Isolation and Characterization of Lytic Bacteriophages Against Multidrug-Resistant Salmonella Typhimurium ATCC13311 from Poultry Farms and Rivers in Addis Ababa, Ethiopia

Résumé fourni par la source

Antimicrobial resistance (AMR) is a growing worldwide challenge, treatment options for bacterial infections are increasingly limited. Non-typhoidal Salmonella (NTS), particularly Salmonella enterica serovar Typhimurium, poses a serious threat to public health due to rising antimicrobial resistance. It can cause invasive bloodstream infections that have a high death rate. This study aimed to identify and isolate exclusively lytic bacteriophages that target multidrug-resistant Salmonella Typhimurium (ATCC 13311) from river water and poultry farm environments in Addis Ababa, Ethiopia and assessed their potential as an alternative treatment. A total of 38 environmental samples were collected from poultry farms and rivers. From these samples, 22 different bacteriophages were successfully isolated using S. Typhimurium ATCC 13311 as the host strain. The majority (63.6%) were isolated from river water samples. Spot assays were used to isolate phages, and the double-layer agar method (DLA) was used for purification. Characterization of phages of phages performed by PCR-based identification and classification, latent period determination, plating efficiency, burst size, stability testing, and assessment of in vitro bactericidal activity. Host range analysis showed that all isolates were active against the primary host, and four isolates showed cross-genus efficacy against specific pathotypes of Escherichia coli. The latent periods of the isolated phages ranged from 10 to 20 minutes, indicating a wide range of infection kinetics. Some of the most productive isolates attained Peak titers as high as 10¹³ PFU/mL, indicating significant replication capacity. Additionally, the ideal multiplicity of infection differed significantly amongst isolates, ranging from 0.001 to 100. Regarding environmental stability, all phages were active in a pH range of 5 to 9 and withstood temperatures ranging from 4°C to 37°C. Molecular analysis classified most isolates into the T4-like and T7-like lineages, two distinct phage groups with known lytic characteristics. This study demonstrates that locally isolated lytic bacteriophages can effectively inhibit multidrug-resistant Salmonella Typhimurium ATCC 13311. The findings support their potential as safe and effective biocontrol agents for combating MDR S. Typhimurium infection. However, clinical trials, in vivo research, and genome sequencing are necessary to confirm these phages' effectiveness and safety.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.