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  1. Susceptibility of Caenorhabditis elegans to Burkholderia infection depends on prior diet and secreted bacterial attractants.

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    Vaughn S Cooper

    Full Text Available The nematode Caenorhabditis elegans may be killed by certain pathogenic bacteria and thus is a model organism for studying interactions between bacteria and animal hosts. However, growing nematodes on prey bacteria may influence their susceptibility to potential pathogens. A method of axenic nematode culture was developed to isolate and quantify interactions between C. elegans and potentially pathogenic strains of the Burkholderia cepacia complex. Studying these dynamics in liquid solution rather than on agar surfaces minimized nematode avoidance behavior and resolved more differences among isolates. Most isolates of B. cenocepacia, B. ambifaria and B. cepacia caused 60-80% mortality of nematodes after 7 days, whereas isolates of B. multivorans caused less mortality (<25% and supported nematode reproduction. However, some B. cenocepacia isolates recovered from chronic infections were much less virulent (5-28% mortality. As predicted, prior diet altered the outcome of interactions between nematodes and bacteria. When given the choice between Burkholderia and E. coli as prey on agar, axenically raised nematodes initially preferred most lethal Burkholderia isolates to E. coli as a food source, but this was not the case for nematodes fed E. coli, which avoided toxic Burkholderia. This food preference was associated with the cell-free supernatant and thus secreted compounds likely mediated bacterial-nematode interactions. This model, which isolates interactions between bacteria and nematodes from the effects of prior feeding, demonstrates that bacteria can influence nematode behavior and their susceptibility to pathogens.

  2. Natural Burkholderia mallei infection in Dromedary, Bahrain.

    Science.gov (United States)

    Wernery, Ulrich; Wernery, Renate; Joseph, Marina; Al-Salloom, Fajer; Johnson, Bobby; Kinne, Joerg; Jose, Shanti; Jose, Sherry; Tappendorf, Britta; Hornstra, Heidie; Scholz, Holger C

    2011-07-01

    We confirm a natural infection of dromedaries with glanders. Multilocus variable number tandem repeat analysis of a Burkholderia mallei strain isolated from a diseased dromedary in Bahrain revealed close genetic proximity to strain Dubai 7, which caused an outbreak of glanders in horses in the United Arab Emirates in 2004.

  3. Experimental Phage Therapy for Burkholderia pseudomallei Infection.

    Science.gov (United States)

    Guang-Han, Ong; Leang-Chung, Choh; Vellasamy, Kumutha Malar; Mariappan, Vanitha; Li-Yen, Chang; Vadivelu, Jamuna

    2016-01-01

    Burkholderia pseudomallei is an intracellular Gram-negative bacterial pathogen intrinsically resistant to a variety of antibiotics. Phages have been developed for use as an alternative treatment therapy, particularly for bacterial infections that do not respond to conventional antibiotics. In this study, we investigated the use of phages to treat cells infected with B. pseudomallei. Phage C34 isolated from seawater was purified and characterised on the basis of its host range and morphology using transmission electron microscopy (TEM). Phage C34 was able to lyse 39.5% of B. pseudomallei clinical strains. Due to the presence of contractile tail, phage C34 is classified as a member of the family Myoviridae, a tailed double-stranded DNA virus. When 2 × 105 A549 cells were exposed to 2 × 107 PFU of phage C34, 24 hours prior to infection with 2 × 106 CFU of B. pseudomallei, it was found that the survivability of the cells increased to 41.6 ± 6.8% as compared to 22.8 ± 6.0% in untreated control. Additionally, application of phage successfully rescued 33.3% of mice infected with B. pseudomallei and significantly reduced the bacterial load in the spleen of the phage-treated mice. These findings indicate that phage can be a potential antimicrobial agent for B. pseudomallei infections. PMID:27387381

  4. Burkholderia pseudomallei musculoskeletal infections (melioidosis in India

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    Pandey Vivek

    2010-01-01

    Full Text Available Melioidosis, an infection due to gram negative Burkholderia pseudomallei, is an important cause of sepsis in east Asia especially Thailand and northern Australia. It usually causes abscesses in lung, liver, spleen, skeletal muscle and parotids especially in patients with diabetes, chronic renal failure and thalassemia. Musculoskeletal melioidosis is not common in India even though sporadic cases have been reported mostly involving soft tissues. During a two-year-period, we had five patients with musculoskeletal melioidosis. All patients presented with multifocal osteomyelitis, recurrent osteomyelitis or septic arthritis. One patient died early because of septicemia and multi-organ failure. All patients were diagnosed on the basis of positive pus culture. All patients were treated by surgical debridement followed by a combination of antibiotics; (ceftazidime, amoxy-clavulanic acid, co-trimoxazole and doxycycline for six months except for one who died due to fulminant septicemia. All other patients recovered completely with no recurrences. With increasing awareness and better diagnostic facilities, probably musculoskeletal melioidosis will be increasingly diagnosed in future.

  5. An ensemble of structures of Burkholderia pseudomallei 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase

    Energy Technology Data Exchange (ETDEWEB)

    Davies, Douglas R.; Staker, Bart L.; Abendroth, Jan A.; Edwards, Thomas E.; Hartley, Robert; Leonard, Jess; Kim, Hidong; Rychel, Amanda L.; Hewitt, Stephen N.; Myler, Peter J.; Stewart, Lance J. (UWASH); (Emerald)

    2011-12-07

    Burkholderia pseudomallei is a soil-dwelling bacterium endemic to Southeast Asia and Northern Australia. Burkholderia is responsible for melioidosis, a serious infection of the skin. The enzyme 2,3-bisphosphoglycerate-dependent phosphoglycerate mutase (PGAM) catalyzes the interconversion of 3-phosphoglycerate and 2-phosphoglycerate, a key step in the glycolytic pathway. As such it is an extensively studied enzyme and X-ray crystal structures of PGAM enzymes from multiple species have been elucidated. Vanadate is a phosphate mimic that is a powerful tool for studying enzymatic mechanisms in phosphoryl-transfer enzymes such as phosphoglycerate mutase. However, to date no X-ray crystal structures of phosphoglycerate mutase have been solved with vanadate acting as a substrate mimic. Here, two vanadate complexes together with an ensemble of substrate and fragment-bound structures that provide a comprehensive picture of the function of the Burkholderia enzyme are reported.

  6. Burkholderia Pseudomallei Causing Bone and Joint Infections: A Clinical Update

    OpenAIRE

    Raja, Nadeem Sajjad; Scarsbrook, Christine

    2016-01-01

    Burkholderia pseudomallei (B. pseudomallei), a causative agent of an emerging infectious disease melioidosis, is endemic in the tropical regions of the world. Due to increased international travel, the infection is now also seen outside of the tropics. The majority of patients with identified risk factors such as diabetes mellitus, heavy alcohol use, malignancy, chronic lung and kidney disease, corticosteroid use, thalassemia, rheumatic heart disease, systemic lupus erythematosus and cardiac ...

  7. Recurrent urinary tract infection by burkholderia cepacia in a live related renal transplant recipient

    International Nuclear Information System (INIS)

    Burkholderia cepacia is high virulent organism usually causing lower respiratory tract infections especially in Cystic fibrosis (CF) patients and post lung transplant. Urinary tract infections with Burkholderia cepacia have been associated after bladder irrigation or use of contaminated hospital objects. Post renal transplant urinary tract infection (UTI) is the most common infectious complications. Recurrent urinary tract infection with Burkholderia cepacia is a rare finding. Complete anatomical evaluation is essential in case recurrent urinary tract infections (UTI) after renal transplant. Vesico-ureteric reflux (VUR) and neurogenic urinary bladder was found to be important risk factors. (author)

  8. Sterile-α- and Armadillo Motif-Containing Protein Inhibits the TRIF-Dependent Downregulation of Signal Regulatory Protein α To Interfere with Intracellular Bacterial Elimination in Burkholderia pseudomallei-Infected Mouse Macrophages

    OpenAIRE

    Baral, Pankaj; Utaisincharoen, Pongsak

    2013-01-01

    Burkholderia pseudomallei, the causative agent of melioidosis, evades macrophage killing by suppressing the TRIF-dependent pathway, leading to inhibition of inducible nitric oxide synthase (iNOS) expression. We previously demonstrated that virulent wild-type B. pseudomallei inhibits the TRIF-dependent pathway by upregulating sterile-α- and armadillo motif-containing protein (SARM) and by inhibiting downregulation of signal regulatory protein α (SIRPα); both molecules are negative regulators o...

  9. Use of the common marmoset to study Burkholderia mallei infection.

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    Tomislav Jelesijevic

    Full Text Available Burkholderia mallei is a host-adapted bacterium that does not persist outside of its equine reservoir. The organism causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by B. mallei typically occurs via the respiratory or percutaneous route, and the most common manifestations are life-threatening pneumonia and bacteremia. Glanders is difficult to diagnose and requires prolonged antibiotic therapy with low success rates. There is no vaccine to protect against B. mallei and there is concern regarding its use as a biothreat agent. Thus, experiments were performed to establish a non-human primate model of intranasal infection to study the organism and develop countermeasures. Groups of marmosets (Callithrix jacchus were inoculated intranasally with B. mallei strain ATCC 23344 and monitored for clinical signs of illness for up to 13 days. We discovered that 83% of marmosets inoculated with doses of 2.5 X 10(4 to 2.5 X 10(5 bacteria developed acute lethal infection within 3-4 days. Signs of disease were severe and included lethargy, inappetence, conjunctivitis, mucopurulent and hemorrhagic nasal discharges, and increased respiratory effort with abdominal lifts. Burkholderia mallei was cultured from the lungs, spleen and liver of these animals, and pathologic examination of tissues revealed lesions characteristic of glanders. Challenge experiments also revealed that 91% of animals infected with doses ranging from 25 to 2.5 X 10(3 bacteria exhibited mild non-specific signs of illness and were culture negative. One marmoset inoculated with 2.5 X 10(3 organisms developed moderate signs of disease and reached humane end-points 8 days post-infection. The liver and spleen of this animal were colonized with the agent and pathological analysis of tissues showed nasal, splenic and hepatic lesions. Taken together, these data indicate that the marmoset is a suitable model to study respiratory infection by B

  10. Use of the common marmoset to study Burkholderia mallei infection.

    Science.gov (United States)

    Jelesijevic, Tomislav; Zimmerman, Shawn M; Harvey, Stephen B; Mead, Daniel G; Shaffer, Teresa L; Estes, D Mark; Michel, Frank; Quinn, Frederick D; Hogan, Robert J; Lafontaine, Eric R

    2015-01-01

    Burkholderia mallei is a host-adapted bacterium that does not persist outside of its equine reservoir. The organism causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by B. mallei typically occurs via the respiratory or percutaneous route, and the most common manifestations are life-threatening pneumonia and bacteremia. Glanders is difficult to diagnose and requires prolonged antibiotic therapy with low success rates. There is no vaccine to protect against B. mallei and there is concern regarding its use as a biothreat agent. Thus, experiments were performed to establish a non-human primate model of intranasal infection to study the organism and develop countermeasures. Groups of marmosets (Callithrix jacchus) were inoculated intranasally with B. mallei strain ATCC 23344 and monitored for clinical signs of illness for up to 13 days. We discovered that 83% of marmosets inoculated with doses of 2.5 X 10(4) to 2.5 X 10(5) bacteria developed acute lethal infection within 3-4 days. Signs of disease were severe and included lethargy, inappetence, conjunctivitis, mucopurulent and hemorrhagic nasal discharges, and increased respiratory effort with abdominal lifts. Burkholderia mallei was cultured from the lungs, spleen and liver of these animals, and pathologic examination of tissues revealed lesions characteristic of glanders. Challenge experiments also revealed that 91% of animals infected with doses ranging from 25 to 2.5 X 10(3) bacteria exhibited mild non-specific signs of illness and were culture negative. One marmoset inoculated with 2.5 X 10(3) organisms developed moderate signs of disease and reached humane end-points 8 days post-infection. The liver and spleen of this animal were colonized with the agent and pathological analysis of tissues showed nasal, splenic and hepatic lesions. Taken together, these data indicate that the marmoset is a suitable model to study respiratory infection by B. mallei.

  11. Recurrent Burkholderia Infection in Patients with Chronic Granulomatous Disease: 11-Year Experience at a Large Referral Center

    OpenAIRE

    Greenberg, David E.; Goldberg, Joanna B.; Stock, Frida; Murray, Patrick R.; Holland, Steven M.; LiPuma, John J.

    2009-01-01

    The epidemiology of Burkholderia infection in persons with chronic granulomatous disease is poorly understood. We used species-specific polymerase chain reaction–based assays and genotyping analyses to identify 32 strains representing 9 Burkholderia species among 50 isolates recovered from 18 patients with chronic granulomatous disease. We found that recurrent pulmonary infection with distinct Burkholderia strains is common in chronic granulomatous disease.

  12. Use of a safe, reproducible, and rapid aerosol delivery method to study infection by Burkholderia pseudomallei and Burkholderia mallei in mice.

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    Eric R Lafontaine

    Full Text Available Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most common manifestation is severe pneumonia leading to fatal bacteremia. Glanders and melioidosis are difficult to diagnose and require prolonged antibiotic therapy with low success rates. There are no vaccines available to protect against either Burkholderia species, and there is concern regarding their use as biological warfare agents given that B. mallei has previously been utilized in this manner. Hence, experiments were performed to establish a mouse model of aerosol infection to study the organisms and develop countermeasures. Using a hand-held aerosolizer, BALB/c mice were inoculated intratracheally with strains B. pseudomallei 1026b and B. mallei ATCC23344 and growth of the agents in the lungs, as well as dissemination to the spleen, were examined. Mice infected with 10(2, 10(3 and 10(4 organisms were unable to control growth of B. mallei in the lungs and bacteria rapidly disseminated to the spleen. Though similar results were observed in mice inoculated with 10(3 and 10(4 B. pseudomallei cells, animals infected with 10(2 organisms controlled bacterial replication in the lungs, dissemination to the spleen, and the extent of bacteremia. Analysis of sera from mice surviving acute infection revealed that animals produced antibodies against antigens known to be targets of the immune response in humans. Taken together, these data show that small volume aerosol inoculation of mice results in acute disease, dose-dependent chronic infection, and immune responses

  13. Use of a safe, reproducible, and rapid aerosol delivery method to study infection by Burkholderia pseudomallei and Burkholderia mallei in mice.

    Science.gov (United States)

    Lafontaine, Eric R; Zimmerman, Shawn M; Shaffer, Teresa L; Michel, Frank; Gao, Xiudan; Hogan, Robert J

    2013-01-01

    Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most common manifestation is severe pneumonia leading to fatal bacteremia. Glanders and melioidosis are difficult to diagnose and require prolonged antibiotic therapy with low success rates. There are no vaccines available to protect against either Burkholderia species, and there is concern regarding their use as biological warfare agents given that B. mallei has previously been utilized in this manner. Hence, experiments were performed to establish a mouse model of aerosol infection to study the organisms and develop countermeasures. Using a hand-held aerosolizer, BALB/c mice were inoculated intratracheally with strains B. pseudomallei 1026b and B. mallei ATCC23344 and growth of the agents in the lungs, as well as dissemination to the spleen, were examined. Mice infected with 10(2), 10(3) and 10(4) organisms were unable to control growth of B. mallei in the lungs and bacteria rapidly disseminated to the spleen. Though similar results were observed in mice inoculated with 10(3) and 10(4) B. pseudomallei cells, animals infected with 10(2) organisms controlled bacterial replication in the lungs, dissemination to the spleen, and the extent of bacteremia. Analysis of sera from mice surviving acute infection revealed that animals produced antibodies against antigens known to be targets of the immune response in humans. Taken together, these data show that small volume aerosol inoculation of mice results in acute disease, dose-dependent chronic infection, and immune responses that correlate

  14. Use of a safe, reproducible, and rapid aerosol delivery method to study infection by Burkholderia pseudomallei and Burkholderia mallei in mice.

