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Gong C, Chakraborty D, Koudelka GB. A prophage encoded ribosomal RNA methyltransferase regulates the virulence of Shiga-toxin-producing Escherichia coli (STEC). Nucleic Acids Res 2024; 52:856-871. [PMID: 38084890 PMCID: PMC10810198 DOI: 10.1093/nar/gkad1150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/09/2023] [Accepted: 11/14/2023] [Indexed: 01/26/2024] Open
Abstract
Shiga toxin (Stx) released by Shiga toxin producing Escherichia coli (STEC) causes life-threatening illness. Its production and release require induction of Stx-encoding prophage resident within the STEC genome. We identified two different STEC strains, PA2 and PA8, bearing Stx-encoding prophage whose sequences primarily differ by the position of an IS629 insertion element, yet differ in their abilities to kill eukaryotic cells and whose prophages differ in their spontaneous induction frequencies. The IS629 element in ϕPA2, disrupts an ORF predicted to encode a DNA adenine methyltransferase, whereas in ϕPA8, this element lies in an intergenic region. Introducing a plasmid expressing the methyltransferase gene product into ϕPA2 bearing-strains increases both the prophage spontaneous induction frequency and virulence to those exhibited by ϕPA8 bearing-strains. However, a plasmid bearing mutations predicted to disrupt the putative active site of the methyltransferase does not complement either of these defects. When complexed with a second protein, the methyltransferase holoenzyme preferentially uses 16S rRNA as a substrate. The second subunit is responsible for directing the preferential methylation of rRNA. Together these findings reveal a previously unrecognized role for rRNA methylation in regulating induction of Stx-encoding prophage.
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Affiliation(s)
- Chen Gong
- Department of Biological Sciences University at Buffalo, Buffalo, NY 14260, USA
| | | | - Gerald B Koudelka
- Department of Biological Sciences University at Buffalo, Buffalo, NY 14260, USA
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2
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Ngoma NFN, Malahlela MN, Marufu MC, Cenci-Goga BT, Grispoldi L, Etter E, Kalake A, Karama M. Antimicrobial growth promoters approved in food-producing animals in South Africa induce shiga toxin-converting bacteriophages from Escherichia coli O157:H7. Gut Pathog 2023; 15:64. [PMID: 38057920 DOI: 10.1186/s13099-023-00590-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/23/2023] [Indexed: 12/08/2023] Open
Abstract
In this study, four antimicrobial growth promoters, including virginiamycin, josamycin, flavophospholipol, poly 2-propenal 2-propenoic acid and ultraviolet light, were tested for their capacity to induce stx-bacteriophages in 47 Shiga toxin-producing E. coli O157:H7 isolates. Induced bacteriophages were characterized for shiga toxin subtypes and structural genes by PCR, DNA restriction fragment length polymorphisms (RFLP) and morphological features by electron microscopy. Bacteriophages were induced from 72.3% (34/47) of the STEC O157:H7 isolates tested. Bacteriophage induction rates per induction method were as follows: ultraviolet light, 53.2% (25/47); poly 2-propenal 2-propenoic acid, 42.6% (20/47); virginiamycin, 34.0% (16/47); josamycin, 34.0% (16/47); and flavophospholipol, 29.8% (14/47). A total of 98 bacteriophages were isolated, but only 59 were digestible by NdeI, revealing 40 RFLP profiles which could be subdivided in 12 phylogenetic subgroups. Among the 98 bacteriophages, stx2a, stx2c and stx2d were present in 85.7%, 94.9% and 36.7% of bacteriophages, respectively. The Q, P, CIII, N1, N2 and IS1203 genes were found in 96.9%, 82.7%, 69.4%, 40.8%, 60.2% and 73.5% of the samples, respectively. Electron microscopy revealed four main representative morphologies which included three bacteriophages which all had long tails but different head morphologies: long hexagonal head, oval/oblong head and oval/circular head, and one bacteriophage with an icosahedral/hexagonal head with a short thick contractile tail. This study demonstrated that virginiamycin, josamycin, flavophospholipol and poly 2-propenal 2-propenoic acid induce genetically and morphologically diverse free stx-converting bacteriophages from STEC O157:H7. The possibility that these antimicrobial growth promoters may induce bacteriophages in vivo in animals and human hosts is a public health concern. Policies aimed at minimizing or banning the use of antimicrobial growth promoters should be promoted and implemented in countries where these compounds are still in use in animal agriculture.
