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Kaestli M, Schmid M, Mayo M, Rothballer M, Harrington G, Richardson L, Hill A, Hill J, Tuanyok A, Keim P, Hartmann A, Currie BJ. Out of the ground: aerial and exotic habitats of the melioidosis bacterium Burkholderia pseudomallei in grasses in Australia. Environ Microbiol 2012; 14:2058-70. [PMID: 22176696 PMCID: PMC3319007 DOI: 10.1111/j.1462-2920.2011.02671.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Melioidosis is an emerging infectious disease of humans and animals in the tropics caused by the soil bacterium Burkholderia pseudomallei. Despite high fatality rates, the ecology of B.pseudomallei remains unclear. We used a combination of field and laboratory studies to investigate B.pseudomallei colonization of native and exotic grasses in northern Australia. Multivariable and spatial analyses were performed to determine significant predictors for B.pseudomallei occurrence in plants and soil collected longitudinally from field sites. In plant inoculation experiments, the impact of B.pseudomallei upon these grasses was studied and the bacterial load semi-quantified. Fluorescence in situ hybridization and confocal laser scanning microscopy were performed to localize the bacteria in plants. Burkholderia pseudomallei was found to inhabit not only the rhizosphere and roots but also aerial parts of specific grasses. This raises questions about the potential spread of B.pseudomallei by grazing animals whose droppings were found to be positive for these bacteria. In particular, B.pseudomallei readily colonized exotic grasses introduced to Australia for pasture. The ongoing spread of these introduced grasses creates new habitats suitable for B.pseudomallei survival and may be an important factor in the evolving epidemiology of melioidosis seen both in northern Australia and elsewhere globally.
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Price EP, Dale JL, Cook JM, Sarovich DS, Seymour ML, Ginther JL, Kaufman EL, Beckstrom-Sternberg SM, Mayo M, Kaestli M, Glass MB, Gee JE, Wuthiekanun V, Warner JM, Baker A, Foster JT, Tan P, Tuanyok A, Limmathurotsakul D, Peacock SJ, Currie BJ, Wagner DM, Keim P, Pearson T. Development and validation of Burkholderia pseudomallei-specific real-time PCR assays for clinical, environmental or forensic detection applications. PLoS One 2012; 7:e37723. [PMID: 22624061 PMCID: PMC3356290 DOI: 10.1371/journal.pone.0037723] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 04/23/2012] [Indexed: 11/18/2022] Open
Abstract
The bacterium Burkholderia pseudomallei causes melioidosis, a rare but serious illness that can be fatal if untreated or misdiagnosed. Species-specific PCR assays provide a technically simple method for differentiating B. pseudomallei from near-neighbor species. However, substantial genetic diversity and high levels of recombination within this species reduce the likelihood that molecular signatures will differentiate all B. pseudomallei from other Burkholderiaceae. Currently available molecular assays for B. pseudomallei detection lack rigorous validation across large in silico datasets and isolate collections to test for specificity, and none have been subjected to stringent quality control criteria (accuracy, precision, selectivity, limit of quantitation (LoQ), limit of detection (LoD), linearity, ruggedness and robustness) to determine their suitability for environmental, clinical or forensic investigations. In this study, we developed two novel B. pseudomallei specific assays, 122018 and 266152, using a dual-probe approach to differentiate B. pseudomallei from B. thailandensis, B. oklahomensis and B. thailandensis-like species; other species failed to amplify. Species specificity was validated across a large DNA panel (>2,300 samples) comprising Burkholderia spp. and non-Burkholderia bacterial and fungal species of clinical and environmental relevance. Comparison of assay specificity to two previously published B. pseudomallei-specific assays, BurkDiff and TTS1, demonstrated comparable performance of all assays, providing between 99.7 and 100% specificity against our isolate panel. Last, we subjected 122018 and 266152 to rigorous quality control analyses, thus providing quantitative limits of assay performance. Using B. pseudomallei as a model, our study provides a framework for comprehensive quantitative validation of molecular assays and provides additional, highly validated B. pseudomallei assays for the scientific research community.
