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Syrmis MW, Moser RJ, Kidd TJ, Hunt P, Ramsay KA, Bell SC, Wainwright CE, Grimwood K, Nissen MD, Sloots TP, Whiley DM. High-throughput single-nucleotide polymorphism-based typing of shared Pseudomonas aeruginosa strains in cystic fibrosis patients using the Sequenom iPLEX platform. J Med Microbiol 2013; 62:734-740. [PMID: 23412772 DOI: 10.1099/jmm.0.055905-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Shared strains of Pseudomonas aeruginosa are now well recognized in people with cystic fibrosis (CF), and suitable P. aeruginosa laboratory typing tools are pivotal to understanding their clinical significance and guiding infection control policies in CF clinics. We therefore compared a single-nucleotide polymorphism (SNP)-based typing method using Sequenom iPLEX matrix-assisted laser desorption ionization with time-of-flight mass spectrometry (MALDI-TOF MS) with typing methods used routinely by our laboratory. We analysed 617 P. aeruginosa isolates that included 561 isolates from CF patients collected between 2001 and 2009 in two Brisbane CF clinics and typed previously by enterobacterial repetitive intergenic consensus (ERIC)-PCR, as well as 56 isolates from non-CF patients analysed previously by multilocus sequence typing (MLST). The isolates were tested using a P. aeruginosa Sequenom iPLEX MALDI-TOF (PA iPLEX) method comprising two multiplex reactions, a 13-plex and an 8-plex, to characterize 20 SNPs from the P. aeruginosa housekeeping genes acsA, aroE, guaA, mutL, nuoD, ppsA and trpE. These 20 SNPs were employed previously in a real-time format involving 20 separate assays in our laboratory. The SNP analysis revealed 121 different SNP profiles for the 561 CF isolates. Overall, there was at least 96% agreement between the ERIC-PCR and SNP analyses for all predominant shared strains among patients attending our CF clinics: AUST-01, AUST-02 and AUST-06. For the less frequently encountered shared strain AUST-07, 6/25 (24%) ERIC-PCR profiles were misidentified initially as AUST-02 or as unique, illustrating the difficulty of gel-based analyses. SNP results for the 56 non-CF isolates were consistent with previous MLST data. Thus, the PA iPLEX format provides an attractive high-throughput alternative to ERIC-PCR for large-scale investigations of shared P. aeruginosa strains.
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Affiliation(s)
- Melanie W Syrmis
- Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - Ralf J Moser
- Sequenom Inc., Sequenom Asia Pacific, Herston, Queensland, Australia
| | - Timothy J Kidd
- Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - Priscilla Hunt
- Sequenom Inc., Sequenom Asia Pacific, Herston, Queensland, Australia
| | - Kay A Ramsay
- Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - Scott C Bell
- Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, Queensland, Australia.,Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia
| | - Claire E Wainwright
- Queensland Children's Respiratory Centre, Royal Children's Hospital, Brisbane, Australia.,Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia
| | - Keith Grimwood
- Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - Michael D Nissen
- Microbiology Division, Pathology Queensland Central Laboratory, Herston, Queensland, Australia.,Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - Theo P Sloots
- Microbiology Division, Pathology Queensland Central Laboratory, Herston, Queensland, Australia.,Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
| | - David M Whiley
- Queensland Children's Medical Research Institute, Royal Children's Hospital, The University of Queensland, Brisbane, Queensland, Australia.,Queensland Paediatric Infectious Diseases Laboratory, Royal Children's Hospital, Brisbane, Queensland, Australia
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Parker JK, Havird JC, De La Fuente L. Differentiation of Xylella fastidiosa strains via multilocus sequence analysis of environmentally mediated genes (MLSA-E). Appl Environ Microbiol 2012; 78:1385-96. [PMID: 22194287 PMCID: PMC3294468 DOI: 10.1128/aem.06679-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 12/13/2011] [Indexed: 11/20/2022] Open
Abstract