    Science.gov (United States)

    Lafontaine, Eric R; Zimmerman, Shawn M; Shaffer, Teresa L; Michel, Frank; Gao, Xiudan; Hogan, Robert J

    2013-01-01

    Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most common manifestation is severe pneumonia leading to fatal bacteremia. Glanders and melioidosis are difficult to diagnose and require prolonged antibiotic therapy with low success rates. There are no vaccines available to protect against either Burkholderia species, and there is concern regarding their use as biological warfare agents given that B. mallei has previously been utilized in this manner. Hence, experiments were performed to establish a mouse model of aerosol infection to study the organisms and develop countermeasures. Using a hand-held aerosolizer, BALB/c mice were inoculated intratracheally with strains B. pseudomallei 1026b and B. mallei ATCC23344 and growth of the agents in the lungs, as well as dissemination to the spleen, were examined. Mice infected with 10(2), 10(3) and 10(4) organisms were unable to control growth of B. mallei in the lungs and bacteria rapidly disseminated to the spleen. Though similar results were observed in mice inoculated with 10(3) and 10(4) B. pseudomallei cells, animals infected with 10(2) organisms controlled bacterial replication in the lungs, dissemination to the spleen, and the extent of bacteremia. Analysis of sera from mice surviving acute infection revealed that animals produced antibodies against antigens known to be targets of the immune response in humans. Taken together, these data show that small volume aerosol inoculation of mice results in acute disease, dose-dependent chronic infection, and immune responses that correlate

  15. Development of ceftazidime resistance in an acute Burkholderia pseudomallei infection

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    Sarovich DS

    2012-08-01

    Full Text Available Derek S Sarovich,1,2,* Erin P Price,1,2,* Direk Limmathurotsakul,3 James M Cook,1 Alex T Von Schulze,1 Spenser R Wolken,1 Paul Keim,1 Sharon J Peacock,3,4 Talima Pearson1 1Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, AZ, USA; 2Tropical and Emerging Infectious Diseases Division, Menzies School of Health Research, Darwin, Australia; 3Department of Microbiology and Immunology, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand; 4Department of Medicine, University of Cambridge, Cambridge, United Kingdom*These authors contributed equally to this workAbstract: Burkholderia pseudomallei, a bacterium that causes the disease melioidosis, is intrinsically resistant to many antibiotics. First-line antibiotic therapy for treating melioidosis is usually the synthetic β-lactam, ceftazidime (CAZ, as almost all B. pseudomallei strains are susceptible to this drug. However, acquired CAZ resistance can develop in vivo during treatment with CAZ, which can lead to mortality if therapy is not switched to a different drug in a timely manner. Serial B. pseudomallei isolates obtained from an acute Thai melioidosis patient infected by a CAZ susceptible strain, who ultimately succumbed to infection despite being on CAZ therapy for the duration of their infection, were analyzed. Isolates that developed CAZ resistance due to a proline to serine change at position 167 in the β-lactamase PenA were identified. Importantly, these CAZ resistant isolates remained sensitive to the alternative melioidosis treatments; namely, amoxicillin-clavulanate, imipenem, and meropenem. Lastly, real-time polymerase chain reaction-based assays capable of rapidly identifying CAZ resistance in B. pseudomallei isolates at the position 167 mutation site were developed. The ability to rapidly identify the emergence of CAZ resistant B. pseudomallei populations in melioidosis patients will allow timely alterations in treatment strategies

  16. Burkholderia Pseudomallei Causing Bone and Joint Infections: A Clinical Update.

    Science.gov (United States)

    Raja, Nadeem Sajjad; Scarsbrook, Christine

    2016-03-01

    Burkholderia pseudomallei (B. pseudomallei), a causative agent of an emerging infectious disease melioidosis, is endemic in the tropical regions of the world. Due to increased international travel, the infection is now also seen outside of the tropics. The majority of patients with identified risk factors such as diabetes mellitus, heavy alcohol use, malignancy, chronic lung and kidney disease, corticosteroid use, thalassemia, rheumatic heart disease, systemic lupus erythematosus and cardiac failure acquire this organism through percutaneous inoculation or inhalation. The clinical manifestations are variable, ranging from localized abscess formation to septicemia. Melioidotic bone and joint infections are rarely reported but are an established entity. The knee joint is the most commonly affected joint in melioidosis, followed by the ankle, hip and shoulder joints. Melioidosis should be in the differential diagnosis of bone and joint infections in residents or returning travelers from the endemic area. Melioidosis diagnosis is missed in many parts of the world due to the lack of awareness of this infection and limited laboratory training and diagnostic techniques. It also mimics other diseases such as tuberculosis. Delay in the diagnosis, or the initiation of appropriate and effective treatment against melioidosis, could worsen the outcome. Initial therapy with ceftazidime, or carbapenem with or without cotrimoxazole is recommended, followed by the oral eradication therapy (based on the antimicrobial susceptibility) with amoxicillin/clavulanic acid or cotrimoxazole. Surgical intervention remains important. This paper reviews current literature on the epidemiology, clinical features, diagnosis, and management of melioidotic bone and joint infections. PMID:26728713

  17. Monitoring Therapeutic Treatments against Burkholderia Infections Using Imaging Techniques

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    Tiffany M. Mott

    2013-05-01

    Full Text Available Burkholderia mallei, the etiologic agent of glanders, are Category B select agents with biothreat potential, and yet effective therapeutic treatments are lacking. In this study, we showed that CpG administration increased survival, demonstrating protection in the murine glanders model. Bacterial recovery from infected lungs, liver and spleen was significantly reduced in CpG-treated animals as compared with non-treated mice. Reciprocally, lungs of CpG-treated infected animals were infiltrated with higher levels of neutrophils and inflammatory monocytes, as compared to control animals. Employing the B. mallei bioluminescent strain CSM001 and the Neutrophil-Specific Fluorescent Imaging Agent, bacterial dissemination and neutrophil trafficking were monitored in real-time using multimodal in vivo whole body imaging techniques. CpG-treatment increased recruitment of neutrophils to the lungs and reduced bioluminescent bacteria, correlating with decreased bacterial burden and increased protection against acute murine glanders. Our results indicate that protection of CpG-treated animals was associated with recruitment of neutrophils prior to infection and demonstrated, for the first time, simultaneous real time in vivo imaging of neutrophils and bacteria. This study provides experimental evidence supporting the importance of incorporating optimized in vivo imaging methods to monitor disease progression and to evaluate the efficacy of therapeutic treatment during bacterial infections.

  18. Two Novel Clinical Presentations of Burkholderia cepacia Infection

    OpenAIRE

    Mukhopadhyay, Chiranjoy; Bhargava, Anudita; Ayyagari, Archana

    2004-01-01

    We report two cases of multidrug-resistant Burkholderia cepacia (B. cepacia genomovar I) and Burkholderia multivorans causing multiple liver abscesses in a patient with bronchial asthma (case 1) and peritonitis in a patient with cirrhosis and hepatitis C virus disease (case 2), respectively. Both patients were treated successfully.

  19. The art of persistence-the secrets to Burkholderia chronic infections.

    Science.gov (United States)

    Lewis, Eric R G; Torres, Alfredo G

    2016-08-01

    The Gram-negative proteobacteria genus Burkholderia encompasses multiple bacterial species that are pathogenic to humans and other vertebrates. Two pathogenic species of interest within this genus are Burkholderia pseudomallei (Bpm) and the B. cepacia complex (Bcc); the former is the causative agent of melioidosis in humans and other mammals, and the latter is associated with pneumonia in immunocompromised patients. One understudied and shared characteristic of these two pathogenic groups is their ability to persist and establish chronic infection within the host. In this review, we will explore the depth of knowledge about chronic infections caused by persistent Bpm and Bcc. We examine the host risk factors and immune responses associated with more severe chronic infections. We also discuss host adaptation and phenotypes associated with persistent Burkholderia species. Lastly, we survey how other intracellular bacteria associated with chronic infections are combatted and explore possible future applications to target Burkholderia Our goal is to highlight understudied areas that should be addressed for a more thorough understanding of chronic Burkholderia infections and how to combat them. PMID:27440810

  20. Use of a Safe, Reproducible, and Rapid Aerosol Delivery Method to Study Infection by Burkholderia pseudomallei and Burkholderia mallei in Mice

    OpenAIRE

    Eric R Lafontaine; Zimmerman, Shawn M.; Teresa L Shaffer; Frank Michel; Xiudan Gao; Hogan, Robert J.

    2013-01-01

    Burkholderia pseudomallei, the etiologic agent of melioidosis, is a saprophytic bacterium readily isolated from wet soils of countries bordering the equator. Burkholderia mallei is a host-adapted clone of B. pseudomallei that does not persist outside of its equine reservoir and causes the zoonosis glanders, which is endemic in Asia, Africa, the Middle East and South America. Infection by these organisms typically occurs via percutaneous inoculation or inhalation of aerosols, and the most comm...

  1. Concomitant Cryptococcosis and Burkholderia Infection in an Asymptomatic Lung Transplant Patient with Cystic Fibrosis

    OpenAIRE

    2010-01-01

    Concomitant pulmonary infections with Cryptococcus neoformans and Burkholderia cepacia in lung transplant recipients are very rare and create unique diagnostic and therapeutic dilemmas. Herein, we present a double lung transplant patient with cystic fibrosis who was found to have coinfection with these two rare organisms, though he was completely asymptomatic.

  2. A Possible Link between Infection with Burkholderia Bacteria and Systemic Lupus Erythematosus Based on Epitope Mimicry

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    Wei Zhang

    2008-01-01

    Full Text Available We previously demonstrated that purified polyclonal and monoclonal anti-dsDNA antibodies bind a 15-mer peptide ASPVTARVLWKASHV in ELISA and Dot blot. This 15-mer peptide partial sequence ARVLWKASH shares similarity with burkholderia bacterial cytochrome B 561 partial sequence ARVLWRATH. In this study, we show that purified anti-dsDNA antibodies react with burkholderia fungorum bacterial cell lysates in Western blot. We used anti-dsDNA antibodies to make an anti-dsDNA antibodies affinity column and used this column to purify the burkholderia fungorum bacterial protein. Purified anti-dsDNA antibodies bind specifically to purified bacterial antigen and purified bacterial antigen blocked the anti-dsDNA antibodies binding to dsDNA antigen. Sera with anti-dsDNA antibodies bind specifically to purified bacterial antigen. We obtained protein partial sequence of RAGTDEGFG which is shared with burkholderia bacterial transcription regulator protein sequence. Sera with anti-dsDNA antibodies bind to RAGTDEGFG peptide better than control groups. These data support our hypothesis that the origin of anti-dsDNA antibodies in SLE may be associated with burkholderia bacterial infection.

  3. Screening for potential anti-infective agents towards Burkholderia pseudomallei infection

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    Eng, Su Anne; Nathan, Sheila

    2014-09-01

    The established treatment for melioidosis is antibiotic therapy. However, a constant threat to this form of treatment is resistance development of the causative agent, Burkholderia pseudomallei, towards antibiotics. One option to circumvent this threat of antibiotic resistance is to search for new alternative anti-infectives which target the host innate immune system and/or bacterial virulence. In this study, 29 synthetic compounds were evaluated for their potential to increase the lifespan of an infected host. The nematode Caenorhabditis elegans was adopted as the infection model as its innate immune pathways are homologous to humans. Screens were performed in a liquid-based survival assay containing infected worms exposed to individual compounds and survival of untreated and compound-treated worms were compared. A primary screen identified nine synthetic compounds that extended the lifespan of B. pseudomallei-infected worms. Subsequently, a disc diffusion test was performed on these selected compounds to delineate compounds into those that enhanced the survival of worms via antimicrobial activity i.e. reducing the number of infecting bacteria, or into those that did not target pathogen viability. Out of the nine hits selected, two demonstrated antimicrobial effects on B. pseudomallei. Therefore, the findings from this study suggest that the other seven identified compounds are potential anti-infectives which could protect a host against B. pseudomallei infection without developing the risk of drug resistance.

  4. Fatal Burkholderia pseudomallei Infection Initially Reported as a Bacillus Species, Ohio, 2013

    OpenAIRE

    Doker, Thomas J.; Quinn, Celia L.; Salehi, Ellen D.; Sherwood, Joshua J.; Benoit, Tina J.; Elrod, Mindy Glass; Gee, Jay E.; Shadomy, Sean V.; Bower, William A.; Hoffmaster, Alex R.; Walke, Henry T.; Blaney, David D.; DiOrio, Mary S.

    2014-01-01

    A fatal case of melioidosis was diagnosed in Ohio one month after culture results were initially reported as a Bacillus species. To identify a source of infection and assess risk in patient contacts, we abstracted patient charts; interviewed physicians and contacts; genetically characterized the isolate; performed a Burkholderia pseudomallei antibody indirect hemagglutination assay on household contacts and pets to assess seropositivity; and collected household plant, soil, liquid, and insect...

  5. A rare case of community acquired Burkholderia cepacia infection presenting as pyopneumothorax in an immunocompetent individual

    Institute of Scientific and Technical Information of China (English)

    Suman S Karanth; Hariharan Regunath; Kiran Chawla; Mukhyaprana Prabhu

    2012-01-01

    Burkholderia cepacia (B. cepacia) infection is rarely reported in an immunocompetent host. It is a well known occurence in patients with cystic fibrosis and chronic granulomatous disease where it increases both morbidity and mortality. It has also been included in the list of organisms causing nosocomial infections in an immunocompetent host, most of them transmitted from the immunocompromised patient in which this organism harbors. We report a rare case of isolation of B. cepacia from the bronchoalveolar lavage fluid of an immunocompetent agriculturist who presented with productive cough and fever associated with a pyopneumothorax. This is the first case of community acquired infection reported in an immunocompetent person in India.

  6. A rare case of community acquired Burkholderia cepacia infection presenting as pyopneumothorax in an immunocompetent individual

    Directory of Open Access Journals (Sweden)

    Suman S Karanth

    2012-02-01

    Full Text Available Burkholderia cepacia (B. cepacia infection is rarely reported in an immunocompetent host. It is a well known occurence in patients with cystic fibrosis and chronic granulomatous disease where it increases both morbidity and mortality. It has also been included in the list of organisms causing nosocomial infections in an immunocompetent host, most of them transmitted from the immunocompromised patient in which this organism harbors. We report a rare case of isolation of B. cepacia from the bronchoalveolar lavage fluid of an immunocompetent agriculturist who presented with productive cough and fever associated with a pyopneumothorax. This is the first case of community acquired infection reported in an immunocompetent person in India.

  7. Incidence of Burkholderia mallei infection among indigenous equines in India

    Science.gov (United States)

    Malik, Praveen; Singha, Harisankar; Goyal, Sachin K; Khurana, Sandip K; Tripathi, Badri Naryan; Dutt, Abha; Singh, Dabal; Sharma, Neeraj; Jain, Sanjay

    2015-01-01

    Burkholderia mallei is the causative agent of glanders which is a highly contagious and fatal disease of equines. Considering the nature and severity of the disease in equines, and potential of transmission to human beings, glanders is recognised as a ‘notifiable’ disease in many countries. An increasing number of glanders outbreaks throughout the Asian continents, including India, have been noticed recently. In view of the recent re-emergence of the disease, the present study was undertaken to estimate the prevalence of glanders among indigenous equines from different parts of India. Serum samples were analysed by complement fixation test (CFT) and ELISA for the detection of B mallei specific antibodies. A total of 7794 equines, which included 4720 horses, 1881 donkeys and 1193 mules were sampled from April 2011 to December 2014 from 10 states of India. Serologically, 36 equines (pony=7, mules=10, horses=19) were found to be positive for glanders by CFT and indirect-ELISA. The highest number of cases were detected in Uttar Pradesh (n=31) followed by Himachal Pradesh (n=4) and Chhattisgarh (n=1). Isolation of B mallei was attempted from nasal and abscess swabs collected from seropositive equines. Four isolates of B mallei were cultured from nasal swabs of two mules and two ponies. Identity of the isolates was confirmed by PCR and sequencing of fliP gene fragment. The study revealed circulation of B mallei in northern India and the need for continued surveillance to support the eradication. PMID:26457190

  8. Workshop on treatment of and postexposure prophylaxis for Burkholderia pseudomallei and B. mallei Infection, 2010.

    Science.gov (United States)

    Lipsitz, Rebecca; Garges, Susan; Aurigemma, Rosemarie; Baccam, Prasith; Blaney, David D; Cheng, Allen C; Currie, Bart J; Dance, David; Gee, Jay E; Larsen, Joseph; Limmathurotsakul, Direk; Morrow, Meredith G; Norton, Robert; O'Mara, Elizabeth; Peacock, Sharon J; Pesik, Nicki; Rogers, L Paige; Schweizer, Herbert P; Steinmetz, Ivo; Tan, Gladys; Tan, Patrick; Wiersinga, W Joost; Wuthiekanun, Vanaporn; Smith, Theresa L

    2012-12-01

    The US Public Health Emergency Medical Countermeasures Enterprise convened subject matter experts at the 2010 HHS Burkholderia Workshop to develop consensus recommendations for postexposure prophylaxis against and treatment for Burkholderia pseudomallei and B. mallei infections, which cause melioidosis and glanders, respectively. Drugs recommended by consensus of the participants are ceftazidime or meropenem for initial intensive therapy, and trimethoprim/sulfamethoxazole or amoxicillin/clavulanic acid for eradication therapy. For postexposure prophylaxis, recommended drugs are trimethoprim/sulfamethoxazole or co-amoxiclav. To improve the timely diagnosis of melioidosis and glanders, further development and wide distribution of rapid diagnostic assays were also recommended. Standardized animal models and B. pseudomallei strains are needed for further development of therapeutic options. Training for laboratory technicians and physicians would facilitate better diagnosis and treatment options.

