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Botka T, Pantůček R, Mašlaňová I, Benešík M, Petráš P, Růžičková V, Havlíčková P, Varga M, Žemličková H, Koláčková I, Florianová M, Jakubů V, Karpíšková R, Doškař J. Lytic and genomic properties of spontaneous host-range Kayvirus mutants prove their suitability for upgrading phage therapeutics against staphylococci. Sci Rep 2019; 9:5475. [PMID: 30940900 PMCID: PMC6445280 DOI: 10.1038/s41598-019-41868-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/17/2019] [Indexed: 12/20/2022] Open
Abstract
Lytic bacteriophages are valuable therapeutic agents against bacterial infections. There is continual effort to obtain new phages to increase the effectivity of phage preparations against emerging phage-resistant strains. Here we described the genomic diversity of spontaneous host-range mutants of kayvirus 812. Five mutant phages were isolated as rare plaques on phage-resistant Staphylococcus aureus strains. The host range of phage 812-derived mutants was 42% higher than the wild type, determined on a set of 186 methicillin-resistant S. aureus strains representing the globally circulating human and livestock-associated clones. Comparative genomics revealed that single-nucleotide polymorphisms from the parental phage 812 population were fixed in next-step mutants, mostly in genes for tail and baseplate components, and the acquired point mutations led to diverse receptor binding proteins in the phage mutants. Numerous genome changes associated with rearrangements between direct repeat motifs or intron loss were found. Alterations occurred in host-takeover and terminal genomic regions or the endolysin gene of mutants that exhibited the highest lytic activity, which implied various mechanisms of overcoming bacterial resistance. The genomic data revealed that Kayvirus spontaneous mutants are free from undesirable genes and their lytic properties proved their suitability for rapidly updating phage therapeutics.
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Affiliation(s)
- Tibor Botka
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Roman Pantůček
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic.
| | - Ivana Mašlaňová
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Martin Benešík
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Petr Petráš
- National Institute of Public Health, Praha, 100 42, Czech Republic
| | - Vladislava Růžičková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Pavla Havlíčková
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Marian Varga
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
| | - Helena Žemličková
- National Institute of Public Health, Praha, 100 42, Czech Republic.,Department of Clinical Microbiology, University Hospital and Faculty of Medicine in Hradec Králové, Charles University, Hradec Králové, 500 05, Czech Republic
| | | | | | - Vladislav Jakubů
- National Institute of Public Health, Praha, 100 42, Czech Republic
| | | | - Jiří Doškař
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, 611 37, Czech Republic
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Wang Q, Zeng X, Yang Q, Yang C. Identification of a bacteriophage from an environmental multidrug-resistant E. coli isolate and its function in horizontal transfer of ARGs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 639:617-623. [PMID: 29803035 DOI: 10.1016/j.scitotenv.2018.05.213] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/08/2018] [Accepted: 05/17/2018] [Indexed: 06/08/2023]
Abstract
Horizontal transfer of ARGs was generally considered to be mediated by three methods - transformation, conjugation and transduction through phages - during which the contribution of bacteriophages to gene transfer in the environment is unclear or even questioned. In this study, a multiple-antibiotic-resistant Escherichia coli strain and its phage (YZ1) were isolated from a municipal wastewater treatment system. The results of the morphological and genomic analyses of phage YZ1 showed that it is a member of the T7 viral genus in the subfamily Autographivirinae. Its genome is similar to that of the E. coli phage K1F in both organization and sequence and does not encode ARGs. However, 28 paired reads in the raw sequencing data aligned to ARGs, including those promoting β-lactam, aminoglycoside, and fluoroquinolone resistance, among others. Quantitative PCR showed that ARGs were present in bacteriophage DNA (approximately 103 copies/mL) and were also detected in the bacterial host DNA. The results suggested that while infrequent, some ARG-carrying transducing phages were presumably generated by erroneous packaging during infection of antibiotic-resistant bacteria, which may create the possibility of horizontal transfer of ARGs.