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Fliser D, Shilo V, Covic A, Besarab A, Provenzano R, Duliege AM, Chen M, Tong S, Francisco C, Gao HY, Polu K, De Francisco AL, Macdougall I, Macdougall I, Schiller B, Locatelli F, Wiecek A, Francisco C, Tang H, Tong S, Chen M, Duliege AM, Polu K, Mayo M, Covic A, Macdougall I, Macdougall I, Casadevall N, Stead R, Taal M, Faller B, Karras A, Chen M, Tong S, Duliege AM, Rowell R, Polu K, Eckardt KU, Locatelli F, Dusilova Sulkova S, Arnaud S, Bruno P, Arnaud G, Dorina V, Eric A, Gerard M, Cases A, Portoles JM, Calls J, Martinez Castelao A, Sanchez-Guisande D, Segarra A, Tsubakihara Y, Tsubakihara Y, Saito A, Saito A, Saito A, Tsubakihara Y, Martinez-Castelao A, Martinez-Castelao A, Cases A, Fort J, Bonal J, Fulladosa X, Galceran JM, Torregrosa V, Coll E, Minutolo R, Cozzolino M, DI Iorio B, Polito P, Santoro D, Manenti F, Nappi F, Feriozzi S, Conte G, De Nicola L, Mikhail A, Provenzano R, Schiller B, Besarab A, Francisco C, Gao HY, Daley R, Tong S, Mayo M, Yang A, Polu K, Macdougall I, Wiecek A, Schiller B, Canaud B, Locatelli F, Yang A, Chen M, Polu K, Francisco C, Gao HY, Tong S, Duliege AM, Provenzano R, Locatelli F, Locatelli F, Provenzano R, Besarab A, Rath T, Yang A, Mayo M, Francisco C, Macdougall I, Bartnicki P, Baj Z, Majewska E, Rysz J, Fievet P, Assem M, Brazier F, Xu X, Soltani ON, Demontis R, Barsan L, Stancu S, Stancu S, Stanciu A, Capusa C, Petrescu L, Zugravu A, Mircescu G, Malyszko JM, Levin-Iaina N, Malyszko J, Glowinska I, Koc-Zorawska E, Slotki I, Mysliwiec M, Mircescu G, Mircescu G, Capusa C, Stancu S, Barsan L, Grabowski D, Blaga V, Dumitru D, Pchelin I, Shishkin A, Kus T, Usalan C, Tiryaki O, Chin HJ, Chae DW, Kim S, Bertram H, Keller F, Rumjon A, Wood C, Wilson P, Khakoo S, Chai MO, Macdougall IC, Nuria GF, Maria Asuncion F, Jose Maria MG, Carmen C, Paloma Leticia MM, Francisco Javier L, Moniek DG, De Goeij M, Yvette M, Diana G, Friedo D, Nynke H, Lezaic V, Miljkovic B, Petkovic N, Maric I, Vucicevic K, Simic Ogrizovic S, Djukanovic L, Cases A, Martinez-Castelao A, Fort A, Bonal J, Fulladosa X, Galceran JM, Torregrosa V, Coll E, DI Giulio S, DI Giulio S, Galle J, Kiss I, Herlitz H, Wirnsberger G, Claes K, Suranyi M, Guerin A, Winearls C, Addison J, D'souza M, Froissart M, Garrido P, Garrido P, Teixeira M, Costa E, Rodrigues-Santos P, Parada B, Belo L, Alves R, Teixeira F, Santos-Silva A, Reis F, Winearls C, Winearls C, DI Giulio S, Galle J, Kiss I, Herlitz H, Wirnsberger G, Claes K, Suranyi M, Guerin A, Addison J, D'souza M, Fouqueray B, Floris M, Conti M, Cao R, Pili G, Melis P, Matta V, Murgia E, Atzeni A, Binda V, Angioi A, Peri M, Pani A, Besarab A, Belo D, Diamond S, Martin E, Sun C, Lee T, Saikali K, Franco M, Leong R, Neff T, Yu KHP, Tiranathanagul K, Praditpornsilpa K, Katavetin P, Kanjanabuch T, Avihingsanon Y, Tungsanga K, Eiam-Ong S, Macdougall IC, Casadevall N, Percheson P, Potamianou A, Foucher A, Fife D, Vercammen E. Renal anaemia - CKD 1-5. Nephrol Dial Transplant 2012. [DOI: 10.1093/ndt/gfs217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sarovich DS, Price EP, Von Schulze AT, Cook JM, Mayo M, Watson LM, Richardson L, Seymour ML, Tuanyok A, Engelthaler DM, Pearson T, Peacock SJ, Currie BJ, Keim P, Wagner DM. Characterization of ceftazidime resistance mechanisms in clinical isolates of Burkholderia pseudomallei from Australia. PLoS One 2012; 7:e30789. [PMID: 22363490 PMCID: PMC3283585 DOI: 10.1371/journal.pone.0030789] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 12/29/2011] [Indexed: 11/22/2022] Open
Abstract
Burkholderia pseudomallei is a Gram-negative bacterium that causes the serious human disease, melioidosis. There is no vaccine against melioidosis and it can be fatal if not treated with a specific antibiotic regimen, which typically includes the third-generation cephalosporin, ceftazidime (CAZ). There have been several resistance mechanisms described for B. pseudomallei, of which the best described are amino acid changes that alter substrate specificity in the highly conserved class A β-lactamase, PenA. In the current study, we sequenced penA from isolates sequentially derived from two melioidosis patients with wild-type (1.5 µg/mL) and, subsequently, resistant (16 or ≥256 µg/mL) CAZ phenotypes. We identified two single-nucleotide