1
|
Mugabi R, Silva APSP, Hu X, Gottschalk M, Aragon V, Macedo NR, Sahin O, Harms P, Main R, Tucker AW, Li G, Clavijo MJ. Molecular characterization of Glaesserella parasuis strains circulating in North American swine production systems. BMC Vet Res 2023; 19:135. [PMID: 37641044 PMCID: PMC10464461 DOI: 10.1186/s12917-023-03698-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/18/2023] [Indexed: 08/31/2023] Open
Abstract
BACKGROUND Glaesserella parasuis is the causative agent of Glässer's disease in pigs. Serotyping is the most common method used to type G. parasuis isolates. However, the high number of non-typables (NT) and low discriminatory power make serotyping problematic. In this study, 218 field clinical isolates and 15 G. parasuis reference strains were whole-genome sequenced (WGS). Multilocus sequence types (MLST), serotypes, core-genome phylogeny, antimicrobial resistance (AMR) genes, and putative virulence gene information was extracted. RESULTS In silico WGS serotyping identified 11 of 15 serotypes. The most frequently detected serotypes were 7, 13, 4, and 2. MLST identified 72 sequence types (STs), of which 66 were novel. The most predominant ST was ST454. Core-genome phylogeny depicted 3 primary lineages (LI, LII, and LIII), with LIIIA sublineage isolates lacking all vtaA genes, based on the structure of the phylogenetic tree and the number of virulence genes. At least one group 1 vtaA virulence genes were observed in most isolates (97.2%), except for serotype 8 (ST299 and ST406), 15 (ST408 and ST552) and NT (ST448). A few group 1 vtaA genes were significantly associated with certain serotypes or STs. The putative virulence gene lsgB, was detected in 8.3% of the isolates which were predominantly of serotype 5/12. While most isolates carried the bcr, ksgA, and bacA genes, the following antimicrobial resistant genes were detected in lower frequency; blaZ (6.9%), tetM (3.7%), spc (3.7%), tetB (2.8%), bla-ROB-1 (1.8%), ermA (1.8%), strA (1.4%), qnrB (0.5%), and aph3''Ia (0.5%). CONCLUSION: This study showed the use of WGS to type G. parasuis isolates and can be considered an alternative to the more labor-intensive and traditional serotyping and standard MLST. Core-genome phylogeny provided the best strain discrimination. These findings will lead to a better understanding of the molecular epidemiology and virulence in G. parasuis that can be applied to the future development of diagnostic tools, autogenous vaccines, evaluation of antibiotic use, prevention, and disease control.
Collapse
Affiliation(s)
- Robert Mugabi
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Ana Paula S Poeta Silva
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Xiao Hu
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Marcelo Gottschalk
- Groupe de Recherche Sur Les Maladies Infectieuses du Porc, Faculté de Médecine Vétérinaire, Université de Montréal, Montréal, Canada
| | - Virginia Aragon
- Centre de Recerca en Sanitat Animal (CReSA), Unitat Mixta d'Investigació IRTA-UAB en Sanitat Animal, UniversitatAutònoma de Barcelona (UAB), Campus, Bellaterra, Barcelona, Spain
- Programa de Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), IRTA, UniversitatAutònoma de Barcelona (UAB), Campus, Bellaterra, Barcelona, Spain
- WOAH Collaborating Centre for the Research and Control of Emerging and Re-Emerging Swine Diseases in Europe (IRTA-CReSA), Bellaterra, Barcelona, Spain
| | - Nubia R Macedo
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Orhan Sahin
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | | | - Rodger Main
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Alexander W Tucker
- Department of Veterinary Medicine, University of Cambridge, Cambridge, CB3 0ES, UK
| | - Ganwu Li
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA
| | - Maria J Clavijo
- Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames, IA, USA.
