Characterisation of isolated from chickens in Vietnam.

The objective of this study was isolating and characterising from chickens in Vietnam and identifying virulence factors involved with enteritis. Five hundred thirty-one faecal and sixty-eight intestinal samples were collected from healthy and diseased chickens for the isolation. The presence of virulence factors was determined by multiplex PCR. The gene of the selected isolates was sequenced and checked for its expression by SDS-PAGE. Two hundred seventy-two isolates were collected. All of them were shown to be positive for the gene. The gene was detected in 26.56% of the isolates from the healthy chickens, while 43.45% of the isolates from the faeces and 45% of the isolates from the intestinal samples were positive for this gene in the diseased birds. All eight isolates positive to  from the diseased chickens showed 100% identity in the sequence and produced the NetB toxin , whereas only two out of eight healthy chicken-derived isolates produced this toxin. Nine out of ten chickens experimentally infected with the -positive isolate showed typical signs of enteritis. The gene was the most prevalent virulence factor identified in the bacteria , but the gene could be a major player responsible for necrotic enteritis progression in chickens.