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TAKAMATSU D. Atypical Melissococcus plutonius strains: their characteristics, virulence, epidemiology, and mysteries. J Vet Med Sci 2023; 85:880-894. [PMID: 37460304 PMCID: PMC10539817 DOI: 10.1292/jvms.23-0180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 07/06/2023] [Indexed: 09/05/2023] Open
Abstract
Melissococcus plutonius is a Gram-positive lanceolate coccus that is the causative agent of European foulbrood, an important bacterial disease of honey bee brood. Although this bacterium was originally described in the early 20th century, a culture method for this bacterium was not established until more than 40 years after its discovery due to its fastidious characteristics, including the requirement for high potassium and anaerobic/microaerophilic conditions. These characteristics were considered to be common to the majority of M. plutonius strains isolated worldwide, and M. plutonius was also thought to be genetically homologous or clonal for years. However, non-fastidious variants of this species (designated as atypical M. plutonius) were very recently identified in Japan. Although the morphology of these unusual strains was similar to that of traditionally well-known M. plutonius strains, atypical strains were genetically very different from most of the M. plutonius strains previously isolated and were highly virulent to individual bee larva. These atypical variants were initially considered to be unique to Japan, but were subsequently found worldwide; however, the frequency of isolation varied from country to country. The background of the discovery of atypical M. plutonius in Japan and current knowledge on atypical strains, including their biochemical and culture characteristics, virulence, detection methods, and global distribution, are described in this review. Remaining mysteries related to atypical M. plutonius and directions for future research are also discussed.
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Affiliation(s)
- Daisuke TAKAMATSU
- Division of Infectious Animal Disease Research, National Institute of Animal Health, National Agriculture and Food Research Organization, Ibaraki, Japan
- The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
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Tabata A, Matsumoto A, Fujimoto A, Ohkura K, Ikeda T, Oda H, Yokohata S, Kobayashi M, Tomoyasu T, Takao A, Ohkuni H, Nagamune H. Dual functions of discoidinolysin, a cholesterol-dependent cytolysin with N-terminal discoidin domain produced from Streptococcus mitis strain Nm-76. J Oral Microbiol 2022; 14:2105013. [PMID: 35937899 PMCID: PMC9351568 DOI: 10.1080/20002297.2022.2105013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Some strains of Streptococcus mitis exhibit β-hemolysis due to the β-hemolytic activity of cholesterol-dependent cytolysin (CDC). Recently, a gene encoding an atypical lectinolysin-related CDC was found in S. mitis strain Nm-76. However, the product of this gene remains uncharacterized. We aimed to characterize this atypical CDC and its molecular functions and contribution to the pathogenicity of S. mitis strain Nm-76. Methods Phylogenetic analysis of the CDC gene was conducted based on the web-deposited information. The molecular characteristics of CDC were investigated using a gene-deletion mutant strain and recombinant proteins expressed in Escherichia coli. Results The gene encoding CDC found in Nm-76 and its homolog are distributed among many S. mitis strains. This CDC is phylogenetically different from other previously characterized CDCs, such as S. mitis-derived human platelet aggregation factor (Sm-hPAF)/lectinolysin and mitilysin. Because this CDC possesses an additional N-terminal domain, including a discoidin motif, it was termed discoidinolysin (DLY). In addition to the preferential lysis of human cells, DLY displayed N-terminal domain-dependent facilitation of human erythrocyte aggregation and intercellular associations between human cells. Conclusion DLY functions as a hemolysin/cytolysin and erythrocyte aggregation/intercellular association molecule. This dual-function DLY could be an additional virulence factor in S. mitis.
