The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Daisuke Takamatsu - One of the best experts on this subject based on the ideXlab platform.
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Different impacts of pMP19 on the virulence of Melissococcus plutonius strains with different genetic backgrounds
Environmental microbiology, 2020Co-Authors: Keiko Nakamura, Masatoshi Okura, Kayo Okumura, Mariko Harada, Mariko Okamoto, Daisuke TakamatsuAbstract: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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Microbicidal effects of slightly acidic hypochlorous acid water and weakly acidified chlorous acid water on foulbrood pathogens.
The Journal of veterinary medical science, 2020Co-Authors: Ikuyo Ohashi, Mariko Okamoto, Kiyoko Kato, Sota Kobayashi, Daisuke TakamatsuAbstract:Paenibacillus larvae and Melissococcus plutonius are bacterial pathogens of honey bee brood. As decontamination of beekeeping equipment, including combs, is essential to control these pathogens, we evaluated the disinfecting effects of slightly acidic hypochlorous acid water (SAHAW) and weakly acidified chlorous acid water (WACAW) on the pathogens. Both disinfectants exhibited strong disinfecting effects in suspension tests under no organic matter conditions and reduced both pathogens by >5 log10 CFU/ml. Although the microbicidal activity of SAHAW with an available chlorine concentration (ACC) of 10-30 ppm was decreased by organic matter, it reduced viable P. larvae spores in combs more efficiently than H2O when the comb was not as dirty. However, its efficacy on combs decreased at 4°C and when overused or highly contaminated combs were tested. WACAW with an ACC of ≥600 ppm had a higher disinfecting capacity than SAHAW, and efficiently removed P. larvae spores from combs even under organic matter-rich and low-temperature conditions. However, even by WACAW, the amount of viable spores in combs was not markedly reduced depending on contamination levels and P. larvae genotypes. These results suggest the usefulness of both disinfectants for decontaminating beekeeping equipment depending on the situations expected.
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Complete Genome Sequences of Two Melissococcus plutonius Strains with Different Virulence Profiles, Obtained by PacBio Sequencing.
Microbiology resource announcements, 2019Co-Authors: Kayo Okumura, Daisuke Takamatsu, Masatoshi OkuraAbstract:Melissococcus plutonius attacks honeybee larvae, causing European foulbrood. Based on their virulence toward larvae, M. plutonius isolates were classified into three types, highly virulent, moderately virulent, and avirulent. We herein performed whole-genome sequencing of M. plutonius isolates with different virulence levels to promote an understanding of the pathogenesis of this disease.
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Complete Genome Sequence of Melissococcus plutonius DAT561, a Strain That Shows an Unusual Growth Profile, Obtained by PacBio Sequencing.
Genome announcements, 2018Co-Authors: Kayo Okumura, Daisuke Takamatsu, Masatoshi OkuraAbstract:Melissococcus plutonius is the causative agent of European foulbrood, and its isolates were believed to be remarkably genetically homogeneous. However, recent epidemiological and pathogenic studies have shown this pathogen to be more heterogeneous than expected. Herein, we present the whole-genome sequence of M. plutonius DAT561, a representative atypical strain.
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high level resistance of Melissococcus plutonius clonal complex 3 strains to antimicrobial activity of royal jelly
Environmental Microbiology Reports, 2017Co-Authors: Daisuke Takamatsu, Mikio Yoshiyama, Keiko Nakamura, Aya Osawa, Masatoshi OkuraAbstract:Melissococcus plutonius is the causative agent of European foulbrood of honey bee larvae. Among its three genetically distinct groups (CC3, CC12 and CC13), CC3 strains have been suggested to be more virulent at the colony level. Honey bee larvae are fed royal or worker jellies by adult bees, and these jellies exhibit antimicrobial activity. Since M. plutonius orally infects larvae via brood food, we herein investigated the resistance of M. plutonius to the antimicrobial activity of royal jelly (RJ). The results obtained revealed that M. plutonius strains were more resistant to RJ and its component, 10-hydroxy-2-decenoic acid, than the other species tested. Moreover, among the M. plutonius strains examined, CC3 strains exhibited the strongest resistance to antimicrobial activity; they temporarily proliferated and survived for a long period in 50% RJ-containing broth. However, resistance was not observed when freshly cultured bacteria were used, it was only detected after a preculture on agar media for five or more days, suggesting that, under certain conditions, CC3 strains change their physiological state to that which is advantageous for survival in brood food. This high-level RJ resistance of CC3 strains may contribute to their virulence in the field.
