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Vives-Soto M, Puerta-García A, Rodríguez-Sánchez E, Pereira JL, Solera J. What risk do Brucella vaccines pose to humans? A systematic review of the scientific literature on occupational exposure. PLoS Negl Trop Dis 2024; 18:e0011889. [PMID: 38190394 PMCID: PMC10830018 DOI: 10.1371/journal.pntd.0011889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 01/31/2024] [Accepted: 12/27/2023] [Indexed: 01/10/2024] Open
Abstract
BACKGROUND Currently, vaccination of livestock with attenuated strains of Brucella remains an essential measure for controlling brucellosis, although these vaccines may be dangerous to humans. The aim of this study was to review the risk posed to humans by occupational exposure to vaccine strains and the measures that should be implemented to minimize this risk. METHODS This article reviewed the scientific literature indexed in PubMed up to September 30, 2023, following "the PRISMA guidelines". Special emphasis was placed on the vaccine strain used and the route of exposure. Non-occupational exposure to vaccine strains, intentional human inoculation, publications on exposure to wild strains, and secondary scientific sources were excluded from the study. RESULTS Nineteen primary reports were found and classified in three subgroups: safety accidents in vaccine factories that led to an outbreak (n = 2), survellaince studies on vaccine manufacturing workers with a serologic diagnosis of Brucella infection (n = 3), and publications of infection by vaccine strains during their administration, including case reports, records of occupational accidents and investigations of outbreaks in vaccination campaigns (n = 14). Although accidental exposure during vaccine manufacturing were uncommon, they could provoke large outbreaks through airborne spread with risk of spread to the neighboring population. Besides, despite strict protection measures, a percentage of vaccine manufacturing workers developed positive Brucella serology without clinical infection. The most frequent type of exposure with symptomatic infection was needle injury during vaccine administration. Prolonged contact with the pathogen, lack of information and a low adherence to personal protective equipment (PPE) use in the work environment were commonly associated with infection. CONCLUSIONS Brucella vaccines pose occupational risk of contagion to humans from their production to their administration to livestock, although morbidity is low and deaths were not reported. Recommended protective measures and active surveillance of exposed workers appeared to reduce this risk. It would be advisable to carry out observational studies and/or systematic registries using solid diagnostic criteria.
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Dang S, Sui H, Zhang S, Wu D, Chen Z, Zhai J, Bai M. CRISPR-Cas12a test strip (CRISPR/CAST) package: In-situ detection of Brucella from infected livestock. BMC Vet Res 2023; 19:202. [PMID: 37833763 PMCID: PMC10571365 DOI: 10.1186/s12917-023-03767-1] [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: 07/13/2022] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Brucellosis is a common zoonotic disease caused by Brucella, which causes enormous economic losses and public burden to epidemic areas. Early and precise diagnosis and timely culling of infected animals are crucial to prevent the infection and spread of Brucella. In recent years, RNA-guided CRISPR/Cas12a(Clustered Regularly Interspaced Short Palindromic Repeats and its associated protein 12a) nucleases have shown great promise in nucleic acid detection. This research aims to develop a CRISPR/CAST (CRISPR/Cas12a Test strip) package that can rapidly detect Brucella nucleic acid during on-site screening, especially on remote family pastures. The CRISPR/Cas12a system combined with recombinase polymerase amplification (RPA), and lateral flow read-out. RESULTS We selected the conserved gene bp26, which commonly used in Brucella infection detection and compared on Genbank with other Brucella species. The genomes of Brucella abortus 2308, Brucella suis S2, Brucella melitansis 16 M, and Brucella suis 1330, et al. were aligned, and the sequences were found to be consistent. Therefore, the experiments were only performed on B. melitensis. With the CRISPR/CAST package, the assay of Brucella nucleic acid can be completed within 30 min under isothermal temperature conditions, with a sensitivity of 10 copies/μl. Additionally, no antigen cross-reaction was observed against Yersinia enterocolitica O:9, Escherichia coli O157, Salmonella enterica serovar Urbana O:30, and Francisella tularensis. The serum samples of 398 sheep and 100 cattle were tested by the CRISPR/CAST package, of which 31 sheep and 8 cattle were Brucella DNA positive. The detection rate was consistent with the qPCR results and higher than that of the Rose Bengal Test (RBT, 19 sheep and 5 cattle were serum positive). CONCLUSIONS The CRISPR/CAST package can accurately detect Brucella DNA in infected livestock within 30 min and exhibits several advantages, including simplicity, speed, high sensitivity, and strong specificity with no window period. In addition, no expensive equipment, standard laboratory, or professional operators are needed for the package. It is an effective tool for screening in the field and obtaining early, rapid diagnoses of Brucella infection. The package is an efficient tool for preventing and controlling epidemics.