- PIC North America, Hendersonville, TN, USA.
| |
Collapse
|
2
|
Cui Y, Guo F, Cai X, Cao X, Guo J, Wang H, Yang B, Zhou H, Su X, Blackall PJ, Xu F. Ct value-based real time PCR serotyping of Glaesserella parasuis. Vet Microbiol 2021; 254:109011. [PMID: 33610013 DOI: 10.1016/j.vetmic.2021.109011] [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: 10/21/2020] [Accepted: 02/03/2021] [Indexed: 11/24/2022]
Abstract
Glaesserella parasuis is the causative agent of Glässer's disease in swine. Serotyping plays an essential role in prevalence investigations and in the development of vaccination strategies for the prevention of this disease. Molecular serotyping based on variation within the capsule loci of the 15 serovars is more accurate and efficient than traditional serological serotyping. To reduce the running time and facilitate ease of data interpretation, we developed a simple and rapid cycle threshold (Ct) value-based real time PCR (qPCR) method for the identification and serotyping of G. parasuis. The qPCR method distinguished between all 15 serovar reference strains of G. parasuis with efficiency values ranging between 85.5 % and 110.4 % and, R2 values > 0.98. The qPCR serotyping was evaluated using 83 clinical isolates with 43 of the isolates having been previously assigned to a serovar by the gel immuno-diffusion (GID) assay and 40 non-typeable isolates. The qPCR results of 41/43 (95.3 %) isolates were concordant with the GID assay except two isolates of serovar 12 were assigned to serovar 5. In addition, the qPCR serotyping assigned a serovar to each of the 40 non-typeable isolates. Of the 83 isolates tested to assign a serovar, a concordance rate of 98.8 % (82/83) was determined between the qPCR and the previously reported multiplex PCR of Howell et al. (2015) (including those that were either serovars 5 or 12). Despite the inability to differentiate between serovars 5 and 12, the Ct value-based qPCR serotyping represents an attractive alternative to current molecular serotyping method for G. parasuis and could be used for both epidemiological monitoring and the guidance of vaccination programs.
Collapse
Affiliation(s)
- Yifang Cui
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Fangfang Guo
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Xuwang Cai
- State Key Laboratory of Agricultural Microbiology, Division of Animal Infectious Disease, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xiaoya Cao
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Jie Guo
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Hongjun Wang
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Bing Yang
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Hongzhuan Zhou
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Xia Su
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China
| | - Patrick J Blackall
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, Queensland, 4072, Australia
| | - Fuzhou Xu
- Beijing Key Laboratory for Prevention and Control of Infectious Diseases in Livestock and Poultry, Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
| |
Collapse
|
3
|
Li J, Xu L, Su F, Yu B, Yuan X. Association between iscR-based phylogeny, serovars and potential virulence markers of Haemophilus parasuis. PeerJ 2019; 7:e6950. [PMID: 31143554 PMCID: PMC6524630 DOI: 10.7717/peerj.6950] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 04/09/2019] [Indexed: 12/03/2022] Open
Abstract
Haemophilus parasuis is an economically important bacterial pathogen of swine. Extensive genetic and phenotypic heterogeneity among H. parasuis strains have been observed, which hinders the deciphering of the population structure and its association with clinical virulence. In this study, two highly divergent clades were defined according to iron-sulphur cluster regulator (iscR)-based phylogeny analysis of 148 isolates. Clear separation of serovars and potential virulence markers (PVMs) were observed between the two clades, which are indicative of independent evolution of the two lineages. Previously suggested virulence factors showed no correlation with clinical virulence, and were probably clade or serovar specific genes emerged during different stage of evolution. PVMs profiles varied widely among isolates in the same serovar. Higher strain diversity in respect of PVMs was found for isolates from multi-strain infected farms than those from single strain infected ones, which indicates that multi-strain infection in one farm may increase the frequency of gene transfer in H. parasuis. Systemic isolates were more frequently found in serovar 13 and serovar 12, while no correlation between clinical virulence and iscR-based phylogeny was observed. It shows that iscR is a reliable marker for studying population structure of H. parasuis, while other factors should be included to avoid the interference of gene exchange of iscR between isolates. The two lineages of H. parasuis may have undergone independent evolution, but show no difference in clinical virulence. Wide distribution of systemic isolates across the entire population poses new challenge for development of vaccine with better cross-protection. Our study provides new information for better deciphering the population structure of H. parasuis, which helps understanding the extreme diversity within this pathogenic bacterium.
