Bacteriophage Cocktail – Salmonella in vitro and in Galleria mellonella
Anyone who has ever had to deal with it can confirm that food poisoning caused by salmonella can lead to unpleasant and even potentially dangerous gastrointestinal symptoms.
New research suggests there may be a solution in the form of phages, viruses that specifically target and eliminate bacterial cells. In a recent study, 21 myoviruses and 1 siphovirus were evaluated for their ability to control Salmonella infections in poultry and pigs. In in vitro and in vivo tests, these phages were successful against the serotype isolates prevalent in these animals.
The results suggest that these phages could be used as a biocontrol strategy to prevent Salmonella contamination in poultry and swine even before the products reach consumers. These findings present an exciting opportunity for further research to prevent Salmonella contamination in our food supply. Phage therapy could not only provide a safer eating experience, but also a more sustainable alternative to traditional antimicrobial treatments for livestock.
The authors Janet Y Nale, Gurinder K Vinner, Viviana C Lopez, Anisha M Thanki, Preeda Phothaworn, Parameth Thiennimitr, Angela Garcia, Manal AbuOun, Muna F Anjum, Sunee Korbsrisate, Edouard E Galyov, Danish J Malik, and Martha R J Clokie published their findings in their article An Optimized Bacteriophage Cocktail Can Effectively Control Salmonella in vitro and in Galleria mellonella, dated 21 January 2021.
- Salmonella spp. is a major cause of gastrointestinal enteritis in humans, transmitted mainly through contaminated poultry and pork.
- Phages can be used to control Salmonella infections in animals to break the infection cycle before consumption.
- Twenty-one myoviruses and 1 siphovirus were evaluated for their potential to eliminate Salmonella in vitro and in vivo
- Phages targeted 23 poultry and 10 swine isolates of the predominant Salmonella serotype
- Individual phages significantly reduced bacterial growth within 6 hours of infection, but bacteria grew again 1 hour later.
Salmonella spp. is a leading cause of gastrointestinal enteritis in humans where it is largely contracted via contaminated poultry and pork.
Phages can be used to control Salmonella infection in the animals, which could break the cycle of infection before the products are accessible for consumption.
Here, the potential of 21 myoviruses and a siphovirus to eliminate Salmonella in vitro and in vivo was examined with the aim of developing a biocontrol strategy to curtail the infection in poultry and swine.
Together, the phages targeted the twenty-three poultry and ten swine prevalent Salmonella serotype isolates tested.
Although individual phages significantly reduced bacterial growth of representative isolates within 6 h post-infection, bacterial regrowth occurred 1 h later, indicating proliferation of resistant strains. To curtail bacteriophage resistance, a novel three-phage cocktail was developed in vitro, and further investigated in an optimized Galleria mellonella larva Salmonella infection model colonized with representative swine, chicken and laboratory strains.
For all the strains examined, G. mellonella larvae given phages 2 h prior to bacterial exposure (prophylactic regimen) survived and Salmonella was undetectable 24 h post-phage treatment and throughout the experimental time (72 h). Administering phages with bacteria (co-infection), or 2 h post-bacterial exposure (remedial regimen) also improved survival (73-100% and 15-88%, respectively), but was less effective than prophylaxis application.
These pre-livestock data support the future application of this cocktail for further development to effectively treat Salmonella infection in poultry and pigs.
Future work will focus on cocktail formulation to ensure stability and incorporation into feeds and used to treat the infection in target animals.
Keywords: Galleria mellonella; Salmonella; bacteriophage; bacteriophage therapy; gastrointestinal enteritis.
Copyright © 2021 Nale, Vinner, Lopez, Thanki, Phothaworn, Thiennimitr, Garcia, AbuOun, Anjum, Korbsrisate, Galyov, Malik and Clokie.