  9. The promise of bacteriophage therapy for Burkholderia cepacia complex respiratory infections.

    Directory of Open Access Journals (Sweden)

    Diana Dawn Semler

    2012-01-01

    Full Text Available In recent times, increased attention has been given to evaluating the efficacy of phage therapy, especially in scenarios where the bacterial infectious agent of interest is highly antibiotic resistant. In this regard, phage therapy is especially applicable to infections caused by the Burkholderia cepacia complex (BCC since members of the BCC are antibiotic pan-resistant. Current studies in BCC phage therapy are unique from many other avenues of phage therapy research in that the research is not only comprised of phage isolation, in vitro phage characterization and in vivo infection model efficacy, but also adapting aerosol drug delivery techniques to aerosol phage formulation delivery and storage.

  10. Clinafloxacin for Treatment of Burkholderia cenocepacia Infection in a Cystic Fibrosis Patient.

    Science.gov (United States)

    Balwan, Akshu; Nicolau, David P; Wungwattana, Minkey; Zuckerman, Jonathan B; Waters, Valerie

    2016-01-01

    Respiratory infection with Burkholderia cenocepacia is associated with accelerated decline in lung function and increased mortality in cystic fibrosis (CF) patients (A. M. Jones, M. E. Dodd, J. R. W. Govan, V. Barcus, C. J. Doherty, J. Morris, and A. K. Webb, Thorax 59:948-951, 2004, http://dx.doi.org/10.1136/thx.2003.017210). B. cenocepacia often possesses innate resistance to multiple antimicrobial classes, making eradication uncommon in established infection (P. B. Davis, Am J Respir Crit Care Med 173:475-482, 2006, http://dx.doi.org/10.1164/rccm.200505-840OE). We report the use of clinafloxacin in a CF patient with advanced B. cenocepacia infection, present pharmacokinetic (PK) data, and discuss the potential therapeutic role of clinafloxacin in patients with this condition.

  11. Outbreak of Subclinical Mastitis in a Flock of Dairy Sheep Associated with Burkholderia cepacia Complex Infection

    Science.gov (United States)

    Berriatua, E.; Ziluaga, I.; Miguel-Virto, C.; Uribarren, P.; Juste, R.; Laevens, S.; Vandamme, P.; Govan, J. R. W.

    2001-01-01

    An outbreak of subclinical mastitis in a flock of 620 milking sheep was investigated. Microbiological and epidemiological analyses identified the causative agent as belonging to the Burkholderia cepacia complex (formerly Pseudomonas cepacia). Every ewe in the milking flock was individually tested for subclinical mastitis on two separate occasions, 6 weeks apart, by the California (rapid) mastitis test (CMT). The proportion of CMT-positive ewes was 69 of 393 (17.6%) on the first sampling and 27 of 490 (5.5%) on the second sampling. Pure B. cepacia cultures identified with the API 20 NE system were grown from 64 of 96 (66.7%) CMT-positive ewes and from 1 of 33 (3.0%) CMT-negative ewes. Statistical analysis confirmed the significant association between a positive CMT result and a positive culture result for B. cepacia complex. Additional polyphasic taxonomic analyses of eight isolates showed that seven belonged to B. cepacia genomovar III; the remaining isolate was identified as Burkholderia vietnamiensis (formerly B. cepacia genomovar V). Bacteriological investigation of samples from milking equipment and other environmental sites failed to identify “B. cepacia” in any of the samples taken. To our knowledge, this is the first report of an outbreak of natural infection in animals caused by B. cepacia complex and the first description of B. cepacia complex infection in sheep. PMID:11230416

  12. Identification of Burkholderia cenocepacia strain H111 virulence factors using nonmammalian infection hosts

    DEFF Research Database (Denmark)

    Schwager, Stephan; Agnoli, Kirsty; Köthe, Manuela;

    2013-01-01

    Burkholderia cenocepacia H111, a strain isolated from a cystic fibrosis patient, has been shown to effectively kill the nematode Caenorhabditis elegans. We used the C. elegans model of infection to screen a mini-Tn5 mutant library of B. cenocepacia H111 for attenuated virulence....... Of the approximately 5,500 B. cenocepacia H111 random mini-Tn5 insertion mutants that were screened, 22 showed attenuated virulence in C. elegans. Except for the quorum-sensing regulator cepR, none of the mutated genes coded for the biosynthesis of classical virulence factors such as extracellular proteases...... or siderophores. Instead, the mutants contained insertions in metabolic and regulatory genes. Mutants attenuated in virulence in the C. elegans infection model were also tested in the Drosophila melanogaster pricking model, and those also attenuated in this model were further tested in Galleria mellonella. Six...

  13. Using multispectral imaging flow cytometry to assess an in vitro intracellular Burkholderia thailandensis infection model.

    Science.gov (United States)

    Jenner, Dominic; Ducker, Catherine; Clark, Graeme; Prior, Jo; Rowland, Caroline A

    2016-04-01

    The use of in vitro models to understand the interaction of bacteria with host cells is well established. In vitro bacterial infection models are often used to quantify intracellular bacterial load by lysing cell populations and subsequently enumerating the bacteria. Modern established techniques employ the use of fluorescence technologies such as flow cytometry, fluorescent microscopy, and/or confocal microscopy. However, these techniques often lack either the quantification of large data sets (microscopy) or use of gross fluorescence signal which lacks the visual confirmation that can provide additional confidence in data sets. Multispectral imaging flow cytometry (MIFC) is a novel emerging field of technology. This technology captures a bright field and fluorescence image of cells in a flow using a charged coupled device camera. It allows the analysis of tens of thousands of single cell images, making it an extremely powerful technology. Here MIFC was used as an alternative method of analyzing intracellular bacterial infection using Burkholderia thailandensis E555 as a model organism. It has been demonstrated that the data produced using traditional enumeration is comparable to data analyzed using MIFC. It has also been shown that by using MIFC it is possible to generate other data on the dynamics of the infection model rather than viable counts alone. It has been demonstrated that it is possible to inhibit the uptake of bacteria into mammalian cells and identify differences between treated and untreated cell populations. The authors believe this to be the first use of MIFC to analyze a Burkholderia bacterial species during intracellular infection. © 2016 Crown copyright. Published by Wiley Periodicals Inc. on behalf of ISAC. PMID:26841315

  14. Interbacterial signaling via Burkholderia contact-dependent growth inhibition system proteins.

    Science.gov (United States)

    Garcia, Erin C; Perault, Andrew I; Marlatt, Sara A; Cotter, Peggy A

    2016-07-19

    In prokaryotes and eukaryotes, cell-cell communication and recognition of self are critical to coordinate multicellular functions. Although kin and kind discrimination are increasingly appreciated to shape naturally occurring microbe populations, the underlying mechanisms that govern these interbacterial interactions are insufficiently understood. Here, we identify a mechanism of interbacterial signal transduction that is mediated by contact-dependent growth inhibition (CDI) system proteins. CDI systems have been characterized by their ability to deliver a polymorphic protein toxin into the cytoplasm of a neighboring bacterium, resulting in growth inhibition or death unless the recipient bacterium produces a corresponding immunity protein. Using the model organism Burkholderia thailandensis, we show that delivery of a catalytically active CDI system toxin to immune (self) bacteria results in gene expression and phenotypic changes within the recipient cells. Termed contact-dependent signaling (CDS), this response promotes biofilm formation and other community-associated behaviors. Engineered strains that are isogenic with B. thailandensis, except the DNA region encoding the toxin and immunity proteins, did not display CDS, whereas a strain of Burkholderia dolosa producing a nearly identical toxin-immunity pair induced signaling in B. thailandensis Our data indicate that bcpAIOB loci confer dual benefits; they direct antagonism toward non-self bacteria and promote cooperation between self bacteria, with self being defined by the bcpAIOB allele and not by genealogic relatedness. PMID:27335458

  15. Antibiotic resistance in Burkholderia species.

    Science.gov (United States)

    Rhodes, Katherine A; Schweizer, Herbert P

    2016-09-01

    The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. PMID:27620956

  16. Fatal Burkholderia pseudomallei infection initially reported as a Bacillus species, Ohio, 2013.

    Science.gov (United States)

    Doker, Thomas J; Quinn, Celia L; Salehi, Ellen D; Sherwood, Joshua J; Benoit, Tina J; Glass Elrod, Mindy; Gee, Jay E; Shadomy, Sean V; Bower, William A; Hoffmaster, Alex R; Walke, Henry T; Blaney, David D; DiOrio, Mary S

    2014-10-01

    A fatal case of melioidosis was diagnosed in Ohio one month after culture results were initially reported as a Bacillus species. To identify a source of infection and assess risk in patient contacts, we abstracted patient charts; interviewed physicians and contacts; genetically characterized the isolate; performed a Burkholderia pseudomallei antibody indirect hemagglutination assay on household contacts and pets to assess seropositivity; and collected household plant, soil, liquid, and insect samples for culturing and real-time polymerase chain reaction testing. Family members and pets tested were seronegative for B. pseudomallei. Environmental samples were negative by real-time polymerase chain reaction and culture. Although the patient never traveled internationally, the isolate genotype was consistent with an isolate that originated in Southeast Asia. This investigation identified the fifth reported locally acquired non-laboratory melioidosis case in the contiguous United States. Physicians and laboratories should be aware of this potentially emerging disease and refer positive cultures to a Laboratory Response Network laboratory. PMID:25092821

  17. Investigation of quorum sensing-dependent gene expression in Burkholderia gladioli BSR3 through RNA-seq analyses.

    Science.gov (United States)

    Kim, Sunyoung; Park, Jungwook; Choi, Okhee; Kim, Jinwoo; Seo, Young-Su

    2014-12-28

    The plant pathogen Burkholderia gladioli, which has a broad host range that includes rice and onion, causes bacterial panicle blight and sheath rot. Based on the complete genome sequence of B. gladioli BSR3 isolated from infected rice sheaths, the genome of B. gladioli BSR3 contains the luxI/luxR family of genes. Members of this family encode N-acyl-homoserine lactone (AHL) quorum sensing (QS) signal synthase and the LuxR-family AHL signal receptor, which are similar to B. glumae BGR1. In B. glumae, QS has been shown to play pivotal roles in many bacterial behaviors. In this study, we compared the QS-dependent gene expression between B. gladioli BSR3 and a QS-defective B. gladioli BSR3 mutant in two different culture states (10 and 24 h after incubation, corresponding to an exponential phase and a stationary phase) using RNA sequencing (RNA-seq). RNA-seq analyses including gene ontology and pathway enrichment revealed that the B. gladioli BSR3 QS system regulates genes related to motility, toxin production, and oxalogenesis, which were previously reported in B. glumae. Moreover, the uncharacterized polyketide biosynthesis is activated by QS, which was not detected in B. glumae. Thus, we observed not only common QS-dependent genes between B. glumae BGR1 and B. gladioli BSR3, but also unique QS-dependent genes in B. gladioli BSR3. PMID:25223327

  18. Nematode Peptides with Host-Directed Anti-inflammatory Activity Rescue Caenorhabditis elegans from a Burkholderia pseudomallei Infection

    Science.gov (United States)

    Lim, Mei-Perng; Firdaus-Raih, Mohd; Nathan, Sheila

    2016-01-01

    Burkholderia pseudomallei, the causative agent of melioidosis, is among a growing number of bacterial pathogens that are increasingly antibiotic resistant. Antimicrobial peptides (AMPs) have been investigated as an alternative approach to treat microbial infections, as generally, there is a lower likelihood that a pathogen will develop resistance to AMPs. In this study, 36 candidate Caenorhabditis elegans genes that encode secreted peptides of nematodes. RNA interference (RNAi)-based knockdown of 12/34 peptide-encoding genes resulted in enhanced nematode susceptibility to B. pseudomallei without affecting worm fitness. A microdilution test demonstrated that two peptides, NLP-31 and Y43C5A.3, exhibited anti-B. pseudomallei activity in a dose dependent manner on different pathogens. Time kill analysis proposed that these peptides were bacteriostatic against B. pseudomallei at concentrations up to 8× MIC90. The SYTOX green assay demonstrated that NLP-31 and Y43C5A.3 did not disrupt the B. pseudomallei membrane. Instead, gel retardation assays revealed that both peptides were able to bind to DNA and interfere with bacterial viability. In parallel, microscopic examination showed induction of cellular filamentation, a hallmark of DNA synthesis inhibition, of NLP-31 and Y43C5A.3 treated cells. In addition, the peptides also regulated the expression of inflammatory cytokines in B. pseudomallei infected macrophage cells. Collectively, these findings demonstrate the potential of NLP-31 and Y43C5A.3 as anti-B. pseudomallei peptides based on their function as immune modulators. PMID:27672387

  19. Nematode Peptides with Host-Directed Anti-inflammatory Activity Rescue Caenorhabditis elegans from a Burkholderia pseudomallei Infection.

    Science.gov (United States)

    Lim, Mei-Perng; Firdaus-Raih, Mohd; Nathan, Sheila

    2016-01-01

    Burkholderia pseudomallei, the causative agent of melioidosis, is among a growing number of bacterial pathogens that are increasingly antibiotic resistant. Antimicrobial peptides (AMPs) have been investigated as an alternative approach to treat microbial infections, as generally, there is a lower likelihood that a pathogen will develop resistance to AMPs. In this study, 36 candidate Caenorhabditis elegans genes that encode secreted peptides of nematodes. RNA interference (RNAi)-based knockdown of 12/34 peptide-encoding genes resulted in enhanced nematode susceptibility to B. pseudomallei without affecting worm fitness. A microdilution test demonstrated that two peptides, NLP-31 and Y43C5A.3, exhibited anti-B. pseudomallei activity in a dose dependent manner on different pathogens. Time kill analysis proposed that these peptides were bacteriostatic against B. pseudomallei at concentrations up to 8× MIC90. The SYTOX green assay demonstrated that NLP-31 and Y43C5A.3 did not disrupt the B. pseudomallei membrane. Instead, gel retardation assays revealed that both peptides were able to bind to DNA and interfere with bacterial viability. In parallel, microscopic examination showed induction of cellular filamentation, a hallmark of DNA synthesis inhibition, of NLP-31 and Y43C5A.3 treated cells. In addition, the peptides also regulated the expression of inflammatory cytokines in B. pseudomallei infected macrophage cells. Collectively, these findings demonstrate the potential of NLP-31 and Y43C5A.3 as anti-B. pseudomallei peptides based on their function as immune modulators. PMID:27672387

  20. Burkholderia cenocepacia type VI secretion system mediates escape of type II secreted proteins into the cytoplasm of infected macrophages.

    Directory of Open Access Journals (Sweden)

    Roberto Rosales-Reyes

    Full Text Available Burkholderia cenocepacia is an opportunistic pathogen that survives intracellularly in macrophages and causes serious respiratory infections in patients with cystic fibrosis. We have previously shown that bacterial survival occurs in bacteria-containing membrane vacuoles (BcCVs resembling arrested autophagosomes. Intracellular bacteria stimulate IL-1β secretion in a caspase-1-dependent manner and induce dramatic changes to the actin cytoskeleton and the assembly of the NADPH oxidase complex onto the BcCV membrane. A Type 6 secretion system (T6SS is required for these phenotypes but surprisingly it is not required for the maturation arrest of the BcCV. Here, we show that macrophages infected with B. cenocepacia employ the NLRP3 inflammasome to induce IL-1β secretion and pyroptosis. Moreover, IL-1β secretion by B. cenocepacia-infected macrophages is suppressed in deletion mutants unable to produce functional Type VI, Type IV, and Type 2 secretion systems (SS. We provide evidence that the T6SS mediates the disruption of the BcCV membrane, which allows the escape of proteins secreted by the T2SS into the macrophage cytoplasm. This was demonstrated by the activity of fusion derivatives of the T2SS-secreted metalloproteases ZmpA and ZmpB with adenylcyclase. Supporting this notion, ZmpA and ZmpB are required for efficient IL-1β secretion in a T6SS dependent manner. ZmpA and ZmpB are also required for the maturation arrest of the BcCVs and bacterial intra-macrophage survival in a T6SS-independent fashion. Our results uncover a novel mechanism for inflammasome activation that involves cooperation between two bacterial secretory pathways, and an unanticipated role for T2SS-secreted proteins in intracellular bacterial survival.

