scholarly journals Distribution of Burkholderia pseudomallei in Northern Australia, a Land of Diversity

2014 ◽  
Vol 80 (11) ◽  
pp. 3463-3468 ◽  
Author(s):  
Evan McRobb ◽  
Mirjam Kaestli ◽  
Erin P. Price ◽  
Derek S. Sarovich ◽  
Mark Mayo ◽  
...  
Keyword(s):  
Population Structure ◽  
Burkholderia Pseudomallei ◽  
Northern Region ◽  
Northern Australia ◽  
Source Attribution ◽  
Environmental Isolates ◽  
Sampling Area ◽  
Dissimilarity Matrix ◽  
Content Type ◽  
Fragmented Habitats

ABSTRACTBurkholderia pseudomalleiis a Gram-negative soil bacillus that is the etiological agent of melioidosis and a biothreat agent. Little is known about the biogeography of this bacterium in Australia, despite its hyperendemicity in the northern region of this continent. The population structure of 953 AustralianB. pseudomalleistrains representing 779 and 174 isolates of clinical and environmental origins, respectively, was analyzed using multilocus sequence typing (MLST). Bayesian population structure and network SplitsTree analyses were performed on concatenated MLST loci, and sequence type (ST) diversity and evenness were examined using Simpson's and Pielou's indices and a multivariate dissimilarity matrix. Bayesian analysis found twoB. pseudomalleipopulations in Australia that were geographically distinct; isolates from the Northern Territory were grouped mainly into the first population, whereas the majority of isolates from Queensland were grouped in a second population. Differences in ST evenness were observed between sampling areas, confirming thatB. pseudomalleiis widespread and established across northern Australia, with a large number of fragmented habitats. ST analysis showed thatB. pseudomalleipopulations diversified as the sampling area increased. This observation was in contrast to smaller sampling areas where a few STs predominated, suggesting thatB. pseudomalleipopulations are ecologically established and not frequently dispersed. Interestingly, there was no identifiable ST bias between clinical and environmental isolates, suggesting the potential for all culturableB. pseudomalleiisolates to cause disease. Our findings have important implications for understanding the ecology ofB. pseudomalleiin Australia and for potential source attribution of this bacterium in the event of unexpected cases of melioidosis.

scholarly journals The BpeEF-OprC Efflux Pump Is Responsible for Widespread Trimethoprim Resistance in Clinical and Environmental Burkholderia pseudomallei Isolates

2013 ◽  
Vol 57 (9) ◽  
pp. 4381-4386 ◽  
Author(s):  
Nicole L. Podnecky ◽  
Vanaporn Wuthiekanun ◽  
Sharon J. Peacock ◽  
Herbert P. Schweizer
Keyword(s):  
Dihydrofolate Reductase ◽  
Burkholderia Pseudomallei ◽  
Efflux Pump ◽  
Eradication Therapy ◽  
Northern Australia ◽  
Northeast Thailand ◽  
Environmental Isolates ◽  
Transcriptional Terminator ◽  
Content Type ◽  
Primary Drug

ABSTRACTTrimethoprim-sulfamethoxazole (co-trimoxazole) is the primary drug used for oral eradication therapy ofBurkholderia pseudomalleiinfections (melioidosis). Here, we demonstrate that trimethoprim resistance is widespread in clinical and environmental isolates from northeast Thailand and northern Australia. This resistance was shown to be due to BpeEF-OprC efflux pump expression. No dihydrofolate reductase target mutations were involved, although frequent insertion of ISBma2 was noted within the putativefolAtranscriptional terminator. All isolates tested remained susceptible to trimethoprim-sulfamethoxazole, suggesting that resistance to trimethoprim alone in these strains probably does not affect the efficacy of co-trimoxazole therapy.

scholarly journals Genomic Diversity of Burkholderia pseudomallei in Ceara, Brazil

mSphere ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Jay E. Gee ◽  
Christopher A. Gulvik ◽  
Debora S. C. M. Castelo-Branco ◽  
José J. C. Sidrim ◽  
Marcos F. G. Rocha ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Burkholderia Pseudomallei ◽  
The State ◽  
Western Hemisphere ◽  
Genomic Diversity ◽  
Polymorphism Analysis ◽  
Environmental Isolates ◽  
Single Nucleotide ◽  
Content Type