polymorphisms (SNPs) that directly increased CAZ hydrolysis. One SNP caused an amino acid substitution (C69Y) near the active site of PenA, whereas a second novel SNP was found within the penA promoter region. In both instances, the CAZ resistance phenotype corresponded directly with the SNP genotype. Interestingly, these SNPs appeared after infection and under selection from CAZ chemotherapy. Through heterologous cloning and expression, and subsequent allelic exchange in the native bacterium, we confirmed the role of penA in generating both low-level and high-level CAZ resistance in these clinical isolates. Similar to previous studies, the amino acid substitution altered substrate specificity to other β-lactams, suggesting a potential fitness cost associated with this mutation, a finding that could be exploited to improve therapeutic outcomes in patients harboring CAZ resistant B. pseudomallei. Our study is the first to functionally characterize CAZ resistance in clinical isolates of B. pseudomallei and to provide proven and clinically relevant signatures for monitoring the development of antibiotic resistance in this important pathogen.
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Hampton V, Kaestli M, Mayo M, Choy JL, Harrington G, Richardson L, Benedict S, Noske R, Garnett ST, Godoy D, Spratt BG, Currie BJ. Melioidosis in Birds and Burkholderia pseudomallei Dispersal, Australia. Emerg Infect Dis 2012; 17:1310-2. [PMID: 21762599 PMCID: PMC3381411 DOI: 10.3201/eid1707.100707] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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Mayo M, Kaesti M, Harrington G, Cheng AC, Ward L, Karp D, Jolly P, Godoy D, Spratt BG, Currie BJ. Burkholderia pseudomallei in unchlorinated domestic bore water, Tropical Northern Australia. Emerg Infect Dis 2012; 17:1283-5. [PMID: 21762588 PMCID: PMC3381386 DOI: 10.3201/eid1707.100614] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
To determine whether unchlorinated bore water in northern Australia contained Burkholderia pseudomallei organisms, we sampled 55 bores; 18 (33%) were culture positive. Multilocus sequence typing identified 15 sequence types. The B. pseudomallei sequence type from 1 water sample matched a clinical isolate from a resident with melioidosis on the same property.
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Tuanyok A, Stone JK, Mayo M, Kaestli M, Gruendike J, Georgia S, Warrington S, Mullins T, Allender CJ, Wagner DM, Chantratita N, Peacock SJ, Currie BJ, Keim P. The genetic and molecular basis of O-antigenic diversity in Burkholderia pseudomallei lipopolysaccharide. PLoS Negl Trop Dis 2012; 6:e1453. [PMID: 22235357 PMCID: PMC3250505 DOI: 10.1371/journal.pntd.0001453] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 11/11/2011] [Indexed: 02/07/2023] Open
Abstract
Lipopolysaccharide (LPS) is one of the most important virulence and antigenic components of Burkholderia pseudomallei, the causative agent of melioidosis. LPS diversity in B. pseudomallei has been described as typical, atypical or rough, based upon banding patterns on SDS-PAGE. Here, we studied the genetic and molecular basis of these phenotypic differences. Bioinformatics was used to determine the diversity of genes known or predicted to be involved in biosynthesis of the O-antigenic moiety of LPS in B. pseudomallei and its near-relative species. Multiplex-PCR assays were developed to target diversity of the O-antigen biosynthesis gene patterns or LPS genotypes in B. pseudomallei populations. We found that the typical LPS genotype (LPS genotype A) was highly prevalent in strains from Thailand and other countries in Southeast Asia, whereas the atypical LPS genotype (LPS genotype B) was most often detected in Australian strains (~13.8%). In addition, we report a novel LPS ladder pattern, a derivative of the atypical LPS phenotype, associated with an uncommon O-antigen biosynthesis gene cluster that is found in only a small B. pseudomallei sub-population. This new LPS group was designated as genotype B2. We also report natural mutations in the O-antigen biosynthesis genes that potentially cause the rough LPS phenotype. We postulate that the diversity of LPS may correlate with differential immunopathogenicity and virulence among B. pseudomallei strains.