Isolates of the plant pathogen Xylella fastidiosa are genetically very similar, but studies on their biological traits have indicated differences in virulence and infection symptomatology. Taxonomic analyses have identified several subspecies, and phylogenetic analyses of housekeeping genes have shown broad host-based genetic differences; however, results are still inconclusive for genetic differentiation of isolates within subspecies. This study employs multilocus sequence analysis of environmentally mediated genes (MLSA-E; genes influenced by environmental factors) to investigate X. fastidiosa relationships and differentiate isolates with low genetic variability. Potential environmentally mediated genes, including host colonization and survival genes related to infection establishment, were identified a priori. The ratio of the rate of nonsynonymous substitutions to the rate of synonymous substitutions (dN/dS) was calculated to select genes that may be under increased positive selection compared to previously studied housekeeping genes. Nine genes were sequenced from 54 X. fastidiosa isolates infecting different host plants across the United States. Results of maximum likelihood (ML) and Bayesian phylogenetic (BP) analyses are in agreement with known X. fastidiosa subspecies clades but show novel within-subspecies differentiation, including geographic differentiation, and provide additional information regarding host-based isolate variation and specificity. dN/dS ratios of environmentally mediated genes, though <1 due to high sequence similarity, are significantly greater than housekeeping gene dN/dS ratios and correlate with increased sequence variability. MLSA-E can more precisely resolve relationships between closely related bacterial strains with low genetic variability, such as X. fastidiosa isolates. Discovering the genetic relationships between X. fastidiosa isolates will provide new insights into the epidemiology of populations of X. fastidiosa, allowing improved disease management in economically important crops.
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Affiliation(s)
- Jennifer K. Parker
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Justin C. Havird
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Leonardo De La Fuente
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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Abstract
Coral disease has emerged over recent decades as a significant threat to coral reef ecosystems, with declines in coral cover and diversity of Caribbean reefs providing an example of the potential impacts of disease at regional scales. If similar trends are to be mitigated or avoided on reefs worldwide, a deeper understanding of the factors underlying the origin and spread of coral diseases and the steps that can be taken to prevent, control, or reduce their impacts is required. In recent years, an increased focus on coral microbiology and the application of classic culture techniques and emerging molecular technologies has revealed several coral pathogens that could serve as targets for novel coral disease diagnostic tools. The ability to detect and quantify microbial agents identified as indicators of coral disease will aid in the elucidation of disease causation and facilitate coral disease detection and diagnosis, pathogen monitoring in individuals and ecosystems, and identification of pathogen sources, vectors, and reservoirs. This information will advance the field of coral disease research and contribute knowledge necessary for effective coral reef management. This paper establishes the need for sensitive and specific molecular-based coral pathogen detection, outlines the emerging technologies that could serve as the basis of a new generation of coral disease diagnostic assays, and addresses the unique challenges inherent to the application of these techniques to environmentally derived coral samples.
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Muellner P, Zadoks RN, Perez AM, Spencer SEF, Schukken YH, French NP. The integration of molecular tools into veterinary and spatial epidemiology. Spat Spatiotemporal Epidemiol 2011; 2:159-71. [PMID: 22748175 DOI: 10.1016/j.sste.2011.07.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
At the interface of molecular biology and epidemiology, the emerging discipline of molecular epidemiology offers unique opportunities to advance the study of diseases through the investigation of infectious agents at the molecular level. Molecular tools can increase our understanding of the factors that shape the spatial and temporal distribution of pathogens and disease. Both spatial and molecular aspects have always been important to the field of infectious disease epidemiology, but recently news tools have been developed which increase our ability to consider both elements within a common framework. This enables the epidemiologist to make inferences about disease patterns in space and time. This paper introduces some basic concepts of molecular epidemiology in a veterinary context and illustrates the application of molecular tools at a range of spatio-temporal scales. Case studies - a multi-state outbreak of Serratia mastitis, a national control program for campylobacteriosis, and evolution of foot-and-mouth-disease viruses - are used to demonstrate the importance of considering molecular aspects in modern epidemiological studies. The discipline of molecular epidemiology is in its infancy and our contribution aims to promote awareness, understanding and uptake of molecular epidemiology in veterinary science.
