The CAMP effect of Actinobacillus pleuropneumoniae is caused by Apx toxins

Jansen, R

doi:10.1016/0378-1097(94)00541-x

Cited by 5 publications

(5 citation statements)

References 6 publications

(15 reference statements)

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“…RTX toxins (ApxI, ApxII, and ApxIII) in A. pleuropneumoniae are responsible for its hemolytic activity and CAMP positivity [ 28 , 29 ]. Orthologs for the apxIICA genes were identified in all strains but not in A. minor NM305 T .…”

Section: Resultsmentioning

confidence: 99%

Comparative Genomics of the First and Complete Genome of “Actinobacillus porcitonsillarum” Supports the Novel Species Hypothesis

Donà

Perreten

2018

International Journal of Genomics

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“Actinobacillus porcitonsillarum” is considered a nonpathogenic member of the Pasteurellaceae family, which phenotypically resembles the pathogen Actinobacillus pleuropneumoniae. Previous studies suggested that “A. porcitonsillarum” may represent a new species closely related to Actinobacillus minor, yet no full genome has been sequenced so far. We implemented the Oxford Nanopore and Illumina sequencing technologies to obtain the highly accurate and complete genome sequence of the “A. porcitonsillarum” strain 9953L55. After validating our de novo assembly strategy by comparing the A. pleuropneumoniae S4074T genome sequence obtained by Oxford Nanopore Technology combined with Illumina reads with a PacBio-sequenced S4074T genome from the NCBI database, we performed comparative analyses of the 9953L55 genome with the A. minor type strain NM305T, A. minor strain 202, and A. pleuropneumoniae S4074T. The 2,263,191 bp circular genome of 9953L55 consisted of 2168 and 2033 predicted genes and proteins, respectively. The lipopolysaccharide cluster resembled the genetic organization of A. pleuropneumoniae serotypes 1, 9, and 11, possibly explaining the positive reactions observed previously in serotyping tests. In contrast to NM305T, we confirmed the presence of a complete apxIICABD operon in 9953L55 and 202 accounting for their hemolytic phenotype and Christie-Atkins-Munch-Petersen (CAMP) reaction positivity. Orthologous gene cluster analysis provided insight into the differential ability of strains of the A. minor/“porcitonsillarum” complex and A. pleuropneumoniae to ferment lactose, raffinose, trehalose, and mannitol. The four strains showed distinct and shared transposable elements, CRISPR/Cas systems, and integrated prophages. Genome comparisons based on average nucleotide identity and in silico DNA-DNA hybridization confirmed the close relationship among strains belonging to the A. minor/“porcitonsillarum” complex compared to other Actinobacillus spp., but also suggested that 9953L55 and 202 belong to the same novel species closely related to A. minor, namely, “A. porcitonsillarum.” Recognition of the taxon as a separate species would improve diagnostics and control strategies of pig pleuropneumonia.

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Section: Resultsmentioning

confidence: 99%

Comparative Genomics of the First and Complete Genome of “Actinobacillus porcitonsillarum” Supports the Novel Species Hypothesis

Donà

Perreten

2018

International Journal of Genomics

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“…Since paxA-containing P. aerogenes did not show direct hemolytic activity on sheep and swine erythrocytes, we performed the CAMP test (9) for cohemolytic activity of this new RTX protein. Cohemolytic activity is known to be associated with Apx toxins, including ApxIIIA (19,22). For this purpose all P. aerogenes strains were grown in the vicinity of a beta-hemolytic S. aureus.…”

Section: Identification Of P Aerogenes By Sequence Analysis Of the 1mentioning

confidence: 99%

Characterization of PaxA and Its Operon: a Cohemolytic RTX Toxin Determinant from Pathogenic Pasteurella aerogenes

