Origin of Clostridium perfringens isolates determines the ability to induce necrotic enteritis in broilers

Area of Science:

• Veterinary Microbiology
• Poultry Pathology
• Bacterial Pathogenesis

Background:

• Necrotic enteritis (NE) is a significant cause of mortality in broiler chickens, particularly after the EU ban on antibiotic growth promoters.
• The precise pathogenesis of NE remains incompletely understood, hindering effective control strategies.

Purpose of the Study:

• To investigate the virulence of Clostridium perfringens (C. perfringens) strains isolated from healthy and diseased broiler flocks.
• To determine the role of alpha toxin production and host specificity in the development of necrotic enteritis.

Main Methods:

• C. perfringens strains with varying in vitro alpha toxin production were isolated from healthy flocks and field outbreaks of NE.
• The ability of these isolates to induce gut necrosis was assessed using an intestinal loop model in laying hens and an experimental infection model in broilers.
• Alpha toxin-producing C. perfringens isolates from calf hemorrhagic enteritis were also tested for poultry pathogenicity.

Main Results:

• Only C. perfringens isolates originating from field outbreaks of NE induced necrotic gut lesions in experimental models.
• The induction of necrotic lesions was independent of the in vitro alpha toxin production levels of the isolates.
• C. perfringens strains isolated from calf hemorrhagic enteritis did not cause necrotic enteritis in poultry.

Conclusions:

• Virulence in C. perfringens strains causing necrotic enteritis in chickens is not solely dependent on alpha toxin production.
• Host-specific virulence factors likely play a crucial role in the pathogenesis of necrotic enteritis in broiler chickens.
• These findings highlight the need to consider strain-specific characteristics and host adaptation in understanding and managing necrotic enteritis.