Editorial

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Open AccessEditorial

Editorial of Viruses Special Issue on Phage–Host Interactions 2021

by Mikael Skurnik

Viruses 2022, 14(2), 236; https://doi.org/10.3390/v14020236 - 25 Jan 2022

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Viruses has now published two Special Issues on phage–host interactions, the latest under the name Phage–Host Interactions 2021 [...] Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

Research

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13 pages, 2278 KiB

Open AccessArticle

Regulation of Gene Expression of phiEco32-like Bacteriophage 7-11

by Daria Lavysh, Vladimir Mekler, Evgeny Klimuk and Konstantin Severinov

Viruses 2022, 14(3), 555; https://doi.org/10.3390/v14030555 - 08 Mar 2022

Cited by 1 | Viewed by 2128

Abstract

Salmonella enterica serovar Newport bacteriophage 7-11 shares 41 homologous ORFs with Escherichia coli phage phiEco32, and both phages encode a protein similar to bacterial RNA polymerase promoter specificity σ subunit. Here, we investigated the temporal pattern of 7-11 gene expression during infection and [...] Read more.

Salmonella enterica serovar Newport bacteriophage 7-11 shares 41 homologous ORFs with Escherichia coli phage phiEco32, and both phages encode a protein similar to bacterial RNA polymerase promoter specificity σ subunit. Here, we investigated the temporal pattern of 7-11 gene expression during infection and compared it to the previously determined transcription strategy of phiEco32. Using primer extension and in vitro transcription assays, we identified eight promoters recognized by host RNA polymerase holoenzyme containing 7-11 σ subunit SaPh711_gp47. These promoters are characterized by a bipartite consensus, GTAAtg-(16)-aCTA, and are located upstream of late phage genes. While dissimilar from single-element middle and late promoters of phiEco32 recognized by holoenzymes formed by the phi32_gp36 σ factor, the 7-11 late promoters are located at genome positions similar to those of phiEco32 middle and late promoters. Two early 7-11 promoters are recognized by the RNA polymerase holoenzyme containing the host primary σ⁷⁰ factor. Unlike the case of phiEco32, no shut-off of σ⁷⁰-dependent transcription is observed during 7-11 infection and there are no middle promoters. These differences can be explained by the fact that phage 7-11 does not encode a homologue of phi32_gp79, an inhibitor of host and early phage transcription and an activator of transcription by the phi32_gp36-holoenzyme. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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14 pages, 5605 KiB

Open AccessArticle

Phage Cocktail Development against Aeromonas salmonicida subsp. salmonicida Strains Is Compromised by a Prophage

by Nava Hosseini, Valérie E. Paquet, Mahdi Chehreghani, Sylvain Moineau and Steve J. Charette

Viruses 2021, 13(11), 2241; https://doi.org/10.3390/v13112241 - 08 Nov 2021

Cited by 5 | Viewed by 2449

Abstract

Aquaculture is a rapidly growing food production sector. Fish farmers are experiencing increasing problems with antibiotic resistance when fighting against pathogenic bacteria such as Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis. Phage therapy may provide an alternative, but effective use [...] Read more.

Aquaculture is a rapidly growing food production sector. Fish farmers are experiencing increasing problems with antibiotic resistance when fighting against pathogenic bacteria such as Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis. Phage therapy may provide an alternative, but effective use must be determined. Here, we studied the inhibition of A. salmonicida subsp. salmonicida strains by five phages (HER98 [44RR2.8t.2], HER110 [65.2], SW69-9, L9-6 and Riv-10) used individually or as combinations of two to five phages. A particular combination of four phages (HER98 [44RR2.8t.2], SW69-9, Riv-10, and HER110 [65.2]) was found to be the most effective when used at an initial multiplicity of infection (MOI) of 1 against the A. salmonicida subsp. salmonicida strain 01-B526. The same phage cocktail is effective against other strains except those bearing a prophage (named Prophage 3), which is present in 2/3 of the strains from the province of Quebec. To confirm the impact of this prophage, we tested the effectiveness of the same cocktail on strains that were either cured or lysogenized with Prophage 3. While the parental strains were sensitive to the phage cocktail, the lysogenized ones were much less sensitive. These data indicate that the prophage content of A. salmonicida subsp. salmonicida can affect the efficacy of a cocktail of virulent phages for phage therapy purposes. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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18 pages, 4486 KiB

