Isolation and Characterization of a Lytic and Highly Specific Phage against Yersinia enterocolitica as a Novel Biocontrol Agent

Abstract

Yersinia enterocolitica is a gram-negative, non-spore-forming, coccobacilli, psychrotrophic, and facultative anaerobe, which is one of three Yersinia species that are pathogenic to humans, along with Y. pestis, and Y. pseudotuberculosis [1, 2]. The most predominant natural hosts for Y. enterocolitica are animals (especially pigs). Y. enterocolitica also exists ubiquitously in water, soil, plant surfaces, and foods [3]. Although animals are the major source of Y. enterocolitica, many cases have recently been reported in which outbreaks of Y. enterocolitica were associated with fresh produce such as salad, bean sprouts and leafy vegetables [4, 5]. Yersinia infection, commonly known as yersiniosis, begins with some common symptoms such as fever, diarrhea (often bloody), and abdominal pain, which is sometimes confused with appendicitis. It is also associated with some severe complications such as skin rash, meningitis, mesenteric lymphadenitis, and sepsis [2, 3]. A European Union Summary Report [6] classified yersiniosis as the third most common zoonosis in Europe [4]. Moreover, recent findings revealed that Yersinia species had developed resistance against penicillin, ampicillin, cephalosporin, and macrolides due to the production of beta-lactamases [7]. Thus, a safe, ecofriendly and effective "green" approach is required to control Y. enterocolitica to ensure food safety and public health [8]. Bacteriophages (phages) are the most abundant entities (10 3 1-10 3 2) in nature and have recently gathered more attention as green biocontrol agents owing to several advantages, including excellent target specificity, the ability to multiply in the presence of hosts, preparation and cost efficiencies, stability in wide-ranging pH levels and temperatures, and harmlessness to humans, animals, and plants [9-11]. The necessity of novel biocontrol agents has prompted us to isolate numerous phages (mainly lytic phages) from various environments and foods [12]. Unlike lysogenic phages, the lytic phage can lyse the target bacteria by integrating their DNA into the bacterial chromosome and then replicating themselves inside the host, a trait that is preferred for their use as biocontrol agents [2, 13, 14].

Exploring the feasibility of Salmonella Typhimurium-specific phage as a novel bio-receptor

“…The room temperature accelerated the reduction of the phage cocktail concentration more than cold temperature in this study. The other study [28] also confirmed the lower feasibility of Yersinia enterocolitica-specific phage when exposed to room temperature rather than deep freezing, freezing, and cold temperatures. In fact, most of the several commercial phage cocktails approved by the FDA were sold under cold storage conditions (2℃-8℃) [30].…”

“…Antibodies are the most popularly employed bio-receptor, however, their most considerable limitations include their need for storage at cold temperatures and their average shelf life of one month [27]. By contrast phage possess excellent stability at relatively broad temperature ranges during long periods [28]. Thus, the influence of storage period and temperature were investigated by measuring the concentration of KFS-ST after exposure to various storage conditions over a period of 12 weeks (Table 3).…”

Characterization of a New and Efficient Polyvalent Phage Infecting E. coli O157:H7, Salmonella spp., and Shigella sonnei

“…Phages have been increasingly investigated as specific, natural, eco-friendly, and promising biocontrol agents against foodborne pathogens [20]. In particular, their ubiquitous existence in nature (10 31 phages) and excellent target-dependent specificity have provided extensive investigation of phage from various sources such as sewage, human and animal feces, and foods [21]. Moreover, the unique characteristics of the phage life cycle, either lytic or lysogenic (temperate), are usually investigated for phage application [22,23].…”

Isolation and Characterization of Bacteriophage ZCSE6 against Salmonella spp.: Phage Application in Milk

“…Regarding the sensitivity of phage ZCSE6 toward temperature, there was a reduction in phage titer after incubating the phage at −20 • C due to the formation of ice crystals, thus the glycerol is preferred to be added to keep the phages safe at temperatures lower than 0 • C [34]. Furthermore, the thermal stability of phage ZCSE6 to a wide range of temperatures ranging from −20 • C to 70 • C was confirmed.…”