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Reclassification of equine isolates previously reported as Actinobacillus equuli, variants of A. equuli, Actinobacillus suis or Bisgaard taxon 11 and proposal of A. equuli subsp. equuli subsp. nov. and A. equuli subsp. haemolyticus subsp. nov.
Abstract: Members of Bisgaard taxon 11 have been isolated from horses. These bacteria are of importance in the veterinary clinic and also to the medical profession, since they may be isolated from infected wounds of humans bitten by horses. Six strains from different continents were identified as taxon 11, with 16S rRNA similarities between 98.0 and 99.7%. A single isolate that represented the so-called (+)L-arabinose-positive Actinobacillus equuli isolated from a diseased foal showed 99.9% 16S rRNA similarity to the type strain of A. equuli. DNA-DNA hybridizations showed that (+)L-arabinose-positive strains of A. equuli represent A. equuli sensu stricto. DNA-DNA hybridizations also showed that A. equuli and Bisgaard taxon 11 represent two genotypes. These genotypes differ with respect to disease pattern and epidemiology. For these reasons, two subspecies of A. equuli are proposed, Actinobacillus equuli subsp. equuli subsp. nov. (type strain NCTC 8529T = ATCC 19392T) and Actinobacillus equuli subsp. haemolyticus subsp. nov. (type strain F 154T = CCUG 19799T = NCTC 13195T).
Publication Date: 2002-10-04 PubMed ID: 12361259DOI: 10.1099/00207713-52-5-1569Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research presents the reclassification of certain horse bacterial strains previously defined under multiple classifications into two new subspecies of Actinobacillus equuli. This reclassification is based on genetic similarities and differences highlighted by the DNA-DNA hybridizations technique.
Background of the Bacteria of Interest
-
(li>The research focuses on bacteria that are members of Bisgaard taxon 11, originally isolated from horses
- These bacteria are relevant to both the veterinary field and human medicine, as they have been found in infected wounds in humans caused by horse bites
Initial Identification and Similarities
- Six strains from various parts of the world were identified as part of taxon 11
- These strains showed similarities between 98.0% and 99.7% in their 16S rRNA, a component of the ribosome critical for protein synthesis
- Another isolated strain, identified as an (+)L-arabinose-positive variant of Actinobacillus equuli, revealed a 99.9% 16S rRNA similarity to the type strain of A. equuli
Role of DNA-DNA hybridizations
- DNA-DNA hybridizations were performed to identify and compare the genetic material within the bacteria
- These tests showed that the (+)L-arabinose-positive variants of A. equuli represent A. equuli in its strict sense (sensu stricto)
- The same technique showed that A. equuli and Bisgaard taxon 11 represent two distinct genotypes differing in their epidemiology and disease patterns
New Subspecies Proposal
- The research proposes two new subspecies of A. equuli based on the above findings: Actinobacillus equuli subsp. equuli and Actinobacillus equuli subsp. haemolyticus
- The proposed reclassification would help to better delineate bacterial strain differences, improving their classification for clinical and veterinary research
Cite This Article
APA
Christensen H, Bisgaard M, Olsen JE.
(2002).
Reclassification of equine isolates previously reported as Actinobacillus equuli, variants of A. equuli, Actinobacillus suis or Bisgaard taxon 11 and proposal of A. equuli subsp. equuli subsp. nov. and A. equuli subsp. haemolyticus subsp. nov.
Int J Syst Evol Microbiol, 52(Pt 5), 1569-1576.
https://doi.org/10.1099/00207713-52-5-1569 Publication
Researcher Affiliations
MeSH Terms
- Actinobacillus / classification
- Actinobacillus / genetics
- Actinobacillus / isolation & purification
- Actinobacillus / metabolism
- Animals
- Base Composition
- DNA, Bacterial / chemistry
- DNA, Bacterial / genetics
- DNA, Ribosomal / genetics
- Horses / microbiology
- Humans
- Molecular Sequence Data
- Nucleic Acid Hybridization
- Phenotype
- Phylogeny
- RNA, Bacterial / genetics
- RNA, Ribosomal, 16S / genetics
- Terminology as Topic
Citations
This article has been cited 10 times.- Songsungthong W, Pornthanakasem W, Leartsakulpanich U, Srijuntongsiri G. In silico-derived Actinobacillus equuli-specific DNA markers and development of associated PCR assays. J Vet Diagn Invest 2026 Jan;38(1):59-65.
- Vereecke N, Vandekerckhove A, Theuns S, Haesebrouck F, Boyen F. Whole genome sequencing to study antimicrobial resistance and RTX virulence genes in equine Actinobacillus isolates. Vet Res 2023 Apr 5;54(1):33.
- Ishihara M, Yamazaki Y, Katsuda K, Ito H. Phenotypic and genotypic characterization of Actinobacillus suis sensu stricto isolated from a dairy calf. J Vet Med Sci 2022 May 1;84(5):624-627.
- Frey J. RTX Toxins of Animal Pathogens and Their Role as Antigens in Vaccines and Diagnostics. Toxins (Basel) 2019 Dec 10;11(12).
- Uchida-Fujii E, Niwa H, Kinoshita Y, Nukada T. Actinobacillus species isolated from Japanese Thoroughbred racehorses in the last two decades. J Vet Med Sci 2019 Sep 3;81(9):1234-1237.
- Huang BF, Kropinski AM, Bujold AR, MacInnes JI. Complete genome sequence of Actinobacillus equuli subspecies equuli ATCC 19392(T). Stand Genomic Sci 2015;10:32.
- Schröttner P, Schultz J, Rudolph W, Gunzer F, Thürmer A, Fitze G, Jacobs E. Actinobacillus equuli ssp. haemolyticus in a semi-occlusively treated horse bite wound in a 2-year-old girl. Ger Med Sci 2013;11:Doc14.
- St-Pierre B, de la Fuente G, O'Neill S, Wright AD, Al Jassim R. Analysis of stomach bacterial communities in Australian feral horses. Mol Biol Rep 2013 Jan;40(1):369-76.
- Thompson AB, Postey RC, Snider T, Pasma T. Actinobacillus equuli as a primary pathogen in breeding sows and piglets. Can Vet J 2010 Nov;51(11):1223-5.
- Kuhnert P, Korczak B, Falsen E, Straub R, Hoops A, Boerlin P, Frey J, Mutters R. Nicoletella semolina gen. nov., sp. nov., a new member of Pasteurellaceae isolated from horses with airway disease. J Clin Microbiol 2004 Dec;42(12):5542-8.
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