AN ABATTOIR SURVEY OF PNEUMONIA AND PLEURITIS IN SLAUGHTER WEIGHT SWINE FROM 9 SELECTED HERDS .4. BACTERIOLOGICAL FINDINGS IN CHRONIC PNEUMONIC LESIONS
S. Hoie et al., AN ABATTOIR SURVEY OF PNEUMONIA AND PLEURITIS IN SLAUGHTER WEIGHT SWINE FROM 9 SELECTED HERDS .4. BACTERIOLOGICAL FINDINGS IN CHRONIC PNEUMONIC LESIONS, Acta veterinaria Scandinavica, 32(3), 1991, pp. 395-402
A total of 855 pig lungs were collected at slaughter and evaluated mac
roscopically. Bacteriological examinations were carried out on tissue
samples from chronic pleuropneumonic lesions (n = 196) and from chroni
c bronchopneumonic lesions with suppuration (n = 14). Samples from nor
mal lung tissue (n = 22) were also included. Pasteurella multocida was
isolated from 54%, Actinobacillus (Haemophilus) pleuropneumoniae from
11%, and Streptococcus spp. from 14% of the pneumonic lesions, respec
tively. From normal lung tissue P. multocida was isolated from 3 (14%)
of the samples, A. pleuropneumoniae was not recovered and streptococc
i were isolated from only 1 (5%) of these samples. The above mentioned
bacterial species were recovered either in pure cultures or mixed wit
h various other microbes. A total of 109 P. multocida strains were fur
ther characterized by capsular serotyping and testing for production o
f dermonecrotic toxin. Ninety-nine (91%) of the strains were capsular
type A 10 (9%) were type D. Out of the type A and the type D strains 9
4% and 90% were toxigenic, respectively. Most of the A. pleuropneumoni
ae strains were serotype 2. Strains of serotypes 1 and 7 were also ide
ntified. The majority of the streptococci were identified as either St
reptococcus suis or Streptococcus dysgalactiae. Actinomyces pyogenes w
as isolated from 14% of the lesions and anaerobic bacteria from 18%, r
espectively. The significance of the various bacterial species in rela
tion to the development of chronic pneumonic lesions is discussed. Spe
cial attention is paid to P. multocida, and it is concluded that this
bacterial species is probably of importance for the development of bot
h types of chronic pneumonias.