Fire blight, caused by the bacterium Erwinia amylovora , is a major threat to pear production worldwide. Bacteriophages, viruses that infect bacteria, are a promising alternative to antibiotics for controlling fire blight. In this study, we isolated a novel bacteriophage, RH-42-1, from Xinjiang, China. We characterized its biological properties, including host range, plaque morphology, infection dynamics, stability, and sensitivity to various chemicals. RH-42-1 infected several E. amylovora strains but not all. It produced clear, uniform plaques and exhibited optimal infectivity at a multiplicity of infection (MOI) of 1, reaching a high titer of 9.6 × 10 9 plaque-forming units (PFU)/mL. The bacteriophage had a short latent period (10 min), a burst size of 207 PFU/cell, and followed a sigmoidal one-step growth curve. It was stable at temperatures up to 60 °C but declined rapidly at higher temperatures. RH-42-1 remained viable within a pH range of 5 to 9 and was sensitive to extreme pH values. The bacteriophage demonstrates sustained activity upon exposure to ultraviolet radiation for 60 min, albeit with a marginal reduction. In our assays, it exhibited a certain level of resistance to 5% chloroform (CHCl 3 ), 5% isopropanol (C 3 H 8 O), and 3% hydrogen peroxide (H 2 O 2 ), which had little effect on its activity, whereas it showed sensitivity to 75% ethanol (C 2 H 5 OH). Electron microscopy revealed that RH-42-1 has a tadpole-shaped morphology. Its genome size is 14,942 bp wit 2024 https://creativecommons.org/licenses/by/4.0/ Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). Fire blight, caused by the bacterium Erwinia amylovora , is a major threat to pear production worldwide. Bacteriophages, viruses that infect bacteria, are a promising alternative to antibiotics for controlling fire blight. In this study, we isolated a novel bacteriophage, RH-42-1, from Xinjiang, China. Biological control agents, such as the fluorescent pseudomonad “Blight Ban A506” [ 6 ], the broad-spectrum Pantoea sp. formulation “Blight BanC9-1” [ 7 ], the Bacillus subtilis QST713 formulation “Serenade” [ 8 ], and BD170 [ 9 ] have been applied on a certain scale, showing comparable efficacy to antibiotics under ideal conditions. In China, a group of antagonistic strains exhibiting good activity against fire blight bacteria has been screened, but they are still in the research or trial phase and have not been registered for use [ 10 ]. Lytic bacteriophages are a class of viruses that lyse and kill target bacteria. They show promising applications in the safe and effective control of pathogenic bacteria in both plants and animals, addressing issues related to bacterial resistance and rapid detection [ 27 ]. Therefore, the identification of bacteriophages with strong lytic activity against target pathogenic bacteria and high stability is crucial for the development of bacteriophage-based biocontrol agents. The key to isolating virulent bacteriophages lies in the collection, enrichment, and purification of environmental samples containing bacteriophages. In this study, using E. This finding aligns with the results of the current study. Compared with phage isolation from the soil of an Xanthomonas -infected rice paddy, the current study had a lower probability of isolating virulent bacteriophages against fire blight bacteria [ 30 ]. This difference might be attributed to the use of a mixture of five strains of fire blight bacteria as the target host in this study. Due to the strong specificity of bacteriophages, the selection for infection of different strains within the fire blight bacteria might have led to the failure of some bacteriophages with strong specificity that could not infect the mixed host strains to be isolated. This result suggests that, when isolating lytic bacteriophages, it is advisable to mix multiple strains from different sources as target host bacteria, which can increase the success rate of isolation. A bacteriophage’s host range is closely related to the source of its isolation material. Balogh et al. [ 31 ] isolated bacteriophages against X. axonopodis pv. citri from citrus canker lesions and found that the host range was narrow. In contrast, bacteriophages isolated from soil and sewage had a broader host range. [ 34 ] isolated the fire blight bacteriophage pEp_SNUABM_08, which has a latent period of 40 min and a burst size of 20 phages. Akremi et al. [ 14 ] isolated the fire blight bacteriophage PEar 6, which has a latent period of 20 min, a rising burst period of 25 min, and a burst size of about 280 PFU/cell. Compared with the above fire blight bacteriophages, PEar 6 belongs to a bacteriophage category with short latent periods and long burst times. This indicates that this bacteriophage has strong replication activity and can invade and lyse the host bacteria in a short Additionally, nine proteins encoded by RH-42-1 displayed amino acid sequence variations compared to their PRD1 counterparts. Additionally, differences exist between them in certain characteristics. Bamford et al. [ 44 ] reported that PRD1 bacteriophages isolated from sewage are sensitive to chloroform, whereas RH-42-1 bacteriophages isolated in this study from soil exhibit tolerance to chloroform. PRD1 bacteriophages infect host bacteria of the pseudomonads and Enterobacteriaceae families containing P or W incompatible plasmids and rely on host plasmids for replication [ 45 ]; whereas, RH-42-1 infects host bacteria of the fire blight bacterium which commonly contain the PEA29 plasmid, and some strains contain plasmids such as PEA68, PEA34, PEA72, and PEA8.7 [ 46 ]. However, whether RH-42-1 relies on host bacterial plasmids for replication and whether the host bacteria contain incompatible group plasmids require further investigation and confirmation.

