Production of Apx toxins by field strains of Actinobacillus pleuropneumoniae and Actinobacillus suis

Kamp, E. M.; Vermeulen, Thomas; Smits, M.A.; Haagsma, J

doi:10.1128/iai.62.9.4063-4065.1994

Cited by 49 publications

(24 citation statements)

References 17 publications

(12 reference statements)

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“…An earlier report that used monoclonal antibodies to detect toxin production reported that an Australian isolate of serovar 2, and one of serovar 9, produced only ApxII, meaning that the serovar 2 strain failed to produce detectable ApxIII and the serovar 9 strain failed to produce ApxI. 7 In addition, this earlier report 7 also found two serovar 7 strains (both from the Netherlands) that had a different profile, both producing both ApxII and ApxIII and not just the expected ApxII. When reviewing these past results, the available technologies to determine the serovar of an A. pleuropneumoniae isolate need to be considered.…”

Section: Discussionmentioning

confidence: 99%

Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs

Yee

Blackall

2018

Aust Veterinary J

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Objective To explore the diversity among isolates of the Actinobacillus pleuropneumoniae serovars most common in Australia (serovars 1, 5, 7 and 15) and to examine the Apx toxin profiles in selected representative isolates.Design A total of 250 isolates selected from different farms were examined for their genotypic profiles and a subset of 122 isolates for their toxin profiles.Methods The isolates of serovars 1, 5, 7 and 15 selected for this study came from different farms and different Australian states and were submitted for serotyping to the reference laboratory. The overall diversity of the strains was explored with the enterobacterial repetitive intergenic consensus (ERIC) PCR and the presence of the toxin genes was investigated with a toxin PCR assay.Results Some degree of variation was observed in the ERIC-PCR pattern within all four serovars, ranging from 38% to 61% genetic diversity. When looking at the toxin gene profile and, therefore, the predicted ability to produce the expected toxin pattern, one isolate each of serovars 1 (n = 20) and 7 (n = 47) and 17 isolates of serovar 15 (n = 40) showed variation to the expected gene profile. ConclusionThe variations in toxin gene patterns, as detected by PCR, found in this study could be related to significant changes in the gene sequence or total absence of the gene. Variation in toxin gene sequences has been observed in other countries. This variation in the toxin profile could also explain possible variation in pathogenicity observed in the field.Keywords Actinobacillus pleuropneumoniae; Apx toxin; apx genes; Australia; pigs Abbreviations ERIC, enterobacterial repetitive intergenic consensus; UV, ultraviolet A ctinobacillus pleuropneumoniae is the causative agent of porcine pleuropneumonia and the virulence of the organism is associated with the exotoxins ApxI, ApxII and ApxIII.

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Section: Discussionmentioning

confidence: 99%

Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs

Yee

Blackall

2018

Aust Veterinary J

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“…Molecular biological methods are used more and more frequently to replace classical serotyping tests. Correlation between serovars, virulence and toxin production of the A. pleuropneumoniae strains described several years ago (Kamp et al, 1994;Frey et al, 1995;Marsteller and Fenwick, 1999) contributes to serotyping by detecting toxin genes; however, strains with atypical toxin production can give misleading results (Rayamajhi et al, 2005;Gottschalk, 2015). Identification of genes involved in the biosynthesis of capsular polysaccharides Bossé et al, 2014;Marois-Crehan et al, 2014) and amplified fragment length polymorphism (AFLP) analysis (Kokotovic and Angen, 2007) can also be used for serotyping.…”

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Actinobacillus pleuropneumoniae serotypes in Hungary

Sárközi

Makrai

Fodor

2018

Acta Veterinaria Hungarica

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A total of 255 Actinobacillus pleuropneumoniae isolates were collected from 634 lung samples representing 70 swine herds in Hungary between January 2012 and June 2016. On the basis of the indirect haemagglutination test 77 independent strains were included in the evaluation after the elimination of duplicate or multiple serotypes from the same herd. In the case of 7 herds strains of two different serotypes were identified. Fourteen Hungarian A. pleuropneumoniae isolates from the culture collection of the Department of Microbiology and Infectious Diseases, isolated before 2012, were also included in the evaluation (one each from 12 herds and two each from two herds, where two serotypes occurred). Out of the altogether 91 A. pleuropneumoniae strains 72 strains belonged to biotype I and 19 strains could be allocated to biotype II. In Hungary, the most common serotypes were serotype 2 (39.5%), 13 (15.4%), 8 (8.8%) and 16 (8.8%), but serotypes 9 (5.5%), 11 (3.3%) and 12 (3.3%) were also isolated. Twelve strains (13.2%) were untypable.

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“…In the diagnostic laboratory, A. suis isolates may be identified on the basis of their hemolytic phenotype and their ability to grow on MacConkey agar; hydrolyze esculin; produce catalase, oxidase, and urease; and produce acid from arabinose, cellobiose, dextrose, lactose, melibiose, salicin, sucrose, and trehalose but not from mannitol or sorbitol (4,9,23,27,32). To date, no attempt has been made to serotype A. suis, and it is known that A. suis possesses some cross-reactive antigens including enterobacterial common antigen (6), outer membrane proteins (19), somatic antigens (29,31), and exotoxins (7,8,16).…”

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“…Little is known about the pathogenesis of A. suis, although it is thought to share many of the virulence factors of Actinobacillus pleuropneumoniae and other gram-negative organisms such as capsule (slime) and lipopolysaccharide (23,36). There are several lines of evidence that A. suis also carries RTX (repeats in toxin) toxins that are related to the Apx toxins of A. pleuropneumoniae (7,8,16). RTX toxins are pore-forming protein exotoxins with hemolytic and/or cytotoxic activity, sonamed because of the presence of characteristic glycine-rich repeats (25,39).…”

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Actinobacillus suis strains isolated from healthy and diseased swine are clonal and carry apxICABDvar. suis and apxIICAvar. suis toxin genes

et al. 1997

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Actinobacillus suis isolates recovered from both healthy and diseased pigs were characterized by biochemical testing, serotyping, restriction endonuclease fingerprinting, and apx toxin gene typing. The clinical isolates analyzed were collected over a 10-year period from approximately 40 different locations in southwestern Ontario, Canada. Little variation in the biochemical profiles of these isolates was seen, and all isolates reacted strongly with rabbit antisera prepared against one of the strains. Similarly, by using BamHI and BglII for restriction endonuclease fingerprinting (REF) analysis, all isolates were found to belong to a single REF group. Minor variations could be detected, especially in the BglII fingerprints, but overall the patterns were remarkably similar. Sequences that could be amplified by PCR with primers to the apxICA and apxIICA genes of Actinobacillus pleuropneumoniae were detected in all strains. Although no amplification was obtained with primers to the A. pleuropneumoniae apxIBD genes, sequences with homology to apxIBD were detected by hybridization. There was no evidence of apxIII homologs. Taken together, these data suggest that A. suis isolates are genotypically and phenotypically very similar, regardless of their source, and that they contain genes similar to, but not identical to, the apxICABD and apxIICA genes of A. pleuropneumoniae.

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Production of Apx toxins by field strains of Actinobacillus pleuropneumoniae and Actinobacillus suis

Cited by 49 publications

References 17 publications

Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs

Genetic diversity and toxin gene distribution among serovars of Actinobacillus pleuropneumoniae from Australian pigs

Actinobacillus pleuropneumoniae serotypes in Hungary

Actinobacillus suis strains isolated from healthy and diseased swine are clonal and carry apxICABDvar. suis and apxIICAvar. suis toxin genes

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