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Affiliation(s)
- Atsushi Tabata
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Airi Matsumoto
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Ai Fujimoto
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kazuto Ohkura
- Division of Clinical Pharmacy and Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
| | - Takuya Ikeda
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Hiroki Oda
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Shuto Yokohata
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Miho Kobayashi
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Toshifumi Tomoyasu
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
| | - Ayuko Takao
- Department of Oral Microbiology, School of Dental Medicine, Tsurumi University, Kanagawa, Japan
| | - Hisashi Ohkuni
- Research Institute, Health Science Research Institute East Japan Co., Ltd., Saitama, Japan
| | - Hideaki Nagamune
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Japan
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Molecular Detection and Differentiation of Arthropod, Fungal, Protozoan, Bacterial and Viral Pathogens of Honeybees. Vet Sci 2022; 9:vetsci9050221. [PMID: 35622749 PMCID: PMC9145064 DOI: 10.3390/vetsci9050221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/26/2022] [Accepted: 04/27/2022] [Indexed: 02/01/2023] Open
Abstract
The honeybee Apis mellifera is highly appreciated worldwide because of its products, but also as it is a pollinator of crops and wild plants. The beehive is vulnerable to infections due to arthropods, fungi, protozoa, bacteria and/or viruses that manage to by-pass the individual and social immune mechanisms of bees. Due to the close proximity of bees in the beehive and their foraging habits, infections easily spread within and between beehives. Moreover, international trade of bees has caused the global spread of infections, several of which result in significant losses for apiculture. Only in a few cases can infections be diagnosed with the naked eye, by direct observation of the pathogen in the case of some arthropods, or by pathogen-associated distinctive traits. Development of molecular methods based on the amplification and analysis of one or more genes or genomic segments has brought significant progress to the study of bee pathogens, allowing for: (i) the precise and sensitive identification of the infectious agent; (ii) the analysis of co-infections; (iii) the description of novel species; (iv) associations between geno- and pheno-types and (v) population structure studies. Sequencing of bee pathogen genomes has allowed for the identification of new molecular targets and the development of specific genotypification strategies.
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Pérez-Ordóñez G, Romo-Chacón A, Rios-Velasco C, Sepúlveda DR, de Jesús Ornelas-Paz J, Acosta-Muñiz CH. Virulence variations between clonal complexes of Melisococcus plutonius and the possible causes. J Invertebr Pathol 2021; 186:107686. [PMID: 34780719 DOI: 10.1016/j.jip.2021.107686] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 09/23/2021] [Accepted: 10/24/2021] [Indexed: 11/17/2022]
Abstract
Melissococcus plutonius is a pathogenic bacterium that affects honeybee brood triggering colony collapse in severe cases. The bacterium causes a European foulbrood (EFB) disease in the honeybee populations, impacting beekeeping and agricultural industries. The pathogenesis, epidemiology, and variants of M. plutonius have been studied, but the virulence factors involved in larval infection are still unknown. Recently, an in-silico study suggested putative genes that might play a role in the pathogenesis of EFB. However, studies are required to determine their function as virulence factors. In addition, the few studies of clonal complexes (CCs), virulence factors, and variation in the honeybee larvae mortality have interfered with the development of more efficient control methods. The research, development, and differences in virulence between genetic variants (CCs) of M. plutonius and potential virulence factors implicated in honeybee larval mortality are discussed in this review.
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Affiliation(s)
- Gerardo Pérez-Ordóñez
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
| | - Alejandro Romo-Chacón
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
| | - Claudio Rios-Velasco
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
| | - David R Sepúlveda
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
| | - José de Jesús Ornelas-Paz
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
| | - Carlos H Acosta-Muñiz
- Centro de Investigación en Alimentación y Desarrollo, A.C. Av. Rio Conchos s/n, parque industrial, Z.C. 31570 Cuauhtémoc, Chihuahua, Mexico.
