The Adh adhesin domain is required for trimeric autotransporter Apa1-mediated Actinobacillus pleuropneumoniae adhesion, autoaggregation, biofilm formation and pathogenicity.

Actinobacillus pleuropneumoniae is a causative agent of porcine pleuropneumonia, which is a highly contagious endemic disease of pigs. Adhesion is a critical first step in the infection process. Trimeric autotransporter adhesions (TAAs) have been identified as novel virulence factors; however, little is known on their roles in A. pleuropneumoniae pathogenicity. Here, our data show that YadA-like head region (Adh) of Apa1 was the optimal adhesion functional domain via segment expression and adhesion assays in vitro. Additionally, Adh induced partial protection against A. pleuropneumoniae 5b L20 and serotypes 1, 3, and 5a in mice. The deletion of Adh gene significantly decreased autoaggregation, biofilm formation and adherence to host cells in vitro. Furthermore, with delaying of clinical symptoms, reducing production of pro-inflammatory cytokines and lessening the lung injury after infection, Adh deletion strain (5bϕAdh) significantly reduced the pathogenicity to piglets. To elucidate the mechanism of lung injury, the differentially expressed genes in the lung tissues of piglets infected with the 5b L20 or 5bϕAdh strains were investigated using microarray analysis and validated by qRT-PCR. Compared with the 5b L20 infected piglets, 495 genes were differentially expressed in 5bϕAdh infected lung tissue (221 upregulated and 274 downregulated). Especially, the antigen processing and presentation gene IFI30 was increased following infection with the 5bϕAdh strain. Thus, Adh may enhance pathogenicity by depressing host immune recognition. We conclude that the head domain of the A. pleuropneumoniae trimeric autotransporter Apa1 regulates autoagglutination, biofilm formation, adhesion to host cells and pathogenicity.

Pathophysiologic correlates of acute porcine pleuropneumonia.

OBJECTIVE: To develop and evaluate an in vivo model to study early events in the pathogenesis of acute porcine pleuropneumonia. ANIMALS: Thirty-six 6- to 8-week-old pigs. PROCEDURE: Pigs were inoculated intranasally or endotracheally with Actinobacillus pleuropneumoniae; inoculation routes were compared by evaluation of clinical signs, gross and microscopic lung lesions, hematologic changes, serum zinc, iron, and haptoglobin concentrations, and inflammatory cytokines. RESULTS: The 2 inoculation routes resulted in similar findings, although intranasal inoculation caused unilateral gross lung lesions, whereas endotracheal inoculation caused bilateral gross lesions. Clinical signs of disease were observed < 2 hours after endotracheal inoculation and 6 to 8 hours after intranasal inoculation. Total WBC counts did not differ significantly after inoculation by either inoculation route, although band neutrophils increased significantly. The earliest findings associated with A pleuropneumoniae inoculation, irrespective of route, were decreased serum zinc and iron concentrations. Serum haptoglobin concentrations were significantly increased after inoculation. Inoculation induced rapid influx of macrophages into the lung and local induction of proinflammatory cytokines. Northern blot analysis of total RNA from lung tissue indicated that inoculated pigs had increased concentrations of interleukin (IL)-1beta, IL-1alpha, and IL-8; tumor necrosis factor messenger RNA concentration was not increased. CONCLUSIONS: Endotracheal inoculation with A pleuropneumoniae rapidly and consistently induced diffuse bilateral pneumonia; thus, this method may be useful for the study of acute pathophysiologic changes associated with bacterial pneumonia and may provide an experimental model for testing modalities for prevention and treatment of this and other respiratory tract diseases of pigs.

[Clinical and laboratory diagnostic findings in chronic pleuropneumonia of swine]. / Klinische und labordiagnostische Befunde bei der chronischen Pleuropneumonie des Schweines.

In the course of an experimental study 12 pigs were infected intrabronchially with the pathogen of infectious porcine pleuropneumonia, Actinobacillus pleuropneumoniae. All animals survived the acute stage of infection due to the application of subtherapeutic doses of antibiotics. After infection all of the animals showed clinical signs of acute pneumonia with an elevation of body temperature to about 41 degrees C. Bronchoalveolar lavage fluid (BALF) was taken every week endoscopically. An increase of neutrophil granulocytes could be observed at day 7 and 14 after infection. In parallel, a clear granulocytosis and a shift to the left of the nuclei was observed at day 7. Comparing the methods for detection of Actinobacillus pleuropneumoniae serological assays like the complement-fixation assay (CFA) and enzyme-linked immunosorbent assay (ELISA) as well as immunofluorescence in lung tissue and BALF were more sensitive than cultural isolation from lung tissue, tonsils and BALF.