Collapse
Affiliation(s)
- Junxing Li
- Zhejiang Academy of Agricultural Sciences, Institute of Animal Husbandry and Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Lihua Xu
- Zhejiang Academy of Agricultural Sciences, Institute of Animal Husbandry and Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Fei Su
- Zhejiang Academy of Agricultural Sciences, Institute of Animal Husbandry and Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Bin Yu
- Zhejiang Academy of Agricultural Sciences, Institute of Animal Husbandry and Veterinary Medicine, Hangzhou, Zhejiang, China
| | - Xiufang Yuan
- Zhejiang Academy of Agricultural Sciences, Institute of Animal Husbandry and Veterinary Medicine, Hangzhou, Zhejiang, China
| |
Collapse
|
4
|
Wang L, Ma L, Liu Y, Gao P, Li Y, Li X, Liu Y. Multilocus sequence typing and virulence analysis of Haemophilus parasuis strains isolated in five provinces of China. INFECTION GENETICS AND EVOLUTION 2016; 44:228-233. [PMID: 27431332 DOI: 10.1016/j.meegid.2016.07.015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 07/08/2016] [Accepted: 07/13/2016] [Indexed: 10/21/2022]
Abstract
Haemophilus parasuis is the etiological agent of Glässers disease, which causes high morbidity and mortality in swine herds. Although H. parasuis strains can be classified into 15 serovars with the Kielstein-Rapp-Gabrielson serotyping scheme, a large number of isolates cannot be classified and have been designated 'nontypeable' strains. In this study, multilocus sequence typing (MLST) of H. parasuis was used to analyze 48 H. parasuis field strains isolated in China and two strains from Australia. Twenty-six new alleles and 29 new sequence types (STs) were detected, enriching the H. parasuis MLST databases. A BURST analysis indicated that H. parasuis lacks stable population structure and is highly heterogeneous, and that there is no association between STs and geographic area. When an UPGMA dendrogram was constructed, two major clades, clade A and clade B, were defined. Animal experiments, in which guinea pigs were challenged intraperitoneally with the bacterial isolates, supported the hypothesis that the H. parasuis STs in clade A are generally avirulent or weakly virulent, whereas the STs in clade B tend to be virulent.
Collapse
Affiliation(s)
- Liyan Wang
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China
| | - Lina Ma
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China
| | - Yongan Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China
| | - Pengcheng Gao
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China
| | - Youquan Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China
| | - Xuerui Li
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China.
| | - Yongsheng Liu
- State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, Gansu, PR China.
| |
Collapse
|
5
|
Zhang P, Hao H, Li J, Ahmad I, Cheng G, Chen D, Tao Y, Huang L, Wang Y, Dai M, Liu Z, Yuan Z. The Epidemiologic and Pharmacodynamic Cutoff Values of Tilmicosin against Haemophilus parasuis. Front Microbiol 2016; 7:385. [PMID: 27047487 PMCID: PMC4802331 DOI: 10.3389/fmicb.2016.00385] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/11/2016] [Indexed: 11/25/2022] Open
Abstract
The aim of this study was to establish antimicrobial susceptibility breakpoints for tilmicosin against Haemophilus parasuis, which is an important pathogen of respiratory tract infections. The minimum inhibitory concentrations (MICs) of 103 H. parasuis isolates were determined by the agar dilution method. The wild type (WT) distribution and epidemiologic cutoff value (ECV) were evaluated by statistical analysis. The new bronchoaveolar lavage was used to establish intrapulmonary pharmacokinetic (PK) model in swine. The pharmacokinetic (PK) parameters of tilmicosin, both in pulmonary epithelial lining fluid (PELF) and in plasma, were determined using high performance liquid chromatography method and WinNonlin software. The pharmacodynamic cutoff (COPD) was calculated using Monte Carlo simulation. Our results showed that 100% of WT isolates were covered when the ECV was set at 16 μg/mL. The tilmicosin had concentration-dependent activity against H. parasuis. The PK data indicated that tilmicosin concentrations in PELF was rapidly increased to high levels at 4 h and kept stable until 48 h after drug administration, while the tilmicosin concentration in plasma reached maximum levels at 4 h and continued to decrease during 4–72 h. Using Monte Carlo simulation, COPD was defined as 1 μg/mL. Conclusively, the ECV and COPD of tilmicosin against H. parasuis were established for the first time based on the MIC distribution and PK-PD analysis in the target tissue, respectively. These values are of great importance for detection of tilmicosin-resistant H. parasuis and for effective treatment of clinical intrapulmonary infection caused by H. parasuis.
