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Ichikawa Y, Borjigin L, Enkhtuul B, Khurtsbaatar O, Aoshima K, Kobayashi A, Batbaatar V, Kimura T. First molecular characterization of Burkholderia mallei strains isolated from horses in Mongolia. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2024; 123:105616. [PMID: 38852916 DOI: 10.1016/j.meegid.2024.105616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/17/2024] [Accepted: 06/05/2024] [Indexed: 06/11/2024]
Abstract
Glanders, a highly contagious and often fatal disease affecting equids, is caused by Burkholderia mallei. Although sporadic cases of equine glanders have recently been documented in Mongolia, genome sequencing and molecular studies of the bacteria within this region are lacking. This study provided the first molecular characterization of B. mallei isolated from four native Mongolian horses from two different provinces in 2019 and 2022 by applying whole-genome sequencing with two SNP types (previously developed genotyping with 15 SNP markers that provide global coverage of the B. mallei population and the core genome coding SNP typing developed in this study). The Mongolian isolates were located within the L3B1 cluster, which was previously associated with the V-120 strain from Russia. Within the L3B1 cluster shared by neighboring countries, they were in a unique subbranch. In this study, specific SNP markers unique to the Mongolian strains were identified to track these strains using a high-resolution melting analysis (HRMA). This study revealed the unique phylogenetic background of Mongolian strains isolated from the eastern part of Mongolia. HRMA specific to the Mongolian subbranch may contribute to the molecular epidemiological monitoring of glanders in Mongolia and surrounding countries.
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Affiliation(s)
- Yoshiki Ichikawa
- Laboratory of Comparative Pathology, Department of Clinical Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Liushiqi Borjigin
- Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Japan
| | - Batchuluun Enkhtuul
- Laboratory of Infectious Disease and Immunology, Institute of Veterinary Medicine, Mongolian University of Life Sciences, Khan-Uul district, Zaisan, 17024 Ulaanbaatar, Mongolia
| | - Ochirbat Khurtsbaatar
- Laboratory of Infectious Disease and Immunology, Institute of Veterinary Medicine, Mongolian University of Life Sciences, Khan-Uul district, Zaisan, 17024 Ulaanbaatar, Mongolia
| | - Keisuke Aoshima
- Laboratory of Comparative Pathology, Department of Clinical Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan
| | - Atsushi Kobayashi
- Department of Biomedical Models, Graduate School of Biomedical Sciences, Nagasaki University, Sakamoto, Nagasaki, Japan
| | - Vanaabaatar Batbaatar
- Laboratory of Infectious Disease and Immunology, Institute of Veterinary Medicine, Mongolian University of Life Sciences, Khan-Uul district, Zaisan, 17024 Ulaanbaatar, Mongolia
| | - Takashi Kimura
- Laboratory of Comparative Pathology, Department of Clinical Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Japan.
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Charron P, Gao R, Chmara J, Hoover E, Nadin-Davis S, Chauvin D, Hazelwood J, Makondo K, Duceppe MO, Kang M. Influence of genomic variations on glanders serodiagnostic antigens using integrative genomic and transcriptomic approaches. Front Vet Sci 2023; 10:1217135. [PMID: 38125681 PMCID: PMC10730941 DOI: 10.3389/fvets.2023.1217135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
Glanders is a highly contagious and life-threatening zoonotic disease caused by Burkholderia mallei (B. mallei). Without an effective vaccine or treatment, early diagnosis has been regarded as the most effective method to prevent glanders transmission. Currently, the diagnosis of glanders is heavily reliant on serological tests. However, given that markedly different host immune responses can be elicited by genetically different strains of the same bacterial species, infection by B. mallei, whose genome is unstable and plastic, may result in various immune responses. This variability can make the serodiagnosis of glanders challenging. Therefore, there is a need for a comprehensive understanding and assessment of how B. mallei genomic variations impact the appropriateness of specific target antigens for glanders serodiagnosis. In this study, we investigated how genomic variations in the B. mallei genome affect gene content (gene presence/absence) and expression, with a special focus on antigens used or potentially used in serodiagnosis. In all the genome sequences of B. mallei isolates available in NCBI's RefSeq database (accessed in July 2023) and in-house sequenced samples, extensive small and large variations were observed when compared to the type strain ATCC 23344. Further pan-genome analysis of those assemblies revealed variations of gene content among all available genomes of