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Affiliation(s)
- Qiang Wang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China; Key Laboratory for Microorganisms and Functional Molecules (Henan Normal University), University of Henan Province, Xinxiang 453007, China
| | - Xiangpeng Zeng
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
| | - Qingxiang Yang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China; Key Laboratory for Microorganisms and Functional Molecules (Henan Normal University), University of Henan Province, Xinxiang 453007, China.
| | - Chuanzhen Yang
- College of Life Sciences, Henan Normal University, Xinxiang 453007, China
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Role of SH3b binding domain in a natural deletion mutant of Kayvirus endolysin LysF1 with a broad range of lytic activity. Virus Genes 2017; 54:130-139. [DOI: 10.1007/s11262-017-1507-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/17/2017] [Indexed: 12/16/2022]
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Bárdy P, Pantůček R, Benešík M, Doškař J. Genetically modified bacteriophages in applied microbiology. J Appl Microbiol 2016; 121:618-33. [PMID: 27321680 DOI: 10.1111/jam.13207] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/07/2016] [Accepted: 06/16/2016] [Indexed: 01/18/2023]
Abstract
Bacteriophages represent a simple viral model of basic research with many possibilities for practical application. Due to their ability to infect and kill bacteria, their potential in the treatment of bacterial infection has been examined since their discovery. With advances in molecular biology and gene engineering, the phage application spectrum has been expanded to various medical and biotechnological fields. The construction of bacteriophages with an extended host range or longer viability in the mammalian bloodstream enhances their potential as an alternative to conventional antibiotic treatment. Insertion of active depolymerase genes to their genomes can enforce the biofilm disposal. They can also be engineered to transfer various compounds to the eukaryotic organisms and the bacterial culture, applicable for the vaccine, drug or gene delivery. Phage recombinant lytic enzymes can be applied as enzybiotics in medicine as well as in biotechnology for pathogen detection or programmed cell death in bacterial expression strains. Besides, modified bacteriophages with high specificity can be applied as bioprobes in detection tools to estimate the presence of pathogens in food industry, or utilized in the control of food-borne pathogens as part of the constructed phage-based biosorbents.
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Affiliation(s)
- P Bárdy
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - R Pantůček
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - M Benešík
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - J Doškař
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic
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Keary R, McAuliffe O, Ross RP, Hill C, O'Mahony J, Coffey A. Genome analysis of the staphylococcal temperate phage DW2 and functional studies on the endolysin and tail hydrolase. BACTERIOPHAGE 2014; 4:e28451. [PMID: 25105056 PMCID: PMC4124061 DOI: 10.4161/bact.28451] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/05/2014] [Accepted: 03/06/2014] [Indexed: 02/06/2023]
Abstract
This study describes the genome of temperate Siphoviridae phage DW2, which is routinely propagated on Staphylococcus aureus DPC5246. The 41941 bp genome revealed an open reading frame (ORF1) which has a high level of homology with members of the resolvase subfamily of site-specific serine recombinase, involved in chromosomal integration and excision. In contrast, the majority of staphylococcal phages reported to date encode tyrosine recombinases. Two putative genes encoded by phage DW2 (ORF15 and ORF24) were highly homologous to the NWMN0273 and NWMN0280 genes encoding virulence factors carried on the genome of ϕNM4, a prophage in the genome of S. aureus Newman. Phage DW2 also encodes proteins highly homologous to two well-characterized Staphylococcus aureus pathogenicity island derepressors encoded by the staphylococcal helper phage 80α indicating that it may similarly act as a helper phage for mobility of pathogenicity islands in S. aureus. This study also focused on the enzybiotic potential of phage DW2. The structure of the putative endolysin and tail hydrolase were investigated and used as the basis for a cloning strategy to create recombinant peptidoglycan hydrolyzing proteins. After overexpression in E. coli, four of these proteins (LysDW2, THDW2, CHAPE1-153, and CHAPE1-163) were demonstrated to have hydrolytic activity against peptidoglycan of S. aureus and thus represent novel candidates for exploitation as enzybiotics.