Collapse
Affiliation(s)
- Peng Zhang
- National Reference Laboratory of Veterinary Drug Residues and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University Wuhan, China
| | - Haihong Hao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Jun Li
- National Reference Laboratory of Veterinary Drug Residues and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University Wuhan, China
| | - Ijaz Ahmad
- National Reference Laboratory of Veterinary Drug Residues and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University Wuhan, China
| | - Guyue Cheng
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Dongmei Chen
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Yanfei Tao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Lingli Huang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Yulian Wang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Menghong Dai
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University Wuhan, China
| | - Zhenli Liu
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural UniversityWuhan, China
| | - Zonghui Yuan
- National Reference Laboratory of Veterinary Drug Residues and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural UniversityWuhan, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural UniversityWuhan, China; Hubei Collaborative Innovation Center for Animal Nutrition and Feed Safety, Huazhong Agricultural UniversityWuhan, China
| |
Collapse
|
6
|
Boerlin P, Poljak Z, Gallant J, Chalmers G, Nicholson V, Soltes GA, MacInnes JI. Genetic diversity of Haemophilus parasuis from sick and healthy pigs. Vet Microbiol 2013; 167:459-67. [PMID: 23972949 DOI: 10.1016/j.vetmic.2013.07.028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/29/2013] [Accepted: 07/31/2013] [Indexed: 10/26/2022]
Abstract
A collection of 94 Haemophilus parasuis isolates was used for this study. It consisted of isolates from organs of pigs with Glässer's disease and pneumonia (n=54), from nasal swabs of healthy pigs in farms without Glässer's disease problems (n=25), and 15 reference strains. These isolates were typed using a new multilocus variable number of tandem repeats analysis (MLVA) protocol and investigated for the presence of nine putative virulence genes. The new MLVA protocol was highly discriminatory (54 types identified and discrimination index of 97.4%) and reproducible. Similar to previous investigations done with other methods, two major genetic clusters were identified by MLVA, which partially correlated with serotype and virulence gene distributions. Gene linkage analysis suggested that lateral gene transfer occurs within each of these clusters, but rarely between them. Although one single MLVA type included more than 20% of the clinical isolates, no significant correlation was detected between a specific MLVA type, the major genetic clusters, or the presence of any of the virulence genes investigated or the source of the isolates (clinical infection vs. healthy pig). The MLVA typing protocol described in this study is a promising new tool for future investigations into the epidemiology of Glässer's disease and could help us to better understand interacting microbial, host and environmental factors that lead to the development of H. parasuis disease.