Open AccessArticle

BtuB-Dependent Infection of the T5-like Yersinia Phage ϕR2-01

by Lotta J. Happonen, Maria I. Pajunen, Jin Woo Jun and Mikael Skurnik

Viruses 2021, 13(11), 2171; https://doi.org/10.3390/v13112171 - 28 Oct 2021

Cited by 2 | Viewed by 2555

Abstract

Yersinia enterocolitica is a food-borne Gram-negative pathogen responsible for several gastrointestinal disorders. Host-specific lytic bacteriophages have been increasingly used recently as an alternative or complementary treatment to combat bacterial infections, especially when antibiotics fail. Here, we describe the proteogenomic characterization and host receptor [...] Read more.

Yersinia enterocolitica is a food-borne Gram-negative pathogen responsible for several gastrointestinal disorders. Host-specific lytic bacteriophages have been increasingly used recently as an alternative or complementary treatment to combat bacterial infections, especially when antibiotics fail. Here, we describe the proteogenomic characterization and host receptor identification of the siphovirus vB_YenS_ϕR2-01 (in short, ϕR2-01) that infects strains of several Yersinia enterocolitica serotypes. The ϕR2-01 genome contains 154 predicted genes, 117 of which encode products that are homologous to those of Escherichia bacteriophage T5. The ϕR2-01 and T5 genomes are largely syntenic, with the major differences residing in areas encoding hypothetical ϕR2-01 proteins. Label-free mass-spectrometry-based proteomics confirmed the expression of 90 of the ϕR2-01 genes, with 88 of these being either phage particle structural or phage-particle-associated proteins. In vitro transposon-based host mutagenesis and ϕR2-01 adsorption experiments identified the outer membrane vitamin B12 receptor BtuB as the host receptor. This study provides a proteogenomic characterization of a T5-type bacteriophage and identifies specific Y. enterocolitica strains sensitive to infection with possible future applications of ϕR2-01 as a food biocontrol or phage therapy agent. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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16 pages, 4735 KiB

Open AccessArticle

Effects of the Newly Isolated T4-like Phage on Transmission of Plasmid-Borne Antibiotic Resistance Genes via Generalized Transduction

by Junxuan Zhang, Xiaolu He, Shuqing Shen, Mengya Shi, Qin Zhou, Junlin Liu, Mianzhi Wang and Yongxue Sun

Viruses 2021, 13(10), 2070; https://doi.org/10.3390/v13102070 - 14 Oct 2021

Cited by 8 | Viewed by 2405

Abstract

Bacteriophages are the most abundant biological entities on earth and may play an important role in the transmission of antibiotic resistance genes (ARG) from host bacteria. Although the specialized transduction mediated by the temperate phage targeting a specific insertion site is widely explored, [...] Read more.

Bacteriophages are the most abundant biological entities on earth and may play an important role in the transmission of antibiotic resistance genes (ARG) from host bacteria. Although the specialized transduction mediated by the temperate phage targeting a specific insertion site is widely explored, the carrying characteristics of “transducing particles” for different ARG subtypes in the process of generalized transduction remains largely unclear. Here, we isolated a new T4-like lytic phage targeting transconjugant Escherichia coli C600 that contained plasmid pHNAH67 (KX246266) and encoded 11 different ARG subtypes. We found that phage AH67C600_Q9 can misload plasmid-borne ARGs and package host DNA randomly. Moreover, for any specific ARG subtype, the carrying frequency was negatively correlated with the multiplicity of infection (MOI). Further, whole genome sequencing (WGS) identified that only 0.338% (4/1183) of the contigs of an entire purified phage population contained ARG sequences; these were floR, sul2, aph(4)-Ia, and fosA. The low coverage indicated that long-read sequencing methods are needed to explore the mechanism of ARG transmission during generalized transduction. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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18 pages, 1903 KiB