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Affiliation(s)
- Ruth Keary
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork Ireland
| | - Olivia McAuliffe
- Biotechnology Department; Teagasc; Moorepark Food Research Centre; Fermoy, Co. Cork Ireland
| | - R Paul Ross
- Biotechnology Department; Teagasc; Moorepark Food Research Centre; Fermoy, Co. Cork Ireland
| | - Colin Hill
- Alimentary Pharmacobiotic Centre; University College Cork; Cork, Ireland
| | - Jim O'Mahony
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork Ireland
| | - Aidan Coffey
- Department of Biological Sciences; Cork Institute of Technology; Bishopstown, Cork Ireland
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Vandersteegen K, Kropinski AM, Nash JHE, Noben JP, Hermans K, Lavigne R. Romulus and Remus, two phage isolates representing a distinct clade within the Twortlikevirus genus, display suitable properties for phage therapy applications. J Virol 2013; 87:3237-47. [PMID: 23302893 PMCID: PMC3592175 DOI: 10.1128/jvi.02763-12] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 12/07/2012] [Indexed: 11/20/2022] Open
Abstract
The renewed interest in controlling Staphylococcus aureus infections using their natural enemies, bacteriophages, has led to the isolation of a limited number of virulent phages so far. These phages are all members of the Twortlikevirus, displaying little variance. We present two novel closely related (95.9% DNA homology) lytic myoviruses, Romulus and Remus, with double-stranded DNA (dsDNA) genomes of 131,333 bp and 134,643 bp, respectively. Despite their relatedness to Staphylococcus phages K, G1, ISP, and Twort and Listeria phages A511 and P100, Romulus and Remus can be proposed as isolates of a new species within the Twortlikevirus genus. A distinguishing feature for these phage genomes is the unique distribution of group I introns compared to that in other staphylococcal myoviruses. In addition, a hedgehog/intein domain was found within their DNA polymerase genes, and an insertion sequence-encoded transposase exhibits splicing behavior and produces a functional portal protein. From a phage therapy application perspective, Romulus and Remus infected approximately 70% of the tested S. aureus isolates and displayed promising lytic activity against these isolates. Furthermore, both phages showed a rapid initial adsorption and demonstrated biofilm-degrading capacity in a proof-of-concept experiment.
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Affiliation(s)
- Katrien Vandersteegen
- Laboratory of Gene Technology, Division of Gene Technology, University of Leuven, Heverlee, Belgium
| | - Andrew M. Kropinski
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, Ontario, Canada
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - John H. E. Nash
- Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, Guelph, Ontario, Canada
| | - Jean-Paul Noben
- Biomedical Research Institute and Transnational University Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Katleen Hermans
- Department of Pathology, Bacteriology and Poultry Diseases, Ghent University, Merelbeke, Belgium
| | - Rob Lavigne
- Laboratory of Gene Technology, Division of Gene Technology, University of Leuven, Heverlee, Belgium
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Łobocka M, Hejnowicz MS, Dąbrowski K, Gozdek A, Kosakowski J, Witkowska M, Ulatowska MI, Weber-Dąbrowska B, Kwiatek M, Parasion S, Gawor J, Kosowska H, Głowacka A. Genomics of staphylococcal Twort-like phages--potential therapeutics of the post-antibiotic era. Adv Virus Res 2012; 83:143-216. [PMID: 22748811 DOI: 10.1016/b978-0-12-394438-2.00005-0] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Polyvalent bacteriophages of the genus Twort-like that infect clinically relevant Staphylococcus strains may be among the most promising phages with potential therapeutic applications. They are obligatorily lytic, infect the majority of Staphylococcus strains in clinical strain collections, propagate efficiently and do not transfer foreign DNA by transduction. Comparative genomic analysis of 11 S. aureus/S. epidermidis Twort-like phages, as presented in this chapter, emphasizes their strikingly high similarity and clear divergence from phage Twort of the same genus, which might have evolved in hosts of a different species group. Genetically, these phages form a relatively isolated group, which minimizes the risk of acquiring potentially harmful genes. The order of genes in core parts of their 127 to 140-kb genomes is conserved and resembles that found in related representatives of the Spounavirinae subfamily of myoviruses. Functions of certain conserved genes can be predicted based on their homology to prototypical genes of model spounavirus SPO1. Deletions in the genomes of certain phages mark genes that are dispensable for phage development. Nearly half of the genes of these phages have no known homologues. Unique genes are mostly located near termini of the virion DNA molecule and are expressed early in phage development as implied by analysis of their potential transcriptional signals. Thus, many of them are likely to play a role in host takeover. Single genes encode homologues of bacterial virulence-associated proteins. They were apparently acquired by a common ancestor of these phages by horizontal gene transfer but presumably evolved towards gaining functions that increase phage infectivity for bacteria or facilitate mature phage release. Major differences between the genomes of S. aureus/S. epidermidis Twort-like phages consist of single nucleotide polymorphisms and insertions/deletions of short stretches of nucleotides, single genes, or introns of group I. Although the number and location of introns may vary between particular phages, intron shuffling is unlikely to be a major factor responsible for specificity differences.