Abstract Bacteriophages (phages) are viruses that kill bacteria specifically but cannot infect other kinds of organisms. They have attracted new attention since the increasing antibiotic resistance developed into a global crisis. Phage therapy, a 100-year-old form of antibacterial treatment in medicine, is gaining momentum because phages represent a therapy concept without such negative side effects as toxicity; phages are the only therapeutic agent that regulates itself at the sites of infection and decays when the infectious bacteria have been killed. Nature is an almost infinite phage resource: New ones can be isolated for most kinds of problem bacteria as needed; bacteria and their phages constantly co-evolve. This is important as new pathogenic bacterial variants evolve and new challenging situations arise. In human therapy, “cocktails” of multiple phages may reduce the probability of selecting bacteria that developed resistance to a certain phage. Antibiotic agents can be applied together with phages in many circumstances; the two often function synergistically. Phages cannot be expected to replace antibiotic agents in our medical arsenal, but can be used where antibiotic agents fail. The selected phages, however, must be obligately virulent, well-characterized, and highly purified before application. Countless patients and their physicians are waiting for re-establishing phage therapy as a flexible, tailored medicine; infrastructures should be built in all countries ur 1172 sur Surgical Infections Surg Infect (Larchmt) SAGE Publications PMC6302670 6302670 6302670 30256176 10.1089/sur.2018.184 Bacteriophages: A Therapy Concept against Multi-Drug–Resistant Bacteria Rohde Christine 1 ✉ Wittmann Johannes 1 Kutter Elizabeth 2 1 Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany. 2 The Evergreen State College, Olympia, Washington. ✉ Address correspondence to: Dr. Christine Rohde, Leibniz Institute DSMZ, German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B 3, 8124 Braunschweig, Germany christine.rohde@dsmz.de 5 12 2018 19 8 737 737–744 26 12 2018 © Christine Rohde et al., 2018; Published by Mary Ann Liebert, Inc. This Open Access article is distributed under the terms of the Creative Commons License ( http://creativecommons.org/licenses/by/4.0 ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. Abstract Bacteriophages (phages) are viruses that kill bacteria specifically but cannot infect other kinds of organisms. This is important as new pathogenic bacterial variants evolve and new challenging situations arise. In human therapy, “cocktails” of multiple phages may reduce the probability of selecting bacteria that developed resistance to a certain phage. Antibiotic agents can be applied together with phages in many circumstances; the two often function synergistically. Phages cannot be expected to replace antibiotic agents in our medical arsenal, but can be used where antibiotic agents fail. The selected phages, however, must be obligately virulent, well-characterized, and highly purified before application. Keywords: antimicrobial drug resistance, bacteriophages, bacteriophage therapy, ESKAPE bacteria, microbiome, nosocomial infections status released display-pdf yes is-olf no is-manuscript no is-preprint no is-journal-matter no is-scanned no is-retracted no Issue date 2018 Nov 1. Antimicrobial Drug Resistance (AMR) Crisis: Can Medicine Still Rely on Antibiotic Agents? F or decades, beginning with penicillin, antibiotic agents completely transformed medicine and ended widespread disasters such as the Black Plague. Today, the most formidable persister with clinical relevance is a new arrival to the general lists, Acinetobacter baumannii , which was placed number one on the WHO list of “priority one–critical” bacteria [ 8 ]. It is followed by long-challenging Pseudomonas aeruginosa, which is also extremely These are silent inhabitants with a highly relevant regulative and co-evolutionary potential for our microbiota, but many of them confer antibiotic resistance and other unwanted gene sequences to their bacterial hosts, sequences that then behave like “jumping genes” when the prophages are released from their host genomes and enter a lytic cycle, free to infect other bacteria. In contrast, obligately lytic phages are virulent and quickly kill their bacterial hosts by lysing them. As soon as they have adsorbed to the bacterial cell receptor, injected their nucleic acid into the bacterial cell, and begun to express their own genes, the host's imminent death is inevitable. Micro-organisms live in complex communities and these make up our microbiomes, the richer the better for health (see above). Bacteria tend to settle on surfaces, layers of bacterial communities grow, and in medical terms, they often take on special relevance—e.g., in our oral cavities—in cases of implantation and chronic wounds, or in the lungs of CF patients. Could phages be an option to help degrade biofilms? Yes. In contrast, its implementation for gram-negative bacteria requires modification of the enzymes to allow the lysin to penetrate their characteristic outer membranes and reach the specific target sites in the peptidoglycan layer; research on this “artilysin” approach is now also far advanced (see Lisando GmbH, Regensburg, Germany) [ 55 ]. Each kind of tailed phage uses tail fibers to bind to highly specific receptors on particular kinds of bacteria, injects its linear double-stranded DNA molecule into the cell through the tail, in a process that requires cellular energy for most phages and, for lytic phages, immediately initiates an extensive re-programming of the host cell, which functions as a phage production factory. The details and extent of the reprogramming are highly varied for those relatively few phages where it has been studied extensively [ 56 ].