B. mallei. Specifically, differences in gene content ranging from 31 to 715 genes with an average of 334 gene presence-absence variations were found in strains with complete or chromosome-level genome assemblies, using the ATCC 23344 strain as a reference. The affected genes included some encoded proteins used as serodiagnostic antigens, which were lost due mainly to structural variations. Additionally, a transcriptomic analysis was performed using the type strain ATCC 23344 and strain Zagreb which has been widely utilized to produce glanders antigens. In total, 388 significant differentially expressed genes were identified between these two strains, including genes related to bacterial pathogenesis and virulence, some of which were associated with genomic variations, particularly structural variations. To our knowledge, this is the first comprehensive study to uncover the impacts of genetic variations of B. mallei on its gene content and expression. These differences would have significant impacts on host innate and adaptive immunity, including antibody production, during infection. This study provides novel insights into B. mallei genetic variants, knowledge which will help to improve glanders serodiagnosis.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Mingsong Kang
- Ottawa Laboratory-Fallowfield, Canadian Food Inspection Agency, Ottawa, ON, Canada
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Brangsch H, Horstkotte MA, Melzer F. Genotypic peculiarities of a human brucellosis case caused by Brucella suis biovar 5. Sci Rep 2023; 13:16586. [PMID: 37789135 PMCID: PMC10547717 DOI: 10.1038/s41598-023-43570-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/26/2023] [Indexed: 10/05/2023] Open
Abstract
Human brucellosis cases are rare in non-endemic countries, such as Germany, where infections are predominantly caused by Brucella melitensis. The German National Reference Laboratory for Bovine, Porcine, Ovine and Caprine Brucellosis received a suspected Brucella sp. isolate from a patient for identification. Bacteriological tests and PCR-based diagnostics showed the isolate to be B. suis, but did not yield cohesive results regarding the biovar. Whole genome sequencing and subsequent genotyping was employed for a detailed characterization of the isolate and elucidating the reason for failure of the diagnostic PCR to correctly identify the biovar. The isolate was found to be B. suis bv. 5, a rare biovar with limited geographical distribution primarily found in the Northern Caucasus. Due to a deletion in one of the target regions of the diagnostic PCR, the isolate could not be correctly typed. Based on in silico genotyping it could be excluded that the isolate was identical to one of the B. suis bv. 5 reference strains. Here, we report a rare case of a B. suis bv. 5 field isolate. Furthermore, by reporting this finding, we want to make practitioners aware of possible misinterpretation of PCR results, as it cannot be excluded that the detected deletion is common among the B. suis bv. 5 community, as there is currently a lack of field isolates.
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Affiliation(s)
- Hanka Brangsch
- Friedrich-Loeffler-Institut - Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany.
| | | | - Falk Melzer
- Friedrich-Loeffler-Institut - Federal Research Institute for Animal Health, Institute of Bacterial Infections and Zoonoses, Jena, Germany
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Suniga PAP, Mantovani C, Santos MG, Rieger JSG, Gaspar EB, Dos Santos FL, Mota RA, Chaves KP, Egito AA, Filho JCO, Nassar AFC, Dos Santos LR, Araújo FR. Molecular detection of Burkholderia mallei in different geographic regions of Brazil. Braz J Microbiol 2023; 54:1275-1285. [PMID: 37074557 PMCID: PMC10235260 DOI: 10.1007/s42770-023-00965-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/03/2023] [Indexed: 04/20/2023] Open
Abstract
Glanders is a contagious disease of equids caused by the Gram-negative bacterium Burkholderia mallei. In Brazil, the disease is considered to be reemerging and has been expanding, with records of equids with positive serology in most of the federative units. However, there are few reports describing the genotypic detection of the agent. This study demonstrated the detection of B. mallei by species-specific PCR directly from tissues or from bacterial cultures, followed by amplicon sequencing in equids (equines, mules, and asinines) with positive serology for glanders in all five geographic regions of Brazil. The molecular evidence of B. mallei infection in serologically positive equids in this study expands the possibility of strain isolation and the conduction of epidemiological characterizations based on molecular information. The microbiological detection of B. mallei in cultures from nasal and palate swabs, even in equids without clinical manifestations, raises the possibility of environmental elimination of the agent.