  1. In vivo bioluminescence imaging of Burkholderia mallei respiratory infection and treatment in the mouse model

    Directory of Open Access Journals (Sweden)

    Shane eMassey

    2011-08-01

    Full Text Available Bioluminescent imaging (BLI technology is a powerful tool for monitoring infectious disease progression and treatment approaches. BLI is particularly useful for tracking fastidious intracellular pathogens that might be difficult to recover from certain organs. Burkholderia mallei, the causative agent of glanders, is a facultative intracellular pathogen and has been classified by the CDC as a Category B select agent due to its highly infectious nature and potential use as a biological weapon. Very little is known regarding pathogenesis or treatment of glanders. We investigated the use of bioluminescent reporter constructs to monitor the dynamics of infection as well as the efficacy of therapeutics for B. mallei in real time. A stable luminescent reporter B. mallei strain was created using the pUTmini-Tn5::luxKm2 plasmid and used to monitor glanders in the BALB/c murine model. Mice were infected via the intranasal route with 5x103 bacteria and monitored by BLI at 24, 48 and 72 h. We verified that our reporter construct maintained similar virulence and growth kinetics compared to wild-type B. mallei and confirmed that it maintains luminescent stability in the presence or absence of antibiotic selection. The luminescent signal was initially seen in the lungs, and progressed to the liver and spleen over the course of infection. We demonstrated that antibiotic treatment 24 h post-infection resulted in reduction of bioluminescence that can be attributed to decreased bacterial burden in target organs. These findings suggest that BLI can be used to monitor disease progression and efficacy of therapeutics during glanders infections. Finally, we report an alternative method to mini-Tn5::luxKm2 transposon using mini-Tn7-lux elements that insert site-specifically at known genomic attachment sites and that can also be used to tag bacteria.

  2. Burkholderia pseudomallei infection in a cystic fibrosis patient from the Caribbean: A case report

    OpenAIRE

    Dimas Mateos Corral; Allan L Coates; Yvonne CW Yau; Raymond Tellier; Mindy Glass; Jones, Steven M.; Waters, Valerie J.

    2008-01-01

    Burkholderia pseudomallei is a pathogen identified with increasing frequency in the respiratory tracts of cystic fibrosis (CF) patients from endemic areas such as Southeast Asia and northern Australia. The following report describes the first known reported case in a CF patient from the Caribbean attending a North American CF clinic.

  3. Infection of Burkholderia cepacia induces homeostatic responses in the host for their prolonged survival: the microarray perspective.

    Directory of Open Access Journals (Sweden)

    Vanitha Mariappan

    Full Text Available Burkholderia cepacia is an opportunistic human pathogen associated with life-threatening pulmonary infections in immunocompromised individuals. Pathogenesis of B. cepacia infection involves adherence, colonisation, invasion, survival and persistence in the host. In addition, B. cepacia are also known to secrete factors, which are associated with virulence in the pathogenesis of the infection. In this study, the host factor that may be the cause of the infection was elucidated in human epithelial cell line, A549, that was exposed to live B. cepacia (mid-log phase and its secretory proteins (mid-log and early-stationary phases using the Illumina Human Ref-8 microarray platform. The non-infection A549 cells were used as a control. Expression of the host genes that are related to apoptosis, inflammation and cell cycle as well as metabolic pathways were differentially regulated during the infection. Apoptosis of the host cells and secretion of pro-inflammatory cytokines were found to be inhibited by both live B. cepacia and its secretory proteins. In contrast, the host cell cycle and metabolic processes, particularly glycolysis/glycogenesis and fatty acid metabolism were transcriptionally up-regulated during the infection. Our microarray analysis provided preliminary insights into mechanisms of B. cepacia pathogenesis. The understanding of host response to an infection would provide novel therapeutic targets both for enhancing the host's defences and repressing detrimental responses induced by the invading pathogen.

  4. φX216, a P2-like bacteriophage with broad Burkholderia pseudomallei and B. mallei strain infectivity

    Directory of Open Access Journals (Sweden)

    Kvitko Brian H

    2012-12-01

    Full Text Available Abstract Background Burkholderia pseudomallei and B. mallei are closely related Category B Select Agents of bioterrorism and the causative agents of the diseases melioidosis and glanders, respectively. Rapid phage-based diagnostic tools would greatly benefit early recognition and treatment of these diseases. There is extensive strain-to-strain variation in B. pseudomallei genome content due in part to the presence or absence of integrated prophages. Several phages have previously been isolated from B. pseudomallei lysogens, for example φK96243, φ1026b and φ52237. Results We have isolated a P2-like bacteriophage, φX216, which infects 78% of all B. pseudomallei strains tested. φX216 also infects B. mallei, but not other Burkholderia species, including the closely related B. thailandensis and B. oklahomensis. The nature of the φX216 host receptor remains unclear but evidence indicates that in B. mallei φX216 uses lipopolysaccharide O-antigen but a different receptor in B. pseudomallei. The 37,637 bp genome of φX216 encodes 47 predicted open reading frames and shares 99.8% pairwise identity and an identical strain host range with bacteriophage φ52237. Closely related P2-like prophages appear to be widely distributed among B. pseudomallei strains but both φX216 and φ52237 readily infect prophage carrying strains. Conclusions The broad strain infectivity and high specificity for B. pseudomallei and B. mallei indicate that φX216 will provide a good platform for the development of phage-based diagnostics for these bacteria.

  5. Outbreak of Subclinical Mastitis in a Flock of Dairy Sheep Associated with Burkholderia cepacia Complex Infection

    OpenAIRE

    Berriatua, E.; Ziluaga, I.; Miguel-Virto, C.; Uribarren, P.; Juste, R.; Laevens, S.; Vandamme, P.; Govan, J. R. W.

    2001-01-01

    An outbreak of subclinical mastitis in a flock of 620 milking sheep was investigated. Microbiological and epidemiological analyses identified the causative agent as belonging to the Burkholderia cepacia complex (formerly Pseudomonas cepacia). Every ewe in the milking flock was individually tested for subclinical mastitis on two separate occasions, 6 weeks apart, by the California (rapid) mastitis test (CMT). The proportion of CMT-positive ewes was 69 of 393 (17.6%) on the first sampling and 2...

  6. Detection of the host immune response to Burkholderia mallei heat-shock proteins GroEL and DnaK in a glanders patient and infected mice.

    Science.gov (United States)

    Amemiya, Kei; Meyers, Jennifer L; Deshazer, David; Riggins, Renaldo N; Halasohoris, Stephanie; England, Marilyn; Ribot, Wilson; Norris, Sarah L; Waag, David M

    2007-10-01

    We examined, by enzyme-linked immunosorbent assay and Western blot analysis, the host immune response to 2 heat-shock proteins (hsps) in a patient and mice previously infected with Burkholderia mallei. The patient was the first reported human glanders case in 50 years in the United States. The expression of the groEL and dnaK operons appeared to be dependent upon a sigma(32) RNA polymerase as suggested by conserved heat-shock promoter sequences, and the groESL operon may be negatively regulated by a controlling invert repeat of chaperone expression (CIRCE) site. In the antisera, the GroEL protein was found to be more immunoreactive than the DnaK protein in both a human patient and mice previously infected with B. mallei. Examination of the supernatant of a growing culture of B. mallei showed that more GroEL protein than DnaK protein was released from the cell. This may occur similarly within an infected host causing an elevated host immune response to the B. mallei hsps.

  7. Variant of X-Linked Chronic Granulomatous Disease Revealed by a Severe Burkholderia cepacia Invasive Infection in an Infant

    Directory of Open Access Journals (Sweden)

    Saul Oswaldo Lugo Reyes

    2013-01-01

    Full Text Available Chronic granulomatous disease (CGD is a primary immunodeficiency characterized by increased susceptibility to bacteria and fungi since early in life, caused by mutations in any of the five genes coding for protein subunits in NADPH oxidase. X-linked variant CGD can be missed during routine evaluation or present later in life due to hypomorphic mutations and a residual superoxide production. The case of a 10-month-old boy who died of pneumonia is reported. The isolation of Burkholderia cepacia from his lung, together with a marginally low nitroblue tetrazolium reduction assay (NBT, made us suspect and pursue the molecular diagnosis of CGD. A postmortem genetic analysis finally demonstrated CGD caused by a hypomorphic missense mutation with normal gp91phox expression. In a patient being investigated for unusually severe or recurrent infection, a high index of suspicion of immunodeficiency must be maintained.

  8. A comparison of virulence of intraperitoneal infection of Burkholderia mallei strains in guinea-pigs

    Directory of Open Access Journals (Sweden)

    Eslampanah, M.

    2015-12-01

    Full Text Available Male guinea pigs show high susceptibility to Burkholderia mallei and have been used as animal models in glanders studies. The purpose of our study was to elucidate glanders comparative pathogenesis in guinea pigs. We present here the histological changes and bacterial isolation that develop over time in guinea pigs inoculated intraperitoneally (IP with two strain of B. mallei. Ten male guinea pigs were inoculated intraperitoneally with either the standard strain of Burkholderia mallei or B. mallei strain from Siberian tiger at the Tehran zoo individually, then euthanized at multiple time points post inoculation. Histopathologic changes were similar in both groups and consisted of pyogranulomatous inflammation. In the standard strain study guinea pigs, changes were first seen at 48 hours in liver and heart then in spleen, lung, and kidney at day 3. These changes generally reached maximal incidence and severity by day 3 but decreased by comparison in all tissues except the liver, lung and kidney. Changes were first seen in Siberian tiger strain study guinea pigs also at 48 hours in lung, liver and spleen. At day 3, changes were present in liver, spleen and mediastinal lymph nodes. These changes were maximal at day 4 and 5. In contrast there are differences in incidence and severity between the two strain study guinea pigs. Our findings based on histopathological study indicate that Siberian tiger strain has more severity in gross and necropsy examination but in pathologic lesion was qualitatively similar generally. Additionally, by bacterial isolation, we confirmed the presence of B. mallei.

  9. The Burkholderia pseudomallei Δasd Mutant Exhibits Attenuated Intracellular Infectivity and Imparts Protection against Acute Inhalation Melioidosis in Mice ▿

    OpenAIRE

    Michael H. Norris; Propst, Katie L.; Kang, Yun; Dow, Steven W.; Schweizer, Herbert P.; Hoang, Tung T.

    2011-01-01

    Burkholderia pseudomallei, the cause of serious and life-threatening diseases in humans, is of national biodefense concern because of its potential use as a bioterrorism agent. This microbe is listed as a select agent by the CDC; therefore, development of vaccines is of significant importance. Here, we further investigated the growth characteristics of a recently created B. pseudomallei 1026b Δasd mutant in vitro, in a cell model, and in an animal model of infection. The mutant was typified b...

  10. Zoospore Homing and Infection Events: Effects of the Biocontrol Bacterium Burkholderia cepacia AMMDR1 on Two Oomycete Pathogens of Pea (Pisum sativum L.)

    OpenAIRE

    Heungens, K; Parke, J. L.

    2000-01-01

    Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments. The goal of this work was to understand the effect of B. cepacia AMMDR1 on Pythium aphanidermatum and Aphanomyces euteiches zoospore homing events and on infection of pea seeds or roots. In vitro, B. cepacia AMMDR1 caused zoospore lysis, prevented cyst germination, and inhibited germ tube growth of both oomycetes. B. cepacia AMMDR1 also reduced the attractive...

  11. POLYCLONAL OUTBREAK OF BLOODSTREAM INFECTIONS CAUSED BY Burkholderia cepacia COMPLEX IN HEMATOLOGY AND BONE MARROW TRANSPLANT OUTPATIENT UNITS

    Directory of Open Access Journals (Sweden)

    Icaro Boszczowski

    2014-01-01

    Full Text Available Aim: The objective was to describe an outbreak of bloodstream infections by Burkholderia cepacia complex (Bcc in bone marrow transplant and hematology outpatients. Methods: On February 15, 2008 a Bcc outbreak was suspected. 24 cases were identified. Demographic and clinical data were evaluated. Environment and healthcare workers' (HCW hands were cultured. Species were determined and typed. Reinforcement of hand hygiene, central venous catheter (CVC care, infusion therapy, and maintenance of laminar flow cabinet were undertaken. 16 different HCWs had cared for the CVCs. Multi-dose heparin and saline were prepared on counter common to both units. Findings: 14 patients had B. multivorans (one patient had also B. cenopacia, six non-multivorans Bcc and one did not belong to Bcc. Clone A B. multivorans occurred in 12 patients (from Hematology; in 10 their CVC had been used on February 11/12. Environmental and HCW cultures were negative. All patients were treated with meropenem, and ceftazidime lock-therapy. Eight patients (30% were hospitalized. No deaths occurred. After control measures (multidose vial for single patient; CVC lock with ceftazidime; cleaning of laminar flow cabinet; hand hygiene improvement; use of cabinet to store prepared medication, no new cases occurred. Conclusions: This polyclonal outbreak may be explained by a common source containing multiple species of Bcc, maybe the laminar flow cabinet common to both units. There may have been contamination by B. multivorans (clone A of multi-dose vials.

  12. The Autotransporter BpaB Contributes to the Virulence of Burkholderia mallei in an Aerosol Model of Infection.

    Science.gov (United States)

    Zimmerman, Shawn M; Michel, Frank; Hogan, Robert J; Lafontaine, Eric R

    2015-01-01

    Burkholderia mallei is a highly pathogenic bacterium that causes the zoonosis glanders. Previous studies indicated that the genome of the organism contains eight genes specifying autotransporter proteins, which are important virulence factors of Gram-negative bacteria. In the present study, we report the characterization of one of these autotransporters, BpaB. Database searches identified the bpaB gene in ten B. mallei isolates and the predicted proteins were 99-100% identical. Comparative sequence analyses indicate that the gene product is a trimeric autotransporter of 1,090 amino acids with a predicted molecular weight of 105-kDa. Consistent with this finding, we discovered that recombinant bacteria expressing bpaB produce a protein of ≥ 300-kDa on their surface that is reactive with a BpaB-specific monoclonal antibody. Analysis of sera from mice infected with B. mallei indicated that animals produce antibodies against BpaB during the course of disease, thus establishing production of the autotransporter in vivo. To gain insight on its role in virulence, we inactivated the bpaB gene of B. mallei strain ATCC 23344 and determined the median lethal dose of the mutant in a mouse model of aerosol infection. These experiments revealed that the bpaB mutation attenuates virulence 8-14 fold. Using a crystal violet-based assay, we also discovered that constitutive production of BpaB on the surface of B. mallei promotes biofilm formation. To our knowledge, this is the first report of a biofilm factor for this organism.

  13. The Autotransporter BpaB Contributes to the Virulence of Burkholderia mallei in an Aerosol Model of Infection.

    Directory of Open Access Journals (Sweden)

    Shawn M Zimmerman

    Full Text Available Burkholderia mallei is a highly pathogenic bacterium that causes the zoonosis glanders. Previous studies indicated that the genome of the organism contains eight genes specifying autotransporter proteins, which are important virulence factors of Gram-negative bacteria. In the present study, we report the characterization of one of these autotransporters, BpaB. Database searches identified the bpaB gene in ten B. mallei isolates and the predicted proteins were 99-100% identical. Comparative sequence analyses indicate that the gene product is a trimeric autotransporter of 1,090 amino acids with a predicted molecular weight of 105-kDa. Consistent with this finding, we discovered that recombinant bacteria expressing bpaB produce a protein of ≥ 300-kDa on their surface that is reactive with a BpaB-specific monoclonal antibody. Analysis of sera from mice infected with B. mallei indicated that animals produce antibodies against BpaB during the course of disease, thus establishing production of the autotransporter in vivo. To gain insight on its role in virulence, we inactivated the bpaB gene of B. mallei strain ATCC 23344 and determined the median lethal dose of the mutant in a mouse model of aerosol infection. These experiments revealed that the bpaB mutation attenuates virulence 8-14 fold. Using a crystal violet-based assay, we also discovered that constitutive production of BpaB on the surface of B. mallei promotes biofilm formation. To our knowledge, this is the first report of a biofilm factor for this organism.

  14. Molecular Procedure for Rapid Detection of Burkholderia mallei and Burkholderia pseudomallei

    OpenAIRE

    Bauernfeind, Adolf; Roller, Carsten; Meyer, Detlef; Jungwirth, Renate; Schneider, Ines

    1998-01-01

    A PCR procedure for the discrimination of Burkholderia mallei and Burkholderia pseudomallei was developed. It is based on the nucleotide difference T 2143 C (T versus C at position 2143) between B. mallei and B. pseudomallei detected in the 23S rDNA sequences. In comparison with conventional methods the procedure allows more rapid identification at reduced risk for infection of laboratory personnel.

