Isolation, characterization and application of bacteriophage PSDA-2 against Salmonella Typhimurium in chilled mutton

Abstract

Salmonella is a common foodborne pathogen, especially in meat and meat products. Lytic phages are promising alternatives to conventional methods for Salmonella biocontrol in food and food processing. In this study, a virulent bacteriophage (PSDA-2) against Salmonella enterica serovar Typhimurium was isolated from the sewage and it was found that PSDA-2 belongs to Cornellvirus genus of Siphoviridae family by morphological and phylogenetic analysis. Based on the one-step growth curve, PSDA-2 has a short latent period (10 min) and a high burst size (120 PFU/cell). The stability test in vitro reveals that PSDA-2 is stable at 30–70°C and pH 3–10. Bioinformatics analysis show that PSDA-2 genome consists of 40,062 bp with a GC content of 50.21% and encodes 63 open reading frames (ORFs); no tRNA genes, lysogenic genes, drug resistance genes and virulence genes were identified in the genome. Moreover, the capacity for PSDA-2 to control Salmonella Typhimurium in chilled mutton was investigated. The results show that incubation of PSDA-2 at 4°C reduced recoverable Salmonella by 1.7 log CFU/mL and 2.1 log CFU/mL at multiplicity of infection (MOI) of 100 and 10,000 respectively, as relative to the phage-excluded control. The features of phage PSDA-2 suggest that it has the potential to be an agent to control Salmonella.

Isolation, characterization, and genomic analysis of a novel bacteriophage MA9V-1 infecting Chryseobacterium indologenes: a pathogen of Panax notoginseng root rot

“…The optimal multiplicity of infection (MOI) is the ratio of phages to bacteria at the time of infection. The experimental method followed was according to the study mentioned in the reference ( Sun et al, 2022 ). In brief, the CFU/ml of the host cell at the exponential growth phase was counted through the dilution coating method with serial dilutions of 10 −4 , 10 −5 , and 10 −6 .…”

“…For determining the thermal and pH stability of phage MA9V-1, the experimental protocol was performed as proposed with slight modification ( Sasikala and Srinivasan, 2016 ; Sun et al, 2022 ). In brief, 1 mL phage MA9V-1 lysate (10 10 PFU/m) was treated under different temperatures from 30 to75°C at 5°C intervals for 1 h. Then, these treated samples checked the survival rate of phage MA9V-1 using the double-layer agar assay.…”

Bacteriophage Delivery Systems for Food Applications: Opportunities and Perspectives

“…The vast majority of phages are fairly easily isolated from sewage and other sources. For instance, Sun et al [ 54 ] isolated a bacteriophage (PSDA-2) against Salmonella enterica serovar Typhimurium from sewage and used it in chilled mutton. After 6 days, results showed a Salmonella reduction of 1.7 log in viable cells at 4 °C when a multiplicity of infection (MOI) of 100 was used and 2.1 log for a MOI of 10.000.…”

Optimization of Escherichia coli Bacteriophages Production

“…This approach is conducted by altering one nutritional/chemical/physical factor of fermentation, while keeping all the other factors constant. Eight of the factors were selected based on the literature [19][20][21]. An attempt is made to identify the impact temperature for increased production of phages using a shake flask.…”