Open AccessEditor’s ChoiceArticle

Reduced Infection Efficiency of Phage NCTC 12673 on Non-Motile Campylobacter jejuni Strains Is Related to Oxidative Stress

by Jessica C. Sacher, Muhammad Afzal Javed, Clay S. Crippen, James Butcher, Annika Flint, Alain Stintzi and Christine M. Szymanski

Viruses 2021, 13(10), 1955; https://doi.org/10.3390/v13101955 - 29 Sep 2021

Cited by 3 | Viewed by 2925

Abstract

Campylobacter jejuni is a Gram-negative foodborne pathogen that causes diarrheal disease and is associated with severe post-infectious sequelae. Bacteriophages (phages) are a possible means of reducing Campylobacter colonization in poultry to prevent downstream human infections. However, the factors influencing phage-host interactions must be [...] Read more.

Campylobacter jejuni is a Gram-negative foodborne pathogen that causes diarrheal disease and is associated with severe post-infectious sequelae. Bacteriophages (phages) are a possible means of reducing Campylobacter colonization in poultry to prevent downstream human infections. However, the factors influencing phage-host interactions must be better understood before this strategy can be predictably employed. Most studies have focused on Campylobacter phage binding to the host surface, with all phages classified as either capsule- or flagella-specific. Here we describe the characterization of a C. jejuni phage that requires functional flagellar glycosylation and motor genes for infection, without needing the flagella for adsorption to the cell surface. Through phage infectivity studies of targeted C. jejuni mutants, transcriptomic analysis of phage-resistant mutants, and genotypic and phenotypic analysis of a spontaneous phage variant capable of simultaneously overcoming flagellar gene dependence and sensitivity to oxidative stress, we have uncovered a link between oxidative stress, flagellar motility, and phage infectivity. Taken together, our results underscore the importance of understanding phage-host interactions beyond the cell surface and point to host oxidative stress state as an important and underappreciated consideration for future phage-host interaction studies. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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21 pages, 3660 KiB

Open AccessArticle

Bacteriophages fEV-1 and fD1 Infect Yersinia pestis

by Mikael Skurnik, Salla Jaakkola, Laura Mattinen, Lotta von Ossowski, Ayesha Nawaz, Maria I. Pajunen and Lotta J. Happonen

Viruses 2021, 13(7), 1384; https://doi.org/10.3390/v13071384 - 16 Jul 2021

Cited by 6 | Viewed by 3693

Abstract

Bacteriophages vB_YpeM_fEV-1 (fEV-1) and vB_YpeM_fD1 (fD1) were isolated from incoming sewage water samples in Turku, Finland, using Yersinia pestis strains EV76 and KIM D27 as enrichment hosts, respectively. Genomic analysis and transmission electron microscopy established that fEV-1 is a novel type of dwarf [...] Read more.

Bacteriophages vB_YpeM_fEV-1 (fEV-1) and vB_YpeM_fD1 (fD1) were isolated from incoming sewage water samples in Turku, Finland, using Yersinia pestis strains EV76 and KIM D27 as enrichment hosts, respectively. Genomic analysis and transmission electron microscopy established that fEV-1 is a novel type of dwarf myovirus, while fD1 is a T4-like myovirus. The genome sizes are 38 and 167 kb, respectively. To date, the morphology and genome sequences of some dwarf myoviruses have been described; however, a proteome characterization such as the one presented here, has currently been lacking for this group of viruses. Notably, fEV-1 is the first dwarf myovirus described for Y. pestis. The host range of fEV-1 was restricted strictly to Y. pestis strains, while that of fD1 also included other members of Enterobacterales such as Escherichia coli and Yersinia pseudotuberculosis. In this study, we present the life cycles, genomes, and proteomes of two Yersinia myoviruses, fEV-1 and fD1. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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16 pages, 17473 KiB