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Affiliation(s)
- Małgorzata Łobocka
- Department of Microbial Biochemistry, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
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Abstract
Peptidoglycan (PG) is the major structural component of the bacterial cell wall. Bacteria have autolytic PG hydrolases that allow the cell to grow and divide. A well-studied group of PG hydrolase enzymes are the bacteriophage endolysins. Endolysins are PG-degrading proteins that allow the phage to escape from the bacterial cell during the phage lytic cycle. The endolysins, when purified and exposed to PG externally, can cause "lysis from without." Numerous publications have described how this phenomenon can be used therapeutically as an effective antimicrobial against certain pathogens. Endolysins have a characteristic modular structure, often with multiple lytic and/or cell wall-binding domains (CBDs). They degrade the PG with glycosidase, amidase, endopeptidase, or lytic transglycosylase activities and have been shown to be synergistic with fellow PG hydrolases or a range of other antimicrobials. Due to the coevolution of phage and host, it is thought they are much less likely to invoke resistance. Endolysin engineering has opened a range of new applications for these proteins from food safety to environmental decontamination to more effective antimicrobials that are believed refractory to resistance development. To put phage endolysin work in a broader context, this chapter includes relevant studies of other well-characterized PG hydrolase antimicrobials.
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Abstract
Cronobacter sakazakii infection is particularly harmful to infants, and putative virulence factors of prophage origin have been identified in C. sakazakii. In this study, the phage ENT39118 was isolated from wild-type C. sakazakii; it belongs to the family Siphoviridae. The genomic sequence of phage ENT39118 was composed of circular double-stranded DNA with a length of 39,012 bp. The sequence of ENT39118 showed weak sequence similarity to some reported regions of the prophage sequences in the C. sakazakii BAA-894 genome. To our knowledge, this is the first study of the genomic sequencing and annotation of this temperate phage, which was obtained from a C. sakazakii isolate from powdered infant formula.
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Moradpour Z, Ghasemian A. Modified phages: Novel antimicrobial agents to combat infectious diseases. Biotechnol Adv 2011; 29:732-8. [DOI: 10.1016/j.biotechadv.2011.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/25/2011] [Accepted: 06/06/2011] [Indexed: 12/12/2022]
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Uchiyama J, Takemura I, Satoh M, Kato SI, Ujihara T, Akechi K, Matsuzaki S, Daibata M. Improved adsorption of an Enterococcus faecalis bacteriophage ΦEF24C with a spontaneous point mutation. PLoS One 2011; 6:e26648. [PMID: 22046321 PMCID: PMC3201976 DOI: 10.1371/journal.pone.0026648] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 09/30/2011] [Indexed: 11/19/2022] Open
Abstract
Some bacterial strains of the multidrug-resistant Gram-positive bacteria Enterococcus faecalis can significantly reduce the efficacy of conventional antimicrobial chemotherapy. Thus, the introduction of bacteriophage (phage) therapy is expected, where a phage is used as a bioagent to destroy bacteria. E. faecalis phage ΦEF24C is known to be a good candidate for a therapeutic phage against E. faecalis. However, this therapeutic phage still produces nonuniform antimicrobial effects with different bacterial strains of the same species and this might prove detrimental to its therapeutic effects. One solution to this problem is the preparation of mutant phages with higher activity, based on a scientific rationale. This study isolated and analyzed a spontaneous mutant phage, ΦEF24C-P2, which exhibited higher infectivity against various bacterial strains when compared with phage ΦEF24C. First, the improved bactericidal effects of phage ΦEF24C-P2 were attributable to its increased adsorption rate. Moreover, genomic sequence scanning revealed that phage ΦEF24C-P2 had a point mutation in orf31. Proteomic analysis showed that ORF31 (mw, 203 kDa) was present in structural components, and immunological analysis using rabbit-derived antibodies showed that it was a component of a long, flexible fine tail fiber extending from the tail end. Finally, phage ΦEF24C-P2 also showed higher bactericidal activity in human blood compared with phage ΦEF24C using the in vitro assay system. In conclusion, the therapeutic effects of phage ΦEF24C-P2 were improved by a point mutation in gene orf31, which encoded a tail fiber component.
