Isolation and characterization of strains isolated from ostriches () in Vietnam.

Background And Aim: can cause enteritis in ostriches. The toxin release is believed to play a major role in determining pathogenesis properties of these pathogenic bacteria. This study was conducted to isolate and characterize strains from ostriches in Vietnam for identifying if particular virulence factors of these pathogenic bacteria are associated with enteritis progress in ostriches.

Materials And Methods: The prevalence of , and genes among isolates was determined by a multiplex polymerase chain reaction (PCR) method. The NetB toxin-encoding gene was detected by PCR and then sequenced to observe their variation. The expression of NetB toxin was checked by SDS-PAGE.

Results: A total of 116 isolates were obtained from 318 fecal samples and 105 intestinal organs. Of 80 isolates from fecal samples, 33 isolates were from healthy and 47 isolates were from diseased ostriches. The results of multiplex PCR showed that all 116 strains from healthy and enteric disordered ostriches were positive for the alpha toxin-encoding gene (). The cpe and genes were found in only one and five diseased ostriches, respectively. The gene was detected in 1/33 (3.03%) isolates from healthy ostriches, in 8/47 (17.05%) isolates from feces, and in 7/36 (19.44%) intestinal contents of diseased ostriches. The full-length sequences of 5 out of 15 -positive isolates from diseased ostriches showed 100% identity to each other as well as to the sequences available in GenBank. All of these five isolates produced NetB toxin .

Conclusion: Type A is the most prevalent among isolates from ostriches in Vietnam. Especially, the study provides data emphasizing the role of NetB toxin in causing necrotic enteritis by in ostriches.