are particularly widespread in species of the family Pasteurellaceae which cause infectious diseases, most frequently in animals but also in humans. Most RTX toxins are proteins with a molecular mass of 100-200 kDa and are post-translationally activated by acylation via a specific activator protein. The repeated structure of RTX toxins, which gave them their name, is composed of iterative glycine-rich nonapeptides binding Ca2+ on the C-terminal half of the protein. Genetic analysis of RTX toxins of various species of Pasteurellaceae and of a few other Gram-negative bacteria gave evidence of horizontal transfer of genes encoding RTX toxins and led to speculations that RTX toxins might have originated from Pasteurellaceae. The toxic activities of RTX toxins in host cells may lead to necrosis and apoptosis and the underlying detailed mechanisms are currently under investigation. The impact of RTX toxins in pathogenicity and the immune responses of the host were described for several species of Pasteurellaceae. Neutralizing antibodies were shown to significantly reduce the cytotoxic activity of RTX toxins. They constitute a valuable strategy in the development of immuno-prophylactics against several animal diseases caused by pathogenic species of Pasteurellaceae. Although many RTX toxins possess cytotoxic and hemolytic activities toward a broad range of cells and erythrocytes, respectively, a few RTX toxins were shown to have cytotoxic activity only against cells of specific hosts and/or show cell-type specificity. Further evidence exists that RTX toxins play a potential role in host specificity of certain pathogens.

Animals↗

PubMed1990

Inter- and intrafamilial similarities of rRNA cistrons of the Pasteurellaceae.

We performed hybridizations between labeled rRNAs from seven representative members of the family Pasteurellaceae and from three other taxa on the one hand and DNAs from 53 strains known or presumed to belong to the Pasteurellaceae on the other hand. The members of the Pasteurellaceae are most closely related to members of the Enterobacteriaceae, the Vibrionaceae, the Aeromonadaceae, and the genus Alteromonas. The family Pasteurellaceae is very heterogeneous. There are at least seven rRNA branches. Several organisms with the same genus name are dispersed over the entire dendrogram. The "Histophilus ovis," [Haemophilus] ducreyi, [Actinobacillus] actinomycetemcomitans, and [Haemophilus] aphrophilus rRNA branches are separate and quite remote from the three authentic genera in this family; this might justify eventual later separate generic status. DNA-rRNA hybridization with suitable, labeled rRNA probes is an excellent method to establish whether an organism belongs in the Pasteurellaceae; e.g., some strains of Bisgaard's taxa 7, 13, and 16 and of the gas-producing "SP" group certainly belong in this family, whereas three bovine lymphangitis organisms (strains NCTC 10547, NCTC 10549, and NCTC 10553), [Haemophilus] piscium ATCC 10801T (T = type strain), and [Pasteurella] piscicida ATCC 17911 belong in the Enterobacteriaceae, the Aeromonadaceae, and the Vibrionaceae, respectively.

Actinobacillus↗

PubMed1990

Isolation of Pasteurellaceae from bovine abortions.

A 2-year study was conducted to determine the incidence of Pasteurellaceae in abortion samples submitted for diagnostic evaluation. A total of 687 cases, including 623 with fetal tissues and/or stomach contents and 302 with placenta and/or uterine discharge, were evaluated. Pasteurellaceae were isolated on a nonselective medium from 9 (1.5%), 14 (2.8%), 13 (12.1%), and 42 (17.4%) of the fetal tissues, stomach contents, uterine discharges, and placentas, respectively. A total of 35 (19.9%) of 176 placental samples cultured on both a selective medium for Pasteurellaceae and a nonselective medium were positive for Pasteurellaceae. Fifteen (42.9%) of these isolates were detected only on the selective medium, whereas 5 (14.2%) were detected only on the nonselective medium and 15 (42.9%) grew on both media. Placentitis of different severity was evident in 13 (68.4%) of the 19 placentas from which Pasteurellaceae were isolated in the absence of other known abortifacient agents.