Masatoshi Okura - One of the best experts on this subject based on the ideXlab platform.
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Different impacts of pMP19 on the virulence of Melissococcus plutonius strains with different genetic backgrounds
Environmental microbiology, 2020Co-Authors: Keiko Nakamura, Masatoshi Okura, Kayo Okumura, Mariko Harada, Mariko Okamoto, Daisuke TakamatsuAbstract: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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Complete Genome Sequences of Two Melissococcus plutonius Strains with Different Virulence Profiles, Obtained by PacBio Sequencing.
Microbiology resource announcements, 2019Co-Authors: Kayo Okumura, Daisuke Takamatsu, Masatoshi OkuraAbstract:Melissococcus plutonius attacks honeybee larvae, causing European foulbrood. Based on their virulence toward larvae, M. plutonius isolates were classified into three types, highly virulent, moderately virulent, and avirulent. We herein performed whole-genome sequencing of M. plutonius isolates with different virulence levels to promote an understanding of the pathogenesis of this disease.
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Complete Genome Sequence of Melissococcus plutonius DAT561, a Strain That Shows an Unusual Growth Profile, Obtained by PacBio Sequencing.
Genome announcements, 2018Co-Authors: Kayo Okumura, Daisuke Takamatsu, Masatoshi OkuraAbstract:Melissococcus plutonius is the causative agent of European foulbrood, and its isolates were believed to be remarkably genetically homogeneous. However, recent epidemiological and pathogenic studies have shown this pathogen to be more heterogeneous than expected. Herein, we present the whole-genome sequence of M. plutonius DAT561, a representative atypical strain.
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High‐level resistance of Melissococcus plutonius clonal complex 3 strains to antimicrobial activity of royal jelly
Environmental microbiology reports, 2017Co-Authors: Daisuke Takamatsu, Mikio Yoshiyama, Keiko Nakamura, Aya Osawa, Masatoshi OkuraAbstract:Melissococcus plutonius is the causative agent of European foulbrood of honey bee larvae. Among its three genetically distinct groups (CC3, CC12 and CC13), CC3 strains have been suggested to be more virulent at the colony level. Honey bee larvae are fed royal or worker jellies by adult bees, and these jellies exhibit antimicrobial activity. Since M. plutonius orally infects larvae via brood food, we herein investigated the resistance of M. plutonius to the antimicrobial activity of royal jelly (RJ). The results obtained revealed that M. plutonius strains were more resistant to RJ and its component, 10-hydroxy-2-decenoic acid, than the other species tested. Moreover, among the M. plutonius strains examined, CC3 strains exhibited the strongest resistance to antimicrobial activity; they temporarily proliferated and survived for a long period in 50% RJ-containing broth. However, resistance was not observed when freshly cultured bacteria were used, it was only detected after a preculture on agar media for five or more days, suggesting that, under certain conditions, CC3 strains change their physiological state to that which is advantageous for survival in brood food. This high-level RJ resistance of CC3 strains may contribute to their virulence in the field.
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high level resistance of Melissococcus plutonius clonal complex 3 strains to antimicrobial activity of royal jelly
Environmental Microbiology Reports, 2017Co-Authors: Daisuke Takamatsu, Mikio Yoshiyama, Keiko Nakamura, Aya Osawa, Masatoshi OkuraAbstract:Melissococcus plutonius is the causative agent of European foulbrood of honey bee larvae. Among its three genetically distinct groups (CC3, CC12 and CC13), CC3 strains have been suggested to be more virulent at the colony level. Honey bee larvae are fed royal or worker jellies by adult bees, and these jellies exhibit antimicrobial activity. Since M. plutonius orally infects larvae via brood food, we herein investigated the resistance of M. plutonius to the antimicrobial activity of royal jelly (RJ). The results obtained revealed that M. plutonius strains were more resistant to RJ and its component, 10-hydroxy-2-decenoic acid, than the other species tested. Moreover, among the M. plutonius strains examined, CC3 strains exhibited the strongest resistance to antimicrobial activity; they temporarily proliferated and survived for a long period in 50% RJ-containing broth. However, resistance was not observed when freshly cultured bacteria were used, it was only detected after a preculture on agar media for five or more days, suggesting that, under certain conditions, CC3 strains change their physiological state to that which is advantageous for survival in brood food. This high-level RJ resistance of CC3 strains may contribute to their virulence in the field.
