Phagovet

Phage therapy and antibiotic therapy on immunological responses of chickens infected with Salmonella

The widespread use of antibiotics has led to the rise of drug-resistant strains of bacteria that pose a significant threat to global health.

Fortunately, scientists are exploring alternative therapies, including the use of phages. Phages, or bacteriophages, are viruses that can infect and kill bacteria. They have been used successfully to treat drug-resistant bacterial infections in animals and are considered safe, with few adverse effects reported.

However, we still do not know exactly how phages interact with animal organisms and affect the immune system. More research is needed before phage therapy can be widely used as a reliable form of treatment for bacterial infections. In the meantime, responsible use of antibiotics is critical to prevent the further development of drug-resistant bacteria.

Authors Łukasz Grabowski, Grzegorz Węgrzyn, Alicja Węgrzyn, and Magdalena Podlacha published the article Highly different effects of phage therapy and antibiotic therapy on immunological responses of chickens infected with Salmonella enterica serovar Typhimurium.

Key points include:

  • Bacteria resistant to antibiotics are a serious medical problem.
  • Phages (viruses that infect bacteria) are a promising and effective alternative form of therapy that is considered safe with few reports of severe complications or adverse effects.
  • The study compared the effects of selected bacteriophages and antibiotics on immune functions of chickens infected with Salmonella enterica serovar Typhimurium
  • The phage cocktail showed anti-inflammatory effects when administered either 1 day after infection or 2 days after detection of S. Typhimurium in feces, as measured by inhibition of the increase in inflammatory markers (IL-1β, IL-6, IFN-γ, IL-8, and IL_12)
  • These results demonstrate for the first time that phage therapy is not only effective but can also be used in veterinary medicine without disrupting immune homeostasis
phage therapy and antibiotic therapy

Abstract

The appearance of bacteria resistant to most or even all known antibiotics has become a serious medical problem.

One such promising and effective alternative form of therapy may be the use of phages, the administration of which is considered to be safe and highly effective, especially in animals with drug-resistant infections. Although there have been no reports to date suggesting that bacteriophages can cause any severe complications or adverse effects, we still know little about their interactions with animal organisms, especially in the context of the functioning of the immune system.

Therefore, the aim of the present study was to compare the impact of the application of selected bacteriophages and antibiotics (enrofloxacin and colistin), commonly used in veterinary medicine, on immune functions in Salmonella enterica serovar Typhimurium-infected chickens. The birds were infected with S. Typhimurium and then treated with a phage cocktail (14 days), enrofloxacin (5 days), or colistin (5 days).

The concentrations of a panel of pro-inflammatory cytokines (IL-1β, IL-6, IFN-γ, IL-8, and IL-12) and cytokines that reveal anti-inflammatory effects (IL-10 and IL-4), the percentage of lymphocytes, and the level of stress hormones (corticosterone and cortisol), which significantly modulate the immune responses, were determined in different variants of the experiment. The phage cocktail revealed anti-inflammatory effects when administered either 1 day after infection or 2 days after S. Typhimurium detection in feces, as measured by inhibition of the increase in levels of inflammatory response markers (IL-1β, IL-6, IFN-γ, IL-8, and IL-12). This was also confirmed by increased levels of cytokines that exert an anti-inflammatory action (IL-10 and IL-4) following phage therapy. Moreover, phages did not cause a negative effect on the number and activity of lymphocytes’ subpopulations crucial for normal immune system function.

These results indicate for the first time that phage therapy not only is effective but also can be used in veterinary medicine without disturbing immune homeostasis, expressed as cytokine imbalance, disturbed percentage of key immune cell subpopulations, and stress axis hyperactivity, which were observed in our experiments as adverse effects accompanying the antibiotic therapy.

Keywords: Salmonella enterica infection; chicken immunity; cytokines; phage therapy; safety and efficacy; stress hormones.

Copyright © 2022 Grabowski, Węgrzyn, Węgrzyn and Podlacha.