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Affiliation(s)
- Nomonde F N Ngoma
- Department of Paraclinical Sciences, Faculty of Veterinary Science, Veterinary Public Health Section, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Mogaugedi N Malahlela
- Department of Paraclinical Sciences, Faculty of Veterinary Science, Veterinary Public Health Section, University of Pretoria, Onderstepoort, 0110, South Africa
| | - Munyaradzi C Marufu
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
| | - Beniamino T Cenci-Goga
- Department of Paraclinical Sciences, Faculty of Veterinary Science, Veterinary Public Health Section, University of Pretoria, Onderstepoort, 0110, South Africa
- Departimento di Medicina Veterinaria, Laboratorio di Ispezione Degli Alimenti di Origine Animale, University of Perugia, Perugia, 06126, Italy
| | - Luca Grispoldi
- Departimento di Medicina Veterinaria, Laboratorio di Ispezione Degli Alimenti di Origine Animale, University of Perugia, Perugia, 06126, Italy
| | - Eric Etter
- CIRAD, UMR ASTRE, Petit-Bourg, F-97170, France
- ASTRE, Université de Montpellier, CIRAD INRAE, Montpellier, France
| | - Alan Kalake
- Gauteng Department of Agriculture and Rural Development, Johannesburg, 2001, South Africa
| | - Musafiri Karama
- Department of Paraclinical Sciences, Faculty of Veterinary Science, Veterinary Public Health Section, University of Pretoria, Onderstepoort, 0110, South Africa.
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3
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Atitkar RR, Melton-Celsa AR. Differences in the Shiga Toxin (Stx) 2a Phage Regulatory Switch Region Influence Stx2 Localization and Virulence of Stx-Producing Escherichia coli in Mice. Microorganisms 2023; 11:1925. [PMID: 37630485 PMCID: PMC10458857 DOI: 10.3390/microorganisms11081925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/21/2023] [Accepted: 07/26/2023] [Indexed: 08/27/2023] Open
Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) is a major cause of foodborne illness globally, and infection with serotype O157:H7 is associated with increased risk of hospitalization and death in the U.S. The Stxs are encoded on a temperate bacteriophage (stx-phage), and phage induction leads to Stx expression; subtype Stx2a in particular is associated with more severe disease. Our earlier studies showed significant levels of RecA-independent Stx2 production by STEC O157:H7 strain JH2010 (stx2astx2c), even though activated RecA is the canonical trigger for stx-phage induction. This study aimed to further compare and contrast RecA-independent toxin production in Stx2-producing clinical isolates. Deletion of recA in JH2010 resulted in higher in vitro supernatant cytotoxicity compared to that from JH2016ΔrecA, and the addition of the chelator ethylenediaminetetraacetic acid (EDTA) and various metal cations to the growth medium exacerbated the difference in cytotoxicity exhibited by the two deletion strains. Both the wild-type and ΔrecA deletion strains exhibited differential cytotoxicity in the feces of infected, streptomycin (Str)-treated mice. Comparison of the stx2a-phage predicted protein sequences from JH2010 and JH2016 revealed low amino acid identity of key phage regulatory proteins that are involved in RecA-mediated stx-phage induction. Additionally, other STEC isolates containing JH2010-like and JH2016-like stx2a-phage sequences led to similar Stx2 localization, as demonstrated by JH2010ΔrecA and JH2016ΔrecA, respectively. Deletion of the stx2a-phage regulatory region in the wild-type strains prevented the differential localization of Stx2 into the culture supernatant, a finding that suggests that the stx2a-phage regulatory region is involved in the differential ΔrecA phenotypes exhibited by the two strains. We hypothesize that the amino acid differences between the JH2010 and JH2016 phage repressor proteins (CIs) lead to structural differences that are responsible for differential interaction with RecA. Overall, we discovered that non-homologous stx2a-phage regulatory proteins differentially influence RecA-independent, and possibly RecA-dependent, Stx2 production. These findings emphasize the importance of studying non-homologous regulatory elements among stx2-phages and their influence on Stx2 production and virulence of STEC isolates.