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Peritrophic matrix-degrading proteins are dispensable virulence factors in a virulent Melissococcus plutonius strain. Sci Rep 2021; 11:8798. [PMID: 33888837 PMCID: PMC8062581 DOI: 10.1038/s41598-021-88302-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 04/12/2021] [Indexed: 11/08/2022] Open
Abstract
European foulbrood (EFB) caused by Melissococcus plutonius is a major bacterial disease of honey bees. Strains of the causative agent exhibit genetic heterogeneity, and the degree of virulence varies among strains. In bee larvae orally infected with the highly virulent strains, ingested bacterial cells colonize the larval midgut and proliferate within the sac of the peritrophic matrix (PM), a barrier lining the midgut epithelium. However, the barrier is degraded during the course of infection, and M. plutonius cells eventually directly interact with the midgut epithelium. As M. plutonius possesses genes encoding putative PM-degrading proteins (enhancin, a chitin-binding domain-containing protein and endo-α-N-acetylgalactosaminidase), we constructed PM-degrading protein gene-knockout mutants from a highly virulent M. plutonius strain and investigated their role in the pathogenesis of EFB. In larvae infected with the triple-knockout mutant, which has no PM-degrading protein genes, M. plutonius that proliferated in the larval midguts was confined to the sac of the PM. However, the midgut epithelial cells degenerated over time, and the mutant killed approximately 70-80% of bee brood, suggesting that although the PM-degrading proteins are involved in the penetration of the PM by M. plutonius, they are not indispensable virulence factors in the highly virulent M. plutonius strain.
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Matsumoto A, Tabata A, Ohkura K, Oda H, Kodama C, Ohkuni H, Takao A, Kikuchi K, Tomoyasu T, Nagamune H. Molecular characteristics of an adhesion molecule containing cholesterol-dependent cytolysin-motif produced by mitis group streptococci. Microbiol Immunol 2021; 65:61-75. [PMID: 33331679 DOI: 10.1111/1348-0421.12868] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 01/06/2023]
Abstract
Streptococcus pseudopneumoniae (SPpn) is a relatively new species closely related to S. pneumoniae (SPn) and S. mitis (SM) belonging to the Mitis group of the genus Streptococcus (MGS). Although genes encoding various pneumococcal virulence factors have been observed in the SPpn genome, the pathogenicity of SPpn against human, including the roles of virulence factor candidates, is still unclear. The present study focused on and characterized a candidate virulence factor previously reported in SPpn with deduced multiple functional domains, such as lipase domain, two lectin domains, and cholesterol-dependent cytolysin-related domain using various recombinant proteins. The gene was found not only in SPpn but also in the strains of SM and SPn. Moreover, the gene product was expressed in the gene-positive strains as secreted and cell-bound forms. The recombinant of gene product showed lipase activity and human cell-binding activity depending on the function of lectin domain(s), but no hemolytic activity. Thus, based on the distribution of the gene within the MGS and its molecular function, the gene product was named mitilectin (MLC) and its contribution to the potential pathogenicity of the MLC-producing strains was investigated. Consequently, the treatment with anti-MLC antibody and the mlc gene-knockout significantly reduced the human cell-binding activity of MLC-producing strains. Therefore, the multifunctional MLC was suggested to be important as an adhesion molecule in considering the potential pathogenicity of the MLC-producing strains belonging to MGS, such as SPpn and SM.
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Affiliation(s)
- Airi Matsumoto
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Tokushima, Japan
| | - Atsushi Tabata
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Tokushima, Japan
| | - Kazuto Ohkura
- Division of Clinical Pharmacy and Pharmaceutical Sciences, Graduate School of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Mie, Japan
| | - Hiroki Oda
- Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Tokushima, Japan
| | - Chihiro Kodama
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Tokushima, Japan
| | - Hisashi Ohkuni
- Health Science Research Institute East Japan, Kounosu, Saitama, Japan
| | - Ayuko Takao
- Department of Oral Microbiology, School of Dental Medicine, Tsurumi University, Yokohama, Kanagawa, Japan
| | - Ken Kikuchi
- Department of Infectious Diseases, Tokyo Women's Medical University, Shinjyuku-ku, Tokyo, Japan