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Affiliation(s)
- Jumpei Uchiyama
- Department of Microbiology and Infection, Faculty of Medicine, Kochi University, Kochi, Japan
| | - Iyo Takemura
- Department of Microbiology and Infection, Faculty of Medicine, Kochi University, Kochi, Japan
| | - Miho Satoh
- Science Research Center, Kochi University, Kochi, Japan
| | | | | | - Kazue Akechi
- Department of Microbiology and Infection, Faculty of Medicine, Kochi University, Kochi, Japan
| | - Shigenobu Matsuzaki
- Department of Microbiology and Infection, Faculty of Medicine, Kochi University, Kochi, Japan
- * E-mail:
| | - Masanori Daibata
- Department of Microbiology and Infection, Faculty of Medicine, Kochi University, Kochi, Japan
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Characterization of lytic enzyme open reading frame 9 (ORF9) derived from Enterococcus faecalis bacteriophage phiEF24C. Appl Environ Microbiol 2010; 77:580-5. [PMID: 21097580 DOI: 10.1128/aem.01540-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In bacteriophage (phage) therapy against Gram-positive bacteria, such as Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis, members of a genus of SPO1-like viruses are typically employed because of their extreme virulence and broad host spectrum. Phage φEF24C, which is a SPO1-like virus infecting E. faecalis, has previously been characterized as a therapeutic phage candidate. In addition to the phage itself, phage endolysin is also recognized as an effective antimicrobial agent. In this study, a putative endolysin gene (orf9) of E. faecalis phage φEF24C was analyzed in silico, and its activity was characterized using the recombinant form. First, bioinformatics analysis predicted that the open reading frame 9 (ORF9) protein is N-acetylmuramoyl-l-alanine amidase. Second, bacteriolytic and bactericidal activities of ORF9 against E. faecalis were confirmed by zymography, decrease of peptidoglycan turbidity, decrease of the viable count, and morphological analysis of ORF9-treated cells. Third, ORF9 did not appear to require Zn(2+) ions for its activity, contrary to the bioinformatics prediction of a Zn(2+) ion requirement. Fourth, the lytic spectrum was from 97.1% (34 out of 35 strains, including vancomycin-resistant strains) of E. faecalis strains to 60% (6 out of 10 strains) of Enterococcus faecium strains. Fifth, N-acetylmuramoyl-l-alanine amidase activity of ORF9 was confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and the subsequent MALDI-postsource decay (PSD) analyses. Finally, functional analysis using N- or C-terminally deleted ORF9 mutants suggested that a complete ORF9 molecule is essential for its activity. These results suggested that ORF9 is an endolysin of phage φEF24C and can be a therapeutic alternative to antibiotics.
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In silico and in vivo evaluation of bacteriophage phiEF24C, a candidate for treatment of Enterococcus faecalis infections. Appl Environ Microbiol 2008; 74:4149-63. [PMID: 18456848 DOI: 10.1128/aem.02371-07] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Along with the increasing threat of nosocomial infections by vancomycin-resistant Enterococcus faecalis, bacteriophage (phage) therapy has been expected as an alternative therapy against infectious disease. Although genome information and proof of applicability are prerequisites for a modern therapeutic phage, E. faecalis phage has not been analyzed in terms of these aspects. Previously, we reported a novel virulent phage, phiEF24C, and its biology indicated its therapeutic potential against E. faecalis infection. In this study, the phiEF24C genome was analyzed and the in vivo therapeutic applicability of phiEF24C was also briefly assessed. Its complete genome (142,072 bp) was predicted to have 221 open reading frames (ORFs) and five tRNA genes. In our functional analysis of the ORFs by use of a public database, no proteins undesirable in phage therapy, such as pathogenic and integration-related proteins, were predicted. The noncompetitive directions of replication and transcription and the host-adapted translation of the phage were deduced bioinformatically. Its genomic features indicated that phiEF24C is a member of the SPO1-like phage genus and especially that it has a close relationship to the Listeria phage P100, which is authorized for prophylactic use. Thus, these bioinformatics analyses rationalized the therapeutic eligibility of phiEF24C. Moreover, the in vivo therapeutic potential of phiEF24C, which was effective at a low concentration and was not affected by host sensitivity to the phage, was proven by use of sepsis BALB/c mouse models. Furthermore, no change in mouse lethality was observed under either single or repeated phage exposures. Although further study is required, phiEF24C can be a promising therapeutic phage against E. faecalis infections.
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