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Affiliation(s)
- Rama R. Atitkar
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD 20817, USA
| | - Angela R. Melton-Celsa
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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4
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Miura S, Satoh R, Tamamura-Andoh Y, Tokugawa K, Beppu M, Nozaki C, Murata R, Kusumoto M, Uchida I. Intra-macrophage expression of ArtAB toxin gene in Salmonella. MICROBIOLOGY (READING, ENGLAND) 2022; 168. [PMID: 35333707 DOI: 10.1099/mic.0.001152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Salmonella enterica subspecies enterica serovar Typhimurium (S. Typhimurium) definitive phage type 104 (DT104), S. Worthington, and S. bongori produce ArtAB toxin, which catalyses ADP-ribosylation of pertussis toxin-sensitive G protein. ArtAB gene (artAB) is encoded on a prophage in Salmonella, and prophage induction by SOS-inducing agents is associated with increases in ArtAB production in vitro. However, little is known about the expression of artAB in vivo. Here, we showed a significant increase in artAB transcription of DT104 within macrophage-like RAW264.7 cells. Intracellular expression of ArtAB was also observed by immunofluorescence staining. The induced expression of artAB in DT104 and S. bongori was enhanced by treatment of RAW264.7 cells with phorbol 12-myristate 13-acetate (PMA), which stimulates the production of reactive oxygen species (ROS); however, such induction was not observed in S. Worthington. Upregulation of oxyR, a major regulator of oxidative stress, and cI, a repressor of prophage induction, was observed in S. Worthington within RAW264.7 cells treated with PMA but not in the DT104 strain. Although the expression of oxyR was increased, artAB was upregulated in S. bongori, which lacks the cI gene in the incomplete artAB-encoded prophage. Taken together, oxidative stress plays a role in the production of artAB toxins in macrophages, and high expression levels of oxyR and cI are responsible for the low expression of artAB. Therefore, strain variation in the level of artAB expression within macrophages could be explained by differences in the oxidative stress response of bacteria and might be reflected in its virulence.
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Affiliation(s)
- Shou Miura
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Rin Satoh
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Yukino Tamamura-Andoh
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, Tsukuba, Ibaraki, 305-0856, Japan
| | - Kanetaka Tokugawa
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Miho Beppu
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Chiharu Nozaki
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Ryo Murata
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
| | - Masahiro Kusumoto
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, Tsukuba, Ibaraki, 305-0856, Japan
| | - Ikuo Uchida
- Veterinary Bacteriology, Department of Pathobiology, School of Veterinary Medicine, Rakuno Gakuen University, 582, Bunkyodai-Midorimachi, Ebetsu, Hokkaido, 069-8501, Japan
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5
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Fagerlund A, Aspholm M, Węgrzyn G, Lindbäck T. High diversity in the regulatory region of Shiga toxin encoding bacteriophages. BMC Genomics 2022; 23:230. [PMID: 35331132 PMCID: PMC8951638 DOI: 10.1186/s12864-022-08428-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/28/2022] [Indexed: 12/26/2022] Open
Abstract
Background Enterohemorrhagic Escherichia coli (EHEC) is an emerging health challenge worldwide and outbreaks caused by this pathogen poses a serious public health concern. Shiga toxin (Stx) is the major virulence factor of EHEC, and the stx genes are carried by temperate bacteriophages (Stx phages). The switch between lysogenic and lytic life cycle of the phage, which is crucial for Stx production and for severity of the disease, is regulated by the CI repressor which maintain latency by preventing transcription of the replication proteins. Three EHEC phage replication units (Eru1-3) in addition to the classical lambdoid replication region have been described previously, and Stx phages carrying the Eru1 replication region were associated with highly virulent EHEC strains. Results In this study, we have classified the Eru replication region of 419 Stx phages. In addition to the lambdoid replication region and three already described Erus, ten novel Erus (Eru4 to Eru13) were detected. The lambdoid type, Eru1, Eru4 and Eru7 are widely distributed in Western Europe. Notably, EHEC strains involved in severe outbreaks in England and Norway carry Stx phages with Eru1, Eru2, Eru5 and Eru7 replication regions. Phylogenetic analysis of CI repressors from Stx phages revealed eight major clades that largely separate according to Eru type. Conclusion The classification of replication regions and CI proteins of Stx phages provides an important platform for further studies aimed to assess how characteristics of the replication region influence the regulation of phage life cycle and, consequently, the virulence potential of the host EHEC strain. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08428-5.
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Affiliation(s)
- Annette Fagerlund
- Norwegian Institute of Food, Fisheries and Aquaculture Research, Ås, Norway
| | - Marina Aspholm
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, Faculty of Biology, University of Gdañsk, Gdañsk, Poland
| | - Toril Lindbäck
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, Ås, Norway.