Bacteriophages are viral parasites of bacteria. A successful infection starts with the adsorption of the bacteriophage to a specific receptor on the host cell surface. Most bacteriophages are thought to have a narrow host range but this can be extended in certain cases. One strategy forextending host range is to first express a known functional bacteriophage receptor protein in bacteria previously non-susceptible to the bacteriophage, thereby enabling adsorption and potential infection by viruses that target the specific receptor. To investigate the feasibility of this approach, a plasmid (pMUT13) encoding the Escherichia coli LamB porin, the receptor for bacteriophage Lambda, was transferred into three different enterobacterial genera, namely Citrobacter, Yersinia, and Serratia. Over 100 environmental bacteriophages were isolated that infected these pMUT13-containing strains, and some bacteriophages were shown to infect their respective hosts in a LamB-dependent way. The host ranges of the environmental bacteriophages were cross-tested across the heterologous genera and surface adsorption kinetics investigated. Unlike bacteriophage Lambda, which is a member of the Siphoviridae, these newly-isolated LamB-dependent bacteriophages were more commonly members of the Myoviridae, based on transmission electron microscopy and whole genome sequences. Furthermore, an interesting selection of evolved bacteriophage mutants with broader host range were isolated, and the key mutations inv

in microbial mats at the surface, and up to 70% of marine bacteria may be infected by bacteriophages. Bacteriophages were used from the 1920s as an alternative A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria. The term is derived from Ancient Greek φαγεῖν (phagein) 'to devour' and bacteria. Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as four genes (e.g. MS2) and as Bacterial cells are protected by a cell wall of polysaccharides, which are important virulence factors protecting bacterial cells against both immune host defenses and antibiotics. To enter a host cell, bacteriophages bind to specific receptors on the surface of bacteria, including lipopolysaccharides, teichoic acids, proteins, or even flagella. This specificity means a bacteriophage can infect only certain bacteria bearing receptors to which they can bind, which in turn, determines the phage's host range. Polysaccharide-degrading enzymes are virion-associated proteins that enzymatically degrade the capsular outer layer of their hosts at the initial step of a tightly programmed phage infection process. Host growth conditions also influence the ability of the phage to attach and invade them. As phage virions do not move independently, they must rely on random encounters with the correct receptors when in solution, such as blood, lymphatic circulation, irrigation, soil water, etc. Myovirus bacteriophages use a hypodermic syringe-like motion to inject their genetic material into the cell. After contacting the appropriate receptor, the tail fibers flex to bring the base plate closer to the surface of the cell. This is known as reversible binding. Once attached completely, irreversible binding is initiated and the tail contracts, possibly with the help of ATP present in the tail, injecting genetic material through the bacterial membrane. The injection is accomplished through a sort of bending motion in the shaft by going to the side, contracting closer to the cell and pushing back up. Podoviruses lack an elongated tail sheath like that of a myovirus, so instead, they use their small, tooth-like tail fibers enzymatically to degrade a portion of the cell membrane before inserting their genetic material.