Open AccessArticle

Aerobic Conditions and Endogenous Reactive Oxygen Species Reduce the Production of Infectious MS2 Phage by Escherichia coli

by Guillaume Bastin, Aurélie Galmiche, François Talfournier, Hortense Mazon, Julie Challant, Maëlle Robin, Didier Majou, Nicolas Boudaud and Christophe Gantzer

Viruses 2021, 13(7), 1376; https://doi.org/10.3390/v13071376 - 15 Jul 2021

Cited by 1 | Viewed by 2881

Abstract

Most of the defective/non-infectious enteric phages and viruses that end up in wastewater originate in human feces. Some of the causes of this high level of inactivity at the host stage are unknown. There is a significant gap between how enteric phages are [...] Read more.

Most of the defective/non-infectious enteric phages and viruses that end up in wastewater originate in human feces. Some of the causes of this high level of inactivity at the host stage are unknown. There is a significant gap between how enteric phages are environmentally transmitted and how we might design molecular tools that would only detect infectious ones. Thus, there is a need to explain the low proportion of infectious viral particles once replicated. By analyzing lysis plaque content, we were able to confirm that, under aerobic conditions, Escherichia coli produce low numbers of infectious MS2 phages (I) than the total number of phages indicated by the genome copies (G) with an I/G ratio of around 2%. Anaerobic conditions of replication and ROS inhibition increase the I/G ratio to 8 and 25%, respectively. These data cannot only be explained by variations in the total numbers of MS2 phages produced or in the metabolism of E. coli. We therefore suggest that oxidative damage impacts the molecular replication and assembly of MS2 phages. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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15 pages, 3363 KiB

Open AccessArticle

A Novel Broad Host Range Phage Infecting Alteromonas

by Xuejin Feng, Wei Yan, Anan Wang, Ruijie Ma, Xiaowei Chen, Ta-Hui Lin, Yi-Lung Chen, Shuzhen Wei, Tao Jin, Nianzhi Jiao and Rui Zhang

Viruses 2021, 13(6), 987; https://doi.org/10.3390/v13060987 - 26 May 2021

Cited by 7 | Viewed by 3882

Abstract

Bacteriophages substantially contribute to bacterial mortality in the ocean and play critical roles in global biogeochemical processes. Alteromonas is a ubiquitous bacterial genus in global tropical and temperate waters, which can cross-protect marine cyanobacteria and thus has important ecological benefits. However, little is [...] Read more.

Bacteriophages substantially contribute to bacterial mortality in the ocean and play critical roles in global biogeochemical processes. Alteromonas is a ubiquitous bacterial genus in global tropical and temperate waters, which can cross-protect marine cyanobacteria and thus has important ecological benefits. However, little is known about the biological and ecological features of Alteromonas phages (alterophages). Here, we describe a novel alterophage vB_AmeP-R8W (R8W), which belongs to the Autographiviridae family and infects the deep-clade Alteromonas mediterranea. R8W has an equidistant and icosahedral head (65 ± 1 nm in diameter) and a short tail (12 ± 2 nm in length). The genome size of R8W is 48,825 bp, with a G + C content of 40.55%. R8W possesses three putative auxiliary metabolic genes encoding proteins involved in nucleotide metabolism and DNA binding: thymidylate synthase, nucleoside triphosphate pyrophosphohydrolase, and PhoB. R8W has a rapid lytic cycle with a burst size of 88 plaque-forming units/cell. Notably, R8W has a wide host range, such that it can infect 35 Alteromonas strains; it exhibits a strong specificity for strains isolated from deep waters. R8W has two specific receptor binding proteins and a compatible holin–endolysin system, which contribute to its wide host range. The isolation of R8W will contribute to the understanding of alterophage evolution, as well as the phage–host interactions and ecological importance of alterophages. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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14 pages, 3182 KiB

