Phagovet

Biological aspects of phage therapy versus antibiotics against Salmonella enterica – poultry

While antibiotics have long been the treatment of choice for bacterial infections, phage therapy is emerging as a promising alternative.

Phages, viruses that specifically target and infect bacteria, offer a potential solution to the problem of antibiotic resistance. In a recent study, phage therapy was found to be as effective as conventional antibiotics in treating Salmonella infections in chickens. This is exciting news for both human and veterinary medicine, as it opens up the possibility of using phages to effectively treat a wide range of bacterial infections.

However, more research is needed to fully understand the potential of phage therapy and determine how it can be safely integrated into clinical practice. These results demonstrate the importance of continuing to invest in phage therapy and other innovative approaches to combat antibiotic resistance.

The authors Katarzyna Kosznik-Kwaśnicka, Magdalena Podlacha, Łukasz Grabowski, Małgorzata Stasiłojć, Alicja Nowak-Zaleska, Karolina Ciemińska, Zuzanna Cyske, Aleksandra Dydecka, Lidia Gaffke, Jagoda Mantej, Dorota Myślińska, Agnieszka Necel, Karolina Pierzynowska, Ewa Piotrowska, Edyta Radzanowska-Alenowicz, Estera Rintz, Krzysztof Sitko, Gracja Topka-Bielecka, Grzegorz Węgrzyn, and Alicja Węgrzyn published the article: Biological aspects of phage therapy versus antibiotics against Salmonella enterica serovar Typhimurium infection of chickens on 4 August 2022.

Topics:

  • Phage therapy is a promising alternative treatment for bacterial infections in humans and animals that has been studied by many groups.
  • In this study, the use of phage therapy and antibiotics was compared in chickens experimentally infected with S. enterica serovar Typhimurium. It showed that both types of therapies were highly effective when applied shortly after infection.
  •  However, later treatment with the phage cocktail was significantly less effective, likely due to the fact that bacteriophages are rapidly eliminated from the gastrointestinal tract (GIT).
  • Importantly, while antibiotics significantly altered the GIT microbiome of chickens over the long term, the analogous changes induced by phages were transient.
Biological aspects of phage therapy against Salmonella

Abstract

Phage therapy is a promising alternative treatment of bacterial infections in human and animals. Nevertheless, despite the appearance of many bacterial strains resistant to antibiotics, these drugs still remain important therapeutics used in human and veterinary medicine.

Although experimental phage therapy of infections caused by Salmonella enterica was described previously by many groups, those studies focused solely on effects caused by bacteriophages.

Here, we compared the use of phage therapy (employing a cocktail composed of two previously isolated and characterized bacteriophages, vB_SenM-2 and vB_Sen-TO17) and antibiotics (enrofloxacin and colistin) in chickens infected experimentally with S. enterica serovar Typhimurium.

We found that the efficacies of both types of therapies (i.e. the use of antibiotics and phage cocktail) were high and very similar to one another when the treatment was applied shortly (one day) after the infection. Under these conditions, S. Typhimurium was quickly eliminated from the gastrointestinal tract (GIT), to the amount not detectable by the used methods.

However, later treatment (2 or 4 days after detection of S. Typhimurium in chicken feces) with the phage cocktail was significantly less effective. Bacteriophages remained in the GIT for up to 2-3 weeks, and then were absent in feces and cloaca swabs.

Interestingly, both phages could be found in various organs of chickens though with a relatively low abundance. No development of resistance of S. Typhimurium to phages or antibiotics was detected during the experiment.

Importantly, although antibiotics significantly changed the GIT microbiome of chickens in a long-term manner, analogous changes caused by phages were transient, and the microbiome normalized a few weeks after the treatment.

In conclusion, phage therapy against S. Typhimurium infection in chickens appeared as effective as antibiotic therapy (with either enrofloxacin or colistin), and less invasive than the use the antibiotics as fewer changes in the microbiome were observed.

Keywords: Salmonella enterica infection; antibiotics; chicken; microbiome; phage therapy.

Copyright © 2022 Kosznik-Kwaśnicka, Podlacha, Grabowski, Stasiłojć, Nowak-Zaleska, Ciemińska, Cyske, Dydecka, Gaffke, Mantej, Myślińska, Necel, Pierzynowska, Piotrowska, Radzanowska-Alenowicz, Rintz, Sitko, Topka-Bielecka, Węgrzyn and Węgrzyn.

The effectiveness of phage therapy versus antibiotics in treating Salmonella enterica serovar Typhimurium infections in chickens can be evaluated by examining the biological mechanisms of each approach. Phage therapy involves the use of viruses that specifically target and kill bacteria, including Salmonella. These viruses, known as bacteriophages or phages, can be administered orally or through other routes to directly infect and lyse bacterial cells. In contrast, antibiotics are chemical compounds that inhibit or kill bacteria by disrupting various essential processes within the cells.

One potential advantage of phage therapy is its targeted nature, as phages specifically infect and kill only certain types of bacteria, whereas antibiotics can have broader effects on the bacterial population. This may result in less disruption to the normal bacterial flora of the chicken, leading to fewer side effects. However, the effectiveness of phage therapy may also depend on the presence of suitable phages that can effectively target the specific strain of Salmonella present in the infected chicken.

On the other hand, antibiotics may be more effective at quickly reducing the bacterial load in infected chickens, as they can inhibit or kill a wider range of bacteria. However, the use of antibiotics can also lead to the development of antibiotic resistance in bacteria, which can make future infections more difficult to treat.

Ultimately, the decision to use phage therapy or antibiotics to treat Salmonella infections in chickens will depend on a variety of factors, including the specific strain of Salmonella involved, the overall health of the infected chicken, and the availability and effectiveness of suitable phages or antibiotics.