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6
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Hu J, Ye H, Wang S, Wang J, Han D. Prophage Activation in the Intestine: Insights Into Functions and Possible Applications. Front Microbiol 2021; 12:785634. [PMID: 34966370 PMCID: PMC8710666 DOI: 10.3389/fmicb.2021.785634] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 11/25/2021] [Indexed: 01/20/2023] Open
Abstract
Prophage activation in intestinal environments has been frequently reported to affect host adaptability, pathogen virulence, gut bacterial community composition, and intestinal health. Prophage activation is mostly caused by various stimulators, such as diet, antibiotics, some bacterial metabolites, gastrointestinal transit, inflammatory environment, oxidative stress, and quorum sensing. Moreover, with advancements in biotechnology and the deepening cognition of prophages, prophage activation regulation therapy is currently applied to the treatment of some bacterial intestinal diseases such as Shiga toxin-producing Escherichia coli infection. This review aims to make headway on prophage induction in the intestine, in order to make a better understanding of dynamic changes of prophages, effects of prophage activation on physiological characteristics of bacteria and intestinal health, and subsequently provide guidance on prophage activation regulation therapy.
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Affiliation(s)
| | | | | | | | - Dandan Han
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China
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7
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Differential induction of Shiga toxin in environmental Escherichia coli O145:H28 strains carrying the same genotype as the outbreak strains. Int J Food Microbiol 2020; 339:109029. [PMID: 33360585 DOI: 10.1016/j.ijfoodmicro.2020.109029] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023]
Abstract
Shiga toxin-producing Escherichia coli (STEC) O145 is a major serotype associated with severe human disease. Production of Shiga toxins (Stxs), especially Stx2a, is thought to be correlated with STEC virulence. Since stx genes are located in prophages genomes, induction of prophages is required for effective Stxs production. Here, we investigated the production of Stxs in 12 environmental STEC O145:H28 strains under stresses STEC encounter in natural habitats and performed comparative analysis with two O145:H28 clinical strains, one linked to a 2010 U.S. lettuce-associated outbreak (RM13514) and the other linked to a 2007 Belgium ice cream-associated outbreak (RM13516). Similar to the outbreak strains, all environmental strains belong to Sequence Type (ST)-78 using the EcMLST typing scheme. Although all Stx1a-prophages were grouped together, variations in Stx1a production were observed prior to or following the inductions. Among all stx2a positive environmental strains, only the Stx2a-prophage in cattle isolate RM9154-C1 was clustered with the Stx2a-prophages in RM13514, the Stx2a-phage induced from a STEC O104:H4 strain linked to the 2011 outbreak of enterohemorrhagic infection in Germany, and the Stx2a-prophage in STEC O157:H7 strain EDL933, a prototype of enterohemorrhagic E. coli. Furthermore, the Stx2a-prophage in RM9154-C1 shared the same chromosomal insertion site and carried the same antiterminator Q gene and the late promoter PR' as the Stx2a-prophage in RM13514. Following mitomycin C or enrofloxacin treatment, the production of Stx2a in RM9154-C1 was the highest among all environmental strains tested. In contrast, following acid challenge and recovery, the production of Stx2a in RM9154-C1 was the lowest among all the environmental strains tested, at a level comparable to the clinical strains. A significant increase in Stx2a production was detected in all strains when exposed to H2O2, although the induction fold was much lower than those by other inducers. This low-efficiency induction of Stx-prophages by H2O2, a natural inducer of Stx-prophages, supports the hypothesis of bacterial altruism in controlling Stxs production, a strategy that assures the survival of the STEC population as a whole by sacrificing a small fraction of cells for Stxs production and release. Differential induction of Stxs among strains carrying nearly identical Stx-prophages suggests a role of host bacteria in regulating Stxs production. Our study revealed diverse Stx-prophages in STEC O145:H28 strains that were genotypically indistinguishable. Identification of a cattle isolate harboring a Stx2a-prophage associated with high virulence supports the premise that cattle, a natural reservoir of STEC, serve as a source of hypervirulent STEC strains.