Open AccessArticle

Novel Acinetobacter baumannii Myovirus TaPaz Encoding Two Tailspike Depolymerases: Characterization and Host-Recognition Strategy

by Anastasia S. Shchurova, Mikhail M. Shneider, Nikolay P. Arbatsky, Alexander S. Shashkov, Alexander O. Chizhov, Yuriy P. Skryabin, Yulia V. Mikhaylova, Olga S. Sokolova, Andrey A. Shelenkov, Konstantin A. Miroshnikov, Yuriy A. Knirel and Anastasia V. Popova

Viruses 2021, 13(6), 978; https://doi.org/10.3390/v13060978 - 25 May 2021

Cited by 8 | Viewed by 2588

Abstract

Acinetobacter baumannii, one of the most significant nosocomial pathogens, is capable of producing structurally diverse capsular polysaccharides (CPSs) which are the primary receptors for A. baumannii bacteriophages encoding polysaccharide-degrading enzymes. To date, bacterial viruses specifically infecting A. baumannii strains belonging to more [...] Read more.

Acinetobacter baumannii, one of the most significant nosocomial pathogens, is capable of producing structurally diverse capsular polysaccharides (CPSs) which are the primary receptors for A. baumannii bacteriophages encoding polysaccharide-degrading enzymes. To date, bacterial viruses specifically infecting A. baumannii strains belonging to more than ten various capsular types (K types) were isolated and characterized. In the present study, we investigate the biological properties, genomic organization, and virus–bacterial host interaction strategy of novel myovirus TaPaz isolated on the bacterial lawn of A. baumannii strain with a K47 capsular polysaccharide structure. The phage linear double-stranded DNA genome of 93,703 bp contains 178 open reading frames. Genes encoding two different tailspike depolymerases (TSDs) were identified in the phage genome. Recombinant TSDs were purified and tested against the collection of A. baumannii strains belonging to 56 different K types. One of the TSDs was demonstrated to be a specific glycosidase that cleaves the K47 CPS by the hydrolytic mechanism. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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11 pages, 854 KiB

Open AccessArticle

Evaluation of the Stability of Bacteriophages in Different Solutions Suitable for the Production of Magistral Preparations in Belgium

by Hans Duyvejonck, Maya Merabishvili, Mario Vaneechoutte, Steven de Soir, Rosanna Wright, Ville-Petri Friman, Gilbert Verbeken, Daniel De Vos, Jean-Paul Pirnay, Els Van Mechelen and Stefan J. T. Vermeulen

Viruses 2021, 13(5), 865; https://doi.org/10.3390/v13050865 - 08 May 2021

Cited by 29 | Viewed by 3523

Abstract

In Belgium, the incorporation of phages into magistral preparations for human application has been permitted since 2018. The stability of such preparations is of high importance to guarantee quality and efficacy throughout treatments. We evaluated the ability to preserve infectivity of four different [...] Read more.

In Belgium, the incorporation of phages into magistral preparations for human application has been permitted since 2018. The stability of such preparations is of high importance to guarantee quality and efficacy throughout treatments. We evaluated the ability to preserve infectivity of four different phages active against three different bacterial species in five different buffer and infusion solutions commonly used in medicine and biotechnological manufacturing processes, at two different concentrations (9 and 7 log pfu/mL), stored at 4 °C. DPBS without Ca²⁺ and Mg²⁺ was found to be the best option, compared to the other solutions. Suspensions with phage concentrations of 7 log pfu/mL were unsuited as their activity dropped below the effective therapeutic dose (6–9 log pfu/mL), even after one week of storage at 4 °C. Strong variability between phages was observed, with Acinetobacter baumannii phage Acibel004 being stable in four out of five different solutions. We also studied the long term storage of lyophilized staphylococcal phage ISP, and found that the titer could be preserved during a period of almost 8 years when sucrose and trehalose were used as stabilizers. After rehydration of the lyophilized ISP phage in saline, the phage solutions remained stable at 4 °C during a period of 126 days. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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26 pages, 2264 KiB

