• Korean Journal of Veterinary Research
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• v.36 no.1
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• pp.131-142
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• 1996

The effect of relative humidity in swine house on swin pleuropneumonia was examined in piglets experimentally infected with Actinobacillus pleuropneumoniae serotype 5. A total of 20 piglet were grown under 30~40%, 41~50%, 51~64% and 65~80% relative humidity chambers after intratracheal inoculation of A pleuropneumoniae. Characteristic fibrinous pleuropneumonia was observed in the pigs grown at the low relative humidity groups. The detailed results were as follows : 1. Growth performance and environment conditions were lower than high relative humidity groups. 2. Characteristic histopathological findings were fibrinous pleuritis and pneumonia accompanied congestion, hemorrhage, thrombosis and edematous change. 3. Antigenic distribution of inoculated bacterium was found mainly in alveolar macrophages or accumulated foci of macrophages adjacent to necrotic area. 4. Characteristic electron microscopic findings were proliferation of type II pneumocyte with increased lamella bodies and activated alveolar macrophages with pseudopods and widening of interstitium.

• Journal of Veterinary Clinics
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• v.14 no.1
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• pp.37-41
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• 1997

For the inspection of the occurrence situation of porcine pleuropneumonia and serotyping of Actinobacillus pleuropneumoniae strains isolated from lung lesions of pig in Korea, a series of experimentation have been carried out by the isolation and identification of A pleuropneumoniae, serotyping by coagglutination test, observation of lung lesion and clinical signs from 360 cases of porcine pneumonia in Clinical Pathology Laboratory, Bayer Veterinary Medical Research Institute. The results could be summarized as follows. The reaction of coagglutination between the reference antigens and the specific reagents of A pleuropneumoniae was strongly agglutinatied within 30 seconds without cross reaction. The 89 strains of A pleuropneumoniae were isolated from 360 cases of porcine pleuropneumonis and the biochemical properties of the isolates were same as the reference strains. The 89 isolated strains could be serotyped 39 strains as setotype 5, 34 strains as serotype 2, 8 strains as serotype 3, 2 strains as serotype 7 by coagglutination test, respectively. The clinical signs of pleuropneumonia were weakness, fever, anorexia, dyspnea and laboured breath in the later stages. The gross lesions of lung were haemorrhages, enlargement of interlobular septa, nodular formation and adhesion of the pleura.

• Korean Journal of Veterinary Service
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• v.44 no.2
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• pp.103-111
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• 2021

Actinobacillus (A.) pleuropneumoniae is the etiological agent of a porcine pleuropneumonia and have great economic importance to the global swine industry. For recent 5 years, a total of 50 pleuropneumonia cases of 24 pig farms were selected from pig lungs submitted to the College of Veterinary Medicine, Jeju National University using polymerase chain reaction (PCR) analysis. Collected lungs were fixed in 10% neutral phosphate-buffered formalin and processed for histological examination. Serotypes of A. pleuropneumoniae in pneumonic lesions were analyzed by PCR methods. And the antimicrobial susceptibility of A. pleuropneumoniae isolates was determined by a disc diffusion test. Grossly, unilateral distribution of hemorrhagic or necrotic pneumonic lesions was more common than bilateral distribution in lungs. In peracute or acute cases, histopathologic changes were characterized by necrosis, hemorrhage, neutrophils infiltration, vascular thrombosis, widespread edema and fibrinous exudates. Following the acute response, macrophage infiltration, marked fibrosis around zonal necrotic areas, and marked fibrous pleuritis were characteristic in chronic cases. A total of 50 pleuropneumonia were associated with A. pleuropneumoniae serotype 5 in 46 cases (92%), serotype 2 in 3 cases (6%), and both 2 and 5 in 1 case (2%). More than 90% of collected isolates showed high sensitivity to ceftiofur, amoxicillin, and colistin. However, ampicillin, penicillin, and tylosin showed low susceptibility. The results of this study demonstrated that A. pleuropneumoniae serotype 5 was predominant at porcine pleuropneumonia cases in Jeju.

• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2005.11a
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• pp.47.1-48
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• 2005

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.1102-1105
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• 2001

In order to find therapeutic agents for porcine pneumonia, we screened far antibacterial activities of methanol extracts of 81 higher plants against four pathogenic microorganisms of Heamophilus parasuis, Pasteurella multocida, Actinobacillus pleuropneumonia, and Bordetella bronchiseptica, and found the bark of Cinnamomi cortex showed potent activities. Since this was inexpensive, we purified active compounds from it. The structures of the final active fractions were obtained through an activity-guided fractionation and their antibacterial activities are reported here.

• Journal of Microbiology and Biotechnology
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• v.25 no.10
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• pp.1606-1613
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• 2015

Porcine pleuropneumonia is an infectious disease caused by Actinobacillus pleuropneumoniae. The identification of A. pleuropneumoniae genes, specially expressed in vivo, is a useful tool to reveal the mechanism of infection. IVIAT was used in this work to identify antigens expressed in vivo during A. pleuropneumoniae infection, using sera from individuals with chronic porcine pleuropneumonia. Sequencing of DNA inserts from positive clones showed 11 open reading frames with high homology to A. pleuropneumoniae genes. Based on sequence analysis, proteins encoded by these genes were involved in metabolism, replication, transcription regulation, and signal transduction. Moreover, three function-unknown proteins were also indentified in this work. Expression analysis using quantitative real-time PCR showed that most of the genes tested were up-regulated in vivo relative to their expression levels in vitro. IVI (in vivo-induced) genes that were amplified by PCR in different A. pleuropneumoniae strains showed that these genes could be detected in almost all of the strains. It is demonstrated that the identified IVI antigen may have important roles in the infection of A. pleuropneumoniae.

