In a study of the classification of members of the family Pasteurelluceae, the polyamine patterns of 101 strains were analyzed. These strains included the type strains of species belonging to the genera Actinobacillus, Haemophilus, and Pasteurellu and additional strains of selected species, as well as numerous unnamed strains. Members of the genus Actinobacillus sensu stricto were characterized by the presence of 1,3-diaminopropane as the predominant compound. In the majority of the species of the genus Haemophilus sensu stricto 1,3-diaminopropane was also the major compound in the polyamine pattern. In contrast, Haemophilus intermedius subsp. gazogenes and Haemophilus parainjluenzae were characterized by high levels of 1,3-diaminopropane, cadaverine, and putrescine. These results confirmed the findings of Dewhirst et al. (F. E. Dewhirst, B. J. Paster, I. Olsen, and G. J. Fraser, Zentralbl. Bakteriol. Parasitenkd. Infektionskr. Hyg. Abt. 1 Orig. 279:35-44, 1993), who demonstrated that H. parainjluenzae is phylogenetically only distantly related to the type species of the genus Haemophilus, Haemophilus injluenzae. The phylogenetic diversity of the genus Pasteurellu sensu stricto determined by Dewhirst et al. was also reflected to some extent by different polyamine patterns. The common characteristics found in Pasteurellu multocida, Pasteurella canis, Pasteurellu dagmatis, Pasteurellu stomatis, and Pasteurella sp. strain B were high levels of putrescine and spermidine and the presence of the unusual triamine sym-now permidine. Pasteurellu avium, Pasteurellu gallinarum, and Pasteurella voluntium contained high concentrations of 1,3-diaminopropane and spermidine. Pasteurellu lungaa contained only high concentrations of 1,3-diaminopropane, and Pasteurellu anatis was characterized by the presence of 1,3-diaminopropane as the predominant compound and high levels of putrescine and spermidine. Our data demonstrate that polyamine patterns are useful for discrimination within the family Pasteurelluceae.The family Pasteurellaceae accomodates species classified in the genera Pasteurella Trevisan 1887 (31), Actinobacillus Brumpt 1910 (3), Haemophilus Winslow et al. 1917 (32), and Lonepinella Osawa et al. 1995 (24), as well as numerous unnamed strains. All members of the family are parasites of vertebrates, such as mammals, birds, and reptiles. Phylogenetically, the family is located in the gamma subclass of the Proteobacten'a and clusters with facultatively anaerobic, gram-negative, chemoorganotrophic bacteria which are members of the families Enterobacteriaceae, Aeromonadaceae, and Vibrionaceae (5, 6, 33).Extensive DNA-DNA hybridization studies have demonstrated the genetic relatedness of members of the family Pasteurellaceae and have resulted in the definition of three genera, the genera Actinobacillus, Pasteurella, and Haemophilus (20). Recent DNA-rRNA hybridization studies and 16s rRNA sequence analyses of members of the family Pasteurellaceae have revealed that there is great heterogeneity within this family (6, 7). Ma...

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The gene encoding an outer membrane lipoprotein (omlA) of Actinobacillus pleuropneumoniae serotype 5 was cloned, and the protein was expressed in Escherichia coli. One open reading frame of 1,104 bp was detected that encoded a protein (OmlA) with a predicted molecular mass of 40 kDa. A comparison with the omlA gene and the corresponding protein of A. pleuropneumoniae serotype 1 (G.-F. Gerlach, C. Anderson, S. Klashinsky, A. Rossi-Kampos, A. A. Potter, and P. J. Wilson, Infect. Immun. 61:565-572, 1993) revealed that the nucleic acid sequences had an overall sequence identity of 62.9% and the deduced amino acid sequences showed a sequence agreement of 57.3%. Both proteins were antigenically distinct. In a Western blot (immunoblot) analysis using a specific antiserum against A. pleuropneumoniae serotype 5 OmlA, a homologous protein was detected in the reference strains of A. pleuropneumoniae serotypes 5A, 5B, and 10. Pigs immunized with this recombinant protein were protected from death in an aerosol challenge experiment with an A. pleuropneumoniae serotype 5 isolate. Actinobacillus pleuropneumoniae is a highly infectious porcine respiratory tract pathogen (22). The disease caused by this bacterium is encountered worldwide and frequently causes severe losses in infected herds (21). Infected animals develop disease symptoms ranging from acute fibrinous pneumonia and pleuritis with high mortality to chronic lung lesions resulting in reduced growth rates (22). Pigs which survive an infection develop a protective immune response but can still be carriers of the pathogen (22). The rapid onset and severity of disease mean that losses may occur before antibiotic therapy has time to become effective. Attempts to immunize against A. pleuropneumoniae disease have been hampered by the occurrence of two biotypes and more than 14 serotypes (2, 6, 10-14, 16) and the lack of reliable cross-protection (9). It has been hypothesized that a cross-protective immune response might be achievable by immunization with a mixture of serotype-specific antigens that are recognized by convalescent sera (3). Recently, we were able to show that two recombinant proteins could protect pigs from death in an A. pleuropneumoniae serotype 7 challenge (17). One of these antigens was a truncated RTX toxin, and the other was an iron-regulated transferrin-binding protein. However, no cross-protection against A. pleuropneumoniae serotype 1 infection was observed (17). In order to achieve protection against A. pleuropneumoniae serotype 1 (3), we were successful in cloning and expressing a protective outer membrane lipoprotein (OmlA) of A. pleuropneumoniae serotype 1. In an A. pleuropneumoniae serotype 1 challenge experiment, all animals immunized with the recombinant OmlA were protected from death (3). However, antiserum raised against the transferrin-binding proteins of A. pleuropneumoniae serotypes

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