Abortion, Veterinary↗

PubMed2006

Detection of tetracycline-resistant and susceptible pasteurellaceae in the nasopharynx of loose group-housed calves.

The aim of the present study was to determine which Pasteurella and Mannheimia species are present in the upper respiratory tract of healthy calves with no history of antimicrobial treatment prior to sampling. The presence of subpopulations of tetracycline-resistant Pasteurellaceae was also investigated. Nasal swabs from 61 loose group-housed, clinically healthy calves, 1 to 4 months old, from 16 dairy herds were inoculated aerobically on a selective medium (Columbia agar with 5% ovine blood and 16 mg/L bacitracin) with or without 4 mg/L oxytetracycline (OTC). A total of 43 strains belonging to the family Pasteurellaceae were isolated from 38 calves (62.3%) out of 13 herds (81.3%). The predominant organisms were Pasteurella multocida subsp. multocida (57.4%), Mannheimia varigena (4.9%) and M. haemolytica (3.2%). Growth of Pasteurellaceae on the OTC-containing medium was seen only with samples from two herds (6 animals; 9.8%), and on only one farm this proved to be an OTC-resistant subpopulation. Minimum inhibitory concentration (MIC) determinations by means of agar dilution confirmed a low prevalence of OTC-resistant Pasteurellaceae, with overall MIC(50) and MIC(90) values of 0.25 and 32 mg/L, respectively. These data do not support the hypothesis that the relative high frequency of tetracycline-resistant P. multocida isolates from fatal cases of bovine respiratory disease is related to the presence of minor tetracycline-resistance subpopulations within this species.

Animals↗

PubMed2001

Phenotypic and genetic characterization of NAD-dependent Pasteurellaceae from the respiratory tract of pigs and their possible pathogenetic importance.

Nicotinamide adenine dinucleotide (NAD)-dependent Pasteurellaceae other than Actinobacillus pleuropneumoniae and Haemophilus parasuis are frequently isolated from the respiratory tract of pigs. The taxonomic classification and relevance for pathogenicity of these bacteria deserves further attention. In the present study, 107 of these NAD-dependent isolates from the porcine respiratory tract, primarily from lungs with pathological changes, were investigated. On the basis of phenotypic criteria, such as haemolysis, urease, catalase, and indole formation as well as other fermentative activities, 50 of the isolates were assigned to Actinobacillus minor, 36 isolates to Actinobacillus porcinus and 21 isolates to Actinobacillus indolicus. However, many isolates among the three species showed fermentative activities differing from those of the respective type strain of the species. Serotyping on the basis of heat-stable polysaccharide antigens and 16 rDNA sequencing also revealed substantial heterogeneity within each of the three species although they clustered together in three distinct groups in the phylogenetic analysis. These three groups of NAD-dependent bacteria are different from, or in a borderline position, to the existing species or genera within the family Pasteurellaceae. A considerable number of isolates of these three groups were isolated in pure cultures from pneumonic lungs. Consequently, it will be necessary to critically review the opinion, that these NAD-dependent Pasteurellaceae are only "agents colonizing the mucosa". Further, taxonomic examinations of the strains within these three groups are indispensable to testing isolates for their virulence in gnotobiotic pigs.

Animals↗

PubMed2004

Nicoletella semolina gen. nov., sp. nov., a new member of Pasteurellaceae isolated from horses with airway disease.

