Phagovet

Novel Salmonella phages

Ciprofloxacin (CIP) is recommended as the drug of choice for the treatment of salmonellosis. However, overuse of this drug can lead to resistance problems and failure to treat disease. Phage therapy is an alternative approach to control CIP-resistant infections.

The aim of this study was to estimate the prevalence of CIP-resistant Salmonella isolated from the broiler production chain and to evaluate the lytic ability of novel Salmonella phages isolated from water samples. The results showed that CIP-resistant Salmonella were widely distributed in chicken fattening and that Salmonella phages exhibited good lytic activity against these strains, with no significant differences in the efficacy of the different phages.

These results suggest that phage therapy may be a promising alternative for the treatment of CIP-resistant salmonellosis in poultry. 

The study found that many different serovars or types of Salmonella are present in the broiler production chain. In addition, a high percentage – nearly 30% – of Salmonella isolates were resistant to the antibiotic chloramphenicol. Chloramphenicol is an important antibiotic used to treat humans and animals.

However, the overuse of antibiotics has led to an increase in antibiotic-resistant bacteria. This study showed that phages, viruses that infect bacteria, lyse or kill CIP-resistant Salmonella isolates very effectively.

This suggests that phage therapy may be a potential solution to the problem of antibiotic resistance. Phage therapy has already been successfully used to treat other bacterial infections, and this study shows that phages could also be used to control Salmonella in the broiler production chain. 

Further studies are needed to evaluate the safety and efficacy of this approach in larger animals.

The authors Wattana Pelyuntha, Arsooth Sanguankiat, Attawit Kovitvadhi, and Kitiya Vongkamjan published their article Broad lytic spectrum of novel Salmonella phages on ciprofloxacin-resistant Salmonella contaminated in the broiler production chain on August 15, 2022.

Key topics include:

  • The objective of this study was to estimate the prevalence of CIP-resistant Salmonella isolated from the broiler production chain and to evaluate the lytic ability of novel Salmonella phages isolated from water samples.
  • In this study, 51 Salmonella isolates were obtained from the broiler production chain (two commercial farms, one free-range farm, two slaughterhouses, and three wet-market barns).
  • The serovars that showed CIP resistance were 14/16 isolates of serovar Kentucky (87.5%) and one isolate of serovar Give (50%), while eight other serovars were sensitive to this drug. Overall, the prevalence of CIP-resistant Salmonella obtained from the sources included in this study was 29.4%.
  • In this study, 11 Salmonella phages isolated from wastewater samples from chicken farms, sewage treatment plants, and natural reservoirs were identified. Our phages showed high lysis ability against these CIP-resistant Salmonella isolates, suggesting a potential application of phage-based treatments or biocontrols in the broiler production chain.
Novel Salmonella phages

Abstract

Background and Purpose

Ciprofloxacin (CIP) is recommended as the drug of choice for the treatment of salmonellosis. However, overuse of this drug can lead to resistance problems and failure to treat disease. Phage therapy is an alternative approach to control CIP-resistant infections. The aim of this study was to estimate the prevalence of CIP-resistant Salmonella isolated from the broiler production chain and to evaluate the lytic ability of novel Salmonella phages isolated from water samples.

Materials and Methods

Samples were obtained from the broiler production chain and used to isolate Salmonella. Serovar and CIP resistance of each isolate were characterized by latex agglutination and agar disk diffusion assay, respectively. Water samples were collected from different sources for phage isolation. The lytic activity of the newly isolated phages was also investigated.

Results

In this study, 51 Salmonella isolates were obtained from the broiler production chain (two commercial farms, one free-range farm, two slaughterhouses, and three wet-market barns). Kentucky was the top characterized serovar (16), followed by Typhimurium (9), Agona (5), Corvalis (5), Schwarzengrund (5), Singapore (3), Weltevreden (3), Mbandaka (2), Give (2), and Albany (1). Serovars that showed CIP resistance were 14/16 isolates of serovar Kentucky (87.5%) and one isolate of serovar Give (50%), while eight other serovars were sensitive to this drug. Overall, the prevalence of CIP-resistant Salmonella obtained from the sources included in this study was 29.4%. This study identified 11 Salmonella phages isolated from wastewater samples collected from chicken farms, sewage treatment plants, and natural reservoirs. Our phages showed an overall percentage of lysis ability ranging from 33.3% to 93.3% against CIP-resistant isolates. However, only one bacterial isolate, 210SL, derived from the food contact surface of a wet market stand, was resistant to all phages.

Conclusion

In this study, various Salmonella serovars were detected in the broiler production chain, and the percentage of isolates that showed CIP-resistant Salmonella was 29.4%. Overall, Salmonella phages showed high lysis ability against these CIP-resistant Salmonella isolates, suggesting a potential application of phage-based treatments or biocontrols in the broiler production chain.

Keywords: antibiotics; bacteriophages; fluoroquinolones; phage lysis; poultry.

Copyright: © Pelyuntha, et al.