Bio-Control of Salmonella Enteritidis in Foods Using Bacteriophages.

Hongduo Bao,Hui Zhang,Lili Zhang,Ran Wang,Yan Zhou,Pengyu Zhang

doi:10.3390/v7082847

Hongduo Bao, Hui Zhang + Show 4 more

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https://doi.org/10.3390/v7082847

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Abstract

Two lytic phages, vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184), were isolated from chicken sewage and characterized with host strains Salmonella Enteritidis (SE) ATCC13076 and CVCC2184, respectively. Transmission electron microscopy revealed that they belonged to the family Myoviridae. The lytic abilities of these two phages in liquid culture showed 104 multiplicity of infection (MOI) was the best in inhibiting bacteria, with PC2184 exhibiting more activity than PA13076. The two phages exhibited broad host range within the genus Salmonella. Phage PA13076 and PC2184 had a lytic effect on 222 (71.4%) and 298 (95.8%) of the 311 epidemic Salmonella isolates, respectively. We tested the effectiveness of phage PA13076 and PC2184 as well as a cocktail combination of both in three different foods (chicken breast, pasteurized whole milk and Chinese cabbage) contaminated with SE. Samples were spiked with 1 × 104 CFU individual SE or a mixture of strains (ATCC13076 and CVCC2184), then treated with 1 × 108 PFU individual phage or a two phage cocktail, and incubated at 4 °C or 25 °C for 5 h. In general, the inhibitory effect of phage and phage cocktail was better at 4 °C than that at 25 °C, whereas the opposite result was observed in Chinese cabbage, and phage cocktail was better than either single phage. A significant reduction in bacterial numbers (1.5–4 log CFU/sample, p < 0.05) was observed in all tested foods. The two phages on the three food samples were relatively stable, especially at 4 °C, with the phages exhibiting the greatest stability in milk. Our research shows that our phages have potential effectiveness as a bio-control agent of Salmonella in foods.

Highlights

Salmonella is a gram-negative bacterium that is one of the principal causes of food-borne diseases.Presently, over 2500 serotypes of Salmonella are known [1], and the most common worldwide is Salmonella Enteritidis (SE) [2]
Two new SE phages were isolated and designated as vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184) by their ability to propagate on host strains SE ATCC13076 and
Two lytic bacteriophages were successfully isolated from chicken sewages and characterized as Salmonella Enteritidis phages vB_SenM-PA13076 (PA13076) and vB_SenM-PC2184 (PC2184) by international common method according to their morphologies and their host’s serovar

Summary

Introduction

Salmonella is a gram-negative bacterium that is one of the principal causes of food-borne diseases.Presently, over 2500 serotypes of Salmonella are known [1], and the most common worldwide is Salmonella Enteritidis (SE) [2]. Salmonella is a gram-negative bacterium that is one of the principal causes of food-borne diseases. Since the period 1996–1999, the recorded incidence of human SE infection in the Foodborne. Diseases Active Surveillance Network (FoodNet) has increased by 44% [3]. In China, Ke’s study of 1764 clinical Salmonella enterica isolates in Guangdong province showed that „15% of isolates were SE, which was the primary cause of salmonellosis in adults [5]. Despite improved preventive and control strategies in chicken commercial flocks and in the food industry, SE infection still poses a constant problem [6,7,8,9]. With the misuse of antimicrobials in many farms including disease treatment and growth promotion in domestic livestock, many SE are resistant to several antimicrobial agents

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