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Liguori AP, Warrington SD, Ginther JL, Pearson T, Bowers J, Glass MB, Mayo M, Wuthiekanun V, Engelthaler D, Peacock SJ, Currie BJ, Wagner DM, Keim P, Tuanyok A. Diversity of 16S-23S rDNA internal transcribed spacer (ITS) reveals phylogenetic relationships in Burkholderia pseudomallei and its near-neighbors. PLoS One 2011; 6:e29323. [PMID: 22195045 PMCID: PMC3237603 DOI: 10.1371/journal.pone.0029323] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 11/24/2011] [Indexed: 11/19/2022] Open
Abstract
Length polymorphisms within the 16S-23S ribosomal DNA internal transcribed spacer (ITS) have been described as stable genetic markers for studying bacterial phylogenetics. In this study, we used these genetic markers to investigate phylogenetic relationships in Burkholderia pseudomallei and its near-relative species. B. pseudomallei is known as one of the most genetically recombined bacterial species. In silico analysis of multiple B. pseudomallei genomes revealed approximately four homologous rRNA operons and ITS length polymorphisms therein. We characterized ITS distribution using PCR and analyzed via a high-throughput capillary electrophoresis in 1,191 B. pseudomallei strains. Three major ITS types were identified, two of which were commonly found in most B. pseudomallei strains from the endemic areas, whereas the third one was significantly correlated with worldwide sporadic strains. Interestingly, mixtures of the two common ITS types were observed within the same strains, and at a greater incidence in Thailand than Australia suggesting that genetic recombination causes the ITS variation within species, with greater recombination frequency in Thailand. In addition, the B. mallei ITS type was common to B. pseudomallei, providing further support that B. mallei is a clone of B. pseudomallei. Other B. pseudomallei near-neighbors possessed unique and monomorphic ITS types. Our data shed light on evolutionary patterns of B. pseudomallei and its near relative species.
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Dale J, Price EP, Hornstra H, Busch JD, Mayo M, Godoy D, Wuthiekanun V, Baker A, Foster JT, Wagner DM, Tuanyok A, Warner J, Spratt BG, Peacock SJ, Currie BJ, Keim P, Pearson T. Epidemiological tracking and population assignment of the non-clonal bacterium, Burkholderia pseudomallei. PLoS Negl Trop Dis 2011; 5:e1381. [PMID: 22180792 PMCID: PMC3236730 DOI: 10.1371/journal.pntd.0001381] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 09/16/2011] [Indexed: 11/24/2022] Open
Abstract
Rapid assignment of bacterial pathogens into predefined populations is an important first step for epidemiological tracking. For clonal species, a single allele can theoretically define a population. For non-clonal species such as Burkholderia pseudomallei, however, shared allelic states between distantly related isolates make it more difficult to identify population defining characteristics. Two distinct B. pseudomallei populations have been previously identified using multilocus sequence typing (MLST). These populations correlate with the major foci of endemicity (Australia and Southeast Asia). Here, we use multiple Bayesian approaches to evaluate the compositional robustness of these populations, and provide assignment results for MLST sequence types (STs). Our goal was to provide a reference for assigning STs to an established population without the need for further computational analyses. We also provide allele frequency results for each population to enable estimation of population assignment even when novel STs are discovered. The ability for humans and potentially contaminated goods to move rapidly across the globe complicates the task of identifying the source of an infection or outbreak. Population genetic dynamics of B. pseudomallei are particularly complicated relative to other bacterial pathogens, but the work here provides the ability for broad scale population assignment. As there is currently no independent empirical measure of successful population assignment, we provide comprehensive analytical details of our comparisons to enable the reader to evaluate the robustness of population designations and assignments as they pertain to individual research questions. Finer scale subdivision and verification of current population compositions will likely be possible with genotyping data that more comprehensively samples the genome. The approach used here may be valuable for other non-clonal pathogens that lack simple group-defining genetic characteristics and provides a rapid reference for epidemiologists wishing to track the origin of infection without the need to compile population data and learn population assignment algorithms. Burkholderia pseudomallei is a soil-dwelling bacterium that can infect a large range of hosts. In humans, B. pseudomallei causes melioidosis, and typical routes of entry include open wounds, inhalation, or ingestion. Clinical features are diverse, although pneumonia and abscess formation are common. High rates of recombination within the genome of this bacterium have confounded attempts to match clinical samples to geographically defined populations. Here we provide a reference that simplifies source attribution issues. We applied population assignment software to previously generated sequence data from seven B. pseudomallei genes to define the major geographic populations within this species. We evaluated the robustness of our results by comparison with two additional population assignment programs. We present the likelihood that each variant is assigned to a particular geographic population. This information can be used to assign novel B. pseudomallei isolates to a geographic population without needing to learn and run cumbersome population assignment applications. This method can also be used for other bacteria that are difficult to source-attribute due to high levels of genomic variation and recombination.
