Characterization of Sucrose-Negative Pasteurella multocida Variants, Including Isolates from Large-Cat Bite Wounds

Abstract

To validate the identification of Pasteurella multocida-like bacteria negative for acid formation from sucrose, including isolates from bite wounds caused by large cats, 17 strains were phenotypically and genotypically characterized. Phylogenetic analysis of partially sequenced rpoB and infB genes showed the monophyly of the strains characterized and the reference strains of P. multocida. The sucrose-negative strains formed two groups, one related to reference strains of P. multocida and the other related to a separate species-like group (taxon 45 of Bisgaard). DNA-DNA hybridization further documented the species-like nature of this group. Ribotyping showed the heterogeneity of all strains except four strains that shared the same ribotype and that were isolated from bovine lungs. Phylogenetic analysis by 16S rRNA sequence comparison showed the monophyly of the strains characterized and the reference strains of P. multocida. Two strains isolated from leopard bite wounds were related to the type strain of P. dagmatis; however, they represented a new taxon (taxon 46 of Bisgaard), in accordance with their distinct phenotypic and genotypic identifications. The present study documents that sucrose-negative strains of P. multocida-like bacteria belong to two genotypically distinct groups. The study further confirms the phenotypic heterogeneity of P. multocida strains and documents two new species-like taxa of Pasteurella related to P. multocida. Until diagnostic tools have been further elaborated, special care should be taken in the identification of Pasteurella-like bacteria isolated from bite wounds caused by large cats. The evidence of phenotypic and genotypic divergence calls for the further development of PCR tests and DNA sequencing to document doubtful isolates.Pasteurella multocida has been isolated from a multitude of hosts (26), and different lineages of P. multocida may be responsible for various diseases in both birds and mammals (9, 15). Human infections with P. multocida are in most cases of animal origin and are most often related to the bites of carnivores. However, other types of infections are also occasionally reported (25,28,34).Significant variations in the phenotypic properties of P. multocida have been reported (27), leading to confusion in the definition and identification of this organism. Mutters et al. (37) reclassified the genus Pasteurella on the basis of DNA-DNA hybridization studies. Three clusters of P. multocida showing 84 to 100, 91 to 100, and 89 to 100% DNA reassociation between strains subsequently described as P. multocida subsp. multocida, P. multocida subsp. gallicida, and P. multocida subsp. septica, respectively, were identified. Representatives of the existing capsular types were found to be closely related on the basis of DNA-DNA hybridization (44), despite the diversity of disease manifestations and hosts. This is contradictory to the diversity shown by outer membrane protein profiling (17,18,19), multilocus enzyme electrophoresis (5), and ribotyping (43). The study of Pet...

Evaluation of different API systems for identification of porcine Pasteurella multocida isolates

“…These results confirm the high diversity showed by P. multocida isolates, previously reported by others (Christensen et al, 2004(Christensen et al, , 2005.…”

“…In our study, a phenotypic diversity concerning ornithine decarboxylase, indole, and fermentation of mannitol and sucrose has been obtained (Table 1), all being characters that have been considered as essential for the identification of P. multocida at the species level (Larivière et al, 1992). However, two recent studies have demonstrated that several isolates from diverse origins that had been regarded atypical for these four phenotypic characters, they were all ascribed genetically to P. multocida by 16S rRNA gene sequencing and DNA-DNA hybridization (Christensen et al, 2004(Christensen et al, , 2005.…”

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

“…5 In particular, P. multocida isolates can be very heterogeneous in their biochemical activity, appearing as variations in a single key character and making the unambiguous assignment of this organism on the species level quite problematic. 8 Moreover, discrimination between subspecies of P. multocida, namely P. multocida subsp. multocida, P. multocida subsp.…”

Pasteurella multocida detection by 5′ Taq nuclease assay: A new tool for use in diagnosing fowl cholera

“…Fowlpox virus was titrated on CK cells and the titre was calculated as 50% tissue culture infectious doses (TCID 50 ) per μl (Reed and Muench, 1938 Christensen et al (2005) proposed that this and similar isolates associated with large-cat bite wounds should be reclassified as a new taxon distinct from P. multocida. Should this taxon (taxon 45 of Bisgaard) be granted official standing in nomenclature, this organism's theoretical reactivity in the 5' Taq nuclease assay will have little bearing on the assay's usefulness as a diagnostic test for fowl cholera or P. multocida infections in production animals, as it would not be expected to occur in these animal species.…”