  15. An ancient but promiscuous host–symbiont association between Burkholderia gut symbionts and their heteropteran hosts

    OpenAIRE

    Kikuchi, Yoshitomo; Hosokawa, Takahiro; Fukatsu, Takema

    2010-01-01

    Here, we investigated 124 stinkbug species representing 20 families and 5 superfamilies for their Burkholderia gut symbionts, of which 39 species representing 6 families of the superfamilies Lygaeoidea and Coreoidea were Burkholderia-positive. Diagnostic PCR surveys revealed high frequencies of Burkholderia infection in natural populations of the stinkbugs, and substantial absence of vertical transmission of Burkholderia infection to their eggs. In situ hybridization confirmed localization of...

  16. Mapping epigenetic changes to the host cell genome induced by Burkholderia pseudomallei reveals pathogen-specific and pathogen-generic signatures of infection

    Science.gov (United States)

    Cizmeci, Deniz; Dempster, Emma L.; Champion, Olivia L.; Wagley, Sariqa; Akman, Ozgur E.; Prior, Joann L.; Soyer, Orkun S.; Mill, Jonathan; Titball, Richard W.

    2016-01-01

    The potential for epigenetic changes in host cells following microbial infection has been widely suggested, but few examples have been reported. We assessed genome-wide patterns of DNA methylation in human macrophage-like U937 cells following infection with Burkholderia pseudomallei, an intracellular bacterial pathogen and the causative agent of human melioidosis. Our analyses revealed significant changes in host cell DNA methylation, at multiple CpG sites in the host cell genome, following infection. Infection induced differentially methylated probes (iDMPs) showing the greatest changes in DNA methylation were found to be in the vicinity of genes involved in inflammatory responses, intracellular signalling, apoptosis and pathogen-induced signalling. A comparison of our data with reported methylome changes in cells infected with M. tuberculosis revealed commonality of differentially methylated genes, including genes involved in T cell responses (BCL11B, FOXO1, KIF13B, PAWR, SOX4, SYK), actin cytoskeleton organisation (ACTR3, CDC42BPA, DTNBP1, FERMT2, PRKCZ, RAC1), and cytokine production (FOXP1, IRF8, MR1). Overall our findings show that pathogenic-specific and pathogen-common changes in the methylome occur following infection. PMID:27484700

  17. Stable, Site-Specific Fluorescent Tagging Constructs Optimized for Burkholderia Species▿

    OpenAIRE

    Norris, Michael H.; Kang, Yun (Kenneth); Wilcox, Bruce; Hoang, Tung T.

    2010-01-01

    Several vectors that facilitate stable fluorescent labeling of Burkholderia pseudomallei and Burkholderia thailandensis were constructed. These vectors combined the effectiveness of the mini-Tn7 site-specific transposition system with fluorescent proteins optimized for Burkholderia spp., enabling bacterial tracking during cellular infection.

  18. Members of the genus Burkholderia: good and bad guys

    Science.gov (United States)

    Eberl, Leo; Vandamme, Peter

    2016-01-01

    In the 1990s several biocontrol agents on that contained Burkholderia strains were registered by the United States Environmental Protection Agency (EPA). After risk assessment these products were withdrawn from the market and a moratorium was placed on the registration of Burkholderia-containing products, as these strains may pose a risk to human health. However, over the past few years the number of novel Burkholderia species that exhibit plant-beneficial properties and are normally not isolated from infected patients has increased tremendously. In this commentary we wish to summarize recent efforts that aim at discerning pathogenic from beneficial Burkholderia strains. PMID:27303639

  19. Zoospore homing and infection events: effects of the biocontrol bacterium Burkholderia cepacia AMMDR1 on two oomycete pathogens of pea (Pisum sativum L.).

    Science.gov (United States)

    Heungens, K; Parke, J L

    2000-12-01

    Burkholderia cepacia AMMDR1 is a biocontrol agent that protects pea and sweet corn seeds from Pythium damping-off in field experiments. The goal of this work was to understand the effect of B. cepacia AMMDR1 on Pythium aphanidermatum and Aphanomyces euteiches zoospore homing events and on infection of pea seeds or roots. In vitro, B. cepacia AMMDR1 caused zoospore lysis, prevented cyst germination, and inhibited germ tube growth of both oomycetes. B. cepacia AMMDR1 also reduced the attractiveness of seed exudates to Pythium zoospores to nondetectable levels. However, when present at high levels on seeds, B. cepacia AMMDR1 had little net effect on zoospore attraction, probably because it also enhanced seed exudation. Seed-applied B. cepacia AMMDR1 dramatically reduced the incidence of infection by Pythium zoospores in situ compared with an antibiosis-deficient Tn5 mutant strain. This mutant strain also decreased Pythium infection incidence to some extent, but only when the pathogen inoculum potential was low. B. cepacia AMMDR1 did not affect attraction of Aphanomyces zoospores or Aphanomyces root rot incidence. These results suggest that B. cepacia AMMDR1 controls P. aphanidermatum largely through antibiosis, but competition for zoospore-attracting compounds can contribute to the effect. Differences in suppression of Aphanomyces and Pythium are discussed in relation to differences in the ecology of the two pathogens. PMID:11097889

  20. Draft Genome Sequences of Burkholderia contaminans, a Burkholderia cepacia Complex Species That Is Increasingly Recovered from Cystic Fibrosis Patients

    OpenAIRE

    Bloodworth, Ruhi A M; Selin, Carrie; López De Volder, Maria Agustina; Drevinek, Pavel; Galanternik, Laura; Degrossi, José; Cardona, Silvia T.

    2015-01-01

    Burkholderia contaminans belongs to the Burkholderia cepacia complex (BCC), a group of bacteria that are ubiquitous in the environment and capable of infecting the immunocompromised and people with cystic fibrosis. We report here draft genome sequences for the B. contaminans type strain LMG 23361 and an Argentinian cystic fibrosis sputum isolate.

  1. Multiplex qPCR for reliable detection and differentiation of Burkholderia mallei and Burkholderia pseudomallei

    OpenAIRE

    Janse Ingmar; Hamidjaja Raditijo A; Hendriks Amber CA; van Rotterdam Bart J

    2013-01-01

    Abstract Background Burkholderia mallei and B. pseudomallei are two closely related species of highly virulent bacteria that can be difficult to detect. Pathogenic Burkholderia are endemic in many regions worldwide and cases of infection, sometimes brought by travelers from unsuspected regions, also occur elsewhere. Rapid, sensitive methods for identification of B. mallei and B. pseudomallei are urgently needed in the interests of patient treatment and epidemiological surveillance. Methods Si...

  2. Common duckweed (Lemna minor is a versatile high-throughput infection model for the Burkholderia cepacia complex and other pathogenic bacteria.

    Directory of Open Access Journals (Sweden)

    Euan L S Thomson

    Full Text Available Members of the Burkholderia cepacia complex (Bcc have emerged in recent decades as problematic pulmonary pathogens of cystic fibrosis (CF patients, with severe infections progressing to acute necrotizing pneumonia and sepsis. This study presents evidence that Lemna minor (Common duckweed is useful as a plant model for the Bcc infectious process, and has potential as a model system for bacterial pathogenesis in general. To investigate the relationship between Bcc virulence in duckweed and Galleria mellonella (Greater wax moth larvae, a previously established Bcc infection model, a duckweed survival assay was developed and used to determine LD50 values. A strong correlation (R(2 = 0.81 was found between the strains' virulence ranks in the two infection models, suggesting conserved pathways in these vastly different hosts. To broaden the application of the duckweed model, enteropathogenic Escherichia coli (EPEC and five isogenic mutants with previously established LD50 values in the larval model were tested against duckweed, and a strong correlation (R(2 = 0.93 was found between their raw LD50 values. Potential virulence factors in B. cenocepacia K56-2 were identified using a high-throughput screen against single duckweed plants. In addition to the previously characterized antifungal compound (AFC cluster genes, several uncharacterized genes were discovered including a novel lysR regulator, a histidine biosynthesis gene hisG, and a gene located near the gene encoding the recently characterized virulence factor SuhB(Bc. Finally, to demonstrate the utility of this model in therapeutic applications, duckweed was rescued from Bcc infection by treating with bacteriophage at 6-h intervals. It was observed that phage application became ineffective at a timepoint that coincided with a sharp increase in bacterial invasion of plant tissue. These results indicate that common duckweed can serve as an effective infection model for the investigation of bacterial

  3. Burkholderia fungorum Septicemia

    OpenAIRE

    Gerrits, G. Peter; Klaassen, Corné; Coenye, Tom; Vandamme, Peter; Meis, Jacques F

    2005-01-01

    We report the first case of community-acquired bacteremia with Burkholderia fungorum, a newly described member of the Burkholderia cepacia complex. A 9-year-old girl sought treatment with septic arthritis in her right knee and ankle with soft tissue involvement. Commercial identification systems did not identify the causative microorganism.

  4. Burkholderia Vaccines: Are We Moving Forward?

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    Leang-Chung eChoh

    2013-02-01

    Full Text Available The genus Burkholderia consists of diverse species which includes both ‘friends’ and ‘foes’. Some of the ‘friendly’ Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines.

  5. Burkholderia vaccines: are we moving forward?

    Science.gov (United States)

    Choh, Leang-Chung; Ong, Guang-Han; Vellasamy, Kumutha M; Kalaiselvam, Kaveena; Kang, Wen-Tyng; Al-Maleki, Anis R; Mariappan, Vanitha; Vadivelu, Jamuna

    2013-01-01

    The genus Burkholderia consists of diverse species which includes both "friends" and "foes." Some of the "friendly" Burkholderia spp. are extensively used in the biotechnological and agricultural industry for bioremediation and biocontrol. However, several members of the genus including B. pseudomallei, B. mallei, and B. cepacia, are known to cause fatal disease in both humans and animals. B. pseudomallei and B. mallei are the causative agents of melioidosis and glanders, respectively, while B. cepacia infection is lethal to cystic fibrosis (CF) patients. Due to the high rate of infectivity and intrinsic resistance to many commonly used antibiotics, together with high mortality rate, B. mallei and B. pseudomallei are considered to be potential biological warfare agents. Treatments of the infections caused by these bacteria are often unsuccessful with frequent relapse of the infection. Thus, we are at a crucial stage of the need for Burkholderia vaccines. Although the search for a prophylactic therapy candidate continues, to date development of vaccines has not advanced beyond research to human clinical trials. In this article, we review the current research on development of safe vaccines with high efficacy against B. pseudomallei, B. mallei, and B. cepacia. It can be concluded that further research will enable elucidation of the potential benefits and risks of Burkholderia vaccines.

  6. The Tomato Rhizosphere, an Environment Rich in Nitrogen-Fixing Burkholderia Species with Capabilities of Interest for Agriculture and Bioremediation▿

    OpenAIRE

    Caballero-Mellado, Jesús; Onofre-Lemus, Janette; Estrada-De Los Santos, Paulina; Martínez-Aguilar, Lourdes

    2007-01-01

    Burkholderia strains are promising candidates for biotechnological applications. Unfortunately, most of these strains belong to species of the Burkholderia cepacia complex (Bcc) involved in human infections, hampering potential applications. Novel diazotrophic Burkholderia species, phylogenetically distant from the Bcc species, have been discovered recently, but their environmental distribution and relevant features for agro-biotechnological applications are little known. In this work, the oc...

  7. The AHL- and BDSF-dependent quorum sensing systems control specific and overlapping sets of genes in Burkholderia cenocepacia H111.

    Directory of Open Access Journals (Sweden)

    Nadine Schmid

    Full Text Available Quorum sensing in Burkholderia cenocepacia H111 involves two signalling systems that depend on different signal molecules, namely N-acyl homoserine lactones (AHLs and the diffusible signal factor cis-2-dodecenoic acid (BDSF. Previous studies have shown that AHLs and BDSF control similar phenotypic traits, including biofilm formation, proteolytic activity and pathogenicity. In this study we mapped the BDSF stimulon by RNA-Seq and shotgun proteomics analysis. We demonstrate that a set of the identified BDSF-regulated genes or proteins are also controlled by AHLs, suggesting that the two regulons partially overlap. The detailed analysis of two mutually regulated operons, one encoding three lectins and the other one encoding the large surface protein BapA and its type I secretion machinery, revealed that both AHLs and BDSF are required for full expression, suggesting that the two signalling systems operate in parallel. In accordance with this, we show that both AHLs and BDSF are required for biofilm formation and protease production.

  8. Development of Burkholderia mallei and pseudomallei vaccines

    Directory of Open Access Journals (Sweden)

    Ediane Batista Silva

    2013-03-01

    Full Text Available B. mallei and B. pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. chronic infection develops after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult.B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms. Thefection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88 and pro-inflammatory cytokines such as IFN- and TNF-α play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for these microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently progress of Burkholderia vaccines has received renewed attention.This review will summarize current and past approaches to develop Burkholderia mallei and pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines.

  9. Healthcare-associated respiratory tract infection and colonization in an intensive care unit caused by Burkholderia cepacia isolated in mouthwash

    Directory of Open Access Journals (Sweden)

    Jeannete Zurita

    2014-12-01

    Conclusions: Our findings strongly suggest that alcohol-free mouthwash solution intrinsically contaminated with B. cepacia was the source of these colonizations and infections involving adults in the ICU.

  10. Development of Burkholderia mallei and pseudomallei vaccines.

    Science.gov (United States)

    Silva, Ediane B; Dow, Steven W

    2013-01-01

    Burkholderia mallei and Burkholderia pseudomallei are Gram-negative bacteria that cause glanders and melioidosis, respectively. Inhalational infection with either organism can result in severe and rapidly fatal pneumonia. Inoculation by the oral and cutaneous routes can also produce infection. Chronic infection may develop after recovery from acute infection with both agents, and control of infection with antibiotics requires prolonged treatment. Symptoms for both meliodosis and glanders are non-specific, making diagnosis difficult. B. pseudomallei can be located in the environment, but in the host, B. mallei and B. psedomallei are intracellular organisms, and infection results in similar immune responses to both agents. Effective early innate immune responses are critical to controlling the early phase of the infection. Innate immune signaling molecules such as TLR, NOD, MyD88, and pro-inflammatory cytokines such as IFN-γ and TNF-α play key roles in regulating control of infection. Neutrophils and monocytes are critical cells in the early infection for both microorganisms. Both monocytes and macrophages are necessary for limiting dissemination of B. pseudomallei. In contrast, the role of adaptive immune responses in controlling Burkholderia infection is less well understood. However, T cell responses are critical for vaccine protection from Burkholderia infection. At present, effective vaccines for prevention of glanders or meliodosis have not been developed, although recently development of Burkholderia vaccines has received renewed attention. This review will summarize current and past approaches to develop B. mallei and B. pseudomalllei vaccines, with emphasis on immune mechanisms of protection and the challenges facing the field. At present, immunization with live attenuated bacteria provides the most effective and durable immunity, and it is important therefore to understand the immune correlates of protection induced by live attenuated vaccines. Subunit

  11. Autotransporters and their role in the virulence of Burkholderia pseudomallei and Burkholderia mallei.

    Directory of Open Access Journals (Sweden)

    Natalie eLazar Adler

    2011-07-01

    Full Text Available Burkholderia pseudomallei and Burkholderia mallei are closely related Gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. Autotransporters (ATs comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases and actin-nucleating factors. The B. pseudomallei K96243 genome contains eleven predicted ATs, eight of which share homologues in the B. mallei ATCC 23344 genome. This review distils key findings from in silico, in vitro and in vivo studies on the ATs of B. pseudomallei and B. mallei. To date, the best characterized of the predicted ATs of B. pseudomallei and B. mallei is BimA, a predicted trimeric AT mediating actin-based motility which varies in sequence and mode of action between Burkholderia species. Of the remaining eight predicted B. pseudomallei trimeric autotransporters, five of which are also present in B. mallei, two (BoaA and BoaB, have been implicated in bacterial adhesion to epithelial cells. Several predicted Burkholderia ATs are recognized by human humoral and cell-mediated immunity, indicating that they are expressed during infection and may be useful for diagnosis and vaccine-mediated protection. Further studies on the mode of secretion and functions of Burkholderia ATs will facilitate the rational design of control strategies.