| | - Toshifumi Tomoyasu
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Tokushima, Japan
| | - Hideaki Nagamune
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Tokushima, Japan.,Department of Bioengineering, Faculty of Bioscience and Bioindustry, Tokushima University, Tokushima, Tokushima, Japan
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Takamatsu D, Okumura K, Tabata A, Okamoto M, Okura M. Transcriptional regulator SpxA1a controls the resistance of the honey bee pathogen Melissococcus plutonius to the antimicrobial activity of royal jelly. Environ Microbiol 2020; 22:2736-2755. [PMID: 32519428 DOI: 10.1111/1462-2920.15125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/25/2020] [Accepted: 06/07/2020] [Indexed: 12/01/2022]
Abstract
Royal jelly (RJ), a brood food of honey bees, has strong antimicrobial activity. Melissococcus plutonius, the causative agent of European foulbrood of honey bees, exhibits resistance to this antimicrobial activity and infects larvae orally. Among three genetically distinct groups (CC3, CC12 and CC13) of M. plutonius, CC3 strains exhibit the strongest RJ resistance. In this study, to identify genes involved in RJ resistance, we generated an RJ-susceptible derivative from a highly RJ-resistant CC3 strain by UV mutagenesis. Genome sequence analysis of the derivative revealed the presence of a frameshift mutation in the putative regulator gene spxA1a. The deletion of spxA1a from a CC3 strain resulted in increased susceptibility to RJ and its antimicrobial component 10-hydroxy-2-decenoic acid. Moreover, the mutant became susceptible to low-pH and oxidative stress, which may be encountered in brood foods. Differentially expressed gene analysis using wild-type and spxA1a mutants revealed that 45 protein-coding genes were commonly upregulated in spxA1a-positive strains. Many upregulated genes were located in a prophage region, and some highly upregulated genes were annotated as universal/general stress proteins, oxidoreductase/reductase, chaperons and superoxide dismutase. These results suggest that SpxA1a is a key regulator to control the tolerance status of M. plutonius against stress in honey bee colonies.
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Affiliation(s)
- Daisuke Takamatsu
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, Gifu, 501-1193, Japan
| | - Kayo Okumura
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan
| | - Atsushi Tabata
- Department of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, 770-8513, Japan
| | - Mariko Okamoto
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masatoshi Okura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
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European Foulbrood in stingless bees (Apidae: Meliponini) in Brazil: Old disease, renewed threat. J Invertebr Pathol 2020; 172:107357. [DOI: 10.1016/j.jip.2020.107357] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 01/13/2023]
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Nakamura K, Okumura K, Harada M, Okamoto M, Okura M, Takamatsu D. Different impacts of pMP19 on the virulence of Melissococcus plutonius strains with different genetic backgrounds. Environ Microbiol 2020; 22:2756-2770. [PMID: 32219986 DOI: 10.1111/1462-2920.14999] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 03/12/2020] [Accepted: 03/22/2020] [Indexed: 01/06/2023]
Abstract
Virulence factors responsible for bacterial pathogenicity are often encoded by plasmids. In Melissococcus plutonius, the causative agent of European foulbrood of honey bees, a putative virulence plasmid (pMP19) possessing mtxA, which encodes a putative insecticidal toxin, was found by comparative genome analyses. However, as the role of pMP19 in the pathogenesis of European foulbrood remains to be elucidated, we generated pMP19 cured-M. plutonius from representative strains of the three genetically distinct groups (CC3, CC12 and CC13) and compared their virulence against Apis mellifera larvae using our in vitro infection model. Under the conditions tested, the loss of pMP19 abrogated the pathogenicity in CC3 strains, and > 94% of pMP19-cured CC3 strain-infected larvae became adult bees, suggesting that pMP19 is a virulence determinant of CC3 strains. However, introduction of mtxA on its own did not increase the virulence of pMP19-cured strains. In contrast to CC3 strains, the representative CC12 strain remained virulent even in the absence of pMP19, whereas the representative CC13 strain was avirulent even in the presence of the plasmid. Thus, pMP19 plays a role in the virulence of M. plutonius; however, its impact on the virulence varies among strains with different genetic backgrounds.