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Howard-Varona C, Vik DR, Solonenko NE, Li YF, Gazitua MC, Chittick L, Samiec JK, Jensen AE, Anderson P, Howard-Varona A, Kinkhabwala AA, Abedon ST, Sullivan MB. Fighting Fire with Fire: Phage Potential for the Treatment of E. coli O157 Infection. Antibiotics (Basel) 2018; 7:E101. [PMID: 30453470 PMCID: PMC6315980 DOI: 10.3390/antibiotics7040101] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/09/2018] [Accepted: 11/14/2018] [Indexed: 02/07/2023] Open
Abstract
Hemolytic⁻uremic syndrome is a life-threating disease most often associated with Shiga toxin-producing microorganisms like Escherichia coli (STEC), including E. coli O157:H7. Shiga toxin is encoded by resident prophages present within this bacterium, and both its production and release depend on the induction of Shiga toxin-encoding prophages. Consequently, treatment of STEC infections tend to be largely supportive rather than antibacterial, in part due to concerns about exacerbating such prophage induction. Here we explore STEC O157:H7 prophage induction in vitro as it pertains to phage therapy-the application of bacteriophages as antibacterial agents to treat bacterial infections-to curtail prophage induction events, while also reducing STEC O157:H7 presence. We observed that cultures treated with strictly lytic phages, despite being lysed, produce substantially fewer Shiga toxin-encoding temperate-phage virions than untreated STEC controls. We therefore suggest that phage therapy could have utility as a prophylactic treatment of individuals suspected of having been recently exposed to STEC, especially if prophage induction and by extension Shiga toxin production is not exacerbated.
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Affiliation(s)
| | - Dean R Vik
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Natalie E Solonenko
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Yueh-Fen Li
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - M Consuelo Gazitua
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Lauren Chittick
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Jennifer K Samiec
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Aubrey E Jensen
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Paige Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | | | | | - Stephen T Abedon
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
| | - Matthew B Sullivan
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
- Department of Civil, Environmental and Geodetic Engineering, The Ohio State University, Columbus, OH 43210, USA.
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9
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Górski A, Jończyk-Matysiak E, Międzybrodzki R, Weber-Dąbrowska B, Łusiak-Szelachowska M, Bagińska N, Borysowski J, Łobocka MB, Węgrzyn A, Węgrzyn G. Phage Therapy: Beyond Antibacterial Action. Front Med (Lausanne) 2018; 5:146. [PMID: 29876350 PMCID: PMC5974148 DOI: 10.3389/fmed.2018.00146] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
Until recently, phages were considered as mere “bacteria eaters” with potential for use in combating antimicrobial resistance. The real value of phage therapy assessed according to the standards of evidence-based medicine awaits confirmation by clinical trials. However, the progress in research on phage biology has shed more light on the significance of phages. Accumulating data indicate that phages may also interact with eukaryotic cells. How such interactions could be translated into advances in medicine (especially novel means of therapy) is discussed herein.
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Affiliation(s)
- Andrzej Górski
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.,Phage Therapy Unit, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.,Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Warsaw, Poland
| | - Ewa Jończyk-Matysiak
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Ryszard Międzybrodzki
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.,Phage Therapy Unit, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.,Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Warsaw, Poland
| | - Beata Weber-Dąbrowska
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland.,Phage Therapy Unit, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Marzanna Łusiak-Szelachowska
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Natalia Bagińska
- Bacteriophage Laboratory, Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
| | - Jan Borysowski
- Department of Clinical Immunology, Transplantation Institute, Medical University of Warsaw, Warsaw, Poland
| | - Małgorzata B Łobocka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.,Autonomous Department of Microbial Biology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences, Warsaw, Poland
| | - Alicja Węgrzyn
- Laboratory of Molecular Biology, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Gdańsk, Poland
| | - Grzegorz Węgrzyn
- Department of Molecular Biology, University of Gdańsk, Gdańsk, Poland
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10
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Thuraisamy T, Lodato PB. Influence of RNase E deficiency on the production of stx2-bearing phages and Shiga toxin in an RNase E-inducible strain of enterohaemorrhagic Escherichia coli (EHEC) O157:H7. J Med Microbiol 2018; 67:724-732. [PMID: 29620505 PMCID: PMC7001489 DOI: 10.1099/jmm.0.000728] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 03/21/2018] [Indexed: 12/14/2022] Open
Abstract
PURPOSE In enterohaemorrhagic Escherichia coli (EHEC), stx1 or stx2 genes encode Shiga toxin (Stx1 or Stx2, respectively) and are carried by prophages. The production and release of both stx phages and toxin occur upon initiation of the phage lytic cycle. Phages can further disseminate stx genes by infecting naïve bacteria in the intestine. Here, the effect of RNase E deficiency on these two virulence traits was investigated. METHODOLOGY Cultures of the EHEC strains TEA028-rne containing low versus normal RNase E levels or the parental strain (TEA028) were treated with mitomycin C (MMC) to induce the phage lytic cycle. Phages and Stx2 titres were quantified by the double-agar assay and the receptor ELISA technique, respectively. RESULTS RNase E deficiency in MMC-treated cells significantly reduced the yield of infectious stx2 phages. Delayed cell lysis and the appearance of encapsidated phage DNA copies suggest a slow onset of the lytic cycle. However, these observations do not entirely explain the decrease of phage yields. stx1 phages were not detected under normal or deficient RNase E levels. After an initial delay, high levels of toxin were finally produced in MMC-treated cultures. CONCLUSION RNase E scarcity reduces stx2 phage production but not toxin. Normal concentrations of RNase E are likely required for correct phage morphogenesis. Our future work will address the mechanism of RNase E action on phage morphogenesis.