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Affiliation(s)
- Sheng Dang
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China
| | - Humujile Sui
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China
| | - Shuai Zhang
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China
- Key Laboratory of Zoonose Prevention and Control at Universities of Inner Mongolia Autonomous Region, Tongliao, 028000, China
- Brucellosis Prevention and Treatment Engineering Research Center of Inner Mongolia Autonomous Region, Tongliao, 028000, China
| | - Dongxing Wu
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China
- Key Laboratory of Zoonose Prevention and Control at Universities of Inner Mongolia Autonomous Region, Tongliao, 028000, China
- Brucellosis Prevention and Treatment Engineering Research Center of Inner Mongolia Autonomous Region, Tongliao, 028000, China
- Mongolian Medical College, Inner Mongolia Minzu University, Tongliao, 028000, China
| | - Zeliang Chen
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China
- Key Laboratory of Zoonose Prevention and Control at Universities of Inner Mongolia Autonomous Region, Tongliao, 028000, China
- Brucellosis Prevention and Treatment Engineering Research Center of Inner Mongolia Autonomous Region, Tongliao, 028000, China
| | - Jingbo Zhai
- Innovative Institute of Zoonoses, Inner Mongolia Minzu University, Tongliao, 028000, China.
- Key Laboratory of Zoonose Prevention and Control at Universities of Inner Mongolia Autonomous Region, Tongliao, 028000, China.
- Brucellosis Prevention and Treatment Engineering Research Center of Inner Mongolia Autonomous Region, Tongliao, 028000, China.
| | - Meirong Bai
- Mongolian Medical College, Inner Mongolia Minzu University, Tongliao, 028000, China.
- Key Laboratory of Mongolian Medicine Research and Development Engineering, Ministry of Education, Tongliao, 028000, China.
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Tan Q, Wang Y, Liu Y, Tao Z, Yu C, Huang Y, Yang X, Ying X, Hu Y, Li S. Molecular epidemiological characteristics of Brucella in Guizhou Province, China, from 2009 to 2021. Front Microbiol 2023; 14:1188469. [PMID: 37426016 PMCID: PMC10326899 DOI: 10.3389/fmicb.2023.1188469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 05/31/2023] [Indexed: 07/11/2023] Open
Abstract
Introduction Brucellosis was made statutorily notifiable in 1955, in China, while in Guizhou Province, the pathogen of human brucellosis was isolated for the first time in 2011. However, currently, the brucellosis epidemic is becoming more and more severe in Guizhou Province. The type distribution and genetic characteristics of Brucella in Guizhou Province, as well as its evolutionary relationship with domestic and foreign strains, are still unclear. Methods MLST, MLVA, and rpoB typing techniques were used for the molecular epidemiological study of the 83 Brucella isolates in Guizhou province. Results Among the 83 Brucella strains, MLST identified three ST genotypes, of which ST39 is a newly reported type in China. MLVA-16 generated 49 genotypes, and MLVA-11 generated 5 known genotypes and 2 unreported genotypes. Six genotypes were identified by rpoB technology. Discussion MLVA has a high resolution, but differences at the Bruce 04 and 16 loci cannot exclude associations between epidemics, and combining MLST and rpoB typing methods for epidemiologic tracing can avoid erroneous judgments. Moreover, through the combined analysis of the three typing techniques, the possible origin of the new Brucella can be reasonably inferred, which is also conducive to promoting the subsequent research of the novel Brucella.