ABSTRACT Burkholderia pseudomallei is a Gram-negative bacterium that causes the sapronotic disease melioidosis. An outbreak in 2003 in the state of Ceara, Brazil, resulted in subsequent surveillance and environmental sampling which led to the recognition of B. pseudomallei as an endemic pathogen in that area. From 2003 to 2015, 24 clinical and 12 environmental isolates were collected across Ceara along with one from the state of Alagoas. Using next-generation sequencing, multilocus sequence typing, and single nucleotide polymorphism analysis, we characterized the genomic diversity of this collection to better understand the population structure of B. pseudomallei associated with Ceara. We found that the isolates in this collection form a distinct subclade compared to other examples from the Western Hemisphere. Substantial genetic diversity among the clinical and environmental isolates was observed, with 14 sequence types (STs) identified among the 37 isolates. Of the 31,594 core single-nucleotide polymorphisms (SNPs) identified, a high proportion (59%) were due to recombination. Because recombination events do not follow a molecular clock, the observation of high occurrence underscores the importance of identifying and removing recombination SNPs prior to evolutionary reconstructions and inferences in public health responses to B. pseudomallei outbreaks. Our results suggest long-term B. pseudomallei prevalence in this recently recognized region of melioidosis endemicity. IMPORTANCE B. pseudomallei causes significant morbidity and mortality, but its geographic prevalence and genetic diversity are not well characterized, especially in the Western Hemisphere. A better understanding of the genetic relationships among clinical and environmental isolates will improve knowledge of the population structure of this bacterium as well as the ability to conduct epidemiological investigations of cases of melioidosis.

scholarly journals Tracing Melioidosis Back to the Source: Using Whole-Genome Sequencing To Investigate an Outbreak Originating from a Contaminated Domestic Water Supply

2015 ◽  
Vol 53 (4) ◽  
pp. 1144-1148 ◽  
Author(s):  
Evan McRobb ◽  
Derek S. Sarovich ◽  
Erin P. Price ◽  
Mirjam Kaestli ◽  
Mark Mayo ◽  
...  
Keyword(s):  
Water Supply ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Clinical Isolates ◽  
Whole Genome ◽  
Northern Australia ◽  
Source Attribution ◽  
Environmental Strain ◽  
Content Type ◽  
Groundwater Supply

Melioidosis, a disease of public health importance in Southeast Asia and northern Australia, is caused by the Gram-negative soil bacillusBurkholderia pseudomallei. Melioidosis is typically acquired through environmental exposure, and case clusters are rare, even in regions where the disease is endemic.B. pseudomalleiis classed as a tier 1 select agent by the Centers for Disease Control and Prevention; from a biodefense perspective, source attribution is vital in an outbreak scenario to rule out a deliberate release. Two cases of melioidosis within a 3-month period at a residence in rural northern Australia prompted an investigation to determine the source of exposure.B. pseudomalleiisolates from the property's groundwater supply matched the multilocus sequence type of the clinical isolates. Whole-genome sequencing confirmed the water supply as the probable source of infection in both cases, with the clinical isolates differing from the likely infecting environmental strain by just one single nucleotide polymorphism (SNP) each. For the first time, we report a phylogenetic analysis of genomewide insertion/deletion (indel) data, an approach conventionally viewed as problematic due to high mutation rates and homoplasy. Our whole-genome indel analysis was concordant with the SNP phylogeny, and these two combined data sets provided greater resolution and a better fit with our epidemiological chronology of events. Collectively, this investigation represents a highly accurate account of source attribution in a melioidosis outbreak and gives further insight into a frequently overlooked reservoir ofB. pseudomallei. Our methods and findings have important implications for outbreak source tracing of this bacterium and other highly recombinogenic pathogens.

scholarly journals Burkholderia pseudomallei Penetrates the Brain via Destruction of the Olfactory and Trigeminal Nerves: Implications for the Pathogenesis of Neurological Melioidosis

mBio ◽  
2014 ◽  
Vol 5 (2) ◽  
Author(s):  
James A. St. John ◽  
Jenny A. K. Ekberg ◽  
Samantha J. Dando ◽  
Adrian C. B. Meedeniya ◽  
Rachel E. Horton ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Nasal Cavity ◽  
Burkholderia Pseudomallei ◽  
Basal Layer ◽  
The Body ◽  
Northern Australia ◽  
Cranial Cavity ◽  
Content Type ◽  
Trigeminal Nerves ◽  
The Brain