  12. Multiplex qPCR for reliable detection and differentiation of Burkholderia mallei and Burkholderia pseudomallei

    Directory of Open Access Journals (Sweden)

    Janse Ingmar

    2013-02-01

    Full Text Available Abstract Background Burkholderia mallei and B. pseudomallei are two closely related species of highly virulent bacteria that can be difficult to detect. Pathogenic Burkholderia are endemic in many regions worldwide and cases of infection, sometimes brought by travelers from unsuspected regions, also occur elsewhere. Rapid, sensitive methods for identification of B. mallei and B. pseudomallei are urgently needed in the interests of patient treatment and epidemiological surveillance. Methods Signature sequences for sensitive, specific detection of pathogenic Burkholderia based on published genomes were identified and a qPCR assay was designed and validated. Results A single-reaction quadruplex qPCR assay for the detection of pathogenic Burkholderia, which includes a marker for internal control of DNA extraction and amplification, was developed. The assay permits differentiation of B. mallei and B. pseudomallei strains, and probit analysis showed a very low detection limit. Use of a multicopy signature sequence permits detection of less than 1 genome equivalent per reaction. Conclusions The new assay permits rapid detection of pathogenic Burkholderia and combines enhanced sensitivity, species differentiation, and inclusion of an internal control for both DNA extraction and PCR amplification.

  13. Draft Genome Sequence of Burkholderia dolosa PC543 Isolated from Cystic Fibrosis Airways

    OpenAIRE

    Workentine, Matthew L; Michael G Surette; Bernier, Steve P

    2014-01-01

    Burkholderia dolosa is a member of the Burkholderia cepacia complex, a group of opportunistic bacterial pathogens often associated with fatal chronic infections in the lungs of patients suffering from cystic fibrosis (CF). Here, we announce the draft genome sequence of B. dolosa PC543 (LMG 19468), a CF airway isolate.

  14. Genome Sequence of Burkholderia cenocepacia H111, a Cystic Fibrosis Airway Isolate

    OpenAIRE

    Carlier, A; Agnoli, K; Pessi, G; Suppiger, A; Jenul, C; Schmid, N; Tummler, B.; Pinto-Carbo, M; Eberl, L

    2014-01-01

    The Burkholderia cepacia complex (BCC) is a group of related bacterial species that are commonly isolated from environmental samples. Members of the BCC can cause respiratory infections in cystic fibrosis patients and immunocompromised individuals. We report here the genome sequence of Burkholderia cenocepacia H111, a well-studied model strain of the BCC.

  15. Phylogenomic Study of Burkholderia glathei-like Organisms, Proposal of 13 Novel Burkholderia Species and Emended Descriptions of Burkholderia sordidicola, Burkholderia zhejiangensis, and Burkholderia grimmiae

    Science.gov (United States)

    Peeters, Charlotte; Meier-Kolthoff, Jan P.; Verheyde, Bart; De Brandt, Evie; Cooper, Vaughn S.; Vandamme, Peter

    2016-01-01

    Partial gyrB gene sequence analysis of 17 isolates from human and environmental sources revealed 13 clusters of strains and identified them as Burkholderia glathei clade (BGC) bacteria. The taxonomic status of these clusters was examined by whole-genome sequence analysis, determination of the G+C content, whole-cell fatty acid analysis and biochemical characterization. The whole-genome sequence-based phylogeny was assessed using the Genome Blast Distance Phylogeny (GBDP) method and an extended multilocus sequence analysis (MLSA) approach. The results demonstrated that these 17 BGC isolates represented 13 novel Burkholderia species that could be distinguished by both genotypic and phenotypic characteristics. BGC strains exhibited a broad metabolic versatility and developed beneficial, symbiotic, and pathogenic interactions with different hosts. Our data also confirmed that there is no phylogenetic subdivision in the genus Burkholderia that distinguishes beneficial from pathogenic strains. We therefore propose to formally classify the 13 novel BGC Burkholderia species as Burkholderia arvi sp. nov. (type strain LMG 29317T = CCUG 68412T), Burkholderia hypogeia sp. nov. (type strain LMG 29322T = CCUG 68407T), Burkholderia ptereochthonis sp. nov. (type strain LMG 29326T = CCUG 68403T), Burkholderia glebae sp. nov. (type strain LMG 29325T = CCUG 68404T), Burkholderia pedi sp. nov. (type strain LMG 29323T = CCUG 68406T), Burkholderia arationis sp. nov. (type strain LMG 29324T = CCUG 68405T), Burkholderia fortuita sp. nov. (type strain LMG 29320T = CCUG 68409T), Burkholderia temeraria sp. nov. (type strain LMG 29319T = CCUG 68410T), Burkholderia calidae sp. nov. (type strain LMG 29321T = CCUG 68408T), Burkholderia concitans sp. nov. (type strain LMG 29315T = CCUG 68414T), Burkholderia turbans sp. nov. (type strain LMG 29316T = CCUG 68413T), Burkholderia catudaia sp. nov. (type strain LMG 29318T = CCUG 68411T) and Burkholderia peredens sp. nov. (type strain LMG 29314T = CCUG

  16. Survival of Burkholderia pseudomallei on Environmental Surfaces.

    Science.gov (United States)

    Shams, Alicia M; Rose, Laura J; Hodges, Lisa; Arduino, Matthew J

    2007-12-01

    The survival of the biothreat agent Burkholderia pseudomallei on the surfaces of four materials was measured by culture and esterase activity analyses. The culture results demonstrated that this organism persisted for <24 h to <7 days depending on the material, bacterial isolate, and suspension medium. The persistence determined by analysis of esterase activity, as measured with a ScanRDI solid-phase cytometer, was always longer than the persistence determined by culture analysis.

  17. The Burkholderia cenocepacia OmpA-like protein BCAL2958: identification, characterization, and detection of anti-BCAL2958 antibodies in serum from B. cepacia complex-infected Cystic Fibrosis patients.

    Science.gov (United States)

    Sousa, Sílvia A; Morad, Mostafa; Feliciano, Joana R; Pita, Tiago; Nady, Soad; El-Hennamy, Rehab E; Abdel-Rahman, Mona; Cavaco, José; Pereira, Luísa; Barreto, Celeste; Leitão, Jorge H

    2016-12-01

    Respiratory infections by bacteria of the Burkholderia cepacia complex (Bcc) remain an important cause of morbidity and mortality among cystic fibrosis patients, highlighting the need for novel therapeutic strategies. In the present work we have studied the B. cenocepacia protein BCAL2958, a member of the OmpA-like family of proteins, demonstrated as highly immunogenic in other pathogens and capable of eliciting strong host immune responses. The encoding gene was cloned and the protein, produced as a 6× His-tagged derivative, was used to produce polyclonal antibodies. Bioinformatics analyses led to the identification of sequences encoding proteins with a similarity higher than 96 % to BCAL2958 in all the publicly available Bcc genomes. Furthermore, using the antibody it was experimentally demonstrated that this protein is produced by all the 12 analyzed strains from 7 Bcc species. In addition, results are also presented showing the presence of anti-BCAL2958 antibodies in sera from cystic fibrosis patients with a clinical record of respiratory infection by Bcc, and the ability of the purified protein to in vitro stimulate neutrophils. The widespread production of the protein by Bcc members, together with its ability to stimulate the immune system and the detection of circulating antibodies in patients with a documented record of Bcc infection strongly suggest that the protein is a potential candidate for usage in preventive therapies of infections by Bcc. PMID:27325348

  18. A case of native valve endocarditis caused by Burkholderia cepacia without predisposing factors

    Directory of Open Access Journals (Sweden)

    Han Seong

    2011-05-01

    Full Text Available Abstract Background Infective endocarditis is rarely caused by Burkholderia cepacia. This infection is known to occur particularly in immunocompromised hosts, intravenous heroin users, and in patients with prosthetic valve replacement. Most patients with Burkholderia cepacia endocarditis usually need surgical treatment in addition to antimicrobial treatment. Case Presentation Here, we report the case of a patient who developed Burkholderia cepacia-induced native valve endocarditis with consequent cerebral involvement without any predisposing factors; she was successfully treated by antimicrobial agents only. Conclusion In this report, we also present literature review of relevant cases.

  19. Identification of Burkholderia spp. in the clinical microbiology laboratory: comparison of conventional and molecular methods

    NARCIS (Netherlands)

    C. van Pelt (Cindy); C.M. Verduin (Cees); W.H.F. Goessens (Wil); M.C. Vos (Margreet); B. Tummler; C. Segonds; F. Reubsaet; A.F. van Belkum (Alex); H.A. Verbrugh (Henri)

    1999-01-01

    textabstractCystic fibrosis (CF) predisposes patients to bacterial colonization and infection of the lower airways. Several species belonging to the genus Burkholderia are potential CF-related pathogens, but microbiological identification may be complicated. This situat

  20. Effects of methamphetamine dependence and HIV infection on cerebral morphology

    DEFF Research Database (Denmark)

    Jernigan, Terry Lynne; Gamst, Abthony C; Archibald, Sarah L.;

    2005-01-01

    OBJECTIVE: The authors examined the separate and combined effects of methamphetamine dependence and HIV infection on brain morphology. METHOD: Morphometric measures obtained from magnetic resonance imaging of methamphetamine-dependent and/or HIV-positive participants and their appropriate age......- and education-matched comparison groups were analyzed. Main effects of age, HIV infection, methamphetamine dependence, and the interactions of these factors were examined in analyses of cerebral gray matter structure volumes. RESULTS: Independent of the effect of age, HIV infection was associated with reduced...... volumes of cortical, limbic, and striatal structures. There was also some evidence of an interaction between age and HIV infection such that older HIV-positive participants suffered disproportionate loss. Methamphetamine dependence was surprisingly associated with basal ganglia and parietal cortex volume...

  1. Antibody dependent enhancement of frog virus 3 infection

    Directory of Open Access Journals (Sweden)

    Penny Emily

    2010-02-01

    Full Text Available Abstract Background Viruses included in the family Iridoviridae are large, icosahedral, dsDNA viruses that are subdivided into 5 genera. Frog virus 3 (FV3 is the type species of the genus Ranavirus and the best studied iridovirus at the molecular level. Typically, antibodies directed against a virus act to neutralize the virus and limit infection. Antibody dependent enhancement occurs when viral antibodies enhance infectivity of the virus rather than neutralize it. Results Here we show that anti-FV3 serum present at the time of FV3 infection enhances infectivity of the virus in two non-immune teleost cell lines. We found that antibody dependent enhancement of FV3 was dependent on the Fc portion of anti-FV3 antibodies but not related to complement. Furthermore, the presence of anti-FV3 serum during an FV3 infection in a non-immune mammalian cell line resulted in neutralization of the virus. Our results suggest that a cell surface receptor specific to teleost cell lines is responsible for the enhancement. Conclusions This report represents the first evidence of antibody dependent enhancement in iridoviruses. The data suggests that anti-FV3 serum can either neutralize or enhance viral infection and that enhancement is related to a novel antibody dependent enhancement pathway found in teleosts that is Fc dependent.

  2. Brain abscess caused by Burkholderia pseudomallei

    International Nuclear Information System (INIS)

    Full text: Melioidosis, or infection with Burkholderia pseudomallei, is an important human disease in South East Asia and Northern Australia. Neurological manifestations are well recognized amongst its protean presentations, but direct focal central nervous system infection is infrequently described with only 9 adult and 5 paediatric cases reported in the English language literature. A case of brain abscess due to Burkholderia pseudomallei occurring in a 20 year old Dutch visitor to Australia which progressed despite antibiotic treatment is described. A review of the clinical manifestations, Magnetic Resonance (MR) appearance, diagnosis and treatment of melioidosis is presented, highlighting that: (i) physicians outside endernic areas should consider melioidosis in any patient with an appropriate travel history, (ii) MR imaging is more sensitive then CT in diagnosing early brain infection, especially of the brainstem; (iii) Bacterial culture, the mainstay of diagnosis, has many shortcomings; (iv)In vitro antibiotic sensitivity testing may not translate into clinical efficacy; and (v) Steroids appear to have little role, even in severe disease

  3. Novel lytic bacteriophages from soil that lyse Burkholderia pseudomallei.

    Science.gov (United States)

    Yordpratum, Umaporn; Tattawasart, Unchalee; Wongratanacheewin, Surasakdi; Sermswan, Rasana W

    2011-01-01

    Burkholderia pseudomallei is a Gram-negative saprophytic bacterium that causes severe sepsis with a high mortality rate in humans and a vaccine is not available. Bacteriophages are viruses of bacteria that are ubiquitous in nature. Several lysogenic phages of Burkholderia spp. have been found but information is scarce for lytic phages. Six phages, ST2, ST7, ST70, ST79, ST88 and ST96, which lyse B. pseudomallei, were isolated from soil in an endemic area. The phages belong to the Myoviridae family. The range of estimated genome sizes is 24.0-54.6 kb. Phages ST79 and ST96 lysed 71% and 67% of tested B. pseudomallei isolates and formed plaques on Burkholderia mallei but not other tested bacteria, with the exception of closely related Burkholderia thailandensis which was lysed by ST2 and ST96 only. ST79 and ST96 were observed to clear a mid-log culture by lysis within 6 h when infected at a multiplicity of infection of 0.1. As ST79 and ST96 phages effectively lysed B. pseudomallei, their potential use as a biocontrol of B. pseudomallei in the environment or alternative treatment in infected hosts could lead to benefits from phages that are available in nature. PMID:21091532

  4. Charakterisierung des Burkholderia cenocepacia Aquaglyceroporins

    OpenAIRE

    Wree, Dorothea

    2010-01-01

    In der vorliegenden Arbeit wurde ein Aquaglyceroporin des Krankenhausproblemkeims Burkholderia cenocepacia, BccGlpF, charakterisiert. Unter besonderer Beobachtung stand die Struktur-Funktionsbeziehung der eigentlich kochkonservierten NPA-Motive.

  5. Burkholderia in gladiool lastige bacterie

    NARCIS (Netherlands)

    Kok, B.J.; Aanholt, van J.T.M.

    2009-01-01

    In de bollen- en bloementeelt van gladiolen komt de laatste jaren de bacterieziekte Burkholderia gladiola voor die onder vochtige warme omstandigheden veel uitval veroorzaken. PPO onderzocht een aantal maatregelen om de ziekte in kralen, pitten en knollen te bestrijden

  6. Burkholderia bacteria infectiously induce the proto-farming symbiosis of Dictyostelium amoebae and food bacteria.

    Science.gov (United States)

    DiSalvo, Susanne; Haselkorn, Tamara S; Bashir, Usman; Jimenez, Daniela; Brock, Debra A; Queller, David C; Strassmann, Joan E

    2015-09-01

    Symbiotic associations can allow an organism to acquire novel traits by accessing the genetic repertoire of its partner. In the Dictyostelium discoideum farming symbiosis, certain amoebas (termed "farmers") stably associate with bacterial partners. Farmers can suffer a reproductive cost but also gain beneficial capabilities, such as carriage of bacterial food (proto-farming) and defense against competitors. Farming status previously has been attributed to amoeba genotype, but the role of bacterial partners in its induction has not been examined. Here, we explore the role of bacterial associates in the initiation, maintenance, and phenotypic effects of the farming symbiosis. We demonstrate that two clades of farmer-associated Burkholderia isolates colonize D. discoideum nonfarmers and infectiously endow them with farmer-like characteristics, indicating that Burkholderia symbionts are a major driver of the farming phenomenon. Under food-rich conditions, Burkholderia-colonized amoebas produce fewer spores than uncolonized counterparts, with the severity of this reduction being dependent on the Burkholderia colonizer. However, the induction of food carriage by Burkholderia colonization may be considered a conditionally adaptive trait because it can confer an advantage to the amoeba host when grown in food-limiting conditions. We observed Burkholderia inside and outside colonized D. discoideum spores after fruiting body formation; this observation, together with the ability of Burkholderia to colonize new amoebas, suggests a mixed mode of symbiont transmission. These results change our understanding of the D. discoideum farming symbiosis by establishing that the bacterial partner, Burkholderia, is an important causative agent of the farming phenomenon.

  7. Effects of methamphetamine dependence and HIV infection on cerebral morphology

    DEFF Research Database (Denmark)

    Jernigan, Terry Lynne; Gamst, Abthony C; Archibald, Sarah L.;

    2005-01-01

    OBJECTIVE: The authors examined the separate and combined effects of methamphetamine dependence and HIV infection on brain morphology. METHOD: Morphometric measures obtained from magnetic resonance imaging of methamphetamine-dependent and/or HIV-positive participants and their appropriate age- an...