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Richardson LJ, Kaestli M, Mayo M, Bowers JR, Tuanyok A, Schupp J, Engelthaler D, Wagner DM, Keim PS, Currie BJ. Towards a rapid molecular diagnostic for melioidosis: Comparison of DNA extraction methods from clinical specimens. J Microbiol Methods 2011; 88:179-81. [PMID: 22108495 DOI: 10.1016/j.mimet.2011.10.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 10/24/2011] [Accepted: 10/24/2011] [Indexed: 12/15/2022]
Abstract
Optimising DNA extraction from clinical samples for Burkholderia pseudomallei Type III secretion system real-time PCR in suspected melioidosis patients confirmed that urine and sputum are useful diagnostic samples. Direct testing on blood remains problematic; testing DNA extracted from plasma was superior to DNA from whole blood or buffy coat.
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Engelthaler DM, Bowers J, Schupp JA, Pearson T, Ginther J, Hornstra HM, Dale J, Stewart T, Sunenshine R, Waddell V, Levy C, Gillece J, Price LB, Contente T, Beckstrom-Sternberg SM, Blaney DD, Wagner DM, Mayo M, Currie BJ, Keim P, Tuanyok A. Molecular investigations of a locally acquired case of melioidosis in Southern AZ, USA. PLoS Negl Trop Dis 2011; 5:e1347. [PMID: 22028940 PMCID: PMC3196475 DOI: 10.1371/journal.pntd.0001347] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 08/19/2011] [Indexed: 02/05/2023] Open
Abstract
Melioidosis is caused by Burkholderia pseudomallei, a Gram-negative bacillus, primarily found in soils in Southeast Asia and northern Australia. A recent case of melioidosis in non-endemic Arizona was determined to be the result of locally acquired infection, as the patient had no travel history to endemic regions and no previous history of disease. Diagnosis of the case was confirmed through multiple microbiologic and molecular techniques. To enhance the epidemiological analysis, we conducted several molecular genotyping procedures, including multi-locus sequence typing, SNP-profiling, and whole genome sequence typing. Each technique has different molecular epidemiologic advantages, all of which provided evidence that the infecting strain was most similar to those found in Southeast Asia, possibly originating in, or around, Malaysia. Advancements in new typing technologies provide genotyping resolution not previously available to public health investigators, allowing for more accurate source identification. Melioidosis is a bacterial disease caused by percutaneous inoculation, aspiration or ingestion of the soil bacteria Burkholderia pseudomallei. Melioidosis is primarily found in Southeast Asia and Northern Australia, and, to a lesser degree, nearby regions. A recent case of melioidosis in Southwestern United States (Southern Arizona) prompted a detailed epidemiological and molecular investigation to discover the source of infection. The authors describe the use of multiple genomic analysis tools to aid in this investigation. The results of these analyses uniformly identified Southeast Asia as the source of the strain that infected the patient, however the epidemiological investigation had determined the patient had no international travel or known exposures to Southeast Asian products. New cutting edge technologies, such as next generation sequencing, are quickly being adapted into epidemiologic investigations, particularly for cases and outbreaks of unknown origin, although older, mature technologies with larger existing databases will still be needed for appropriate comparative analyses.
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Mukhopadhyay C, Kaestli M, Vandana KE, Sushma K, Mayo M, Richardson L, Tuanyok A, Keim P, Godoy D, Spratt BG, Currie BJ. Molecular characterization of clinical Burkholderia pseudomallei isolates from India. Am J Trop Med Hyg 2011; 85:121-3. [PMID: 21734136 DOI: 10.4269/ajtmh.2011.11-0166] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Multilocus sequence typing of seven isolates of Burkholderia pseudomallei from India showed considerable diversity, with six different sequence types. Possible dissemination of melioidosis by historical trading routes is supported by links to strains from Southeast Asia, China, and Africa and the presence of the Burkholderia mallei allele of the bimA gene.