ABSTRACT Melioidosis is a potentially fatal disease that is endemic to tropical northern Australia and Southeast Asia, with a mortality rate of 14 to 50%. The bacterium Burkholderia pseudomallei is the causative agent which infects numerous parts of the human body, including the brain, which results in the neurological manifestation of melioidosis. The olfactory nerve constitutes a direct conduit from the nasal cavity into the brain, and we have previously reported that B. pseudomallei can colonize this nerve in mice. We have now investigated in detail the mechanism by which the bacteria penetrate the olfactory and trigeminal nerves within the nasal cavity and infect the brain. We found that the olfactory epithelium responded to intranasal B. pseudomallei infection by widespread crenellation followed by disintegration of the neuronal layer to expose the underlying basal layer, which the bacteria then colonized. With the loss of the neuronal cell bodies, olfactory axons also degenerated, and the bacteria then migrated through the now-open conduit of the olfactory nerves. Using immunohistochemistry, we demonstrated that B. pseudomallei migrated through the cribriform plate via the olfactory nerves to enter the outer layer of the olfactory bulb in the brain within 24 h. We also found that the bacteria colonized the thin respiratory epithelium in the nasal cavity and then rapidly migrated along the underlying trigeminal nerve to penetrate the cranial cavity. These results demonstrate that B. pseudomallei invasion of the nerves of the nasal cavity leads to direct infection of the brain and bypasses the blood-brain barrier. IMPORTANCE Melioidosis is a potentially fatal tropical disease that is endemic to northern Australia and Southeast Asia. It is caused by the bacterium Burkholderia pseudomallei, which can infect many organs of the body, including the brain, and results in neurological symptoms. The pathway by which the bacteria can penetrate the brain is unknown, and we have investigated the ability of the bacteria to migrate along nerves that innervate the nasal cavity and enter the frontal region of the brain by using a mouse model of infection. By generating a mutant strain of B. pseudomallei which is unable to survive in the blood, we show that the bacteria rapidly penetrate the cranial cavity using the olfactory (smell) nerve and the trigeminal (sensory) nerve that line the nasal cavity.

scholarly journals First Genome Sequence of a Burkholderia pseudomallei Isolate in China, Strain BPC006, Obtained from a Melioidosis Patient in Hainan

2012 ◽  
Vol 194 (23) ◽  
pp. 6604-6605 ◽  
Author(s):  
Yao Fang ◽  
Yong Huang ◽  
Qian Li ◽  
Hai Chen ◽  
Zhen Yao ◽  
...  
Keyword(s):  
Antibiotic Therapy ◽  
Southeast Asia ◽  
Genome Sequence ◽  
High Mortality ◽  
Burkholderia Pseudomallei ◽  
Northern Australia ◽  
Content Type ◽  
Relapse Rates

ABSTRACTMelioidosis, caused byBurkholderia pseudomallei, is considered to be endemic to Northern Australia and Southeast Asia, with high mortality and relapse rates, regardless of powerful antibiotic therapy. Here we report the first genome sequence ofBurkholderia pseudomalleistrain BPC006, obtained from a melioidosis patient in Hainan, China. The genome sizes of the 2 chromosomes were determined to be 4,001,777 bp and 3,153,284 bp.

scholarly journals Unprecedented Melioidosis Cases in Northern Australia Caused by an Asian Burkholderia pseudomallei Strain Identified by Using Large-Scale Comparative Genomics

2015 ◽  
Vol 82 (3) ◽  
pp. 954-963 ◽  
Author(s):  
Erin P. Price ◽  
Derek S. Sarovich ◽  
Emma J. Smith ◽  
Barbara MacHunter ◽  
Glenda Harrington ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Large Scale ◽  
Phylogenetic Reconstruction ◽  
Genomic Analysis ◽  
Comparative Genomic ◽  
Antibiotic Administration ◽  
Northern Australia ◽  
Content Type ◽  
Clone Sequence ◽  
Asian Isolate