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Affiliation(s)
- Qinqin Tan
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, School of Public Health, University of Guizhou Medical, Guiyang, Guizhou, China
| | - Yue Wang
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
| | - Ying Liu
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
| | - Zhongfa Tao
- Center for Disease Control and Prevention of Guizhou Provincial, Institute of Infectious Disease Control, Guiyang, Guizhou, China
| | - Chun Yu
- Center for Disease Control and Prevention of Guizhou Provincial, Institute of Infectious Disease Control, Guiyang, Guizhou, China
| | - Yan Huang
- Center for Disease Control and Prevention of Guizhou Provincial, Institute of Infectious Disease Control, Guiyang, Guizhou, China
| | - Xinggui Yang
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
| | - Xia Ying
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, School of Public Health, University of Guizhou Medical, Guiyang, Guizhou, China
| | - Yong Hu
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, School of Public Health, University of Guizhou Medical, Guiyang, Guizhou, China
| | - Shijun Li
- Laboratory Center, Center for Disease Control and Prevention of Guizhou Provincial, Guiyang, Guizhou, China
- The Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, School of Public Health, University of Guizhou Medical, Guiyang, Guizhou, China
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Ye YB, Yang JH, Li DL, Hao LH, Zhang Z, Mei SY, Zhang H, Du FY, Yv LH, Liu BS, Chen ZL. A specific reverse complement sequence for distinguishing Brucella canis from other Brucella species. Front Vet Sci 2022; 9:983482. [DOI: 10.3389/fvets.2022.983482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022] Open
Abstract
Canine brucellosis is primarily caused by Brucella canis, but other Brucella species can also cause the disease. Identifying sequences specific to B. canis and establishing PCR assays that can distinguish between B. canis and other Brucella species is essential to determine the etiology of canine brucellosis and the source of infection and to achieve effective control. We analyzed the gaps and SNPs of genomes I and II from B. canis strain RM6/66 and B. melitensis strain 16M using the Mauve genome alignment software, and the specificity of each of these differential regions was analyzed by BLAST. A 132 bp specific sequence was found between the DK60_915 (glycosyl hydrolase 108 family protein) and DK60_917 (aldose 1-epimerase) loci in B. canis chromosome 1. Further comparative analysis revealed that this is a reverse complement sequence between B. canis and other Brucella species. Then, three primers were designed based on the sequence that could detect B. canis with a 310 bp amplification product or other Brucella species with a 413 bp product. The PCR based on these primers had reasonable specificity and a sensitivity of 100 copies of Brucella DNA. The detection results for the blood samples of the aborted dogs showed a favorable accordance with the Bruce-ladder multiplex PCR assay. In conclusion, we found a specific reverse complement sequence between B. canis and other Brucella and developed a PCR method that allows a more comprehensive identification of the pathogen involved in canine brucellosis. These findings provide an effective means for preventing and controlling brucellosis.
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Establishment of loop-mediated isothermal amplification for Brucella detection using a warmer pad as a heating source. Biotechniques 2022; 73:142-150. [PMID: 35997071 DOI: 10.2144/btn-2021-0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The study sought to establish a sensitive and specific on-site loop-mediated isothermal amplification (LAMP) for Brucella heated using a warmer pad. LAMP primers specific to the conserved BvrR gene were designed, and the LAMP reaction was optimized. The heating characteristics of the warmer pad were investigated. The detection validity (specificity, sensitivity) of clinical samples by warmer-pad LAMP (WP-LAMP) was compared with that of qPCR. The WP-LAMP method displayed high specificity and sensitivity for five Brucella gene copies. The detection of 104 clinical samples was 97.1% concordant with quantitative polymerase chain reaction. The results showed the success of the WP-LAMP for on-site detection. The method requires no special equipment and is conducive to the prevention and control of brucellosis.
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He CY, Zhang YZ, Liu MZ, Zhao HL, Ren LS, Liu BS, He S, Chen ZL. Combined immunization with inactivated vaccine reduces the dose of live B. abortus A19 vaccine. BMC Vet Res 2022; 18:128. [PMID: 35366881 PMCID: PMC8976406 DOI: 10.1186/s12917-022-03229-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 03/23/2022] [Indexed: 11/18/2022] Open
Abstract
Background Brucella spp. is an important zoonotic pathogen responsible for brucellosis in humans and animals. Brucella abortus A19 strain is a widespread vaccine in China. However, it has a drawback of residual virulence in animals and humans. Methods In this study, the BALB/c mice were inoculated with either 100 μL PBS(control group, C group), 109 CFU/mL inactivated B. abortus A19 strain (I group), 105 CFU/mL (low-dose group, L group) 106 CFU/mL live B. abortus A19 strain (high-dose group, H group), or 105 CFU/mL live B. abortus A19 strain combined with 109 CFU/mL inactivated B. abortus A19 strain (LI group). Mice were challenged with B. abortus strain 2308 at 7 week post vaccination. Subsequently, the immune and protective efficacy of the vaccines were evaluated by measuring splenic bacterial burden, spleen weight, serum IgG, interferon-gamma (IFN-γ), interleukin-4 (IL-4) percentage of CD4 + and CD8 + T cells of mice via bacterial isolation, weighing, ELISA and flow cytometry, respectively. Results The splenic bacterial burden and spleen weight of the mice in group LI were mostly equivalent to the mice of group H. Moreover, Brucella-specific serum IgG, IFN-γ, IL-4, and the percentage of CD4+ and CD8+ T cells of the LI group mice were similar to those of the H group. In the subsequent challenge test, both vaccines conferred protective immunity to wild-type (WT) 2308 strain. In addition, the levels of IL-4 and IFN-γ, CD4+ and CD8+ T cells in these mice were similar to those of the mice in the H group. Conclusions Combined immunization with low dose live vaccine and inactivated vaccine allowed to reduce the live B. abortus A19 vaccine, dose with an equivalent protection of the high-dose live vaccine. Supplementary Information The online version contains supplementary material available at 10.1186/s12917-022-03229-0.