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Affiliation(s)
- Petra Muellner
- Epi-interactive, 8a Darlington Road, Miramar, Wellington 6022, New Zealand.
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Gómez-Díaz E, Boulinier T, Sertour N, Cornet M, Ferquel E, McCoy KD. Genetic structure of marine Borrelia garinii and population admixture with the terrestrial cycle of Lyme borreliosis. Environ Microbiol 2011; 13:2453-67. [PMID: 21651685 DOI: 10.1111/j.1462-2920.2011.02515.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite the importance of population structure for the epidemiology of pathogenic bacteria, the spatial and ecological heterogeneity of these populations is often poorly characterized. Here, we investigated the genetic diversity and population structure of the Lyme borreliosis (LB) spirochaete Borrelia garinii in its marine cycle involving colonial seabirds and different host races of the seabird tick Ixodes uriae. Multilocus sequence analyses (MLSA) on eight chromosomal and two plasmid loci (ospA and ospC) indicate that B. garinii circulating in the marine system is highly diverse. Microevolution in marine B. garinii seems to be mainly clonal, but recombination and selection do occur. Sequence types were not evenly distributed among geographic regions, with substantial population subdivision between Atlantic and Pacific Ocean basins. However, no geographic structuring was evident within regions. Results of selection analyses and phylogenetic discordance between chromosomal and plasmid loci indicate adaptive evolution is likely occurring in this system, but no pattern of host or vector-associated divergence was found. Recombination analyses showed evidence for population admixture between terrestrial and marine strains, suggesting that LB spirochaetes are exchanged between these enzootic cycles. Importantly, our results highlight the need to explicitly consider the marine system for a complete understanding of the evolutionary ecology and global epidemiology of Lyme borreliosis.
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Affiliation(s)
- Elena Gómez-Díaz
- MIVEGEC, CNRS 5290-IRD 224-UM1-UM2, IRD, 34394, Montpellier, France.
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Tardy F, Gaurivaud P, Manso-Silván L, Thiaucourt F, Pellet MP, Mercier P, Le Grand D, Poumarat F. Extended surveillance for CBPP in a free country: Challenges and solutions regarding the potential caprine reservoir. Prev Vet Med 2011; 101:89-95. [PMID: 21620492 DOI: 10.1016/j.prevetmed.2011.04.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 04/21/2011] [Accepted: 04/29/2011] [Indexed: 10/18/2022]
Abstract
Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease of cattle and buffalo caused by Mycoplasma mycoides subsp. mycoides "Small Colony" (MmmSC). The agent of CBPP has been isolated from goats in different countries including CBPP-free areas. Goats can therefore be regarded as a putative MmmSC reservoir. No diagnostic test for CBPP surveillance in goats has been proposed as yet. Furthermore, serological tests could be seriously hampered by a widespread caprine infection due to the subspecies M. mycoides subsp. capri (Mmc), which is antigenically very close to MmmSC and displays high levels of genetic variability. A competition ELISA (cELISA) is currently used to screen for CBPP in cattle at the herd level in infected areas. The aim of this study was to see if the same cELISA would be specific enough to be used to screen goats despite the potential concomitant infection with Mmc. The cELISA titers of goats from Mmc-infected and non-infected herds were comparable and negative using the accepted cutoff for bovine sera. In contrast, seroconversion was observed in goats experimentally inoculated with an Mmc strain that cross-reacted with a monoclonal antibody targeting the same epitope as that used in cELISA. The probability of such false positivity occurring under field conditions is very low since Mmc strains with such an atypical antigenic profile emerge only rarely as a result of random nucleotide variation of the epitope-coding region. In conclusion, the commercially available cELISA can be considered specific enough to be used as a primary test to monitor passage of the CBPP agent in goats, but its sensitivity in goats requires further investigation.
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Affiliation(s)
- Florence Tardy
- Anses, Lyon Laboratory, UMR Mycoplasmoses of Ruminants, 31 Avenue Tony Garnier F-69364 Lyon cedex 07, France.
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