Bacteria in nature can exist in multicellular communities called biofilms. Biofilms also form in the course of many infections. Pseudomonas aeruginosa infections frequently involve biofilms, which contribute materially to the difficulty to treat these infections with antibiotic therapy. Many biofilm-related characteristics are controlled by the second messenger, cyclic-di-GMP, which is upregulated on surface contact. Among these factors is the exopolysaccharide Psl, which is a critically important component of the biofilm matrix. Here, we describe the discovery of a P. aeruginosa bacteriophage, which we have called Clew-1, that directly binds to and uses Psl as a receptor. While this phage does not efficiently infect planktonically growing bacteria, it can disrupt P. aeruginosa biofilms and replicate in biofilm bacteria. We further demonstrate that the Clew-1 can reduce the bacterial burden in a mouse model of P. aeruginosa keratitis, which is characterized by the formation of a biofilm on the cornea. Due to its reliance on Psl for infection, Clew-1 does not actually form plaques on wild-type bacteria under standard in vitro conditions. This argues that our standard isolation proce

The BacterioPHAGE for Gastrointestinal Health-2 study is designed to determine if a commercial bacteriophage product can increase the survival and efficacy of probiotic bacteria that will be concurrently administered. Bacteriophages may act as prebiotics, which are traditionally defined as indigestible dietary components that selectively enhance specific bacterial species in the intestines to confer a health benefit. In this study, the "prebiotic" is a unique combination of bacteriophages, or viruses that infect bacteria. These phages are generally regarded as safe for human consumption and ar

Summary Bacteriophages are one of the most abundant entities on the planet and are present in high concentrations within humans and animals, mostly in the gut. Phages that infect intestinal bacteria are released by defecation and remain free in extra‐intestinal environments, where they usually persist for longer than their bacterial hosts. Recent studies indicate that a large amount of the genetic information in bacterial genomes and in natural environments is of phage origin. In addition, metagenomic analysis reveals that a substantial number of bacterial genes are present in viral DNA in different environments. These facts support the belief that phages can play a significant role in horizontal gene transfer between bacteria. Bacteriophages are known to transfer genes by generalized and specialized transduction and indeed there are some examples of phages found in the environment carrying and transducing genes of bacterial origin. A successful transduction in the environment requires certain conditions, e.g. phage and bacterial numbers need to exceed certain threshold concentrations, the bacteria need to exist in an infection‐competent physiological state, and lastly, the physical conditions in the environment (pH, temperature, etc. of the supporting matrix) have to be suitable for phage infection. All three factors are reviewed here, and the available information suggests: (i) that the number of intestinal bacteria and phages in faecally contaminated environments guarantee