ABSTRACTMelioidosis is a disease of humans and animals that is caused by the saprophytic bacteriumBurkholderia pseudomallei. Once thought to be confined to certain locations, the known presence ofB. pseudomalleiis expanding as more regions of endemicity are uncovered. There is no vaccine for melioidosis, and even with antibiotic administration, the mortality rate is as high as 40% in some regions that are endemic for the infection. Despite high levels of recombination, phylogenetic reconstruction ofB. pseudomalleipopulations using whole-genome sequencing (WGS) has revealed surprisingly robust biogeographic separation between isolates from Australia and Asia. To date, there have been no confirmed autochthonous melioidosis cases in Australia caused by an Asian isolate; likewise, no autochthonous cases in Asia have been identified as Australian in origin. Here, we used comparative genomic analysis of 455B. pseudomalleigenomes to confirm the unprecedented presence of an Asian clone, sequence type 562 (ST-562), in Darwin, northern Australia. First observed in Darwin in 2005, the incidence of melioidosis cases attributable to ST-562 infection has steadily risen, and it is now a common strain in Darwin. Intriguingly, the Australian ST-562 appears to be geographically restricted to a single locale and is genetically less diverse than other common STs from this region, indicating a recent introduction of this clone into northern Australia. Detailed genomic and epidemiological investigations of new clinical and environmentalB. pseudomalleiisolates in the Darwin region and ST-562 isolates from Asia will be critical for understanding the origin, distribution, and dissemination of this emerging clone in northern Australia.

scholarly journals Neutrophil Extracellular Traps Exhibit Antibacterial Activity against Burkholderia pseudomallei and Are Influenced by Bacterial and Host Factors

2012 ◽  
Vol 80 (11) ◽  
pp. 3921-3929 ◽  
Author(s):  
Donporn Riyapa ◽  
Surachat Buddhisa ◽  
Sunee Korbsrisate ◽  
Jon Cuccui ◽  
Brendan W. Wren ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Capsular Polysaccharide ◽  
Neutrophil Extracellular Traps ◽  
Polymorphonuclear Neutrophils ◽  
Dependent Manner ◽  
Predisposing Factor ◽  
Bacterial Killing ◽  
Content Type ◽  
Extracellular Traps ◽  
Type Iii Protein Secretion

ABSTRACTBurkholderia pseudomalleiis the causative pathogen of melioidosis, of which a major predisposing factor is diabetes mellitus. Polymorphonuclear neutrophils (PMNs) kill microbes extracellularly by the release of neutrophil extracellular traps (NETs). PMNs play a key role in the control of melioidosis, but the involvement of NETs in killing ofB. pseudomalleiremains obscure. Here, we showed that bactericidal NETs were released from human PMNs in response toB. pseudomalleiin a dose- and time-dependent manner.B. pseudomallei-induced NET formation required NADPH oxidase activation but not phosphatidylinositol-3 kinase, mitogen-activated protein kinases, or Src family kinase signaling pathways.B. pseudomalleimutants defective in the virulence-associated Bsa type III protein secretion system (T3SS) or capsular polysaccharide I (CPS-I) induced elevated levels of NETs. NET induction by such mutants was associated with increased bacterial killing, phagocytosis, and oxidative burst by PMNs. Taken together the data imply that T3SS and the capsule may play a role in evading the induction of NETs. Importantly, PMNs from diabetic subjects released NETs at a lower level than PMNs from healthy subjects. Modulation of NET formation may therefore be associated with the pathogenesis and control of melioidosis.

scholarly journals Antibiotic Resistance Markers in Burkholderia pseudomallei Strain Bp1651 Identified by Genome Sequence Analysis

2017 ◽  
Vol 61 (6) ◽  
Author(s):  
Julia V. Bugrysheva ◽  
David Sue ◽  
Jay E. Gee ◽  
Mindy G. Elrod ◽  
Alex R. Hoffmaster ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Clavulanic Acid ◽  
Burkholderia Pseudomallei ◽  
Efflux Pump ◽  
Point Mutations ◽  
Comparative Genomic ◽  
Content Type ◽  
Reductase Gene ◽  
Amoxicillin Clavulanic Acid ◽  
Imipenem Resistance