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Wang Z, Aksamit I, Tuscher L, Tom BS, Del Buono CB, Campbell U, Shields S, Lam T, Whitlock KB, Mayo M, Huang J, Christman AM, Bergstrom KA. Guideline adherence rates and costs of chemotherapy treatment for NSCLC patients treated in U.S. community oncology practices. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.15_suppl.7538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Kovtun Y, Jones G, Audette C, Mayo M, Leece B, Zhao R, Clancy L, Sun X, Chari R, Singh R. 235 Negatively-charged sulfonate group in linker improves potency of antibody–maytansinoid conjugates against multidrug-resistant cancer cells. EJC Suppl 2010. [DOI: 10.1016/s1359-6349(10)71940-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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90
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Wang Z, Bergstrom KA, Aksamit I, Tuscher L, Lam T, Tom BS, Baker CG, Whitlock KB, Ansari-Jaberi Z, Mayo M. Guideline adherence rates of chemotherapy treatment for colon cancer patients treated in U.S. community oncology practices. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.3620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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91
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Bergstrom KA, Wang Z, Aksamit I, Tuscher L, Lam T, Tom BS, Baker CG, Whitlock KB, Ansari-Jaberi Z, Mayo M. Guideline adherence rates of chemotherapy treatment for breast cancer patients treated in U.S. community oncology practices. J Clin Oncol 2010. [DOI: 10.1200/jco.2010.28.15_suppl.596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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92
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Pearson T, Giffard P, Beckstrom-Sternberg S, Auerbach R, Hornstra H, Tuanyok A, Price EP, Glass MB, Leadem B, Beckstrom-Sternberg JS, Allan GJ, Foster JT, Wagner DM, Okinaka RT, Sim SH, Pearson O, Wu Z, Chang J, Kaul R, Hoffmaster AR, Brettin TS, Robison RA, Mayo M, Gee JE, Tan P, Currie BJ, Keim P. Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer. BMC Biol 2009; 7:78. [PMID: 19922616 PMCID: PMC2784454 DOI: 10.1186/1741-7007-7-78] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 11/18/2009] [Indexed: 12/02/2022] Open
Abstract
Background Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion We describe an Australian origin for B. pseudomallei, characterized by a single introduction event into Southeast Asia during a recent glacial period, and variable levels of lateral gene transfer within populations. These patterns provide insights into mechanisms of genetic diversification in B. pseudomallei and its closest relatives, and provide a framework for integrating the traditionally separate fields of population genetics and phylogenetics for other bacterial species with high levels of lateral gene transfer.
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Currie BJ, Haslem A, Pearson T, Hornstra H, Leadem B, Mayo M, Gal D, Ward L, Godoy D, Spratt BG, Keim P. Identification of melioidosis outbreak by multilocus variable number tandem repeat analysis. Emerg Infect Dis 2009; 15:169-74. [PMID: 19193259 PMCID: PMC2657638 DOI: 10.3201/eid1502.081036] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
One-sentence summary for table of contents: This analysis can identify a clonal outbreak of this disease within 8 hours of receipt of bacterial isolates. Endemic melioidosis is caused by genetically diverse Burkholderia pseudomallei strains. However, clonal outbreaks (multiple cases caused by 1 strain) have occurred, such as from contaminated potable water. B. pseudomallei is designated a group B bioterrorism agent, which necessitates rapidly recognizing point-source outbreaks. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) can identify genetically related isolates, but results take several days to obtain. We developed a simplified 4-locus multilocus variable number tandem repeat analysis (MLVA-4) for rapid typing and compared results with PFGE and MLST for a large number of well-characterized B. pseudomallei isolates. MLVA-4 compared favorably with MLST and PFGE for the same isolates; it discriminated between 65 multilocus sequence types and showed relatedness between epidemiologically linked isolates from outbreak clusters and between isolates from individual patients. MLVA-4 can establish or refute that a clonal outbreak of melioidosis has occurred within 8 hours of receipt of bacterial strains.
