Pathogenicity of various isolates of Alcaligenes faecalis for broilers

Area of Science:

• Veterinary Microbiology
• Avian Pathology
• Bacterial Pathogenesis

Background:

• Alcaligenes faecalis is a bacterium that can affect poultry health.
• Understanding the pathogenicity of different field isolates is crucial for disease control in broiler chickens.

Purpose of the Study:

• To evaluate the pathogenicity and colonization potential of eight distinct Alcaligenes faecalis field isolates in chickens.
• To identify specific isolates responsible for respiratory disease signs and persistent tracheal colonization.

Main Methods:

• Intranasal inoculation of day-old broilers and specific-pathogen-free chickens with approximately 1 x 10(8) organisms of eight Alcaligenes faecalis isolates.
• Observation of clinical signs of respiratory disease (snicking, dyspnea).
• Assessment of bacterial colonization in the respiratory tract, particularly the trachea, over time.

Main Results:

• Significant variations in pathogenicity and tracheal colonization were observed among the eight Alcaligenes faecalis isolates.
• Two isolates (Wilson and Lockamy) induced mild respiratory signs and established persistent, high-level tracheal colonization for at least 31 days.
• Five other isolates colonized the respiratory tract to a lesser extent and with reduced persistence, without causing clinical signs.
• One isolate (CS) failed to establish colonization after intranasal inoculation.

Conclusions:

• The pathogenicity and colonization ability of Alcaligenes faecalis field isolates in chickens are highly variable.
• Specific Alcaligenes faecalis isolates possess the capacity for significant tracheal colonization and can induce mild respiratory disease in broilers.
• Further research may be needed to understand the factors contributing to the differential pathogenicity of Alcaligenes faecalis isolates.