Detection of Salmonella by bacteriophage Felix 01

vB_EcoS_IME347 a novel T1-like Escherichia coli bacteriophage

Advances in phage therapy and its application require more information on phage genome characteristics and host-phage interaction mechanisms. In this study, a so far unknown T1-like Escherichia coli phage was identified and named vB_EcoS_IME347 (IME347). The genome length of phage IME347 is 50,048 bp with a G + C content of 49.7%. BLASTn alignment showed that the phage has its highest homology (identity 78%, query cover 72%) with phage SRT8 (GenBank: MF996376). Electron microscopy showed that phage IME347 has an icosahedral head and a long non-contractiled tail, features of the family Siphoviridae. Phylogenetic analysis of the large subunit of the terminal enzyme and tail fiber protein revealed that phage IME347 is a novel member of the T1 virus. Furthermore, through comparative genomics, silencing mutation, phage spotting assay, and phage adsorption assay, an E. coli BL21 TonB-dependent receptor YncD was identified to be responsible for phage IME347 adsorption and entry. The identification of the phage receptor YncD enriches the phage receptor database and provides a theoretical basis for bacteriophage therapy.

Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria

Since their discovery in 1915, bacteriophages have been used to treat bacterial infections in animals and humans because of their unique ability to infect their specific bacterial hosts without affecting other bacterial populations. The research carried out in this field throughout the 20th century, largely in Georgia, part of USSR and Poland, led to the establishment of phage therapy protocols. However, the discovery of penicillin and sulfonamide antibiotics in the Western World during the 1930s was a setback in the advancement of phage therapy. The misuse of antibiotics has reduced their efficacy in controlling pathogens and has led to an increase in the number of antibiotic-resistant bacteria. As an alternative to antibiotics, bacteriophages have become a topic of interest with the emergence of multidrug-resistant bacteria, which are a threat to public health. Recent studies have indicated that bacteriophages can be used indirectly to detect pathogenic bacteria or directly as biocontrol agents. Moreover, they can be used to develop new molecules for clinical applications, vaccine production, drug design, and in the nanomedicine field via phage display.

Understanding the enormous diversity of bacteriophages: the tailed phages that infect the bacterial family Enterobacteriaceae

Bacteriophages are the predominant biological entity on the planet. The recent explosion of sequence information has made estimates of their diversity possible. We describe the genomic comparison of 337 fully sequenced tailed phages isolated on 18 genera and 31 species of bacteria in the Enterobacteriaceae. These phages were largely unambiguously grouped into 56 diverse clusters (32 lytic and 24 temperate) that have syntenic similarity over >50% of the genomes within each cluster, but substantially less sequence similarity between clusters. Most clusters naturally break into sets of more closely related subclusters, 78% of which are correlated with their host genera. The largest groups of related phages are superclusters united by genome synteny to lambda (81 phages) and T7 (51 phages). This study forms a robust framework for understanding diversity and evolutionary relationships of existing tailed phages, for relating newly discovered phages and for determining host/phage relationships.

Bacteriophages for detection and control of bacterial pathogens in food and food-processing environment

This chapter presents recent advances in bacteriophage research and their application in the area of food safety. Section 1 describes general facts on phage biology that are relevant to their application for control and detection of bacterial pathogens in food and environmental samples. Section 2 summarizes the recently acquired data on application of bacteriophages to control growth of bacterial pathogens and spoilage organisms in food and food-processing environment. Section 3 deals with application of bacteriophages for detection and identification of bacterial pathogens. Advantages of bacteriophage-based methods are presented and their shortcomings are discussed. The chapter is intended for food scientist and food product developers, and people in food inspection and health agencies with the ultimate goal to attract their attention to the new developing technology that has a tremendous potential in providing means for producing wholesome and safe food.