ABSTRACT Burkholderia pseudomallei Bp1651 is resistant to several classes of antibiotics that are usually effective for treatment of melioidosis, including tetracyclines, sulfonamides, and β-lactams such as penicillins (amoxicillin-clavulanic acid), cephalosporins (ceftazidime), and carbapenems (imipenem and meropenem). We sequenced, assembled, and annotated the Bp1651 genome and analyzed the sequence using comparative genomic analyses with susceptible strains, keyword searches of the annotation, publicly available antimicrobial resistance prediction tools, and published reports. More than 100 genes in the Bp1651 sequence were identified as potentially contributing to antimicrobial resistance. Most notably, we identified three previously uncharacterized point mutations in penA, which codes for a class A β-lactamase and was previously implicated in resistance to β-lactam antibiotics. The mutations result in amino acid changes T147A, D240G, and V261I. When individually introduced into select agent-excluded B. pseudomallei strain Bp82, D240G was found to contribute to ceftazidime resistance and T147A contributed to amoxicillin-clavulanic acid and imipenem resistance. This study provides the first evidence that mutations in penA may alter susceptibility to carbapenems in B. pseudomallei. Another mutation of interest was a point mutation affecting the dihydrofolate reductase gene folA, which likely explains the trimethoprim resistance of this strain. Bp1651 was susceptible to aminoglycosides likely because of a frameshift in the amrB gene, the transporter subunit of the AmrAB-OprA efflux pump. These findings expand the role of penA to include resistance to carbapenems and may assist in the development of molecular diagnostics that predict antimicrobial resistance and provide guidance for treatment of melioidosis.

Institutional context and hotel social responsibility

Kybernetes ◽  
2014 ◽  
Vol 43 (3/4) ◽  
pp. 413-426 ◽  
Author(s):  
María Dolores Sánchez-Fernández ◽  
Alfonso Vargas-Sánchez ◽  
Paula Remoaldo
Keyword(s):  
Social Responsibility ◽  
Institutional Theory ◽  
Geographical Area ◽  
Institutional Context ◽  
Theoretical Framework ◽  
Northern Region ◽  
Structural Equations ◽  
Partial Least Square ◽  
Least Square ◽  
Content Type

Purpose – The authors want to study the connection between institutional theory and corporate social responsibility (CSR) in the set of hotels with three, four and five star situated in Galicia (Spain) and in the Northern region of Portugal. The authors aim to see whether there is a contrast of isomorphic behaviour in the institutional context of both regions. Design/methodology/approach – A quantitative study in which the authors apply the partial least square (PLS) technique, a methodology based on structural equations models using the software Visual-PLS. The authors intend to study the relationships between the pressures of institutional context and CSR practices, together with the relationship between legitimacy and these practices. The focus of the proposed model is based on the system theory. Findings – The main findings of this research clearly show that hotels are incorporated into an institutional context marked by enforced and regulatory pressures. Research limitations/implications – The proposed research model can be replicated using other units of study, sectors, geographic areas, among others, due to the explanatory capacity of the theoretical framework used. Originality/value – The originality of this work derives from the main contributions based on the theoretical framework (institutional theory and CSR), the object of study and geographical area (three, four and five star hotels located in Galicia and in the North of Portugal), the context (economic crisis), the field of study (private sphere) and the type of organizations (profit making).

scholarly journals Contaminated Handwashing Sinks as the Source of a Clonal Outbreak of KPC-2-Producing Klebsiella oxytoca on a Hematology Ward

2014 ◽  
Vol 59 (1) ◽  
pp. 714-716 ◽  
Author(s):  
Eva Leitner ◽  
Gernot Zarfel ◽  
Josefa Luxner ◽  
Kathrin Herzog ◽  
Shiva Pekard-Amenitsch ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Genetic Relatedness ◽  
Klebsiella Oxytoca ◽  
Klebsiella Pneumonia ◽  
Environmental Isolates ◽  
Content Type ◽  
Carbapenem Resistant

ABSTRACTWe investigated sinks as possible sources of a prolongedKlebsiella pneumoniacarbapenemase (KPC)-producingKlebsiella oxytocaoutbreak. Seven carbapenem-resistantK. oxytocaisolates were identified in sink drains in 4 patient rooms and in the medication room. Investigations for resistance genes and genetic relatedness of patient and environmental isolates revealed that all the isolates harbored theblaKPC-2andblaTEM-1genes and were genetically indistinguishable. We describe here a clonal outbreak caused by KPC-2-producingK. oxytoca, and handwashing sinks were a possible reservoir.

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