  8. Molecular detection of Xanthomonas oryzae pv.oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

    Institute of Scientific and Technical Information of China (English)

    Wen; Lu; Luqi; Pan; Haijun; Zhao; Yulin; Jia; Yanli; Wang; Xiaoping; Yu; Xueyan; Wang

    2014-01-01

    The polymerase chain reaction(PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR Green real-time PCR were developed to facilitate the simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv.oryzae, X. oryzae pv. oryzicola, and Burkholderia glumae. The unique PCR primer sets were designed from portions of a putative glycosyltransferase gene of X. oryzae pv. oryzae, an Avr Rxo gene of X. oryzae pv. oryzicola, and an internal transcribed spacer(ITS) sequence of B. glumae. Using a multiplex PCR assay, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected in one PCR reaction that contained the newly developed primer set mix. Using SYBR Green real-time PCR assays, X. oryzae pv. oryzae, X. oryzae pv. oryzicola, and B. glumae were detected at 1, 1, and 10 fg μL-1, respectively. These newly designed molecular assays are sensitive and could be reliable tools for pathogen detection and disease forecasting.

  9. Receptor-Dependent Coronavirus Infection of Dendritic Cells

    Science.gov (United States)

    Turner, Brian C.; Hemmila, Erin M.; Beauchemin, Nicole; Holmes, Kathryn V.

    2004-01-01

    In several mammalian species, including humans, coronavirus infection can modulate the host immune response. We show a potential role of dendritic cells (DC) in murine coronavirus-induced immune modulation and pathogenesis by demonstrating that the JAW SII DC line and primary DC from BALB/c mice and p/p mice with reduced expression of the murine coronavirus receptor, murine CEACAM1a, are susceptible to murine coronavirus infection by a receptor-dependent pathway. PMID:15113927

  10. A SIRS epidemic model with infection-age dependence

    Science.gov (United States)

    Zhang, Zhonghua; Peng, Jigen

    2007-07-01

    Based on J. Mena-Lorca and H.W. Hethcote's epidemic model, a SIRS epidemic model with infection-age-dependent infectivity and general nonlinear contact rate is formulated. Under general conditions, the unique existence of its global positive solutions is obtained. Moreover, under more general assumptions than the existing, the existence and asymptotical stability of its equilibria are discussed. In the end, the condition on the stability of endemic equilibrium is verified by a special model.

  11. Mechanisms of Disease: Host-Pathogen Interactions between Burkholderia Species and Lung Epithelial Cells

    OpenAIRE

    David, Jonathan; Bell, Rachel E.; Clark, Graeme C.

    2015-01-01

    Members of the Burkholderia species can cause a range of severe, often fatal, respiratory diseases. A variety of in vitro models of infection have been developed in an attempt to elucidate the mechanism by which Burkholderia spp. gain entry to and interact with the body. The majority of studies have tended to focus on the interaction of bacteria with phagocytic cells with a paucity of information available with regard to the lung epithelium. However, the lung epithelium is becoming more widel...

  12. Characterization of integrons in Burkholderia cepacia clinical isolates

    Directory of Open Access Journals (Sweden)

    Linda Furlanis

    2010-03-01

    Full Text Available Burkholderia cepacia is an opportunistic pathogen able to colonize the airways of Cystic Fibrosis (CF patients, frequently developing chronic infections. In 20% of cases these infections cause severe and poorly controlled pathological situations because of the intrinsic antibiotic resistance expressed by the microorganism. CF patients are often subjected to antibiotic therapy: this facilitates the acquisition of antibiotic resistance determinants by the infecting bacteria. Integrons are mobile genetic elements that are widespread in bacterial populations and favor the acquisition of gene cassettes coding for these determinants.The presence of class 1 integrons was investigated by PCR with primers specific for the 5’ and 3’ ends in Burkholderia isolates recovered from patients in treatment at the CF center of Friuli Venezia Giulia. The same integron, carrying an uncommon allelic form (Ib of the aacA4 gene in its cassette array and conferring resistance to some aminoglycosides, was found in two independent isolates (different RAPD profiles infecting two different patients. In both isolates the integron was carried by plasmids and was still present 3 and 6 years later the first finding. Despite the exchange of integrons between bacterial pathogens is fully described, these items were not frequently found in Burkholderia isolates. Although the clinical relevance of the integron we identified is low (a single gene cassette encoding a widespread resistance,we feel concerned that these genetic elements begin to circulate in this bacterial species, as this could make more and more troublesome the treatment of infections notoriously difficult to eradicate.

  13. Efflux Pump-mediated Drug Resistance in Burkholderia

    Directory of Open Access Journals (Sweden)

    Nicole L Podnecky

    2015-04-01

    Full Text Available Several members of the genus Burkholderia are prominent pathogens. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. Virtually all Burkholderia species are also resistant to polymyxin, prohibiting use of drugs like colistin that are available for treatment of infections caused by most other drug resistant Gram-negative bacteria. Despite clinical significance and antibiotic resistance of Burkholderia species, characterization of efflux pumps lags behind other non-enteric Gram-negative pathogens such as Acinetobacter baumannii and Pseudomonas aeruginosa. Although efflux pumps have been described in several Burkholderia species, they have been best studied in B. cenocepacia and B. pseudomallei. As in other non-enteric Gram-negatives, efflux pumps of the resistance nodulation cell division (RND family are the clinically most significant efflux systems in these two species. Several efflux pumps were described in B. cenocepacia, which when expressed confer resistance to clinically significant antibiotics, including aminoglycosides, chloramphenicol, fluoroquinolones, and tetracyclines. Three RND pumps have been characterized in B. pseudomallei, two of which confer either intrinsic or acquired resistance to aminoglycosides, macrolides, chloramphenicol, fluoroquinolones, tetracyclines, trimethoprim, and in some instances trimethoprim+sulfamethoxazole. Several strains of the host-adapted B. mallei, a clone of B. pseudomallei, lack AmrAB-OprA and are therefore aminoglycoside and macrolide susceptible. B. thailandensis is closely related to B. pseudomallei, but non-pathogenic to humans. Its pump repertoire and ensuing drug resistance profile parallels that of B. pseudomallei. An efflux pump in B. vietnamiensis plays a significant role in acquired aminoglycoside resistance. Summarily, efflux pumps are significant players in Burkholderia drug resistance.

  14. Hepatitis Infection in the Treatment of Opioid Dependence and Abuse

    Directory of Open Access Journals (Sweden)

    Alain H. Litwin

    2008-01-01

    Full Text Available Many new and existing cases of viral hepatitis infections are related to injection drug use. Transmission of these infections can result directly from the use of injection equipment that is contaminated with blood containing the hepatitis B or C virus or through sexual contact with an infected individual. In the latter case, drug use can indirectly contribute to hepatitis transmission through the dis-inhibited at-risk behavior, that is, unprotected sex with an infected partner. Individuals who inject drugs are at-risk for infection from different hepatitis viruses, hepatitis A, B, or C. Those with chronic hepatitis B virus infection also face additional risk should they become co-infected with hepatitis D virus. Protection from the transmission of hepatitis viruses A and B is best achieved by vaccination. For those with a history of or who currently inject drugs, the medical management of viral hepatitis infection comprising screening, testing, counseling and providing care and treatment is evolving. Components of the medical management of hepatitis infection, for persons considering, initiating, or receiving pharmacologic therapy for opioid addiction include: testing for hepatitis B and C infections; education and counseling regarding at-risk behavior and hepatitis transmission, acute and chronic hepatitis infection, liver disease and its care and treatment; vaccination against hepatitis A and B infection; and integrative primary care as part of the comprehensive treatment approach for recovery from opioid abuse and dependence. In addition, participation in a peer support group as part of integrated medical care enhances treatment outcomes. Liver disease is highly prevalent in patient populations seeking recovery from opioid addiction or who are currently receiving pharmacotherapy for opioid addiction. Pharmacotherapy for opioid addiction is not a contraindication to evaluation, care, or treatment of liver disease due to hepatitis virus

  15. Evolving serodiagnostics by rationally designed peptide arrays: the Burkholderia paradigm in Cystic Fibrosis.

    Science.gov (United States)

    Peri, Claudio; Gori, Alessandro; Gagni, Paola; Sola, Laura; Girelli, Daniela; Sottotetti, Samantha; Cariani, Lisa; Chiari, Marcella; Cretich, Marina; Colombo, Giorgio

    2016-01-01

    Efficient diagnosis of emerging and novel bacterial infections is fundamental to guide decisions on therapeutic treatments. Here, we engineered a novel rational strategy to design peptide microarray platforms, which combines structural and genomic analyses to predict the binding interfaces between diverse protein antigens and antibodies against Burkholderia cepacia complex infections present in the sera of Cystic Fibrosis (CF) patients. The predicted binding interfaces on the antigens are synthesized in the form of isolated peptides and chemically optimized for controlled orientation on the surface. Our platform displays multiple Burkholderia-related epitopes and is shown to diagnose infected individuals even in presence of superinfections caused by other prevalent CF pathogens, with limited cost and time requirements. Moreover, our data point out that the specific patterns determined by combined probe responses might provide a characterization of Burkholderia infections even at the subtype level (genomovars). The method is general and immediately applicable to other bacteria.

  16. Evolving serodiagnostics by rationally designed peptide arrays: the Burkholderia paradigm in Cystic Fibrosis

    Science.gov (United States)

    Peri, Claudio; Gori, Alessandro; Gagni, Paola; Sola, Laura; Girelli, Daniela; Sottotetti, Samantha; Cariani, Lisa; Chiari, Marcella; Cretich, Marina; Colombo, Giorgio

    2016-09-01

    Efficient diagnosis of emerging and novel bacterial infections is fundamental to guide decisions on therapeutic treatments. Here, we engineered a novel rational strategy to design peptide microarray platforms, which combines structural and genomic analyses to predict the binding interfaces between diverse protein antigens and antibodies against Burkholderia cepacia complex infections present in the sera of Cystic Fibrosis (CF) patients. The predicted binding interfaces on the antigens are synthesized in the form of isolated peptides and chemically optimized for controlled orientation on the surface. Our platform displays multiple Burkholderia-related epitopes and is shown to diagnose infected individuals even in presence of superinfections caused by other prevalent CF pathogens, with limited cost and time requirements. Moreover, our data point out that the specific patterns determined by combined probe responses might provide a characterization of Burkholderia infections even at the subtype level (genomovars). The method is general and immediately applicable to other bacteria.

  17. CHROMOSOMAL MULTIPLICITY IN BURKHOLDERIA CEPACIA

    Science.gov (United States)

    We have used CHEF gel electrophoresis to screen preparations of large DNA from different Burkholderia cepacia isolates for the presence of DNA species corresponding to the linearized forms of the three chromosomes of 3.4,2.5, and 0.9 Mb identified in B. cepacia strain 17616. DNA ...

  18. Cytotoxicity Associated with Trichloroethylene Oxidation in Burkholderia cepacia G4

    OpenAIRE

    Yeager, Chris M.; Bottomley, Peter J; Arp, Daniel J.

    2001-01-01

    The effects of trichloroethylene (TCE) oxidation on toluene 2-monooxygenase activity, general respiratory activity, and cell culturability were examined in the toluene-oxidizing bacterium Burkholderia cepacia G4. Nonspecific damage outpaced inactivation of toluene 2-monooxygenase in B. cepacia G4 cells. Cells that had degraded approximately 0.5 μmol of TCE (mg of cells−1) lost 95% of their acetate-dependent O2 uptake activity (a measure of general respiratory activity), yet toluene-dependent ...

  19. The genome of Burkholderia cenocepacia J2315, an epidemic pathogen of cystic fibrosis patients

    DEFF Research Database (Denmark)

    Holden, Matthew T G; Seth-Smith, Helena M B; Crossman, Lisa C;

    2009-01-01

    Bacterial infections of the lungs of cystic fibrosis (CF) patients cause major complications in the treatment of this common genetic disease. Burkholderia cenocepacia infection is particularly problematic since this organism has high levels of antibiotic resistance, making it difficult to eradica...

  20. Actin-Based Motility of Burkholderia thailandensis Requires a Central Acidic Domain of BimA That Recruits and Activates the Cellular Arp2/3 Complex▿

    OpenAIRE

    Sitthidet, Chayada; Stevens, Joanne M; Field, Terence R.; Layton, Abigail N.; Korbsrisate, Sunee; Stevens, Mark P.

    2010-01-01

    Burkholderia species use BimA for intracellular actin-based motility. Uniquely, Burkholderia thailandensis BimA harbors a central and acidic (CA) domain. The CA domain was required for actin-based motility, binding to the cellular Arp2/3 complex, and Arp2/3-dependent polymerization of actin monomers. Our data reveal distinct strategies for actin-based motility among Burkholderia species.

  1. Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides.

    Science.gov (United States)

    Kooi, Cora; Sokol, Pamela A

    2009-09-01

    Burkholderia cenocepacia secretes two zinc-dependent metalloproteases, designated ZmpA and ZmpB. Previously, ZmpA and ZmpB have been shown to cleave several proteins important in host defence. In this study, the ability of ZmpA and ZmpB to digest and inactivate antimicrobial peptides involved in innate immunity was examined. ZmpB but not ZmpA cleaved beta-defensin-1. ZmpA but not ZmpB cleaved the cathelicidin LL-37. Both enzymes cleaved elafin and secretory leukocyte inhibitor, which are antimicrobial peptides as well as neutrophil elastase inhibitors. Both ZmpA and ZmpB cleaved protamine, a fish antimicrobial peptide, and a zmpA zmpB mutant was more sensitive to protamine killing than the parental strain. ZmpA or ZmpB cleavage of elafin inactivated its anti-protease activity. The effect of ZmpA and ZmpB on the neutrophil proteases elastase and cathepsin G was also examined but neither enzyme was active against these host proteases. These studies suggest that ZmpA and ZmpB may influence the resistance of B. cenocepacia to host antimicrobial peptides as well as alter the host protease/anti-protease balance in chronic respiratory infections.

  2. Developing Peptide Mimotopes of Capsular Polysaccharides and Lipopolysaccharides Protective Antigens of Pathogenic Burkholderia Bacteria.

    Science.gov (United States)

    Guo, Pengfei; Zhang, Jing; Tsai, Shien; Li, Bingjie; Lo, Shyh-Ching

    2016-06-01

    Burkholderia pseudomallei (BP) and Burkholderia mallei (BM) are two species of pathogenic Burkholderia bacteria. Our laboratory previously identified four monoclonal antibodies (MAbs) that reacted against Burkholderia capsular polysaccharides (PS) and lipopolysaccharides (LPS) and effectively protected against a lethal dose of BP/BM infections in mice. In this study, we used phage display panning against three different phage peptide libraries to select phage clones specifically recognized by each of the four protective MAbs. After sequencing a total of 179 candidate phage clones, we examined in detail six selected phage clones carrying different peptide inserts for the specificity of binding by the respective target MAbs. Chemically synthesized peptides corresponding to those displayed by the six phage clones were conjugated to keyhole limpet hemocyanin carrier protein and tested for their binding specificity to the respective protective MAbs. The study revealed that four of the six peptides, all derived from the library displaying dodecapeptides, functioned well as "mimotopes" of Burkholderia PS and LPS as demonstrated by a high degree of specific competition against the binding of three protective MAbs to BP and BM. Our results suggest that the four selected peptide mimics corresponding to PS/LPS protective antigens of BP and BM could potentially be developed into peptide vaccines against pathogenic Burkholderia bacteria. PMID:27328059

  3. Meropenem in cystic fibrosis patients infected with resistant Pseudomonas aeruginosa or Burkholderia cepacia and with hypersensitivity to beta-lactam antibiotics

    DEFF Research Database (Denmark)

    Ciofu, Oana; Jensen, Tim; Pressler, Tacjana;

    1996-01-01

    OBJECTIVE: To assess the efficacy and safety of meropenem, administered on a compassionate basis to 62 cystic fibrosis (CF) patients (age: 24plus minus6 years) with hypersensitivity reactions to beta-lactam antibiotics and/or infection by bacteria resistant to other antibiotics. METHODS: Fifty...... in pulmonary function (as a percentage of the predictive values) was 5.6% for FEV1 (forced expiratory volume in the first second) and 8.6% for FVC (forced vital capacity). C-reactive protein and erythrocyte sedimentation rate (ESR) and leukocyte count decreased significantly. In courses administered...... complaint. The following side effects were observed: nausea (0.8%), itching (4%), rash (3.2%), drug fever (1.6%). CONCLUSIONS: Meropenem proved to be a valuable drug in the treatment of CF patients with chronic pulmonary infection with multiresistant P. aeruginosa and B. cepacia and with hypersensitivity...