Eva Forsgren - One of the best experts on this subject based on the ideXlab platform.
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Putative determinants of virulence in Melissococcus plutonius, the bacterial agent causing European foulbrood in honey bees
Virulence, 2020Co-Authors: Daniela Grossar, Eva Forsgren, Verena Kilchenmann, Jean-daniel Charrière, Laurent Gauthier, Michel Chapuisat, Vincent DietemannAbstract:is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechani...
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The Curious Case of Achromobacter eurydice, a Gram-Variable Pleomorphic Bacterium Associated with European Foulbrood Disease in Honeybees
Microbial Ecology, 2018Co-Authors: Silvio Erler, Anja Poehlein, Oleg Lewkowski, Eva ForsgrenAbstract:Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of the brood. European foulbrood is caused by the bacterium Melissococcus plutonius in combination with several other Gram-positive bacteria ( Achromobacter eurydice , Bacillus pumilus , Brevibacillus laterosporus , Enterococcus faecalis , Paenibacillus alvei , Paenibacillus dendritiformis ) involved as secondary invaders following the initial infection. More than a century ago, A . eurydice was discovered to be associated with European foulbrood and morphologically and biochemically characterized. However, since the 1950s–1960s, only a few studies are known covering the biological relevance of this bacterium. Here, we review the biology, ecology, morphology, and biochemistry and discuss the still unclear systematic classification of A . eurydice .
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The Curious Case of Achromobacter eurydice, a Gram-Variable Pleomorphic Bacterium Associated with European Foulbrood Disease in Honeybees
Microbial Ecology, 2018Co-Authors: Silvio Erler, Anja Poehlein, Oleg Lewkowski, Eva ForsgrenAbstract:Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of the brood. European foulbrood is caused by the bacterium Melissococcus plutonius in combination with several other Gram-positive bacteria ( Achromobacter eurydice , Bacillus pumilus , Brevibacillus laterosporus , Enterococcus faecalis , Paenibacillus alvei , Paenibacillus dendritiformis ) involved as secondary invaders following the initial infection. More than a century ago, A . eurydice was discovered to be associated with European foulbrood and morphologically and biochemically characterized. However, since the 1950s–1960s, only a few studies are known covering the biological relevance of this bacterium. Here, we review the biology, ecology, morphology, and biochemistry and discuss the still unclear systematic classification of A . eurydice .
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Standard methods for European foulbrood research
Journal of Apicultural Research, 2013Co-Authors: Eva Forsgren, Giles E Budge, Jean-daniel Charrière, Michael A. HornitzkyAbstract:Summary European foulbrood (EFB) is a severe bacterial honey bee brood disease caused by the Gram-positive bacterium Melissocccus plutonius. The disease is widely distributed worldwide, and is an increasing problem in some areas. Although the causative agent of EFB was described almost a century ago, many basic aspects of its pathogenesis are still unknown. Earlier studies were hampered by insensitive and unspecific methods such as culture based techniques. Recent advances in molecular technology are making it increasingly easy to detect and characterize microbes, and nucleic acid detection technologies are quickly displacing the traditional phenotypic assays in microbiology. This paper presents selected methodologies which focus on EFB and its causative agent M. plutonius.
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European foulbrood in honey bees.
Journal of Invertebrate Pathology, 2010Co-Authors: Eva ForsgrenAbstract:European foulbrood (EFB) is a severe bacterial brood disease caused by the Gram-positive bacterium Melissocccus plutonius. The disease has a worldwide distribution and is an increasing problem in some areas. Although the causative agent of EFB was described almost a century ago, many basic aspects of its pathogenesis are still unknown. This review presents both historical results and recent molecular data to synthesize present knowledge of this enigmatic honey bee disease.
Jean-daniel Charrière - One of the best experts on this subject based on the ideXlab platform.
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Melissococcus plutonius Can Be Effectively and Economically Detected Using Hive Debris and Conventional PCR.