Gram-negative, nonmotile bacteria that are catalase, oxidase, and urease positive are regularly isolated from the airways of horses with clinical signs of respiratory disease. On the basis of the findings by a polyphasic approach, we propose that these strains be classified as Nicoletella semolina gen. nov, sp. nov., a new member of the family Pasteurellaceae. N. semolina reduces nitrate to nitrite but is otherwise biochemically inert; this includes the lack of an ability to ferment glucose and other sugars. Growth is fastidious, and the isolates have a distinctive colony morphology, with the colonies being dry and waxy and looking like a semolina particle that can be moved around on an agar plate without losing their shape. DNA-DNA hybridization data and multilocus phylogenetic analysis, including 16S rRNA gene (rDNA), rpoB, and infB sequencing, clearly placed N. semolina as a new genus in the family Pasteurellaceae. In all the phylogenetic trees constructed, N. semolina is on a distinct branch displaying approximately 5% 16S rDNA, approximately 16% rpoB, and approximately 20% infB sequence divergence from its nearest relative within the family Pasteurellaceae. High degrees of conservation of the 16S rDNA (99.8%), rpoB (99.6%), and infB (99.7%) sequences exist within the species, indicating that N. semolina isolates not only are phenotypically homogeneous but also are genetically homogeneous. The type strain of N. semolina is CCUG43639(T) (DSM16380(T)).

Animals↗

PubMed1994

Colonization and antibody response in mice and rats experimentally infected with Pasteurellaceae from different rodent species.

Mice and rats were experimentally infected with Pasteurellaceae isolated from mice, rats, hamsters and gerbils. Mice and rats were most heavily colonized by strains originally isolated from mice and rats respectively, and to a lesser extent by Pasteurellaceae from hamsters and gerbils. Colonization was generally accompanied by seroconversion. Gross pathology of the lungs was not observed. We conclude that Pasteurellaceae-free SPF mice and rats can be colonized by members of this bacterial family present in other rodent species.

Animals↗

PubMed2006

Phylogenetic diversity of Pasteurellaceae and horizontal gene transfer of leukotoxin in wild and domestic sheep.

Wild and domestic animal populations are known to be sources and reservoirs of emerging diseases. There is also a growing recognition that horizontal genetic transfer (HGT) plays an important role in bacterial pathogenesis. We used molecular phylogenetic methods to assess diversity and cross-transmission rates of Pasteurellaceae bacteria in populations of bighorn sheep, Dall's sheep, domestic sheep and domestic goats. Members of the Pasteurellaceae cause an array of deadly illnesses including bacterial pneumonia known as "pasteurellosis", a particularly devastating disease for bighorn sheep. A phylogenetic analysis of a combined dataset of two RNA genes (16S ribosomal RNA and RNAse P RNA) revealed remarkable evolutionary diversity among Pasteurella trehalosi and Mannheimia (Pasteurella) haemolytica bacteria isolated from sheep and goats. Several phylotypes appeared to associate with particular host species, though we found numerous instances of apparent cross-transmission among species and populations. Statistical analyses revealed that host species, geographic locale and biovariant classification, but not virulence, correlated strongly with Pasteurellaceae phylogeny. Sheep host species correlated with P. trehalosi isolates phylogeny (PTP test; P=0.002), but not with the phylogeny of M. haemolytica isolates, suggesting that P. trehalosi bacteria may be more host specific. With regards to populations within species, we also discovered a strong correlation between geographic locale and isolate phylogeny in the Rocky Mountain bighorn sheep (PTP test; P=0.001). We also investigated the potential for HGT of the leukotoxin A (lktA) gene, which produces a toxin that plays an integral role in causing disease. Comparative analysis of the combined RNA gene phylogeny and the lktA phylogenies revealed considerable incongruence between the phylogenies, suggestive of HGT. Furthermore, we found identical lktA alleles in unrelated bacterial species, some of which had been isolated from sheep in distantly removed populations. For example, lktA sequences from P. trehalosi isolated from remote Alaskan Dall's sheep were 100% identical over a 900-nucleotide stretch to sequences determined from M. haemolytica isolated from domestic sheep in the UK. This extremely high degree of sequence similarity of lktA sequences among distinct bacterial species suggests that HGT has played a role in the evolution of lktA in wild hosts.

Alleles↗

PubMed1998

Adhesin-receptor interactions in Pasteurellaceae.