Open AccessArticle

The Development of Bacteriophage Resistance in Vibrio alginolyticus Depends on a Complex Metabolic Adaptation Strategy

by Dimitrios Skliros, Panos G. Kalatzis, Chrysanthi Kalloniati, Fotios Komaitis, Sokratis Papathanasiou, Evangelia D. Kouri, Michael K. Udvardi, Constantina Kokkari, Pantelis Katharios and Emmanouil Flemetakis

Viruses 2021, 13(4), 656; https://doi.org/10.3390/v13040656 - 10 Apr 2021

Cited by 5 | Viewed by 3723

Abstract

Lytic bacteriophages have been well documented to play a pivotal role in microbial ecology due to their complex interactions with bacterial species, especially in aquatic habitats. Although the use of phages as antimicrobial agents, known as phage therapy, in the aquatic environment has [...] Read more.

Lytic bacteriophages have been well documented to play a pivotal role in microbial ecology due to their complex interactions with bacterial species, especially in aquatic habitats. Although the use of phages as antimicrobial agents, known as phage therapy, in the aquatic environment has been increasing, recent research has revealed drawbacks due to the development of phage-resistant strains among Gram-negative species. Acquired phage resistance in marine Vibrios has been proven to be a very complicated process utilizing biochemical, metabolic, and molecular adaptation strategies. The results of our multi-omics approach, incorporating transcriptome and metabolome analyses of Vibrio alginolyticus phage-resistant strains, corroborate this prospect. Our results provide insights into phage-tolerant strains diminishing the expression of phage receptors ompF, lamB, and btuB. The same pattern was observed for genes encoding natural nutrient channels, such as rbsA, ptsG, tryP, livH, lysE, and hisp, meaning that the cell needs to readjust its biochemistry to achieve phage resistance. The results showed reprogramming of bacterial metabolism by transcript regulations in key-metabolic pathways, such as the tricarboxylic acid cycle (TCA) and lysine biosynthesis, as well as the content of intracellular metabolites belonging to processes that could also significantly affect the cell physiology. Finally, SNP analysis in resistant strains revealed no evidence of amino acid alterations in the studied putative bacterial phage receptors, but several SNPs were detected in genes involved in transcriptional regulation. This phenomenon appears to be a phage-specific, fine-tuned metabolic engineering, imposed by the different phage genera the bacteria have interacted with, updating the role of lytic phages in microbial marine ecology. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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21 pages, 3446 KiB

Open AccessArticle

Genome Sequence of the Bacteriophage CL31 and Interaction with the Host Strain Corynebacterium glutamicum ATCC 13032

by Max Hünnefeld, Ulrike Viets, Vikas Sharma, Astrid Wirtz, Aël Hardy and Julia Frunzke

Viruses 2021, 13(3), 495; https://doi.org/10.3390/v13030495 - 17 Mar 2021

Cited by 2 | Viewed by 2806

Abstract

In this study, we provide a comprehensive analysis of the genomic features of the phage CL31 and the infection dynamics with the biotechnologically relevant host strain Corynebacterium glutamicum ATCC 13032. Genome sequencing and annotation of CL31 revealed a 45-kbp genome composed of 72 [...] Read more.

In this study, we provide a comprehensive analysis of the genomic features of the phage CL31 and the infection dynamics with the biotechnologically relevant host strain Corynebacterium glutamicum ATCC 13032. Genome sequencing and annotation of CL31 revealed a 45-kbp genome composed of 72 open reading frames, mimicking the GC content of its host strain (54.4%). An ANI-based distance matrix showed the highest similarity of CL31 to the temperate corynephage Φ16. While the C. glutamicum ATCC 13032 wild type strain showed only mild propagation of CL31, a strain lacking the cglIR-cglIIR-cglIM restriction-modification system was efficiently infected by this phage. Interestingly, the prophage-free strain C. glutamicum MB001 featured an even accelerated amplification of CL31 compared to the ∆resmod strain suggesting a role of cryptic prophage elements in phage defense. Proteome analysis of purified phage particles and transcriptome analysis provide important insights into structural components of the phage and the response of C. glutamicum to CL31 infection. Isolation and sequencing of CL31-resistant strains revealed SNPs in genes involved in mycolic acid biosynthesis suggesting a role of this cell envelope component in phage adsorption. Altogether, these results provide an important basis for further investigation of phage-host interactions in this important biotechnological model organism. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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18 pages, 2514 KiB