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Affiliation(s)
- Paula A Pereira Suniga
- MAI/DAI Scholarship, Federal University of Mato Grosso Do Sul, Cidade Universitária, Av. Costa E Silva, Campo Grande, MS, 79070-900, Brazil
- Postgraduate Program in Animal Science, Federal University of Mato Grosso Do Sul, Faculty of Veterinary Medicine and Animal Science-FAMEZ/UFMS, Av. Senador Filinto Muller, 2443, Campo Grande, MS, 79074-460, Brazil
| | - Cynthia Mantovani
- Embrapa Beef Cattle/Ministry of Agriculture, Livestock and Food Supply Scholarship, Embrapa Beef Cattle, Av. Rádio Maia, 830, Campo Grande, MS, 79106-550, Brazil
| | - Maria G Santos
- Embrapa Beef Cattle, Av. Rádio Maia, 830, Campo Grande, MS, 79106-550, Brazil
| | - Juliana S Gomes Rieger
- Embrapa Beef Cattle/Ministry of Agriculture, Livestock and Food Supply Scholarship, Embrapa Beef Cattle, Av. Rádio Maia, 830, Campo Grande, MS, 79106-550, Brazil
| | - Emanuelle B Gaspar
- Embrapa South Livestock, Rodovia BR-153, Km 632,9 Vila Industrial, Zona Rural, Caixa Postal 242, Bagé, RS, 96401-970, Brazil
| | | | - Rinaldo A Mota
- Department of Veterinary Medicine, Federal Rural University of Pernambuco, Recife, Pernambuco, Brazil
| | - Karla P Chaves
- Department of Veterinary Medicine, Federal University of Alagoas, Maceió, Alagoas, Brazil
| | - Andréa A Egito
- Postgraduate Program in Animal Science, Federal University of Mato Grosso Do Sul, Faculty of Veterinary Medicine and Animal Science-FAMEZ/UFMS, Av. Senador Filinto Muller, 2443, Campo Grande, MS, 79074-460, Brazil
- Embrapa Beef Cattle, Av. Rádio Maia, 830, Campo Grande, MS, 79106-550, Brazil
| | - José Carlos O Filho
- Veterinary Pathology Sector, Universidade Federal Do Recôncavo da Bahia (UFRB), Rua Rui Barbosa 710, Cruz Das Almas, BA, 44380-000, Brazil
| | - Alessandra F Castro Nassar
- Centro de Pesquisa Em Sanidade Animal, Instituto Biológico, Av. Conselheiro Rodrigues Alves, 1252, São Paulo, SP, 04014-002, Brazil
| | | | - Flábio R Araújo
- Embrapa Beef Cattle, Av. Rádio Maia, 830, Campo Grande, MS, 79106-550, Brazil
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Brangsch H, Singha H, Laroucau K, Elschner M. Sequence-based detection and typing procedures for Burkholderia mallei: Assessment and prospects. Front Vet Sci 2022; 9:1056996. [PMID: 36452150 PMCID: PMC9703372 DOI: 10.3389/fvets.2022.1056996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 10/26/2022] [Indexed: 10/28/2023] Open
Abstract
Although glanders has been eradicated in most of the developed world, the disease still persists in various countries such as Brazil, India, Pakistan, Bangladesh, Nepal, Iran, Bahrain, UAE and Turkey. It is one of the notifiable diseases listed by the World Organization for Animal Health. Occurrence of glanders imposes restriction on equestrian events and restricts equine movement, thus causing economic losses to equine industry. The genetic diversity and global distribution of the causing agent, Burkholderia (B.) mallei, have not been assessed in detail and are complicated by the high clonality of this organism. Among the identification and typing methods, PCR-based methods for distinguishing B. mallei from its close relative B. pseudomallei as well as genotyping using tandem repeat regions (MLVA) are established. The advent and continuous advancement of the sequencing techniques and the reconstruction of closed genomes enable the development of genome guided epidemiological tools. For achieving a higher genomic resolution, genotyping methods based on whole genome sequencing data can be employed, like genome-wide single nucleotide polymorphisms. One of the limitations in obtaining complete genomic sequences for further molecular characterization of B. mallei is its high GC content. In this review, we aim to provide an overview of the widely used detection and typing methods for B. mallei and illustrate gaps that still require development. The genomic features of Burkholderia, their high homology and clonality will be first described from a comparative genomics perspective. Then, the commonly used molecular detection (PCR systems) and typing systems (e.g., multilocus sequence typing, variable number of tandem repeat analysis) will be presented and put in perspective with recently developed genomic methods. Also, the increasing availability of B. mallei genomic sequences and evolution of the sequencing methods offers exciting prospects for further refinement of B. mallei typing, that could overcome the difficulties presently encountered with this particular bacterium.
