The origin of Pasteurella multocida impacts pathology and inflammation when assessed in a mouse model

Area of Science:

• Veterinary Microbiology
• Infectious Diseases
• Immunology

Background:

• Pasteurella multocida is a significant bacterial pathogen affecting various animal species.
• Understanding host-pathogen interactions is crucial for controlling P. multocida infections.

Purpose of the Study:

• To compare the pathogenicity and host-pathogen interactions of P. multocida isolates from porcine pneumonia and fowl cholera in a murine model.
• To investigate the expression of matrix metalloproteinase 9 (MMP9) and its inhibitor TIMP1 during infection.

Main Methods:

• Intranasal inoculation of mice with different doses (10(6), 10(4), 10(2) CFU) of avian and porcine P. multocida isolates.
• Assessment of clinical signs, gross pathology, bacterial load in lung and liver, and expression of MMP9 and TIMP1.

Main Results:

• The avian isolate exhibited high pathogenicity, causing severe necrotizing pneumonia and liver necrosis with high bacterial loads.
• The porcine isolate showed dose-dependent pathogenicity, leading to bronchopneumonia and liver abscesses with lower bacterial loads.
• Both isolates increased the expression of MMP9 and TIMP1.

Conclusions:

• The intranasal murine model effectively differentiates the pathogenicity of P. multocida isolates from different hosts.
• Host-pathogen interactions, including MMP9 and TIMP1 expression, vary between avian and porcine P. multocida isolates.