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He C, Yang J, Zhao H, Liu M, Wu D, Liu B, He S, Chen Z. Vaccination with a Brucella ghost developed through a double inactivation strategy provides protection in Guinea pigs and cattle. Microb Pathog 2021; 162:105363. [PMID: 34919994 DOI: 10.1016/j.micpath.2021.105363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/12/2021] [Accepted: 12/12/2021] [Indexed: 01/19/2023]
Abstract
Vaccination can prevent and control animal brucellosis. Currently, live attenuated vaccines are extensively used to prevent Brucella infection. However, traditional vaccines such as live attenuated vaccines are associated with biological safety risks for both humans and animals. The bacterial ghost (BG) is a new form of vaccine with great prospects. However, bacterial cells cannot be completely inactivated by biological lysis, conferring a safety risk associated with the vaccine. In this study, we developed a Brucella abortus A19 bacterial ghost (A19BG) through a double inactivation strategy with sequential biological lysis and hydrogen peroxide treatment. This strategy resulted in 100% inactivation of Brucella, such that viable bacterial cells were not detected even at an ultrahigh concentration of 1010 colony-forming units/mL. Furthermore, A19BG had a typical BG morphology and good genetic stability. Moreover, it did not induce adverse reactions in guinea pigs. The levels of antibodies, interferon-γ, interleukin-4, and CD4+ T cells in guinea pigs inoculated with the A19BG vaccine were similar to those inoculated with the existing A19 vaccine. Immunization with A19BG conferred a similar level of protection with that of A19 against Brucella melitensis M28 in both guinea pigs and cattle. In conclusion, the combination of biological lysis and H2O2-mediated inactivation is a safe and effective strategy that can serve as a reference for the preparation of BG vaccines.
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Affiliation(s)
- Chuanyu He
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Liaoning Province, Shenyang, 110866, PR China; Tecon Biological Co, Ltd, Urumqi, 830011, PR China
| | - Jianghua Yang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Liaoning Province, Shenyang, 110866, PR China
| | - Hailong Zhao
- Tecon Biological Co, Ltd, Urumqi, 830011, PR China
| | - Mengzhi Liu
- Tecon Biological Co, Ltd, Urumqi, 830011, PR China
| | - Dongling Wu
- Tecon Biological Co, Ltd, Urumqi, 830011, PR China
| | - Baoshan Liu
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Liaoning Province, Shenyang, 110866, PR China.
| | - Sun He
- Tecon Biological Co, Ltd, Urumqi, 830011, PR China.
| | - Zeliang Chen
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Liaoning Province, Shenyang, 110866, PR China; Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, PR China; Brucellosis Prevention and Treatment Engineering Technology Research Center of Inner Mongolia Autonomous Region, Inner Mongolia University for Nationalities, Tongliao, 028000, PR China; School of Public Health, Sun Yat-sen University, Guangzhou, 510275, PR China.
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Ramírez OLH, Santos HA, Paulino PG, van der Meer CS, Bautista JLR, Delgado ILJ, Obando JG, Garcia RR, da Costa Angelo I. Cross-sectional study of Brucella spp. using real-time PCR from bovine whole blood in Colombia. Vet Res Commun 2021; 46:189-201. [PMID: 34791575 DOI: 10.1007/s11259-021-09846-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 10/03/2021] [Indexed: 10/19/2022]
Abstract
A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an SNP-based assay, vaccine strains were differentiated from field strains. The associated factors were evaluated using logistical regression models. A total of 656 random cows from 40 herds were selected and analyzed using serology and PCR. The qPCR assay detected 9.5% (n = 62/656; 95% CI: 7.3, 12.0) of the animals with Brucella-DNA presence, while the serological test detected a 6.6% (n = 43/656; CI: 4.8, 8.7). 62.5% (n = 25/40; 95% CI: 45.8, 77.3) of positive cases were detected at the herd-level by the qPCR, while only 27.5% (n = 11/40; 95% CI: 14.6, 43.9) were detected by the serological test. All positive samples were identified as field Brucella strains employing the SNP-based assay. In the final regression model at the animal-level, five variables were associated with Brucella-DNA presence: the use of bulls for mating recorded history of reproductive problems, pregnant cows, parlor milking, and cows belonging to farms ≤200 m from the main road. At the herd-level, two variables were associated with Brucella-DNA presence: recorded history of reproductive problems and the use of bulls for mating. Given the fluctuant brucellosis prevalence in endemic areas, updated epidemiological studies are necessary to evaluate the disease dynamic and if established prevention and control measures have been effective or need to be adjusted. The increase in the prevalence of brucellosis in animal reservoirs creates an important risk of transmission in humans.