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Affiliation(s)
- Keiko Nakamura
- Research and Business Promotion Division, Research Institute for Animal Science in Biochemistry and Toxicology, Sagamihara, Kanagawa, 252-0132, Japan
| | - Kayo Okumura
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, 080-8555, Japan
| | - Mariko Harada
- Research and Business Promotion Division, Research Institute for Animal Science in Biochemistry and Toxicology, Sagamihara, Kanagawa, 252-0132, Japan
| | - Mariko Okamoto
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masatoshi Okura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Daisuke Takamatsu
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Gifu, 501-1193, Japan
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Tabata A, Yamada T, Ohtani H, Ohkura K, Tomoyasu T, Nagamune H. β-Hemolytic Streptococcus anginosus subsp. anginosus causes streptolysin S-dependent cytotoxicity to human cell culture lines in vitro. J Oral Microbiol 2019; 11:1609839. [PMID: 31105901 PMCID: PMC6508071 DOI: 10.1080/20002297.2019.1609839] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/09/2019] [Accepted: 04/12/2019] [Indexed: 11/30/2022] Open
Abstract
Background: Streptococcus anginosus subsp. anginosus (SAA) is one of the opportunistic pathogens in humans that inhabits the oral cavity. The type strain of SAA, NCTC10713T, showed clear β-hemolysis on blood agar plates, and the sole β-hemolytic factor revealed two streptolysin S (SLS) molecules. SLS is well known as the peptide hemolysin produced from the human pathogen S. pyogenes and shows not only hemolytic activity on erythrocytes but also cytotoxic activity in cell culture lines in vitro and in vivo, such as in a mouse infection model. However, no cytotoxic activity of SLS produced from β-hemolytic SAA (β-SAA) has been reported so far. Objective and Design: In this study, the SLS-dependent cytotoxicity of the β-SAA strains including the genetically modified strains was investigated in vitro. Results: The SLS-producing β-SAA showed cytotoxicity in human cell culture lines under the co-cultivation condition and it was found that this cytotoxicity was caused by the SLS secreted into the extracellular milieu. Conclusion: The results from this study suggest that the SLS produced from β-SAA might indicate the cytotoxic potential similar to that of the SLS from S. pyogenes and the SLS-producing β-SAA would be recognized as “a wolf in sheep’s clothing” More attention will be paid to the pathogenicity of β-hemolytic Anginosus group streptococci.
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Affiliation(s)
- Atsushi Tabata
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan.,Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Takuya Yamada
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Hiromi Ohtani
- Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Kazuto Ohkura
- Graduate School of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
| | - Toshifumi Tomoyasu
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan.,Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
| | - Hideaki Nagamune
- Department of Bioengineering, Division of Bioscience and Bioindustry, Graduate School of Technology, Industrial and Social Sciences, Tokushima University Graduate School, Tokushima, Japan.,Department of Biological Science and Technology, Life System, Institute of Technology and Science, Tokushima University Graduate School, Tokushima, Japan
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Takamatsu D, Yoshida E, Watando E, Ueno Y, Kusumoto M, Okura M, Osaki M, Katsuda K. A frameshift mutation in the rRNA large subunit methyltransferase gene rlmA II determines the susceptibility of a honey bee pathogen Melissococcus plutonius to mirosamicin. Environ Microbiol 2018; 20:4431-4443. [PMID: 30043554 DOI: 10.1111/1462-2920.14365] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/04/2018] [Accepted: 07/19/2018] [Indexed: 11/29/2022]
Abstract
American foulbrood (AFB) and European foulbrood (EFB) caused by Paenibacillus larvae and Melissococcus plutonius, respectively, are major bacterial infections of honey bees. Although macrolides (mirosamicin [MRM] and tylosin) have been used to prevent AFB in Japan, macrolide-resistant P. larvae have yet to be found. In this study, we revealed that both MRM-resistant and -susceptible strains exist in Japanese M. plutonius and that a methyltransferase gene (rlmA II ) was disrupted exclusively in MRM-susceptible strains due to a single-nucleotide insertion. The M. plutonius RlmAII modified G748 of 23S rRNA, and the deletion of rlmA II resulted in increased susceptibility to MRM and the loss of modification at G748, suggesting that methylation at G748 by RlmAII confers MRM resistance in M. plutonius. The single-nucleotide mutation in MRM-susceptible strains was easily repaired by spontaneous deletion of the inserted nucleotide; however, intact rlmA II was only found in Japanese M. plutonius and not in a Paraguayan strain tested or any of the whole-genome-sequenced European strains. MRM has been used in apiculture only in Japan. Although M. plutonius is not the target of this drug, the use of MRM as a prophylactic drug for AFB may have influenced the antibiotic susceptibility of the causative agent of EFB.