Insects, 2021Co-Authors: Jana Biová, Jean-daniel Charrière, Silvie Dostálková, Mária Škrabišová, Marek Petřivalský, Jaroslav Bzdil, Jiří DanihlíkAbstract:European foulbrood (EFB) is an infectious disease of honey bees caused by the bacterium Melissococcus plutonius. A method for DNA isolation and conventional PCR diagnosis was developed using hive debris, which was non-invasively collected on paper sheets placed on the bottom boards of hives. Field trials utilized 23 honey bee colonies with clinically positive symptoms and 21 colonies without symptoms. Bayes statistics were applied to calculate the comparable parameters for EFB diagnostics when using honey, hive debris, or samples of adult bees. The reliability of the conventional PCR was 100% at 6.7 × 103 Colony Forming Unit of M. plutonius in 1 g of debris. The sensitivity of the method for the sampled honey, hive debris, and adult bees was 0.867, 0.714, and 1.000, respectively. The specificity for the tested matrices was 0.842, 0.800, and 0.833. The predictive values for the positive tests from selected populations with 52% prevalence were 0.813, 0.833, and 0.842, and the real accuracies were 0.853, 0.750, and 0.912, for the honey, hive debris, and adult bees, respectively. It was concluded that hive debris can effectively be utilized to non-invasively monitor EFB in honey bee colonies.
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Putative determinants of virulence in Melissococcus plutonius, the bacterial agent causing European foulbrood in honey bees
Virulence, 2020Co-Authors: Daniela Grossar, Eva Forsgren, Verena Kilchenmann, Jean-daniel Charrière, Laurent Gauthier, Michel Chapuisat, Vincent DietemannAbstract:is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechani...
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Real-time PCR as a decision aid in the control of European foulbrood
Journal of Apicultural Research, 2015Co-Authors: Valérie Grangier, Jean-daniel Charrière, Luc Belloy, Marcus G. Doherr, Albert Fritsche, Andreas S. WaldvogelAbstract:The number of cases of European foulbrood (EFB) increased massively in Switzerland since 2000. According to Swiss legislation, the health status of all colonies within one kilometer from a case needs to be identified by a bee inspector. This results in a workload too high to be handled in due time in areas with a high prevalence and high colony density. Therefore, the primary goal of this study was testing the hypothesis that the number of visual inspections could be reduced if brood nest bees sampled by owners were tested by real-time PCR for the presence of Melissococcus plutonius, and results were assigned to one of the three categories “negative”, “positive,” or “strong positive” depending on the amount of bacterial DNA. Only apiaries with strong positive results were inspected visually. Furthermore, the development of the bacterial load over time was analyzed on an apiary level to determine whether this would allow predicting the outcome of an infection. For this purpose, bee samples of 88 apiaries w...
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Standard methods for European foulbrood research
Journal of Apicultural Research, 2013Co-Authors: Eva Forsgren, Giles E Budge, Jean-daniel Charrière, Michael A. HornitzkyAbstract:Summary European foulbrood (EFB) is a severe bacterial honey bee brood disease caused by the Gram-positive bacterium Melissocccus plutonius. The disease is widely distributed worldwide, and is an increasing problem in some areas. Although the causative agent of EFB was described almost a century ago, many basic aspects of its pathogenesis are still unknown. Earlier studies were hampered by insensitive and unspecific methods such as culture based techniques. Recent advances in molecular technology are making it increasingly easy to detect and characterize microbes, and nucleic acid detection technologies are quickly displacing the traditional phenotypic assays in microbiology. This paper presents selected methodologies which focus on EFB and its causative agent M. plutonius.
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Spatial distribution of Melissococcus plutonius in adult honey bees collected from apiaries and colonies with and without symptoms of European foulbrood.
