Transfer of Haemophilus pleuropneumoniae and the Pasteurella haemolytica-Like Organism Causing Porcine Necrotic Pleuropneumonia to the Genus Actinobacillus (Actinobacillus pleuropneumoniae comb. nov.) on the Basis of Phenotypic and Deoxyribonucleic Acid Relatedness

Abstract

The Pasteurella-like organism of porcine necrotizing pleuropneumonia described by Bertschinger and Seifert in 1978 was shown to be phenotypically similar to the V factor-requiring strains hitherto classified as Haemophilus pleuropneumoniae (Matthews and Pattison 1961) Shope 1964. Deoxyribonucleic acid-deoxyribonucleic acid hybridization experiments in which the optical method was used yielded 91% binding of the genomes of the type and reference strains of these two taxa, thus indicating that they belong to the same species. The levels of deoxyribonucleic acid binding between these strains and the type strain of Haemophilus influenzae indicated no measurable relatedness. Therefore, these organisms do not belong to the genus Haemophilus sensu stricto. On the other hand, they are closely related to Actinobacillus lignieresii, as determined by both phenotypic characteristics and deoxyribonucleic acid base sequence relatedness (72 to 75% binding). To take into account the different host ranges of these organisms, we propose to classify them as a species distinct from, but closely related to, A. lignieresii, under the new combination Actinobacillus pleuropneumoniae. The emended species A. pleuropneumoniae is composed of V factorrequiring and V factor-independent biovars. The type strain (strain Shope 4047 [= CCM 5869 = ATCC 270881) requires V factor; the V factor-independent biovar is represented by strain Bertschinger 2008/76 (= Frederiksen P 597 = HIM 677-3/4). granules or actinomycotic granules. Such granules were never observed in porcine infections with the new organism. Furthermore, the organism isolated by Bertschinger and Seifert (designated the BS organism) resembled Haemophilus pleuropneumoniae in many physiological properties; an exception was the V factor requirement (10). In this paper we describe the genetic relationships among the organisms mentioned above, as revealed by deoxyribonucleic acid (DNA)-DNA hybridization, and propose a classification of these organisms. MATERIALS AND METHODSon the basis Of Phenotypic charac-studied are listed in Table 1. They were kept lyophi-

Genotypic Prevalence of apxIV in Actinobacillus Pleuropneumoniae Field Isolates

“…Based on requirements for nicotinamide adenine dinucleotide (NAD), NAD-dependent strains (biotype 1) and NAD-independent Received for publication April 11, 2000. strains (biotype 2) can be distinguished. 12 To date, at least 12 serotypes have been described, with various expression of 3 different proteinaceous cytotoxins belonging to the RTX family of toxins: ApxI, ApxII, and ApxIII. 5 ApxI, a strong hemolytic and cytotoxic protein of 105 kDa, is secreted by the most virulent serotypes: 1, 5, 9, 10, and 11.…”

Isolation Rates, Serovars, and Toxin Genotypes of Nicotinamide Adenine Dinucleotide-Independent Actinobacillus Pleuropneumoniae among Pigs Suffering from Pleuropneumonia in Spain

“…Biovar 2 strains of A. pleuropneumoniae were first isolated in the late 1970s from cases of necrotic swine pneumonia and were described as Pasteurella haemolyticalike organisms; these isolates were later classified into the genus Actinobacillus. 16 The isolation of A. pleuropneumoniae biovar 2 has been reported from the early 1980s onward, both in some European countries and in the United States. 6,7,15 More recently, biovar 2 field isolates have been implicated in episodes of clinical disease and outbreaks, with high mortality in fattening pigs.…”

Reclassification of Pasteurella gallinarum, [Haemophilus] paragallinarum, Pasteurella avium and Pasteurella volantium as Avibacterium gallinarum gen. nov., comb. nov., Avibacterium paragallinarum comb. nov., Avibacterium avium comb. nov. and Avibacterium volantium comb. nov.

“…A number of species within the Pasteurellaceae that contain both NADdependent and NAD-independent strains have been reported, e.g. Actinobacillus pleuropneumoniae, which causes pleuropneumonia in swine (Pohl et al, 1983), Avibacterium ([Haemophilus]) paragallinarum (Bragg et al, 1993;Mouahid et al, 1992), Haemophilus parainfluenzae, which can cause pneumonia and meningitis in humans (Gromkova & Koornhof, 1990), and Haemophilus ducreyi, which causes the sexually transmitted disease chancroid in humans (Windsor et al, 1993). To date, there have been no extensive studies on the variations, if any, between the 16S rRNA gene sequences of NAD-dependent and NADindependent strains within these species.…”