Collapse
Affiliation(s)
- Patrick Boerlin
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
| | | | | | | | | | | | | |
Collapse
|
7
|
Gene content and diversity of the loci encoding biosynthesis of capsular polysaccharides of the 15 serovar reference strains of Haemophilus parasuis. J Bacteriol 2013; 195:4264-73. [PMID: 23873912 DOI: 10.1128/jb.00471-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Haemophilus parasuis is the causative agent of Glässer's disease, a systemic disease of pigs, and is also associated with pneumonia. H. parasuis can be classified into 15 different serovars. Here we report, from the 15 serotyping reference strains, the DNA sequences of the loci containing genes for the biosynthesis of the group 1 capsular polysaccharides, which are potential virulence factors of this bacterium. We contend that these loci contain genes for polysaccharide capsule structures, and not a lipopolysaccharide O antigen, supported by the fact that they contain genes such as wza, wzb, and wzc, which are associated with the export of polysaccharide capsules in the current capsule classification system. A conserved region at the 3' end of the locus, containing the wza, ptp, wzs, and iscR genes, is consistent with the characteristic export region 1 of the model group 1 capsule locus. A potential serovar-specific region (region 2) has been found by comparing the predicted coding sequences (CDSs) in all 15 loci for synteny and homology. The region is unique to each reference strain with the exception of those in serovars 5 and 12, which are identical in terms of gene content. The identification and characterization of this locus among the 15 serovars is the first step in understanding the genetic, molecular, and structural bases of serovar specificity in this poorly studied but important pathogen and opens up the possibility of developing an improved molecular serotyping system, which would greatly assist diagnosis and control of Glässer's disease.
Collapse
|
8
|
Mullins MA, Register KB, Brunelle BW, Aragon V, Galofré-Mila N, Bayles DO, Jolley KA. A curated public database for multilocus sequence typing (MLST) and analysis of Haemophilus parasuis based on an optimized typing scheme. Vet Microbiol 2012; 162:899-906. [PMID: 23218953 DOI: 10.1016/j.vetmic.2012.11.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 11/09/2012] [Accepted: 11/13/2012] [Indexed: 11/17/2022]
Abstract
Haemophilus parasuis causes Glässer's disease and pneumonia in swine. Serotyping is often used to classify isolates but requires reagents that are costly to produce and not standardized or widely available. Sequence-based methods, such as multilocus sequence typing (MLST), offer many advantages over serotyping. An MLST scheme was previously proposed for H. parasuis but genome sequence data only recently available reveals the primers recommended, based on sequences of related bacteria, are not optimal. Here we report modifications to enhance the original method, including primer redesign to eliminate mismatches with H. parasuis sequences and to avoid regions of high sequence heterogeneity, standardization of primer T(m)s and identification of universal PCR conditions that result in robust and reproducible amplification of all targets. The modified typing method was applied to a collection of 127 isolates from North and South America, Europe and Asia. An alignment of the concatenated sequences obtained from seven target housekeeping genes identified 278 variable nucleotide sites that define 116 unique sequence types. A comparison of the original and modified methods using a subset of 86 isolates indicates little difference in overall locus diversity, discriminatory power or in the clustering of strains within Neighbor-Joining trees. Data from the optimized MLST were used to populate a newly created and publicly available H. parasuis database. An accompanying database designed to capture provenance and epidemiological information for each isolate was also created. The modified MLST scheme is highly discriminatory but more robust, reproducible and user-friendly than the original. The MLST database provides a novel resource for investigation of H. parasuis outbreaks and for tracking strain evolution.
Collapse
Affiliation(s)
- Michael A Mullins
- Virus and Prion Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, 1920 Dayton Avenue, Ames, Iowa, 50010, United States
| | - Karen B Register
- Virus and Prion Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, 1920 Dayton Avenue, Ames, Iowa, 50010, United States.
| | - Brian W Brunelle
- Food Safety and Enteric Pathogens Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, 1920 Dayton Avenue, Ames, Iowa, 50010, United States
| | - Virginia Aragon
- Centre de Recerca en Sanitat Animal, Campus de la Universitat Autònoma de Barcelona, Barcelona, Spain; Institut de Recerca i Tecnologia Agroalimentàries, Barcelona, Spain
| | - Nuria Galofré-Mila
- Centre de Recerca en Sanitat Animal, Campus de la Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Darrell O Bayles
- Infectious Bacterial Diseases Research Unit, USDA/Agricultural Research Service/National Animal Disease Center, 1920 Dayton Avenue, Ames, Iowa, 50010, United States
| | - Keith A Jolley
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| |
Collapse
|