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Parkes HM, Shilton CM, Jerrett IV, Benedict S, Spratt BG, Godoy D, O'Brien CR, Krockenberger MB, Mayo M, Currie BJ, Malik R. Primary ocular melioidosis due to a single genotype of Burkholderia pseudomallei in two cats from Arnhem Land in the Northern Territory of Australia. J Feline Med Surg 2009; 11:856-63. [PMID: 19428280 DOI: 10.1016/j.jfms.2009.02.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/17/2009] [Indexed: 10/20/2022]
Abstract
Melioidosis was diagnosed in two domestic crossbred cats presented for unilateral ocular disease. One patient was born and bred in Nhulunbuy, Arnhem Land, while the other had moved there 6 months previously from Townsville, Queensland. Both patients were presented with sudden onset of a 'red eye' and blepharospasm, which progressed to an enlarged, painful, firm globe with loss of pupillary light reflexes and vision. An obvious primary focus of infection outside the eye was not detected in either cat. In both patients, the affected eye was surgically removed and vitreal culture revealed a pure growth of Burkholderia pseudomallei. In each instance, the infection had penetrated the sclera to produce retrobulbar cellulitis, and in one case frank retrobulbar abscessation. Histologically, there was a pyogranulomatous uveitis with extensive destruction of intraocular structures. The first case was still alive approximately 1 year following enucleation and limited antimicrobial therapy using amoxicillin clavulanate and doxycycline. The second was euthanased when a localised abscess developed on the same side of the face as the healed surgical incision, despite appropriate antimicrobial therapy. Both cases were caused by the same multilocus sequence type of B pseudomallei (ST 116), which had only been isolated previously from two human patients, both living in the same isolated geographical area as the cats of this report. Apart from the geographical clustering, no epidemiological links were evident between the two cats and/or the two people. The presumptive pathogenesis of these infections is discussed in relation to current knowledge about melioidosis in northern Australia.
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Kaestli M, Mayo M, Harrington G, Ward L, Watt F, Hill JV, Cheng AC, Currie BJ. Landscape changes influence the occurrence of the melioidosis bacterium Burkholderia pseudomallei in soil in northern Australia. PLoS Negl Trop Dis 2009; 3:e364. [PMID: 19156200 PMCID: PMC2617783 DOI: 10.1371/journal.pntd.0000364] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 12/17/2008] [Indexed: 01/19/2023] Open
Abstract
Background The soil-dwelling saprophyte bacterium Burkholderia pseudomallei is the cause of melioidosis, a severe disease of humans and animals in southeast Asia and northern Australia. Despite the detection of B. pseudomallei in various soil and water samples from endemic areas, the environmental habitat of B. pseudomallei remains unclear. Methodology/Principal Findings We performed a large survey in the Darwin area in tropical Australia and screened 809 soil samples for the presence of these bacteria. B. pseudomallei were detected by using a recently developed and validated protocol involving soil DNA extraction and real-time PCR targeting the B. pseudomallei–specific Type III Secretion System TTS1 gene cluster. Statistical analyses such as multivariable cluster logistic regression and principal component analysis were performed to assess the association of B. pseudomallei with environmental factors. The combination of factors describing the habitat of B. pseudomallei differed between undisturbed sites and environmentally manipulated areas. At undisturbed sites, the occurrence of B. pseudomallei was found to be significantly associated with areas rich in grasses, whereas at environmentally disturbed sites, B. pseudomallei was associated with the presence of livestock animals, lower soil pH and different combinations of soil texture and colour. Conclusions/Significance This study contributes to the elucidation of environmental factors influencing the occurrence of B. pseudomallei and raises concerns that B. pseudomallei may spread due to changes in land use. Melioidosis is a severe disease affecting humans and animals in the tropics. It is caused by the bacterium Burkholderia pseudomallei, which lives in tropical soil and especially occurs in southeast Asia and northern Australia. Despite the recognition that melioidosis is an emerging infectious disease, little is known about the habitat of B. pseudomallei in the environment. We performed a survey in the Darwin area in tropical Australia, screening 809 soil samples for the presence of these bacteria using molecular methods. We found that environmental factors describing the habitat of these bacteria differed between environmentally undisturbed and disturbed sites. At undisturbed sites, B. pseudomallei was primarily found in close proximity to streams and in grass- and roots-rich areas. In disturbed soil, B. pseudomallei was associated with the presence of animals, farming or irrigation. Highest B. pseudomallei counts were retrieved from paddocks, pens and kennels holding livestock and dogs. This study contributes to the elucidation of the habitat of B. pseudomallei in northern Australia. It also raises concerns that B. pseudomallei may spread due to changes in land management.