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Affiliation(s)
- Hanka Brangsch
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut – Federal Research Institute for Animal Health, Jena, Germany
| | | | - Karine Laroucau
- Bacterial Zoonosis Unit, Animal Health Laboratory, French Food Agency (Anses), Maisons-Alfort, France
| | - Mandy Elschner
- Institute of Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut – Federal Research Institute for Animal Health, Jena, Germany
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Brangsch H, Saqib M, Sial AUR, Melzer F, Linde J, Elschner MC. Sequencing-Based Genotyping of Pakistani Burkholderia mallei Strains: A Useful Way for Investigating Glanders Outbreaks. Pathogens 2022; 11:pathogens11060614. [PMID: 35745468 PMCID: PMC9227068 DOI: 10.3390/pathogens11060614] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/05/2022] [Accepted: 05/19/2022] [Indexed: 12/10/2022] Open
Abstract
Burkholderia (B.) mallei is a host-adapted equine pathogen that causes glanders, a re-emerging zoonotic disease, which is endemic in Pakistan and other developing countries and seriously impacts the global equine movement. Due to globalization, the geographical restriction of diseases vanishes and the lack of awareness of and experience with eradicated diseases in industrialized countries also promotes the re-introduction of infections in these regions. Owing to the high equine population, the Pakistani province Punjab is a potential hotspot where several glanders outbreaks have been seen over last two decades. For determining the genomic diversity of B. mallei in this and other equine-populated prefectures, the genomes of 19 B. mallei strains isolated between 1999 and 2020 in different locations were sequenced and their genotypes were determined. Particularly, for genetically highly homogenous pathogens like B. mallei genotyping techniques require a high discriminatory power for enabling differentiation on the strain level. Thus, core-genome single nucleotide polymorphism (cgSNP) analysis was applied for distinguishing the highly similar strains. Furthermore, a whole-genome sequence-based core genome multi locus sequence typing (cgMLST) scheme, specific to B. mallei, was developed and additionally applied to the data. It was found that B. mallei genotypes in Pakistan persisted over time and space and genotype clusters preferred connection with a time point rather than the place of isolation, probably due to frequent equine movement, which promotes the spread of glanders. The cgMLST approach proved to work in accord with SNP typing and may help to investigate future glanders outbreaks.
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Affiliation(s)
- Hanka Brangsch
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institute, Naumburger Str. 96a, 07743 Jena, Thuringia, Germany; (F.M.); (J.L.); (M.C.E.)
