Interaction study of Pasteurella multocida with culturable aerobic bacteria isolated from porcine respiratory tracts
Nonzee Hanchanachai1,2, Pramote Chumnanpuen2,3, Teerasak E-Kobon4,5,6
1Interdisciplinary Graduate Program in Bioscience, Faculty of Science, Kasetsart University, Bangkok, 10900, Thailand.
Background:
The porcine respiratory tract harbours multiple microorganisms, and the interactions between these organisms could be associated with animal health status. Pasteurella multocida is a culturable facultative anaerobic bacterium isolated from healthy and diseased porcine respiratory tracts. The interaction between P. multocida and other aerobic commensal bacteria in the porcine respiratory tract is not well understood. This study aimed to determine the interactions between porcine P. multocida capsular serotype A and D strains and other culturable aerobic bacteria isolated from porcine respiratory tracts using a coculture assay in conditioned media followed by calculation of the growth rates and interaction parameters.
Results:
One hundred and sixteen bacterial samples were isolated from five porcine respiratory tracts, and 93 isolates were identified and phylogenetically classified into fourteen genera based on 16S rRNA sequences. Thirteen isolates from Gram-negative bacterial genera and two isolates from the Gram-positive bacterial genus were selected for coculture with P. multocida. From 17 × 17 (289) interaction pairs, the majority of 220 pairs had negative interactions indicating competition for nutrients and space, while 17 pairs were identified as mild cooperative or positive interactions indicating their coexistence. All conditioned media, except those of Acinetobacter, could inhibit P. multocida growth. Conversely, the conditioned media of P. multocida also inhibited the growth of nine isolates plus themselves.
Conclusion:
Negative interaction was the major interactions among the coculture of these 15 representative isolates and the coculture with P. multocida. The conditioned media in this study might be further analysed to identify critical molecules and examined by the in vivo experiments. The study proposed the possibility of using these molecules in conditioned media to control P. multocida growth.
Insights
Interactions between Pasteurella multocida and other porcine respiratory bacteria are mostly competitive. Conditioned media from these bacteria may offer novel strategies for controlling P. multocida growth in swine.
Area of Science:
- Microbiology
- Animal Health
- Bacterial Interactions
Background:
- The porcine respiratory tract hosts diverse microorganisms with potential impacts on animal health.
- Pasteurella multocida, a common bacterium in swine respiratory tracts, has poorly understood interactions with other commensal bacteria.
- Understanding these interactions is crucial for managing swine respiratory diseases.
Purpose of the Study:
- To investigate the interactions between Pasteurella multocida (serotypes A and D) and other aerobic bacteria from porcine respiratory tracts.
- To quantify growth rates and interaction parameters in coculture systems.
- To explore potential applications of bacterial interactions in controlling P. multocida.
Main Methods:
- Isolation and phylogenetic classification of 93 bacterial isolates from porcine respiratory tracts using 16S rRNA sequencing.
- Coculture assays involving 15 representative bacterial isolates and Pasteurella multocida in conditioned media.
- Calculation of growth rates and interaction parameters to determine the nature of bacterial interactions.
Main Results:
- Most bacterial pairs (220 out of 289) exhibited negative interactions, indicating competition.
- Seventeen pairs showed mild cooperative or positive interactions.
- Conditioned media from most isolates, except Acinetobacter, inhibited P. multocida growth, and P. multocida conditioned media inhibited other isolates.
Conclusions:
- Competition is the predominant interaction among the studied porcine respiratory bacteria and P. multocida.
- Bacterial conditioned media may contain molecules with potential for controlling P. multocida growth.
- Further analysis of conditioned media and in vivo studies are warranted to validate these findings.