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Affiliation(s)
- Daisuke Takamatsu
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, Gifu, Gifu, 501-1193, Japan
| | - Emi Yoshida
- Iwate Prefectural Chuo Livestock Hygiene Service Center, Takizawa, Iwate, 020-0605, Japan
| | - Eri Watando
- Aichi Prefectural Chuo Livestock Hygiene Service Center, Okazaki, Aichi, 444-0805, Japan
| | - Yuichi Ueno
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masahiro Kusumoto
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Masatoshi Okura
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Makoto Osaki
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
| | - Ken Katsuda
- Division of Bacterial and Parasitic Disease, National Institute of Animal Health, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-0856, Japan
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12
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Virulence Differences among Melissococcus plutonius Strains with Different Genetic Backgrounds in Apis mellifera Larvae under an Improved Experimental Condition. Sci Rep 2016; 6:33329. [PMID: 27625313 PMCID: PMC5022037 DOI: 10.1038/srep33329] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 08/24/2016] [Indexed: 11/18/2022] Open
Abstract
European foulbrood (EFB) caused by Melissococcus plutonius is an important bacterial disease of honeybee larvae. M. plutonius strains can be grouped into three genetically distinct groups (CC3, CC12 and CC13). Because EFB could not be reproduced in artificially reared honeybee larvae by fastidious strains of CC3 and CC13 previously, we investigated a method to improve experimental conditions using a CC3 strain and found that infection with a potassium-rich diet enhanced proliferation of the fastidious strain in larvae at the early stage of infection, leading to the appearance of clear clinical symptoms. Further comparison of M. plutonius virulence under the conditions revealed that the representative strain of CC12 was extremely virulent and killed all tested bees before pupation, whereas the CC3 strain was less virulent than the CC12 strain, and a part of the infected larvae pupated. In contrast, the tested CC13 strain was avirulent, and as with the non-infected control group, most of the infected brood became adult bees, suggesting differences in the insect-level virulence among M. plutonius strains with different genetic backgrounds. These strains and the improved experimental infection method to evaluate their virulence will be useful tools for further elucidation of the pathogenic mechanisms of EFB.
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13
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Takamatsu D, Sato M, Yoshiyama M. Infection of Melissococcus plutonius clonal complex 12 strain in European honeybee larvae is essentially confined to the digestive tract. J Vet Med Sci 2015; 78:29-34. [PMID: 26256232 PMCID: PMC4751113 DOI: 10.1292/jvms.15-0405] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Melissococcus plutonius is an important pathogen that causes
European foulbrood (EFB) in honeybee larvae. Recently, we discovered a group of M.
plutonius strains that are phenotypically and genetically distinct from other
strains. These strains belong to clonal complex (CC) 12, as determined by multilocus
sequence typing analysis, and show atypical cultural and biochemical characteristics
in vitro compared with strains of other CCs tested. Although EFB is
considered to be a purely intestinal infection according to early studies, it is unknown
whether the recently found CC12 strains cause EFB by the same pathomechanism. In this
study, to obtain a better understanding of EFB, we infected European honeybee
(Apis mellifera) larvae per os with a
well-characterized CC12 strain, DAT561, and analyzed the larvae histopathologically.
Ingested DAT561 was mainly localized in the midgut lumen surrounded by the peritrophic
matrix (PM) in the larvae. In badly affected larvae, the PM and midgut epithelial cells
degenerated, and some bacterial cells were detected outside of the midgut. However, they
did not proliferate in the deep tissues actively. By immunohistochemical analysis, the PM
was stained with anti-M. plutonius serum in most of the DAT561-infected
larvae. In some larvae, luminal surfaces of the PM were more strongly stained than the
inside. These results suggest that infection of CC12 strain in honeybee larvae is
essentially confined to the intestine. Moreover, our results imply the presence of
M. plutonius-derived substances diffusing into the larval tissues in
the course of infection.
