Acta Veterinaria et Zootechnica Sinica ›› 2020, Vol. 51 ›› Issue (8): 2032-2038.doi: 10.11843/j.issn.0366-6964.2020.08.030

• RESEARCH NOTES • Previous Articles    

Isolation and Characterization of a Lytic Polyvalent Bacteriophage Infecting Salmonella choleraesuis and Escherichia coli

ZHANG Yuyu, ZHANG Min, HUANG Zan, LIN Yan*   

  1. Laboratory of Gastrointestinal Microbiology of Nanjing Agricultural University, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, National Center for International Research on Animal Gut Nutrition, Nanjing 210095, China
  • Received:2020-01-28 Online:2020-08-25 Published:2020-08-19

Abstract: This experiment was conducted to isolate and characterize a lytic bacteriophage against Salmonella choleraesuis (S. choleraesuis) from the healthy pig gut. Chyme and mucosal samples from pig jejunum and colon were assayed for the presence of bacteriophage capable of forming plaques on S. choleraesuis 13122. Bacteriophage classification was confirmed by TEM observation and sequencing. The host range was determined by the spot test method and double-layer agar plate method. Bacteriostatic ability was evaluated by turbidity measurement. A bacteriophage named L6jm was isolated, which had a regular polyhedron head approximately 75 nm in diameter and a long noncontractile tail with 190 nm in length. As the sequencing result showed no integrase or bacterial genome was in the genome of L6jm, L6jm was defined as lytic bacteriophage. L6jm can infect S. choleraesuis 13312 and Escherichia coli (E. coli) 244. Also, L6jm lysed 9 E. coli strains including one enterotoxigenic E. coli (ETEC) strain. The optimal MOI of L6jm against S. choleraesuis 13122 and E. coli 244 were 0.01 and 0.001 respectively. The latent periods were both 15 min in two strains whereas the rise periods were 145 min and 125 min. L6jm was stable over a wide range of temperatures (30-60 ℃) and pH (3.0-11.0). L6jm could significantly (P<0.05) inhibit the growth of S. choleraesuis 13312, and inhibit ETEC 104 at MOI 100. The polyvalent bacteriophage L6jm infecting S. choleraesuis and E. coli as well as lysing ETEC104 has potential application value in preventing and controlling S. choleraesuis and E. coli infection.

Key words: Salmonella choleraesuis, bacteriophage, polyvalent bacteriophage, characterization of bacteriophage, bacteriostatic effect

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