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Tuanyok A, Leadem BR, Auerbach RK, Beckstrom-Sternberg SM, Beckstrom-Sternberg JS, Mayo M, Wuthiekanun V, Brettin TS, Nierman WC, Peacock SJ, Currie BJ, Wagner DM, Keim P. Genomic islands from five strains of Burkholderia pseudomallei. BMC Genomics 2008; 9:566. [PMID: 19038032 PMCID: PMC2612704 DOI: 10.1186/1471-2164-9-566] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 11/27/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Burkholderia pseudomallei is the etiologic agent of melioidosis, a significant cause of morbidity and mortality where this infection is endemic. Genomic differences among strains of B. pseudomallei are predicted to be one of the major causes of the diverse clinical manifestations observed among patients with melioidosis. The purpose of this study was to examine the role of genomic islands (GIs) as sources of genomic diversity in this species. RESULTS We found that genomic islands (GIs) vary greatly among B. pseudomallei strains. We identified 71 distinct GIs from the genome sequences of five reference strains of B. pseudomallei: K96243, 1710b, 1106a, MSHR668, and MSHR305. The genomic positions of these GIs are not random, as many of them are associated with tRNA gene loci. In particular, the 3' end sequences of tRNA genes are predicted to be involved in the integration of GIs. We propose the term "tRNA-mediated site-specific recombination" (tRNA-SSR) for this mechanism. In addition, we provide a GI nomenclature that is based upon integration hotspots identified here or previously described. CONCLUSION Our data suggest that acquisition of GIs is one of the major sources of genomic diversity within B. pseudomallei and the molecular mechanisms that facilitate horizontally-acquired GIs are common across multiple strains of B. pseudomallei. The differential presence of the 71 GIs across multiple strains demonstrates the importance of these mobile elements for shaping the genetic composition of individual strains and populations within this bacterial species.
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Kovtun Y, Audette C, Maloney E, Mayo M, Jones G, Erickson H, Wilhelm S, Singh R, Goldmacher V, Chari R. 518 POSTER Novel antibody-maytansinoid conjugates with efficacy against multidrug resistant tumors. EJC Suppl 2008. [DOI: 10.1016/s1359-6349(08)72452-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Silverberg GD, Mayo M, Saul T, Fellmann J, Carvalho J, McGuire D. Continuous CSF drainage in AD: results of a double-blind, randomized, placebo-controlled study. Neurology 2008; 71:202-9. [PMID: 18525029 DOI: 10.1212/01.wnl.0000316197.04157.6f] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Alzheimer disease (AD) has been associated with abnormal cerebral clearance of macromolecules, such as amyloid and microtubule-associated-protein tau (MAP-tau). We hypothesized that improving clearance of macromolecules from the CNS might slow the progression of dementia. OBJECTIVE This prospective, randomized, double-blinded, placebo-controlled trial evaluated the safety and effectiveness of a surgically implanted shunt in subjects with probable AD. METHODS A total of 215 subjects with probable AD by National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria received either a low-flow ventriculoperitoneal shunt or a sham (occluded) shunt for 9 months. Longitudinal CSF sampling was performed in both active and control subjects. Primary outcome measures were the Mattis Dementia Rating Scale and the Global Deterioration Scale. CSF Abeta((1-42)) and MAP-tau also were assayed. RESULTS After a planned interim analysis, the study was halted for futility. Using the intent-to-treat population, no between-group differences were observed in the primary outcome measures. The surgical procedure and device were associated with 12 CNS infections, some temporally associated with CSF sampling. All were treated successfully. CONCLUSIONS We found no benefit to low-flow CSF shunting in subjects with mild to severe Alzheimer disease. CSF infections, while treatable, occurred more frequently than expected, in some cases likely related to CSF sampling.
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Huang CH, Williamson SK, VanVeldhuizen PJ, Hsueh CT, Allen A, Smith H, Mayo M, Tawfik O, Uypeckcuat AM, Kelly K. PDGFR inhibition using imatinib (I) combined with docetaxel (D), a potential new treatment strategy in the treatment of recurrent non-small cell lung cancer (NSCLC): Preliminary efficacy results. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.19055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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100
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Currie BJ, Thomas AD, Godoy D, Dance DA, Cheng AC, Ward L, Mayo M, Pitt TL, Spratt BG. Australian and Thai isolates of Burkholderia pseudomallei are distinct by multilocus sequence typing: revision of a case of mistaken identity. J Clin Microbiol 2007; 45:3828-9. [PMID: 17898162 PMCID: PMC2168502 DOI: 10.1128/jcm.01590-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A recent study using multilocus sequence typing (MLST) of Burkholderia pseudomallei isolates found a sequence type (ST60) to be common to both Thailand and Australia, contradicting earlier studies showing complete distinction between isolates from these regions. The ST60 isolates reportedly from Australia had been obtained for MLST from United Kingdom and U.S. collections. We have located and characterized the original Australian isolates; they were collected in 1983, and they are neither ST60 nor B. pseudomallei isolates. The B. pseudomallei MLST database has been corrected, and there is no ST common to isolates verified as obtained from Australia or from Thailand.
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