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Affiliation(s)
- Daisuke Takamatsu
- Bacterial and Parasitic Diseases Research Division, National Institute of Animal Health, National Agriculture and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
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14
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Budge GE, Shirley MDF, Jones B, Quill E, Tomkies V, Feil EJ, Brown MA, Haynes EG. Molecular epidemiology and population structure of the honey bee brood pathogen Melissococcus plutonius. THE ISME JOURNAL 2014; 8:1588-97. [PMID: 24599072 PMCID: PMC4817608 DOI: 10.1038/ismej.2014.20] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 01/17/2014] [Accepted: 01/18/2014] [Indexed: 12/17/2022]
Abstract
Melissococcus plutonius is the causative agent of European foulbrood (EFB), which is a serious brood disease of the European honey bee (Apis mellifera). EFB remains a threat because of a poor understanding of disease epidemiology. We used a recently published multi-locus sequence typing method to characterise 206 M. plutonius isolates recovered from outbreaks in England and Wales over the course of 2 years. We detected 15 different sequence types (STs), which were resolved by eBURST and phylogenetic analysis into three clonal complexes (CCs) 3, 12 and 13. Single and double locus variants within CC3 were the most abundant and widespread genotypes, accounting for 85% of the cases. In contrast, CCs 12 and 13 were rarer and predominantly found in geographical regions of high sampling intensity, consistent with a more recent introduction and localised spread. K-function analysis and interpoint distance tests revealed significant geographical clustering in five common STs, but pointed to different dispersal patterns between STs. We noted that CCs appeared to vary in pathogenicity and that infection caused by the more pathogenic variants is more likely to lead to honey bee colony destruction, as opposed to treatment. The importance of these findings for improving our understanding of disease aetiology and control are discussed.
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Affiliation(s)
| | - Mark D F Shirley
- School of Biology, Newcastle University, Ridley Building, Newcastle Upon Tyne, UK
| | | | | | | | - Edward J Feil
- Department of Biology and Biochemistry, University of Bath, Bath, UK
| | | | - Edward G Haynes
- Food and Environment Research Agency, York, UK
- Department of Biology, University of York, York, UK
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15
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Arai R, Miyoshi-Akiyama T, Okumura K, Morinaga Y, Wu M, Sugimura Y, Yoshiyama M, Okura M, Kirikae T, Takamatsu D. Development of duplex PCR assay for detection and differentiation of typical and atypical Melissococcus plutonius strains. J Vet Med Sci 2013; 76:491-8. [PMID: 24334815 PMCID: PMC4064131 DOI: 10.1292/jvms.13-0386] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Melissococcus
plutonius is the causative agent of an important honeybee disease, European
foulbrood (EFB). In addition to M. plutonius strains with typical
characteristics (typical M. plutonius), we recently reported the presence
of atypical M. plutonius, which are phenotypically and genetically
distinguished from typical M. plutonius. Because typical and atypical
M. plutonius may have different pathogenic mechanisms, differentiation
of these two types is very important for diagnosis and more effective control of EFB. In
this study, therefore, a duplex PCR assay was developed to detect and differentiate
typical and atypical M. plutonius rapidly and easily. On the basis of the
results of comparative genomic analyses, we selected Na+/H+
antiporter gene and Fur family transcriptional regulator gene as targets for detection of
typical and atypical strains, respectively, by PCR. Under optimized conditions, the duplex
PCR system using the designed primers successfully detected and differentiated all typical
and atypical M. plutonius strain/isolates tested, while no product was
generated from any other bacterial strains/isolates used in this study, including those
isolated from healthy honeybee larval guts. Detection limits of the PCR were 50 copies of
chromosome/reaction for both types, and it could detect typical and atypical M.
plutonius directly from diseased honeybee larvae. Moreover, the duplex PCR
diagnosed mixed infections with both M. plutonius types more precisely
than standard culture methods. These results indicate that the duplex PCR assay developed
in this study is extremely useful for precise diagnosis and epidemiological study of
EFB.
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Affiliation(s)
- Rie Arai
- Saitama Prefectural Chuo Livestock Hygiene Service Center, 107-1 Besshocho, Kita-ku, Saitama, Saitama 331-0821, Japan
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