Phagovet

Bacteriophage S55

Salmonellosis, often caused by contaminated food, affects millions of people worldwide each year.

This bacterial infection can cause severe gastrointestinal symptoms, making it a serious public health concern. The misuse of antibiotics has increased the prevalence of antibiotic-resistant bacteria, including strains of Salmonella, making prevention and control even more challenging.

But there may be hope in a surprising source – phages. Phages are viruses that specifically infect and destroy bacteria without harming human cells.

In this study, researchers isolated a lytic phage called S55 from fecal samples collected from poultry farms. This particular phage targets Salmonella pullorum and Salmonella enteritidis, two common causes of salmonellosis. Their experiments showed that S55 effectively lyses most strains of these bacteria, suggesting that it could potentially be used as an alternative method to combat their spread.

Although further research is needed, these results demonstrate the potential power of phages in fighting bacterial infections such as salmonellosis.

The authors Haojie Ge, Yanping Xu, Maozhi Hu, Kai Zhang, Shuxuan Zhang, Xin’an Jiao, and Xiang Chen published their research in their article Isolation, Characterization, and Application in Poultry Products of a Salmonella-Specific Bacteriophage, S55, dated 1 July 2021.

Key points include:

  • Salmonellosis is a worldwide problem that is only getting worse due to antibiotic resistance.
  • Phages, viruses that infect bacteria, could help control the spread of Salmonella.
  • In this study, the lytic phage S55 was isolated from poultry farm fecal samples and demonstrated to be effective against Salmonella pullorum and Salmonella enteritidis strains.
  • S55 does not carry virulence or resistance factor genes, so it can be safely used as a biological agent against Salmonella infections.
Application in Poultry Products of a Salmonella Specific Bacteriophage S55

Abstract

Salmonellosis occurs frequently worldwide, causing serious threats to public health.

The abuse of antibiotics is increasing antibiotic resistance in bacteria, thereby making the prevention and control of Salmonella more difficult.

A phage can help control the spread of bacteria.

In this study, the lytic phage S55, whose host bacterium is Salmonella Pullorum, was isolated from fecal samples obtained from poultry farms. This phage belongs to the Siphoviridae and has a polyhedral head and a retraction-free tail. S55 lysed most cells of Salmonella Pullorum (58 of 60 strains, 96.67%) and Salmonella Enteritidis (97 of 104 strains, 93.27%).

One-step growth kinetics revealed that the latent period was 10 min, the burst period was 80 min, and the burst size was 40 PFU per cell. The optimal multiplicity of infection was 0.01, and the phage was able to survive at pH values of 4 to 11 and temperatures of 40 to 60°C for 60 min. Complete genome sequence analysis revealed that the S55 genome consists of 42,781 bp (50.28% GC content) and 58 open reading frames, including 25 frames with known or assumed functions without tRNA genes. S55 does not carry genes that encode virulence or resistance factors. At 4 and 25°C, S55 reduced the populations of Salmonella Pullorum and Salmonella Enteritidis on chicken skin surfaces.

S55 may be useful as a biological agent for the prevention and control of Salmonella infections.

Keywords: Salmonella; Bacteriophage; Complete genome sequence; Poultry product.

Copyright: the authors, International Association for Food Protection.