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Molecular Mechanisms Governing "Hair-Trigger" Induction of Shiga Toxin-Encoding Prophages. Viruses 2018; 10:v10050228. [PMID: 29710828 PMCID: PMC5977221 DOI: 10.3390/v10050228] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 01/12/2023] Open
Abstract
Shiga toxin (Stx)-encoding E. coli (STEC) strains are responsible for sporadic outbreaks of food poisoning dating to 1982, when the first STEC strain, E. coli O157:H7, was isolated. Regardless of STEC serotype, the primary symptoms of STEC infections are caused by Stx that is synthesized from genes resident on lambdoid prophage present in STEC. Despite similar etiology, the severity of STEC-mediated disease varies by outbreak. However, it is unclear what modulates the severity of STEC-mediated disease. Stx production and release is controlled by lytic growth of the Stx-encoding bacteriophage, which in turn, is controlled by the phage repressor. Here, we confirm our earlier suggestion that the higher spontaneous induction frequency of Stx-encoding prophage is a consequence, in part, of lower intracellular repressor levels in STEC strains versus non-STEC strains. We also show that this lowered intracellular repressor concentration is a consequence of the utilization of alternative binding/regulatory strategies by the phage repressor. We suggest that a higher spontaneous induction frequency would lead to increased virulence.
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Expert Opinion on Three Phage Therapy Related Topics: Bacterial Phage Resistance, Phage Training and Prophages in Bacterial Production Strains. Viruses 2018; 10:v10040178. [PMID: 29621199 PMCID: PMC5923472 DOI: 10.3390/v10040178] [Citation(s) in RCA: 114] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 04/03/2018] [Accepted: 04/03/2018] [Indexed: 12/11/2022] Open
Abstract
Phage therapy is increasingly put forward as a “new” potential tool in the fight against antibiotic resistant infections. During the “Centennial Celebration of Bacteriophage Research” conference in Tbilisi, Georgia on 26–29 June 2017, an international group of phage researchers committed to elaborate an expert opinion on three contentious phage therapy related issues that are hampering clinical progress in the field of phage therapy. This paper explores and discusses bacterial phage resistance, phage training and the presence of prophages in bacterial production strains while reviewing relevant research findings and experiences. Our purpose is to inform phage therapy stakeholders such as policy makers, officials of the competent authorities for medicines, phage researchers and phage producers, and members of the pharmaceutical industry. This brief also points out potential avenues for future phage therapy research and development as it specifically addresses those overarching questions that currently call for attention whenever phages go into purification processes for application.
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Shigatoxin encoding Bacteriophage ϕ24 B modulates bacterial metabolism to raise antimicrobial tolerance. Sci Rep 2017; 7:40424. [PMID: 28106081 PMCID: PMC5247750 DOI: 10.1038/srep40424] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/07/2016] [Indexed: 01/15/2023] Open
Abstract
How temperate bacteriophages play a role in microbial infection and disease progression is not fully understood. They do this in part by carrying genes that promote positive evolutionary selection for the lysogen. Using Biolog phenotype microarrays and comparative metabolite profiling we demonstrate the impact of the well-characterised Shiga toxin-prophage ϕ24B on its Escherichia coli host MC1061. As a lysogen, the prophage alters the bacterial physiology by increasing the rates of respiration and cell proliferation. This is the first reported study detailing phage-mediated control of the E. coli biotin and fatty acid synthesis that is rate limiting to cell growth. Through ϕ24B conversion the lysogen also gains increased antimicrobial tolerance to chloroxylenol and 8-hydroxyquinoline. Distinct metabolite profiles discriminate between MC1061 and the ϕ24B lysogen in standard culture, and when treated with 2 antimicrobials. This is also the first reported use of metabolite profiling to characterise the physiological impact of lysogeny under antimicrobial pressure. We propose that temperate phages do not need to carry antimicrobial resistance genes to play a significant role in tolerance to antimicrobials.
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