Apidologie, 2007Co-Authors: Luc Belloy, Eva Forsgren, Ingemar Fries, Anton Imdorf, Hélène Berthoud, Rolf Kuhn, Jean-daniel CharrièreAbstract:In Switzerland, the incidence of European foulbrood (EFB), caused by the Gram-positive bacterium Melissococcus plutonius, has increased dramatically between 1997 and 2005 but the epidemiology, including the transmission of M. plutonius, remains poorly understood. In this study, the distribution of M. plutonius among bees originating from apiaries and colonies with and without symptoms of EFB was evaluated using a specific and sensitive hemi-nested PCR. In more than 90% of colonies without EFB symptoms located in apiaries with EFB symptoms, the bees were carriers of M. plutonius. In apiaries without EFB symptoms, but near apiaries with EFB symptoms, bees carrying M. plutonius were detected in about 30% of the colonies. In regions without European foulbrood history, all bee samples were negative. The proportion of adult bees carrying M. plutonius in colonies without symptoms appeared to increase when the distance to apiaries with clinical EFB symptoms decreased.
Giles E Budge - One of the best experts on this subject based on the ideXlab platform.
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Molecular epidemiology and population structure of the honey bee brood pathogen Melissococcus plutonius
The ISME Journal, 2014Co-Authors: Giles E Budge, Emiline Quill, Victoria Tomkies, Edward J Feil, Mark D F Shirley, Mike A Brown, Benjamin Jones, Edward G HaynesAbstract: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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A typing scheme for the honeybee pathogen Melissococcus plutonius allows detection of disease transmission events and a study of the distribution of variants
Environmental microbiology reports, 2013Co-Authors: Edward G Haynes, Thorunn Helgason, J. Peter W. Young, Richard Thwaites, Giles E BudgeAbstract:Summary Melissococcus plutonius is the bacterial pathogen that causes European Foulbrood of honeybees, a globally important honeybee brood disease. We have used next-generation sequencing to identify highly polymorphic regions in an otherwise genetically homogenous organism, and used these loci to create a modified MLST scheme. This synthesis of a proven typing scheme format with next-generation sequencing combines reliability and low costs with insights only available from high-throughput sequencing technologies. Using this scheme we show that the global distribution of M. plutonius variants is not uniform. We use the scheme in epidemiological studies to trace movements of infective material around England, insights that would have been impossible to confirm without the typing scheme. We also demonstrate the persistence of local variants over time.
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Standard methods for European foulbrood research
Journal of Apicultural Research, 2013Co-Authors: Eva Forsgren, Giles E Budge, Jean-daniel Charrière, Michael A. HornitzkyAbstract:Summary European foulbrood (EFB) is a severe bacterial honey bee brood disease caused by the Gram-positive bacterium Melissocccus plutonius. The disease is widely distributed worldwide, and is an increasing problem in some areas. Although the causative agent of EFB was described almost a century ago, many basic aspects of its pathogenesis are still unknown. Earlier studies were hampered by insensitive and unspecific methods such as culture based techniques. Recent advances in molecular technology are making it increasingly easy to detect and characterize microbes, and nucleic acid detection technologies are quickly displacing the traditional phenotypic assays in microbiology. This paper presents selected methodologies which focus on EFB and its causative agent M. plutonius.
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The occurrence of Melissococcus plutonius in healthy colonies of Apis mellifera and the efficacy of European foulbrood control measures
Journal of invertebrate pathology, 2010Co-Authors: Giles E Budge, Panuwan Chantawannakul, Richard Thwaites, Andrew G.s. Cuthbertson, Ben Barrett, Ben Jones, Stéphane Pietravalle, Jayne Hall, Mike A BrownAbstract:European foulbrood (EFB) persists in England and Wales despite current treatment methods, all of which include feeding honey bee colonies with the antibiotic oxytetracycline (OTC). A large-scale field experiment was conducted to monitor a husbandry-based method, using comb replacement (known as Shook swarm), as a drug free EFB control option. The understanding of EFB epidemiology is limited, with little information on the presence of Melissococcus plutonius in disease free colonies. Additional samples were collected from diseased and disease free apiaries to identify symptomless infection. EFB reoccurrence was not significantly different between OTC and husbandry methods and real-time PCR data demonstrated that fewer Shook swarm treated colonies contained M. plutonius carryover to the Spring following treatment. Asymptomatic colonies from diseased apiaries showed an increased risk of testing positive for M. plutonius compared to asymptomatic colonies from disease free apiaries. The probability of a sample being symptomatic increased when a greater quantity of M. plutonius was detected in adult bees and larvae. The possibility of treating EFB as an apiary disease rather than a colony disease and the implications of a control strategy without antibiotics are discussed.