- Correspondence:
| | - Muhammad Saqib
- Veterinary Preventive Medicine and Public Health Laboratory, Department of Clinical Medicine and Surgery, University of Agriculture, Faisalabad 38000, Pakistan;
| | - Awais ur Rehman Sial
- Department of Clinical Studies, Faculty of Veterinary and Animal Science, Pir Mehr Ali Shah, Arid Agriculture University Rawalpindi, Rawalpindi 46000, Pakistan;
| | - Falk Melzer
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institute, Naumburger Str. 96a, 07743 Jena, Thuringia, Germany; (F.M.); (J.L.); (M.C.E.)
| | - Jörg Linde
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institute, Naumburger Str. 96a, 07743 Jena, Thuringia, Germany; (F.M.); (J.L.); (M.C.E.)
| | - Mandy Carolina Elschner
- Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institute, Naumburger Str. 96a, 07743 Jena, Thuringia, Germany; (F.M.); (J.L.); (M.C.E.)
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P K, M M, S M, Kr P, T D, G W, Ma V, K L. First glanders cases detected in Nepal underscore the need for surveillance and border controls. BMC Vet Res 2022; 18:132. [PMID: 35387664 PMCID: PMC8985341 DOI: 10.1186/s12917-022-03233-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/29/2022] [Indexed: 11/25/2022] Open
Abstract
Background Glanders is a transmissible zoonotic disease caused by Burkholderia mallei that infects equids and humans. No glanders cases in equids were reported so far in Nepal. Case presentation Following suspected glanders in animals with clinical signs in different regions in Nepal, serum samples were tested by CFT, ELISA and Luminex® tests. Two horses and a mule tested positive for glanders by all tests, while two other equids only tested positive by ELISA and Luminex®. Analysis of swabs and pus samples by a PCR system targeting B. mallei confirmed the presence of the bacterium in the samples collected from the 3 equids that yielded positive results in all serological tests. Genotyping of the three PCR positive samples with a SNP-based method identified a genotype closely related to the B. mallei strains circulating in India. Conclusion Confirmation of glanders cases underscores the need of implementing a surveillance program in Nepal and a strict control of the animal movement across the borders.
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Affiliation(s)
- Koirala P
- Central Veterinary Laboratory, Kathmandu, Nepal.
| | - Maharjan M
- Central Veterinary Laboratory, Kathmandu, Nepal
| | - Manandhar S
- Central Veterinary Laboratory, Kathmandu, Nepal
| | - Pandey Kr
- Veterinary Laboratory, Surkhet, Nepal
| | - Deshayes T
- ANSES, Laboratory for Animal Health, Bacterial Zoonosis Unit, European and OIE Reference Laboratory for Glanders, Paris-Est University, Maisons-Alfort, France
| | - Wang G
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Valvano Ma
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University Belfast, Belfast, UK
| | - Laroucau K
- ANSES, Laboratory for Animal Health, Bacterial Zoonosis Unit, European and OIE Reference Laboratory for Glanders, Paris-Est University, Maisons-Alfort, France.
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Schmidt CG, Herskin M, Michel V, Miranda Chueca MÁ, Padalino B, Pasquali P, Spoolder H, Ståhl K, Velarde A, Viltrop A, Winckler C, Gubbins S, Laroucau K, Antoniou S, Aznar I, Broglia A, Lima E, Van der Stede Y, Zancanaro G, Roberts HC. Assessment of the control measures of the category A diseases of Animal Health Law: Burkholderia mallei (Glanders). EFSA J 2022; 20:e07069. [PMID: 35035583 PMCID: PMC8753583 DOI: 10.2903/j.efsa.2022.7069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for glanders. In this opinion, EFSA and the AHAW Panel of experts review the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period and (iii) the minimum radius of the protection and surveillance zone, and the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere. Considering the epidemiology and distribution of glanders, it was foreseen that three different situations could lead to a suspicion of the disease. Sampling procedures were defined for each of the three different suspicion types, which can also be applied in most of the other scenarios assessed. The monitoring period (6 months) was assessed as effective in all scenarios. The AHAW Panel of experts considered the minimum radius and duration of the existing protection and surveillance zone, set at the establishment level, effective. Recommendations provided for each of the scenarios assessed aim to support the European Commission in the drafting of further pieces of legislation, as well as for plausible ad hoc requests in relation to glanders.