Prognosis for return to racing after recovery from infectious pleuropneumonia in thoroughbred racehorses: 70 cases (1984-1989).

OBJECTIVE: To determine the percentage of Thoroughbred racehorses that would be capable of racing performance after recovery from infectious pleuropneumonia. DESIGN: Retrospective case series. ANIMALS: 70 Thoroughbred horses that had recovered from pleuropneumonia. Only horses < or = 5 years old and horses > 5 years old known to be in race training at the time of illness were included in the study. RESULTS: Forty-three of the 70 (61%) horses raced after recovery, and 24 of the 43 (56%) won at least 1 race. Horses that required placement of an indwelling thoracic drain apparently did not have a worse prognosis than did horses that did not require placement of a drain. The prognosis for racing for horses that developed pleuropneumonia-associated complications (pulmonary abscess, cranial thoracic mass, bronchopleural fistula) was worse than the prognosis for horses that did not develop these complications. Duration of hospitalization was not considered indicative of outcome. CLINICAL IMPLICATIONS: In Thoroughbreds, the prognosis for return to racing after recovery from uncomplicated pleuropneumonia appears to be good.

[Treatment of parapneumonic empyema in children]. / Trattamento dell'empiema parapneumonico in età pediatrica.

A 31 case series of pleuropneumonia is presented, in a 7 year period. All patients were treated following same standards consisting of a pleural catheter insertion. Results support conservative treatment: short hospitalization and absence of psychological or physical traumas was achieved. Follow up is very good for all patients and none had invalidating consequences.

La toracoplastia / Thoracoplasty

La toracoplastia disenada por Sehede, es la reseccion parcial o total de la pared toracica, usada para el tratamiento de secuelas de tuberculosis pleuropulmonar, reduccion de cavidades residuales, o exceresis de neoplasias de pulmon con invasion a pared o tumores de pared toracica. Las indicaciones pueden ser pulmonares, pleurales o en cavidades residuales postoperatorias. En nuestra casuistica, fueron sometidos a toracoplastia 5 pacientes de sexo masculino por secuelas sangrantes de tuberculosis pulmonar y supurativas pleurales; se hizo reseccion entre 3 o 4 costillas. Los resultados fueron satisfactorios en tres pacientes y fracasaron en dos. Esto nos hace ver que a pesar de lo antiguo del procedimiento en la actualidad aun podemos contar con el para los casos de secuelas bacilares sin condiciones de reseccion pulmonar.

[Bronchial hyperreactivity to physiological saline solution]. / Bronchiale Hyperreaktivität auf physiologische Kochsalzlösung.

A case of a 10-year old boy suffering from asthma bronchiale following pleuropneumonia is reported. Paradoxically, bronchospasmolysis tests using physiological saline + salbutamol or ipratropium bromide impaired the lung function of this patient. Salt solutions inhaled in increasing doses until 1.4% generated severe bronchoconstriction, however, inhalation of DNCG + salbutamol normalized the lung function completely.

The influence of disease on feed and water consumption and on pharmacokinetics of orally administered oxytetracycline in pigs.

In the present study the feed and water consumption and pharmacokinetic parameters of orally administered oxytetracycline were compared in clinically healthy pigs and in the same pigs following a challenge with Actinobacillus (Haemophilus) pleuropneumoniae toxins. Endobronchial challenge with A. pleuropneumniae toxins was accompanied by anorexia, increased lassitude, labored breathing, fever, and increased white blood cell counts. Pleuropneumonia was evident in all pigs on autopsy. Following the challenge, both feed and water consumption were markedly reduced. In contrast to recommendations in the literature, it is concluded that drugs should not be administered to pneumonic pigs via water. In healthy pigs the oral bioavailability of oxytetracycline (50 mg/kg), given on an empty stomach, was 4.8% and the elimination half-life (t1/2 beta) was 5.92 h. After challenge, the pigs showed great variation in oxytetracycline plasma concentrations. In addition, the mean computed elimination rate constant (beta), t1/2 beta, the area under the plasma concentration-time curve (AUC), and clearance in pneumonic pigs differed significantly (P less than .05) from the values found in healthy pigs. The elimination half-life (t1/2 beta), AUC, and volume of distribution (Vd area) were increased. In diseased pigs the mean of maximum plasma concentrations (.87 micrograms/ml) was reached after 7 h, in contrast to 1.74 h (1.87 micrograms/ml) in the healthy pigs.