Newly Isolated Virulent Salmophages for Biocontrol of Multidrug-Resistant Salmonella in Ready-to-Eat Plant-Based Food

Abstract

Due to irrational antibiotic stewardship, an increase in the incidence of multidrug resistance of bacteria has been observed recently. Therefore, the search for new therapeutic methods for pathogen infection treatment seems to be necessary. One of the possibilities is the utilization of bacteriophages (phages)—the natural enemies of bacteria. Thus, this study is aimed at the genomic and functional characterization of two newly isolated phages targeting MDR Salmonella enterica strains and their efficacy in salmonellosis biocontrol in raw carrot–apple juice. The Salmonella phage vB_Sen-IAFB3829 (Salmonella phage strain KKP 3829) and Salmonella phage vB_Sen-IAFB3830 (Salmonella phage strain KKP 3830) were isolated against S. I (6,8:l,-:1,7) strain KKP 1762 and S. Typhimurium strain KKP 3080 host strains, respectively. Based on the transmission electron microscopy (TEM) and whole-genome sequencing (WGS) analyses, the viruses were identified as members of tailed bacteriophages from the Caudoviricetes class. Genome sequencing revealed that these phages have linear double-stranded DNA and sizes of 58,992 bp (vB_Sen-IAFB3829) and 50,514 bp (vB_Sen-IAFB3830). Phages retained their activity in a wide range of temperatures (from −20 °C to 60 °C) and active acidity values (pH from 3 to 11). The exposure of phages to UV radiation significantly decreased their activity in proportion to the exposure time. The application of phages to the food matrices significantly reduced the level of Salmonella contamination compared to the control. Genome analysis showed that both phages do not encode virulence or toxin genes and can be classified as virulent bacteriophages. Virulent characteristics and no possible pathogen factors make examined phages feasible to be potential candidates for food biocontrol.

First European Erwinia amylovora Lytic Bacteriophage Cocktails Effective in the Host: Characterization and Prospects for Fire Blight Biocontrol

“…The most sensitive strain was IVIA 1892.1, which was lysed by all the bacteriophages with barely any changes in the OD 600nm values from time 0 to 20–23 h ( Figure 1 A). In the remaining E. amylovora strains, towards the last 3–4 h of the experiment, a slight increase in bacterial populations was observed while being treated with different phages ( Figure 1 B,C), similar to other works [ 70 , 71 ]. This can be explained by the selection of phage-resistant host cell subpopulations under the assayed in vitro conditions [ 22 , 63 , 72 , 73 ].…”

Characterization and Genome Study of a Newly Isolated Temperate Phage Belonging to a New Genus Targeting Alicyclobacillus acidoterrestris

“…Bacteriophage genomic DNA from lysates was isolated using the PureLink TM RNA/DNA Mini Kit (Thermo Fisher Scientific Inc., Carlsbad, CA, USA) according to the manufacturer’s protocol, with modifications by Wójcicki et al [ 53 ]. The first step was to concentrate the phage lysate by ultracentrifugation.…”

Molecular Aspects of the Functioning of Pathogenic Bacteria Biofilm Based on Quorum Sensing (QS) Signal-Response System and Innovative Non-Antibiotic Strategies for Their Elimination

“…In recent years, bacteriophages (phages) have re-gained interest mainly due to their host specificity and bacteriolytic activity against antibiotic-resistant strains and their biofilms [ 313 , 314 , 315 ]. Applying phages in bacterial biofilm eradication involves using naturally occurring strictly virulent or lytic phages that do not encode genes for virulence, toxins or AMR [ 313 , 315 ]. Phage should not be able to mediate horizontal gene transfer or transduce infected bacterial cells [ 316 ].…”

“…In numerous in vitro biofilm studies, phages have shown their efficacy in penetrating established biofilms and eradicating bacteria [ 321 ], and the effectiveness of single phages and phage cocktails to infect and lyse bacterial cells in single and multispecies biofilms has been confirmed [ 314 , 315 , 316 , 322 ]. Recent reports found that phages are highly effective at in vitro reducing and controlling bacterial biofilms, particularly those formed by S. aureus , K. pneumoniae , Acinetobacter baumannii , P. aeruginosa , Listeria monocytogenes , Salmonella sp., and E. coli [ 40 , 323 , 324 , 325 , 326 ].…”

“…Recent studies showed that applying phage cocktails in biofilm models is highly efficient at destroying bacterial biofilms [ 313 , 314 , 315 ]. For example, in vitro lytic efficacies of phage cocktails AB-SA01 and AB-PA01, which target S. aureus and P. aeruginosa , respectively, significantly reduced biofilm biomass in mixed-species biofilms, compared to the respective phage cocktail treatment [ 339 ].…”