Submitted to: Veterinary Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2003
Publication Date: March 26, 2004
Citation: Brockmeier, S. 2004. Prior infection with bordetella bronchiseptica increases colonization with haemophilus parasuis in swine. Veterinary Microbiology. Vol. 99, p. 75-78. Interpretive Summary: Bordetella bronchiseptica is a common bacterium recovered from swine respiratory tracts. B. bronchiseptica can cause nasal infections and pneumonia, but as important as the primary disease which it causes, is the fact that this bacteria predisposes to colonization and disease with other bacteria. For example, B. bronchiseptica has been shown to predispose to infection with two common secondary pathogens, Pasteurella multocida and Streptococcus suis, in pigs. Haemophilus parasuis is another common secondary pathogen of pigs. The purpose of this experiment was to determine whether B. bronchiseptica could predispose to colonization and/or disease with H. parasuis, similar to what it has been shown to do for P. multocida and S. suis. Experiments were performed comparing pigs inoculated with B. bronchiseptica or H. parasuis by themselves or together. Nasal colonization by H. parasuis was significantly higher in the coinfected groups as compared to the groups infected with H. parasuis alone, and in one of the experiments, pneumonia was present in more coinfected pigs than pigs infected with either agent alone. Thus, control of B. bronchiseptica infection may be important in maintaining respiratory health in pigs.
Technical Abstract: The objective of this study was to determine if Bordetella bronchiseptica would predispose to colonization or disease with Haemophilus parasuis. Three experiments were completed. In the first experiment, 3 groups of pigs (10 pigs/group) were inoculated intranasally with either B. bronchiseptica, H. parasuis, or B. bronchiseptica followed by H. parasuis one week later. A fourth group of 10 pigs served as a non-infected control group. The second experiment was like the first, except that there were only 5 pigs per experimental group. The third experiment consisted of only two groups (10 pigs/group), one of which was inoculated intranasally with H. parasuis; the other was inoculated with B. bronchiseptica followed by H. parasuis one week later. Pigs were necropsied 1 to 2 weeks post inoculation with H. parasuis. Mean nasal colonization by H. parasuis was significantly higher in the coinfected groups as compared to the groups infected with H. parasuis alone. Pneumonia was present in 9/25 pigs coinfected with B. bronchiseptica and H. parasuis, 5/25 pigs infected with H. parasuis alone, 1/15 pigs infected with B. bronchiseptica alone, and none of the pigs in the non-inoculated groups. Thus, B. bronchiseptica increased colonization of the respiratory tract with H. parasuis.