The ability of bacteria to adhere to mucosal epithelium is dependent on the expression of adhesive molecules or structures, called adhesins, that allow attachment of the organisms to complementary molecules on mucosal surfaces, the receptors. Important human and animal pathogens are found among the Pasteurellaceae family which includes Haemophilus, Actinobacillus, and Pasteurella organisms. The purpose of this paper is to review the adhesin-receptor systems found in Pasteurellaceae, with an emphasis on recent developments in this specific area. Most of these organisms can employ multiple molecular mechanisms of adherence (or multiple adhesins) to initiate infection. Indeed, a wide variety of adhesins are expressed by members of the Pasteurellaceae, and different proteins (e.g. fimbriae, fibrils, outer membrane proteins) as well as polysaccharides (lipooligosaccharides, lipopolysaccharides, capsular polysaccharides) were clearly shown to play an important role in adherence. In many instances, these adhesins have proved to represent good vaccine candidates. Surprisingly, the receptors on host mucosal surfaces have yet been identified in very few cases.

Adhesins, Bacterial↗

PubMed1993

Phylogeny of the Pasteurellaceae as determined by comparison of 16S ribosomal ribonucleic acid sequences.

Previously, virtually complete 16S ribosomal ribonucleic acid sequences were determined for 54 strains of species in the family Pasteurellaceae. The sequences for 16 additional strains have been determined, bringing the total number of strains sequenced to 70. The additional strains include: Actinobacillus hominis, A. muris, A. salpingitis, Pasteurella bettyae, P. mairii, P. testudinis, and Bisgaard taxa 2, 3, 5, 6, 7, 8, 9, 13, and 14 (2 strains). A phylogenetic tree was constructed based upon sequence similarity using the Neighbor-Joining method. The additional sequence information and phylogenetic analysis generally supported our previously described phylogenetic structure for the family Pasteurellaceae. Cluster 1, containing Haemophilus sensu stricto, was unchanged. P. mairii was closely related to P. aerogenes and Bisgaard taxon 6 was related to H. somnus in Cluster 2. A. salpingitidis and Bisgaard taxa 2, 3, 7, and 13 fell in Cluster 3 which contains Pasteurella sensu stricto. A. hominis was closely related to Actinobacillus sensu stricto species in Cluster 4A. Bisgaard taxa 5, 8, 9 and P. bettyae fell in Cluster 4B. A. muris was related to P. pneumotropica in Cluster 5. Haemophilus parainfluenzae strains branched deeply as a 6th cluster. Bisgaard taxon 14 and P. testudinis formed a 7th cluster which branched deeper than any previously described clusters in the family Pasteurellaceae. The branching was extremely complex and taxonomic division of the family into phylogenetically and phenotypically coherent genera will be difficult.

Actinobacillus↗

PubMed2003

Phylogenetic analysis by 16S rDNA gene sequence comparison of avian taxa of Bisgaard and characterization and description of two new taxa of Pasteurellaceae.

AIMS: Characterization and classification of members of Pasteurellaceae isolated from birds by extended phenotypic characterization and 16S rDNA gene sequence comparison. METHODS AND RESULTS: A total of 95 avian isolates were subjected to extended phenotypic characterization. Thirteen bacterial strains selected from main phenotypic clusters and isolated from parrot, parakeet, budgerigar, partridge, pheasant, chicken, duck, hawk and gull were subsequently characterized by 16S rDNA gene sequencing. Eight of the sequenced strains were classified with six taxa of Bisgaard of which two (34 and 40) have not been published before, and the properties of four others (14, 22, 26 and 32) changed upon the characterization of these new isolates. Of the remaining strains, one was identified as a phenotypic variant in maltose and dextrin of Pasteurella gallinarum another as a trehalose positive variant of taxon 3 of Bisgaard. The remaining three strains sequenced were not closely related to existing taxa of Pasteurellaceae. However, they were found to belong to the Avian cluster with 92-97% 16S rDNA gene sequence similarity. CONCLUSION: The study allowed the classification of bacteria isolated from birds by the integrated use of extended phenotypic characterization and 16S rDNA gene sequence analysis. Only the application of 16S rDNA gene sequencing allows a correct identification of variant strains. SIGNIFICANCE AND IMPACT OF THE STUDY: The description of new taxa within the bacterial family Pasteurellaceae will subsequently allow additional isolates of these taxa to be identified and improve the diagnosis and epidemiological understanding of bacteria causing disease in birds.