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Affiliation(s)
- Olga Lucia Herrán Ramírez
- Postgraduate Program in Veterinarian Science, Veterinary Institute, Federal Rural University of Rio de Janeiro, P.O. Box 23897-000, Seropedica, RJ, Brazil
| | - Huarrisson Azevedo Santos
- Department of Epidemiology and Public Health, Veterinary Institute, Federal Rural University of Rio de Janeiro, PO Box 23897-000, Seropedica, RJ, Brazil
| | - Patrícia Gonzaga Paulino
- Postgraduate Program in Veterinarian Science, Veterinary Institute, Federal Rural University of Rio de Janeiro, P.O. Box 23897-000, Seropedica, RJ, Brazil
| | - Carolina Soares van der Meer
- Postgraduate Program in Veterinarian Science, Veterinary Institute, Federal Rural University of Rio de Janeiro, P.O. Box 23897-000, Seropedica, RJ, Brazil
| | - José Luis Rodríguez Bautista
- Postgraduate Program in Veterinarian Science, Veterinary Institute, Federal Rural University of Rio de Janeiro, P.O. Box 23897-000, Seropedica, RJ, Brazil
| | | | - Juliana González Obando
- Department of Epidemiology and Public Health, Agrarian Sciences Faculty, Antioquia University, P.O. Box 1228, Medellín, Antioquia, Colombia
| | - Rene Ramirez Garcia
- INCA-CES, Faculty of Veterinary medicine and zootechnics, CES University, Box 050021, Medellin, Colombia
| | - Isabele da Costa Angelo
- Department of Epidemiology and Public Health, Veterinary Institute, Federal Rural University of Rio de Janeiro, PO Box 23897-000, Seropedica, RJ, Brazil.
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Deng X, He J, Wang Y, Yang Q, Yi JH, Zhang H, Wang Y, Miao Y, Wang Z, Chen C. Deletion of the type IV secretion system promoter VirB in Brucella abortus A19 strain attenuated the virulence of the bacteria and promotes autophagy. Can J Microbiol 2021; 68:165-176. [PMID: 34644507 DOI: 10.1139/cjm-2021-0053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Brucella abortus is a Gram-negative intracellular parasite bacteria causing serious health hazards in humans and animals. The type IV secretion system (T4SS), encoded by the virB promoter, has been identified as an important virulence factor for Brucella abortus, but the impact on Brucella abortus A19 remains unclear. In this study, the T4SS of Brucella abortus A19 was inactivated by deleting the virB promoter, resulting in a mutant strain A19ΔvirB. Real-time PCR and Western-blotting analysis demonstrated that T4SS-related proteins were not expressed after virB promoter deletion. Moreover, the survival rate of A19 in high salt and strong acidic environments was decreased after virB promoter deletion. Compared to the parental strain A19, the A19ΔvirB mutant strain showed reduced growth rate in TSB, decreased invasion ability to macrophages and dendritic cells, and reduced virulence of the mutant strain in macrophages, dendritic cells and mice. In addition, the A19ΔvirB mutant strain showed enhanced autophagy on macrophages and dendritic cells compared with A19, and the A19ΔvirB mutant strain was able to upregulate IL-6 and downregulate IL-10 in macrophages. These data help us to better understand the T4SS of the A19 vaccine strain and contribute to our efforts to improve Brucella vaccines.
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Affiliation(s)
- XiaoYu Deng
- Shihezi University, 70586, Shihezi, Xinjiang, China;
| | - Jinke He
- Xinjiang Second Medical College, Shihe zi, China;
| | - Yueli Wang
- Shihezi University, 70586, Shihezi, Xinjiang, China;
| | - Qin Yang
- Shihezi University, 70586, Shihezi, China;
| | - Ji Hai Yi
- Shihezi University, 70586, Shihezi, Xinjiang, China;
| | - Huan Zhang
- Shihezi University, 70586, Xinjiang Shihezi University, Shihezi, China, 832003;
| | - Yong Wang
- Shihezi University, 70586, Shihezi, Xinjiang, China;
| | | | - Zhen Wang
- Shihezi University, 70586, Shihezi, Xinjiang, China;
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