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Title: REP-PCR SUBTYPING OF TYPE A CLOSTRIDIUM PERFRINGENS ISOLATES FROM HEALTHY AND NECROTIC BROILERS AND THEIR ENVIRONS REARED UNDER DRUG-FREE CONDITIONS

Author
item Siragusa, Gregory

Submitted to: Poultry Science Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/9/2005
Publication Date: 9/18/2005
Citation: Siragusa, G.R. 2005. Rep-pcr subtyping of type a clostridium perfringens isolates from healthy and necrotic broilers and their environs reared under drug-free conditions. Poultry Science Symposium Proceedings.

Interpretive Summary:

Technical Abstract: A library of Clostridium perfringens (Cp) isolates from healthy and necrotic broiler chickens from 13 different drug-free farms (no antibiotic growth promotants), darkling beetles and larvae were examined for genetic relationships using rep-PCR (repetitive element, DiversiLab system) molecular subtyping. Two major groupings were observed. Group I consisted of 73% (8 of 11) Cp of necrotic origin; group II was composed of 54% (20/37) Cp isolates of necrotic origin. Within Group I, isolates were distributed amongst intestinal, cecal and larval origin from five different growout houses and ranged in similarity of 80 to 99% (Pearson's Correlation index). From Group II, isolates were within 70% similarity and of cecal, intestinal, and beetle origin; clustering of isolates from necrotic birds, healthy birds and both was observed. It appears that outside of the two major subgroupings I and II and the three Group II minor clades, that four main groupings were observed within this collection. Although from different growout houses representing 13 different farms, at least one of the clades (kabeled IIB) consisted only of Cp isolates from healthy broiler intestinal/cecal origin and a second clade (labeled IIA1a) was composed of 70% Cp isolats of necrotic origin. These were not affiliated with one single house or farm. While the significance of these cladistic observations remains to be studied, it is our hypothesis that focusing study on Cp subtypes of necrotic enteritis linkage will lead to a better understanding of those Cp strains most important in necrotic enteritis in drug-free rearing operations.