Animals↗

PubMed2004

Comparative phylogenies of the housekeeping genes atpD, infB and rpoB and the 16S rRNA gene within the Pasteurellaceae.

Phylogenies of housekeeping gene and 16S rRNA gene sequences were compared to improve the classification of the bacterial family Pasteurellaceae and knowledge of the evolutionary relationships of its members. Deduced partial protein sequences of the housekeeping genes atpD, infB and rpoB were compared in 28, 36 and 28 representative taxa of the Pasteurellaceae, respectively. The monophyly of representatives of the genus Gallibacterium was recognized by analysis of all housekeeping genes, while members of Mannheimia, Actinobacillus sensu stricto and the core group of Pasteurella sensu stricto formed monophyletic groups with two out of three housekeeping genes. Representatives of Mannheimia, Actinobacillus sensu stricto, [Haemophilus] ducreyi and [Pasteurella] trehalosi formed a monophyletic unit by analysis of all three housekeeping genes, which was in contrast to the 16S rRNA gene-derived phylogeny, where these taxa occurred at separate positions in the phylogenetic tree. Representatives of the Rodent, Avian and Aphrophilus-Haemophilus 16S rRNA gene groups were weakly supported by phylogenetic analysis of housekeeping genes. Phylogenies derived by comparison of the housekeeping genes diverged significantly from the 16S rRNA gene-derived phylogeny as evaluated by the likelihood ratio test. A low degree of congruence was also observed between the individual housekeeping gene-derived phylogenies. Estimates on speciation derived from 16S rRNA and housekeeping gene sequence comparisons resulted in quite different evolutionary scenarios for members of the Pasteurellaceae. The phylogeny based on the housekeeping genes supported observed host associations between Mannheimia, Actinobacillus sensu stricto and [Pasteurella] trehalosi and animals with paired hooves.

Actinobacillus↗

PubMed2004

Phylogeny of the family Pasteurellaceae based on rpoB sequences.

Sequences of the gene encoding the beta-subunit of the RNA polymerase (rpoB) were used to delineate the phylogeny of the family Pasteurellaceae. A total of 72 strains, including the type strains of the major described species as well as selected field isolates, were included in the study. Selection of universal rpoB-derived primers for the family allowed straightforward amplification and sequencing of a 560 bp fragment of the rpoB gene. In parallel, 16S rDNA was sequenced from all strains. The phylogenetic tree obtained with the rpoB sequences reflected the major branches of the tree obtained with the 16S rDNA, especially at the genus level. Only a few discrepancies between the trees were observed. In certain cases the rpoB phylogeny was in better agreement with DNA-DNA hybridization studies than the phylogeny derived from 16S rDNA. The rpoB gene is strongly conserved within the various species of the family of Pasteurellaceae. Hence, rpoB gene sequence analysis in conjunction with 16S rDNA sequencing is a valuable tool for phylogenetic studies of the Pasteurellaceae and may also prove useful for reorganizing the current taxonomy of this bacterial family.

Bacterial Proteins↗

PubMed2007

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

Principles 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.

Bacterial Typing Techniques↗

PubMed1990

V factor-dependent members of the family Pasteurellaceae in the porcine upper respiratory tract.