• Korean Journal of Veterinary Research
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• v.52 no.3
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• pp.177-181
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• 2012

Actinobacillus (A.) pleuropneumoniae is the causative agent of pleuropneumonia which is one of the most important respiratory diseases in pigs worldwide. A total of 32 A. pleuropneumoniae isolates from diseased pigs during 2008 to 2010 were serotyped by polymerase chain reaction method. The susceptibility of the isolates to 13 antimicrobial agents were determined by disk diffusion test. In all the 32 isolates examined in this study, serotype 5 (16 isolates: 50%), 1 (7 isolates: 21.9%), 2 (5 isolates: 15.6%) and 12 (1 isolate: 3.1%) were found. Of all tested antimicrobial agents, resistance to oxytetracycline was found in 96.9% of isolates, followed by resistance to amikacin (81.2%), neomycin (68.7%), kanamycin (53.1%), penicillin (50.0%), gentamicin (43.7%), florfenicol (25.0%), ampicillin (18.7%), colistin (9.4%), trimethoprim/sulfamethoxazole, ceftiofur (8.3%), amoxicillin/clavulanic acid (3.1%) and enrofloxacin (0%). Oxytetracycline or florfenicol-resistant isolates were examined for the presence of resistance gene. Among the 31 oxytetracycline-resistant isolates, tetB, tetH and tetO genes were detected in 22 (71%), 8 (26%) and 1 (3%) isolates, respectively. The floR genes were detected in 8 (100%) of the 8 florfenicol-resistant A. pleuropneumoniae isolates.

• Korean Journal of Veterinary Service
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• v.23 no.3
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• pp.255-262
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• 2000

A survey on pneumonic lungs and its histopathological changes of the slaughtered pigs from the southern area of Chungbuk province was carried out during the period from January to December 1999. Pneumonic lungs were attempted bactenological findings and antibiotic susceptibilities. The results obtained were as follows; 1. Of 158 slaughtered pigs, 97(61.4%) pigs had pneumonic lesions in the lung, and the prevalence was high in winter, spring, autumn, and summer in order. f. The bacteria isolated from pneumonic lesions were pasteurella spp, 13 heads(34.2%), streptococcus spp, 6(IS.8%), actinobacillus spp, 3(7.9%), coliform 4(10.5%) and the other bacteria, 12(31.6%). 3. These isolates were highly susceptible to the antibiotics of enrofloxacin 30(78.9%), cephalothin 23(73.6%) and ceftiofur 27(71 %). 4. Histopathologically, swine enzootic pneumonia and pleuropneumonia lesions were observed. The swine enzootic pneumonia lesions were consisted of peribronchiolar lymphoid hyperplasia and exudate in alveolar lumen. The pleuropneumonia lesions were consisted of thrombosis, alveolar wall thickened by mononuclear cells and neutrophil deposition.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1037-1043
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• 2020

Actinobacillus pleuropneumoniae (APP) is a causative agent of porcine pleuropneumonia. Therefore, the development of an effective vaccine for APP is necessary. Here, we optimized the culture medium and conditions to enhance the production yields of Apx toxins in APP serotype 1, 2, and 5 cultures. The use of Mycoplasma Broth Base (PPLO) medium improved both the quantity and quality of the harvested Apx toxins compared with Columbia Broth medium. Calcium chloride (CaCl₂) was first demonstrated as a stimulation factor for the production of Apx toxins in APP serotype 2 cultures. Cultivation of APP serotype 2 in PPLO medium supplemented with 10 ㎍/ml of nicotinamide adenine dinucleotide (NAD) and 20 mM CaCl₂ yielded the highest levels of Apx toxins. These findings suggest that the optimization of the culture medium and conditions increases the concentration of Apx toxins in the supernatants of APP serotype 1, 2, and 5 cultures and may be applied for the development of vaccines against APP infection.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.185-189
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• 2005

Actinobacillus pleuropneumoniae is the causative agent of a porcine contagious pleuropneumonia. Among several virulence factors including exotoxin (Apx toxins), LPS, transferrin-binding proteins, OMPs, and some proteases, Apx toxins have been major targets for the protection study. In this study, cloning and expression of A. pleuropneumoniae Apx I and Apx II toxin, which are produced by all highly virulent strains, were performed by Escherichia coli expression system. Genes coding Apx I and II toxin were amplified from the A. pleuropneumoniae serotype 5 genomic DNA using polymerase chain reaction and cloned to a prokaryotic expression vector, pRSET. Expression of the Apx I and Apx II coding sequences in E. coli resulted in the formation of insoluble inclusion bodies purified according to a denaturing purification protocol, which employs the use of guanidium. Recombinant proteins were purified using $Ni^{2+}$-charged resin affinity purification. This expression and purification system made it possible to produce Apx I and Apx II in large amounts for further immunologic studies.