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Wernery U, Chan E, Raghavan R, Teng JLL, Syriac G, Siu SY, Joseph M, Yeung ML, Jia L, Cai JP, Chiu TH, Lau SKP, Woo PCY. Development of a sensitive competitive enzyme-linked immunosorbent assay for serodiagnosis of Burkholderia mallei, a Tier 1 select agent. PLoS Negl Trop Dis 2021; 15:e0010007. [PMID: 34932554 PMCID: PMC8691619 DOI: 10.1371/journal.pntd.0010007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/18/2021] [Indexed: 11/19/2022] Open
Abstract
Glanders is a highly contagious and potentially serious disease caused by Burkholderia mallei, a Tier 1 select agent. In this study, we raised a monoclonal antibody (mAb) against the lipopolysaccharide (LPS) of B. mallei and developed a competitive enzyme-linked immunosorbent assay (cELISA) for B. mallei infection. Using the titrated optimal conditions of B. mallei-LPS (2 ng) for microtiter plate coating, sample serum dilution at 1:20 and 3.5 ng/μL anti-LPS mAb B5, the cutoff value of the cELISA was determined using serum samples from 136 glanders-free seronegative horses in Hong Kong. All calculated percentage inhibition (PI) values from these seronegative samples were below 39.6% inhibition (1.5 standard deviations above mean PI) and was used as the cutoff value. The diagnostic sensitivity of the developed LPS-based cELISA was first evaluated using sera from donkeys and mice inoculated with B. mallei. An increasing trend of PI values above the defined cELISA cutoff observed in the donkey and mouse sera suggested positive detection of anti-LPS antibodies. The sensitivity and specificity of the LPS-based cELISA was further evaluated using 31 serologically positive horse sera from glanders outbreaks in Bahrain and Kuwait, of which 30 were tested positive by the cELISA; and 21 seronegative horse sera and 20 seronegative donkey sera from Dubai, of which all were tested negative by the cELISA. A cELISA with high sensitivity (97.2%) and specificity (100%) for the detection of B. mallei antibodies in different animals was developed. Glanders is a highly contagious and life-threatening disease caused by Burkholderia mallei, a Tier 1 select agent, with no available vaccine. The disease is endemic in the Middle East, Asia, Africa and South America with sporadic outbreaks and mainly occurs in horses, donkeys and mules, although it has also been reported in camels, tigers, lions, and even humans. As the bacterium is not easily isolated from clinical specimens and correct identification based on clinical signs is difficult, it is thus important to develop serological tests which can quickly diagnose B. mallei infection. In this study, we generated a monoclonal antibody against B. mallei lipopolysaccharide and used it to develop a competitive enzyme-linked immunosorbent assay (cELISA) for the serodiagnosis of B. mallei infection. The developed cELISA was optimized and evaluated using glanders-free and glanders-positive horses, donkeys and mice from Hong Kong and the Middle East, and was shown to be highly sensitive and specific for the detection of glanders in different animals. A simple and inexpensive test to allow for the early detection and diagnosis of suspected clinical cases as well as the screening of apparently asymptomatic animals will be helpful in controlling the spread and elimination of the disease.
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Affiliation(s)
- Ulrich Wernery
- Central Veterinary Research Laboratory, Dubai, United Arab Emirates
- * E-mail: (UW); (PCYW)
| | - Elaine Chan
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Rekha Raghavan
- Central Veterinary Research Laboratory, Dubai, United Arab Emirates
| | - Jade L. L. Teng
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
| | - Ginu Syriac
- Central Veterinary Research Laboratory, Dubai, United Arab Emirates
| | - Sing-Yung Siu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Marina Joseph
- Central Veterinary Research Laboratory, Dubai, United Arab Emirates
| | - Man-Lung Yeung
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
| | - Lilong Jia
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Jian-Piao Cai
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Tsz-Ho Chiu
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Susanna K. P. Lau
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
| | - Patrick C. Y. Woo
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- State Key Laboratory of Emerging Infectious Diseases, The University of Hong Kong, Hong Kong
- Carol Yu Centre for Infection, The University of Hong Kong, Hong Kong
- * E-mail: (UW); (PCYW)
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