A study was performed to obtain a better understanding of the diversity and ecology of members of the family Pasteurellaceae in the porcine respiratory tract. A collection of 132 V factor-dependent strains of Pasteurellaceae selected from porcine field isolates mainly from the respiratory tract were subjected to detailed characterization. In addition to the three hitherto recognized species Actinobacillus pleuropneumoniae, Haemophilus parasuis, and Haemophilus taxon "minor group," three distinct taxa were observed. Some of these taxa, which are provisionally designated taxa D, E, and F, would by traditional criteria be mistaken for H. parasuis but differed by several biochemical characteristics. To study the ecology of the V factor-dependent species, swabs from the nasal and oral cavities of 29 pigs were cultivated on selective and nonselective media. By studying approximately 30 isolates from each sample, the distribution and relative proportion of the individual taxa were determined. A. pleuropneumoniae was detected in samples from the tonsil areas of only two acutely ill animals. H. parasuis was isolated from the nasal cavities of four out of nine healthy pigs but from the oral cavities of only two animals. In contrast, taxon "minor group" and taxa D, E, and F were present in the oral cavities of the majority of pigs but were not detected in samples from their nasal cavities. The results indicate that all the observed V factor-dependent species of Pasteurellaceae except A. pleuropneumoniae, are members of the resident microflora of various mucosal surfaces of the porcine upper respiratory tract.

Animals↗

PubMed2006

Evolution of competence and DNA uptake specificity in the Pasteurellaceae.

BACKGROUND: Many bacteria can take up DNA, but the evolutionary history and function of natural competence and transformation remain obscure. The sporadic distribution of competence suggests it is frequently lost and/or gained, but this has not been examined in an explicitly phylogenetic context. Additional insight may come from the sequence specificity of uptake by species such as Haemophilus influenzae, where a 9 bp uptake signal sequence (USS) repeat is both highly overrepresented in the genome and needed for efficient DNA uptake. We used the distribution of competence genes and DNA uptake specificity in H. influenzae's family, the Pasteurellaceae, to examine the ancestry of competence. RESULTS: A phylogeny of the Pasteurellaceae based on 12 protein coding genes from species with sequenced genomes shows two strongly supported subclades: the Hin subclade (H. influenzae, Actinobacillus actinomycetemcomitans, Pasteurella multocida, Mannheimia succiniciproducens, and H. somnus), and the Apl subclade (A. pleuropneumoniae, M. haemolytica, and H. ducreyi). All species contained homologues of all known H. influenzae competence genes, consistent with an ancestral origin of competence. Competence gene defects were identified in three species (H. somnus, H. ducreyi and M. haemolytica); each appeared to be of recent origin. The assumption that USS arise by mutation rather than copying was first confirmed using alignments of H. influenzae proteins with distant homologues. Abundant USS-like repeats were found in all eight Pasteurellacean genomes; the repeat consensuses of species in the Hin subclade were identical to that of H. influenzae (AAGTGCGGT), whereas members of the Apl subclade shared the consensus ACAAGCGGT. All species' USSs had the strong consensus and flanking AT-rich repeats of H. influenzae USSs. DNA uptake and competition experiments demonstrated that the Apl-type repeat is a true USS distinct from the Hin-type USS: A. pleuropneumoniae preferentially takes up DNA fragments containing the Apl-type USS over both H. influenzae and unrelated DNAs, and H. influenzae prefers its own USS over the Apl type. CONCLUSION: Competence and DNA uptake specificity are ancestral properties of the Pasteurellaceae, with divergent USSs and uptake specificity distinguishing only the two major subclades. The conservation of most competence genes over the approximately 350 million year history of the family suggests that lineages that lose competence may be evolutionary dead ends.

Amino Acid Sequence↗

PubMed1995

An enzyme-linked immunosorbent assay (ELISA) for monitoring antibodies to SP group Pasteurellaceae in guineapigs.

Cross-reactivity studies with Pasteurellaceae from guineapigs revealed 5 serologically distinct groups, comprising Pasteurella multocida, Sp group bacteria, SP-like bacteria, Pasteurella pneumotropica and an actinobacillus-like bacterium. Guineapig Pasteurellaceae differed serologically from mouse-derived P. pneumotropica NCTC 8284. An enzyme-linked immunosorbent assay (ELISA) using SP group antigen, developed to monitor 'natural' infections by SP group Pasteurellaceae in guineapigs, detected significantly more infection than did cultivation, and was found superior to an ELISA performed with P. pneumotropica NCTC 8284.

Animals↗