Actinobacillus pleuropneumoniae

The Actinobacillus pleuropneumoniae sequencing project is a collaboration between Drs. David Dyer, Ph.D., and Allison Gillaspy, Ph.D., of the Laboratory for Genomics and Bioinformatics, and Dr. Bradley Fenwick, D.V.M., Ph.D., of the College of Veterinary Medicine at Kansas State University. These studies are supported by USDA/CSREES grant #2001-02213.

 

 Data access

Download contigs from the latest Actinobacillus pleuropneumoniae assembly

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Download the stats from the latest Actinobacillus pleuropneumoniae assembly

Use Sequal to view the Phrap quality scores from each contig in this project in both graphical and color-coded forms.

 

 Description

Actinobacillus pleuropneumoniae (Ap) was first identified as a causative agent of swine pleuropneumonia in 1963 (1). The organism recently has been shown in one study to be the most common cause of primary bacterial pneumonia in swine (20% of cases); of these, 30% were uncomplicated by other pathogens (2). In another study, 41% of outbreaks were associated with Ap infection (3). The pattern of clinical disease seen in these infections ranges from nearly undetectable subclinical disease to acute bronchopneumonia with rapid focal vascular necrosis, localized thrombosis, edema, ischemic necrosis and fibrinous pleuritis (4). These latter infections can be fulminant and rapidly fatal. Disease in herds can be ameliorated to some extent by husbandry practices. For instance, since Ap may colonize the neonatal pig's respiratory tract while nursing an infected sow, early weaning prior to colonization can prevent sow-to-piglet transmission (1). However, vaccines have been less than satisfactory in controlling the infection, with its attendant adverse affects on weight gain and feed conversion (5,6). This is in part due to the fact that the organism has 12 major immunological serotypes and several serotypic variants, revealing a significant antigenic heterogeneity that complicates vaccine development. In the US, serotypes 1, 5 and 7 predominate (1). Of these, serotype 1 strains appear to be the most virulent, while serotype 7 strains are of lowest virulence. In this project, we will completely sequence the genome of Ap serotype 1 strain 4074, the type strain for serotype 1 organisms, and widely used for studies on the virulence of this organism.

 

 Literature cited

  1. Marsteller, T. A., and B. Fenwick. 1999. Actinobacillus pleuropneumoniae disease and serology. Swine Health and Production. 4:161-165.
  2. Hoefling, D. C. 1998. Tracking the incidence of porcine respiratory diseases. Food-Animal Practice. April:391-398.
  3. Loeffen, W. L., E. M. Kamp, N. Stockhofe-Zurwieden, A. P. van Nieuwstadt, J. H. Bongers, W. A. Hunneman, A. R. Elbers, J. Baars, T. Nell, and F. G. van Zijderveld. 1999. Survey of infectious agents involved in acute respiratory disease in finishing pigs. Vet Rec. 145(5):123-9.
  4. Fenwick, B., and S. Henry. 1994. Porcine pleuropneumonia. Journal of the American Veterinary Medical Association. 204(9):1334-1340.
  5. Wongnarkpet, S., R. S. Morris, and D. U. Pfeiffer. 1999. Field efficacy of a combined use of Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae vaccines in growing pigs. Prev Vet Med. 39(1):13-24.
  6. Wongnarkpet, S., D. U. Pfeiffer, R. S. Morris, and S. G. Fenwick. 1999. An on-farm study of the epidemiology of Actinobacillus pleuropneumoniae infection in pigs as part of a vaccine efficacy trial. Prev Vet Med. 39(1):1-11

 

 Figure 1

Figure 1. Histophomicrograph of the lung from a pig that died of Actinobacillus pneumoniae caused pneumonia which is characterized by necrosis, hemorrhage, and the accumulation of large number of neutrophils.

 

 Figure 2

Figure 2. Immuno-gold electron photomicrograph of A. pleuropneumoniae. A. pleuropneumoniae is an encapsulated gram-negative coccobacilli that in some culture conditions can have a pleomorphic phenotype and express pili.

 

 Figure 3

Figure 3. Classic lung lesions caused by Actinobacillus pleuropneumoniae. Focal areas of necrotizing pneumonia isolated in the dorsal and caudal portions of the lungs is a diagnostic feature. The entire lung lobe can also be involved. In both cases, the fibrinous pleuritis is common.

 

 Figure 4

Figure 4. Actinobacillus pleuropneumoniae cross streaked with a feeder colony of Beta-hemolytic staphylococcus demonstrating a CAMP reaction, hemolytic activity, and dependence on NAD (V-factor) for growth.

 

 Figure 5

Figure 5. Pig in severe respiratory distress associated with acute pneumonia caused by Actinobacillus pneumoniae.

 

 Figure 6

Figure 6. Cross section of the lung of a pig in the early stages of infection with Actinobacillus pneumoniae showing large areas of vascular congestion, edema, and hemorrhage.