Open AccessArticle

T4-like Bacteriophages Isolated from Pig Stools Infect Yersinia pseudotuberculosis and Yersinia pestis Using LPS and OmpF as Receptors

by Mabruka Salem, Maria I. Pajunen, Jin Woo Jun and Mikael Skurnik

Viruses 2021, 13(2), 296; https://doi.org/10.3390/v13020296 - 13 Feb 2021

Cited by 15 | Viewed by 3152

Abstract

The Yersinia bacteriophages fPS-2, fPS-65, and fPS-90, isolated from pig stools, have long contractile tails and elongated heads, and they belong to genus Tequatroviruses in the order Caudovirales. The phages exhibited relatively wide host ranges among Yersinia pseudotuberculosis and related species. One-step [...] Read more.

The Yersinia bacteriophages fPS-2, fPS-65, and fPS-90, isolated from pig stools, have long contractile tails and elongated heads, and they belong to genus Tequatroviruses in the order Caudovirales. The phages exhibited relatively wide host ranges among Yersinia pseudotuberculosis and related species. One-step growth curve experiments revealed that the phages have latent periods of 50–80 min with burst sizes of 44–65 virions per infected cell. The phage genomes consist of circularly permuted dsDNA of 169,060, 167,058, and 167,132 bp in size, respectively, with a G + C content 35.3%. The number of predicted genes range from 267 to 271. The phage genomes are 84–92% identical to each other and ca 85% identical to phage T4. The phage receptors were identified by whole genome sequencing of spontaneous phage-resistant mutants. The phage-resistant strains had mutations in the ompF, galU, hldD, or hldE genes. OmpF is a porin, and the other genes encode lipopolysaccharide (LPS) biosynthetic enzymes. The ompF, galU, and hldE mutants were successfully complemented in trans with respective wild-type genes. The host recognition was assigned to long tail fiber tip protein Gp38, analogous to that of T-even phages such as Salmonella phage S16, specifically to the distal β-helices connecting loops. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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Review

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32 pages, 2440 KiB

Open AccessReview

The Potential of Phage Therapy against the Emerging Opportunistic Pathogen Stenotrophomonas maltophilia

by Jaclyn G. McCutcheon and Jonathan J. Dennis

Viruses 2021, 13(6), 1057; https://doi.org/10.3390/v13061057 - 03 Jun 2021

Cited by 26 | Viewed by 4937

Abstract

The isolation and characterization of bacteriophages for the treatment of infections caused by the multidrug resistant pathogen Stenotrophomonas maltophilia is imperative as nosocomial and community-acquired infections are rapidly increasing in prevalence. This increase is largely due to the numerous virulence factors and antimicrobial [...] Read more.

The isolation and characterization of bacteriophages for the treatment of infections caused by the multidrug resistant pathogen Stenotrophomonas maltophilia is imperative as nosocomial and community-acquired infections are rapidly increasing in prevalence. This increase is largely due to the numerous virulence factors and antimicrobial resistance genes encoded by this bacterium. Research on S. maltophilia phages to date has focused on the isolation and in vitro characterization of novel phages, often including genomic characterization, from the environment or by induction from bacterial strains. This review summarizes the clinical significance, virulence factors, and antimicrobial resistance mechanisms of S. maltophilia, as well as all phages isolated and characterized to date and strategies for their use. We further address the limited in vivo phage therapy studies conducted against this bacterium and discuss the future research needed to spearhead phages as an alternative treatment option against multidrug resistant S. maltophilia. Full article

(This article belongs to the Special Issue Phage-Host Interactions 2021)

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