et al. 2000

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Pasteurella aerogenes is known as a commensal bacterium or as an opportunistic pathogen, as well as a primary pathogen found to be involved in abortion cases of humans, swine, and other mammals. Using broadrange DNA probes for bacterial RTX toxin genes, we cloned and subsequently sequenced a new operon named paxCABD encoding the RTX toxin PaxA in P. aerogenes. The pax operon is organized analogous to the classical RTX operons containing the activator gene paxC upstream of the structural toxin gene paxA, which is followed by the secretion protein genes paxB and paxD. The highest sequence similarity of paxA with known RTX toxin genes is found with apxIIIA (82%). PaxA is structurally similar to ApxIIIA and also shows functional analogy to ApxIIIA, since it shows cohemolytic activity with the sphingomyelinase of Staphylococcus aureus, known as the CAMP effect, but is devoid of direct hemolytic activity. In addition, it shows to some extent immunological cross-reactions with ApxIIIA. P. aerogenes isolated from various specimens showed that the pax operon was present in about one-third of the strains. All of the pax-positive strains were specifically related to swine abortion cases or septicemia of newborn piglets. These strains were also shown to produce the PaxA toxin as determined by the CAMP phenomenon, whereas none of the pax-negative strains did. This indicated that the PaxA toxin is involved in the pathogenic potential of P. aerogenes. The examined P. aerogenes isolates were phylogenetically analyzed by 16S rRNA gene (rrs) sequencing in order to confirm their species. Only a small heterogeneity (<0.5%) was observed between the rrs genes of the strains originating from geographically distant farms and isolated at different times.The gram-negative bacterium Pasteurella aerogenes was first isolated from porcine intestine and described as a gas-producing Pasteurella-like organism (30). Reported cases of isolation in animals have included the buccal flora of wild boars (33), the urine of rabbit, or the uterine cervix discharge of cow (3). In humans P. aerogenes has been isolated from lesions caused by cats, pigs, or wild boar (27,30,32).Clinically, the isolation of P. aerogenes is mainly associated with abortion cases. The first case described in which P. aerogenes was directly involved as a pathogen was an abortion in swine, where it was isolated from several organs of the aborted fetuses (30). At least two additional cases of P. aerogenesinduced abortion in swine have been reported (13, 21). Abortion cases, where P. aerogenes could be responsible, were also reported in other mammals. It was isolated in pure culture from the uterus and peritoneal cavity of a rabbit which died 4 days after abortion (34). Also a human case is described where P. aerogenes could be isolated from a stillborn child and from its mother's vaginal vault (P. Thorsen, B. R. Moller, M. Arpi, A. Bremmelgaard, and W. Fredericksen, Letter, Lancet 343: [485][486] 1994). During pregnancy, the mother had been working as an assistant on a pig farm. O...

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“…The cohemolysis observed with other species is due to substances different from protein B. The CAMP reaction-like reaction of Listeria monocytogenes is caused by listeriolysin O (26), and that of Actinobacillus pleuropneumoniae is caused by an RTX toxin (17).…”

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confidence: 99%

Method for Quantitative Detection and Presumptive Identification of Group B Streptococci on Primary Plating

Hansen

Sørensen

2003

J Clin Microbiol

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Maternal prenatal screening for group B streptococci (GBS) followed by offering of intrapartum chemoprophylaxis to carriers is one of the strategies used to reduce the incidence of neonatal early-onset GBS infections. Culturing of vaginal and anorectal swab specimens in selective broth is the screening procedure recommended by the Centers for Disease Control and Prevention. This technique is sensitive; it does not, however, allow either evaluation of the degree of colonization or detection of cocolonization with several GBS clones. We have examined the carriage rate and population dynamics of GBS in a group of Danish women during pregnancy and 1 year after delivery using a new detection method. In the present paper we describe a mixed blood agar medium (MB agar) that identifies GBS in the primary cultures by detection of a double hemolysis pattern consisting of characteristic, large zones of partial hemolysis ("CAMP zones") and of narrow zones of complete hemolysis. The MB agar was at least as sensitive as culturing in selective broth for detection of GBS in vaginal and anorectal swab specimens, and GBS strains could be identified directly on the primary plate due to the CAMP zones without the need for subculturing. The carriage rate of GBS in a group of Danish women was found to be more than 30%, a figure considerably higher than the rate that was reported previously.

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The CAMP effect of Actinobacillus pleuropneumoniae is caused by Apx toxins

Cited by 5 publications

References 6 publications

Comparative Genomics of the First and Complete Genome of “Actinobacillus porcitonsillarum” Supports the Novel Species Hypothesis

Comparative Genomics of the First and Complete Genome of “Actinobacillus porcitonsillarum” Supports the Novel Species Hypothesis

Characterization of PaxA and Its Operon: a Cohemolytic RTX Toxin Determinant from Pathogenic Pasteurella aerogenes

Method for Quantitative Detection and Presumptive Identification of Group B Streptococci on Primary Plating

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