Antibiotics are powerful medicines that fight certain infections and can save lives when used properly. However, with bacteria becoming more resistant to antibiotics, new methods to treat bacterial infections are needed. One promising method for treating bacteria is the use of bacteriophages: viruses that infect and kill bacteria. This experiment investigated the effect of phage-antibiotic synergism on Klebsiella pneumoniae, Hafnia alvei, and transductant ampicillin-resistant Hafnia alvei. The trait for ampicillin resistance was transferred from K. pneumoniae to H. alvei using a device that was constructed in the lab. The zones of inhibition were then measured around the bacteria that were treated with the antibiotic discs alone and the bacteria that were treated with both the bacteriophage and the antibiotic discs. Hafnia alvei, Klebsiella pneumoniae, and the transductant ampicillin-resistant Hafnia alvei colonies exhibited larger zones of inhibition when the antibiotics were used in conjunction with the bacteriophages compared to when the antibiotics were used alone. The bacteriophages also made the transductant ampicillin-resistant Hafnia alvei colonies slightly susceptible to ampicillin again. This project demonstrates STEM integration into a high school biological science project.

Lactococcus lactis is a lactic acid bacterium widely used as a starter culture in the manufacture of dairy products, especially a wide variety of cheeses. Improved industrial strains would help to manufacture better food products that can meet the industry’s and consumer’s demands with respect to e.g. quality, taste, texture and shelf life. Bacteriophage infection of L. lactis starter cultures represents one of the main causes of fermentation failure and consequent economic losses for the dairy industry. In this study, however, we aim at employing bacteriophages for beneficial purposes. We dev

Bacteriophages are the only viruses where this phenomenon is called lytic and lysogenic cycle. There is a similiar phenomenon in humans (and other mammals as well) which is called "endogenous retrovirus" and is pretty common. For humans, there are estimations that something between 5 and 8% of the human genome are made of endogeneous retroviruses. See these two references: Long-term reinfection of the human genome by endogenous retroviruses. Endogenous Retroviruses and Human Evolution Otherwise I can recommend reading the article on " Endogeneous retroviruses " in the Wikipedia, it is pretty extensive and has a lot of references.

I'm not so sure about my answer. But I think "bacteriophage" is a polyphyletic name of which was defined by the ability of infecting bacteria, but not defined by the genetic, evolutionary, or morphological relationships. It seems that if a species (or a taxon in a higher taxonomic level) of virus is infectious to bacteria, it will be classified as a member of the bacteriophage. Here is a review article about the phage classification.

This study addresses the increasingly severe global public health challenge of antibiotic resistance, focusing on exploring phage therapy as a potential treatment strategy for multidrug-resistant bacterial skin infections. Bacteriophages, with advantages such as high specificity, low propensity for inducing resistance, and minimal side effects, have shown promise in preliminary clinical research for scenarios like chronic wound infections, demonstrating potential in reducing bacterial load and promoting healing. To this end, the study is designed as a prospective, double-blind, non-inferiority

observation that certain bacteria (actinomycetes) stopped the growth of other bacteria. In 1928 Fleming … feldspar, and certain marbles), which allow the sun’s rays to penetrate so these bacteria can carry out … growth. (1) Most bacteria can grow over a 30°C temperature range. (2) Bacteria can be classi- fied according

observation that certain bacteria (actinomycetes) stopped the growth of other bacteria. Lieske made … (1) Most bacteria can grow over a 30°C temperature range. (2) Bacteria can be classified … Thiobacillus, which oxides sulfur, and certain other bacteria that reduce sulfur. Sulfur bacteria