  4. Burkholderia pseudomallei transcriptional adaptation in macrophages

    Directory of Open Access Journals (Sweden)

    Chieng Sylvia

    2012-07-01

    Full Text Available Abstract Background Burkholderia pseudomallei is a facultative intracellular pathogen of phagocytic and non-phagocytic cells. How the bacterium interacts with host macrophage cells is still not well understood and is critical to appreciate the strategies used by this bacterium to survive and how intracellular survival leads to disease manifestation. Results Here we report the expression profile of intracellular B. pseudomallei following infection of human macrophage-like U937 cells. During intracellular growth over the 6 h infection period, approximately 22 % of the B. pseudomallei genome showed significant transcriptional adaptation. B. pseudomallei adapted rapidly to the intracellular environment by down-regulating numerous genes involved in metabolism, cell envelope, motility, replication, amino acid and ion transport system and regulatory function pathways. Reduced expression in catabolic and housekeeping genes suggested lower energy requirement and growth arrest during macrophage infection, while expression of genes encoding anaerobic metabolism functions were up regulated. However, whilst the type VI secretion system was up regulated, expression of many known virulence factors was not significantly modulated over the 6hours of infection. Conclusions The transcriptome profile described here provides the first comprehensive view of how B. pseudomallei survives within host cells and will help identify potential virulence factors and proteins that are important for the survival and growth of B. pseudomallei within human cells.

  5. Oropharyngeal aspiration of Burkholderia mallei and Burkholderia pseudomallei in BALB/c mice.

    Directory of Open Access Journals (Sweden)

    Kevin L Schully

    Full Text Available Burkholderia mallei and Burkholderia pseudomallei are potentially lethal pathogens categorized as biothreat agents due, in part, to their ability to be disseminated via aerosol. There are no protective vaccines against these pathogens and treatment options are limited and cumbersome. Since disease severity is greatest when these agents are inhaled, efforts to develop pre- or post-exposure prophylaxis focus largely on inhalation models of infection. Here, we demonstrate a non-invasive and technically simple method for affecting the inhalational challenge of BALB/c mice with B. pseudomallei and B. mallei. In this model, two investigators utilized common laboratory tools such as forceps and a micropipette to conduct and characterize an effective and reproducible inhalational challenge of BALB/c mice with B. mallei and B. pseudomallei. Challenge by oropharyngeal aspiration resulted in acute disease. Additionally, 50% endpoints for B. pseudomallei K96243 and B. mallei ATCC 23344 were nearly identical to published aerosol challenge methods. Furthermore, the pathogens disseminated to all major organs typically targeted by these agents where they proliferated. The pro-inflammatory cytokine production in the proximal and peripheral fluids demonstrated a rapid and robust immune response comparable to previously described murine and human studies. These observations demonstrate that OA is a viable alternative to aerosol exposure.

  6. Comparison of Ashdown's Medium, Burkholderia cepacia Medium, and Burkholderia pseudomallei Selective Agar for Clinical Isolation of Burkholderia pseudomallei

    OpenAIRE

    Peacock, Sharon J.; Chieng, Grace; Cheng, Allen C.; Dance, David A. B.; Amornchai, Premjit; Wongsuvan, Gumphol; Teerawattanasook, Nittaya; Chierakul, Wirongrong; Day, Nicholas P J; Wuthiekanun, Vanaporn

    2005-01-01

    Ashdown's medium, Burkholderia pseudomallei selective agar (BPSA), and a commercial Burkholderia cepacia medium were compared for their abilities to grow B. pseudomallei from 155 clinical specimens that proved positive for this organism. The sensitivity of each was equivalent; the selectivity of BPSA was lower than that of Ashdown's or B. cepacia medium.

  7. Proteasome Inhibition Suppresses Dengue Virus Egress in Antibody Dependent Infection.

    Science.gov (United States)

    Choy, Milly M; Zhang, Summer L; Costa, Vivian V; Tan, Hwee Cheng; Horrevorts, Sophie; Ooi, Eng Eong

    2015-11-01

    The mosquito-borne dengue virus (DENV) is a cause of significant global health burden, with an estimated 390 million infections occurring annually. However, no licensed vaccine or specific antiviral treatment for dengue is available. DENV interacts with host cell factors to complete its life cycle although this virus-host interplay remains to be fully elucidated. Many studies have identified the ubiquitin proteasome pathway (UPP) to be important for successful DENV production, but how the UPP contributes to DENV life cycle as host factors remains ill defined. We show here that proteasome inhibition decouples infectious virus production from viral RNA replication in antibody-dependent infection of THP-1 cells. Molecular and imaging analyses in β-lactone treated THP-1 cells suggest that proteasome function does not prevent virus assembly but rather DENV egress. Intriguingly, the licensed proteasome inhibitor, bortezomib, is able to inhibit DENV titers at low nanomolar drug concentrations for different strains of all four serotypes of DENV in primary monocytes. Furthermore, bortezomib treatment of DENV-infected mice inhibited the spread of DENV in the spleen as well as the overall pathological changes. Our findings suggest that preventing DENV egress through proteasome inhibition could be a suitable therapeutic strategy against dengue. PMID:26565697

  8. Proteasome Inhibition Suppresses Dengue Virus Egress in Antibody Dependent Infection.

    Directory of Open Access Journals (Sweden)

    Milly M Choy

    2015-11-01

    Full Text Available The mosquito-borne dengue virus (DENV is a cause of significant global health burden, with an estimated 390 million infections occurring annually. However, no licensed vaccine or specific antiviral treatment for dengue is available. DENV interacts with host cell factors to complete its life cycle although this virus-host interplay remains to be fully elucidated. Many studies have identified the ubiquitin proteasome pathway (UPP to be important for successful DENV production, but how the UPP contributes to DENV life cycle as host factors remains ill defined. We show here that proteasome inhibition decouples infectious virus production from viral RNA replication in antibody-dependent infection of THP-1 cells. Molecular and imaging analyses in β-lactone treated THP-1 cells suggest that proteasome function does not prevent virus assembly but rather DENV egress. Intriguingly, the licensed proteasome inhibitor, bortezomib, is able to inhibit DENV titers at low nanomolar drug concentrations for different strains of all four serotypes of DENV in primary monocytes. Furthermore, bortezomib treatment of DENV-infected mice inhibited the spread of DENV in the spleen as well as the overall pathological changes. Our findings suggest that preventing DENV egress through proteasome inhibition could be a suitable therapeutic strategy against dengue.

  9. Stage-dependent model for Hantavirus infection: The effect of the initial infection-free period

    Science.gov (United States)

    Reinoso, José A.; de la Rubia, F. Javier

    2013-04-01

    We propose a stage-dependent model with constant delay to study the effect of the initial infection-free period on the spread of Hantavirus infection in rodents. We analyze the model under various extreme weather conditions, in the context of the El Niño-La Niña Southern Oscillation phenomenon, and show how these variations determine the evolution of the system significantly. When the scenario corresponds to El Niño, the system presents a demographic explosion and a delayed outbreak of Hantavirus infection, whereas if the scenario is the opposite there is a rapid decline of the population, but with a possible persistence period that may imply a considerable risk for public health, a fact that is in agreement with available field data. We use the model to simulate a historical evolution that resembles the processes that occurred in the 1990s.

  10. Cytokine response and outcome of infection depends on the infective dose of parasites in experimental infection by Echinococcus granulosus.

    Science.gov (United States)

    Dematteis, Sylvia; Rottenberg, Martin; Baz, Adriana

    2003-04-01

    We here analysed whether the cytokine responses in early and late experimental infection with Echinococcus granulosus depend on the dose of parasites to which the host is exposed. To this purpose Balb/c mice were inoculated intraperitoneally (i.p.) with either 500 or 2000 protoscoleces. Splenocytes of mice were obtained at days 3, 7, 14 and 21 and also on week 37 post-infection and cultured in vitro with protoscolex antigens. Type-1 and type-2 cytokines were analysed in supernatants by ELISA. Results showed that the inoculation of 500 protoscoleces induced an early type-0 and a late type-2 cytokine response, whereas the inoculation of 2000 protoscoleces induced an early type-2 and a late type-0 cytokine response. Parasite growth was lower in the group inoculated with the low infective dose. These results indicate that the cytokine response during the infection by the helminth E. granulosus depends on the dose of parasites to which the host has been exposed.

  11. Accurate and rapid identification of the Burkholderia pseudomallei near-neighbour, Burkholderia ubonensis, using real-time PCR.

    Directory of Open Access Journals (Sweden)

    Erin P Price

    Full Text Available Burkholderia ubonensis is an environmental bacterium belonging to the Burkholderia cepacia complex (Bcc, a group of genetically related organisms that are associated with opportunistic but generally nonfatal infections in healthy individuals. In contrast, the near-neighbour species Burkholderia pseudomallei causes melioidosis, a disease that can be fatal in up to 95% of cases if left untreated. B. ubonensis is frequently misidentified as B. pseudomallei from soil samples using selective culturing on Ashdown's medium, reflecting both the shared environmental niche and morphological similarities of these species. Additionally, B. ubonensis shows potential as an important biocontrol agent in B. pseudomallei-endemic regions as certain strains possess antagonistic properties towards B. pseudomallei. Current methods for characterising B. ubonensis are laborious, time-consuming and costly, and as such this bacterium remains poorly studied. The aim of our study was to develop a rapid and inexpensive real-time PCR-based assay specific for B. ubonensis. We demonstrate that a novel B. ubonensis-specific assay, Bu550, accurately differentiates B. ubonensis from B. pseudomallei and other species that grow on selective Ashdown's agar. We anticipate that Bu550 will catalyse research on B. ubonensis by enabling rapid identification of this organism from Ashdown's-positive colonies that are not B. pseudomallei.

  12. In Vitro Susceptibilities of Burkholderia mallei in Comparison to Those of Other Pathogenic Burkholderia spp.

    OpenAIRE

    Kenny, D J; Russell, P; Rogers, D.; Eley, S M; Titball, R W

    1999-01-01

    The in vitro antimicrobial susceptibilities of isolates of Burkholderia mallei to 16 antibiotics were assessed and compared with the susceptibilities of Burkholderia pseudomallei and Burkholderia cepacia. The antibiotic susceptibility profile of B. mallei resembled that of B. pseudomallei more closely than that of B. cepacia, which corresponds to their similarities in terms of biochemistry, antigenicity, and pathogenicity. Ceftazidime, imipenem, doxycycline, and ciprofloxacin were active agai...

  13. Glanders: off to the races with Burkholderia mallei.

    Science.gov (United States)

    Whitlock, Gregory C; Estes, D Mark; Torres, Alfredo G

    2007-12-01

    Burkholderia mallei, the etiologic agent of the disease known as glanders, is primarily a disease affecting horses and is transmitted to humans by direct contact with infected animals. The use of B. mallei as a biological weapon has been reported and currently, there is no vaccine available for either humans or animals. Despite the history and highly infective nature of B. mallei, as well as its potential use as a bio-weapon, B. mallei research to understand the pathogenesis and the host responses to infection remains limited. Therefore, this minireview will focus on current efforts to elucidate B. mallei virulence, the associated host immune responses elicited during infection and discuss the feasibility of vaccine development.

  14. Hepatitis Infection in the Treatment of Opioid Dependence and Abuse

    OpenAIRE

    Litwin, Alain H; Kenneth Hoffman; Robert Lubran; H. Westley Clark; Leonard Seeff; Diana Sylvestre; Kresina, Thomas F.

    2008-01-01

    Many new and existing cases of viral hepatitis infections are related to injection drug use. Transmission of these infections can result directly from the use of injection equipment that is contaminated with blood containing the hepatitis B or C virus or through sexual contact with an infected individual. In the latter case, drug use can indirectly contribute to hepatitis transmission through the dis-inhibited at-risk behavior, that is, unprotected sex with an infected partner. Individuals wh...

  15. 洋葱伯克霍尔德菌感染家兔抗感染疗效与体外药物敏感性的比较%Comparison of the anti-infective drug sensitivity in rabbit model of Burkholderia cepacia infection and the effect of antimicrobial sensitivity monitoring in vitro

    Institute of Scientific and Technical Information of China (English)

    吕火祥; 胡庆丰; 沈蓓琼; 杨广宇; 俞赛

    2011-01-01

    目的 使用无CLSI完整解释标准的药物,哌拉西林/他唑巴坦、替卡西林/棒酸、头孢吡肟治疗洋葱伯克霍尔德菌感染的家兔模型,观察比较何种体外药物敏感试验更能准确反应临床疗效.方法 57株临床分离的洋葱伯克霍尔德菌,感染57只家兔腹腔.将感染家兔分成3组(A、B、C组),每组19只;分别在48、72、96、120和144 h注射药物:A组每只家兔注射1 mL浓度为2 g/mL哌拉西林/他唑巴坦;B组每只家兔注射1 mL浓度为0.1 g/mL头孢吡肟;C组每只家兔注射1 mL浓度为0.6 g/mL替卡西林/棒酸.比较肉汤稀释法(MIC法)、K-B法及VITEK法检测的药物敏感性结果与体内药物治疗的疗效关系.结果 哌拉西林/他唑巴坦治疗组(A组),K-B法检测结果与家兔感染模型治疗过程相符率为72.2%,MIC法66.7%,VITEK法为66.7%.替卡西林/棒酸治疗组(B组),MIC法83.3%,VITEK法为77.8%,K-B法检测结果与家兔感染模型治疗过程相符率为50.0%.头孢吡肟治疗组(C组),MIC法88.9%,VITEK法为77.8%,K-B法检测结果与家兔感染模型治疗过程相符率为72.2%.结论 在3种药物敏感性检测法中,哌拉西林/他唑巴坦以K-B法检测结果与感染家兔的抗感染疗效最为接近;替卡西林/棒酸及头孢吡肟均以MIC法与感染家兔的抗感染疗效最为接近;针对洋葱伯克霍尔德菌的感染建议临床使用不同的方法检测不同的药物体外敏感性.%Objective To treat rabbit models of Burkholderia cepacia infection by using drugs without complete CLSI interpretive standard, including piperacillin/tazobactam, ticarcillin/clavulanic acid and cefepime, and compare which drug sensitivity test in vitro can more accurately reflect the clinical efficacy. Methods 57 clinical isolates of Burkholderia cepacia were used to infect 57 rabbits intraperitoneally. The infected rabbits were divided into 3 groups ( A, B and C), 19 in each group. Then, at48, 72, 96, 12 and 144 h, respectively, each

  16. Strategies for Intracellular Survival of Burkholderia pseudomallei.

    Science.gov (United States)

    Allwood, Elizabeth M; Devenish, Rodney J; Prescott, Mark; Adler, Ben; Boyce, John D

    2011-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a disease with high mortality that is prevalent in tropical regions of the world. A key component of the pathogenesis of melioidosis is the ability of B. pseudomallei to enter, survive, and replicate within mammalian host cells. For non-phagocytic cells, bacterial adhesins have been identified both on the bacterial surface and associated with Type 4 pili. Cell invasion involves components of one or more of the three Type 3 Secretion System clusters, which also mediate, at least in part, the escape of bacteria from the endosome into the cytoplasm, where bacteria move by actin-based motility. The mechanism of actin-based motility is not clearly understood, but appears to differ from characterized mechanisms in other bacterial species. A small proportion of intracellular bacteria is targeted by host cell autophagy, involving direct recruitment of LC3 to endosomes rather than through uptake by canonical autophagosomes. However, the majority of bacterial cells are able to circumvent autophagy and other intracellular defense mechanisms such as the induction of inducible nitric oxide synthase, and then replicate in the cytoplasm and spread to adjacent cells via membrane fusion, resulting in the formation of multi-nucleated giant cells. A potential role for host cell ubiquitin in the autophagic response to bacterial infection has recently been proposed. PMID:22007185

  17. PPO zoekt naar mogelijkheden aanpak Burkholderia

    OpenAIRE

    Dwarswaard, A.; Van Dam

    2014-01-01

    In de bloemen- en knollenteelt van gladiool komt de afgelopen decennia met enige regelmaat de bacterieziekte Burkholderia voor. Vorig jaar startte PPO met een onderzoek naar de mogelijkheden om deze ziekte aan te pakken. Een tussenstand.

  18. Distinct human antibody response to the biological warfare agent Burkholderia mallei.

    Science.gov (United States)

    Varga, John J; Vigil, Adam; DeShazer, David; Waag, David M; Felgner, Philip; Goldberg, Joanna B

    2012-10-01

    The genetic similarity between Burkholderia mallei (glanders) and Burkholderia pseudomallei (melioidosis) had led to the general assumption that pathogenesis of each bacterium would be similar. In 2000, the first human case of glanders in North America since 1945 was reported in a microbiology laboratory worker. Leveraging the availability of pre-exposure sera for this individual and employing the same well-characterized protein array platform that has been previously used to study a large cohort of melioidosis patients in southeast Asia, we describe the antibody response in a human with glanders. Analysis of 156 peptides present on the array revealed antibodies against 17 peptides with a > 2-fold increase in this infection. Unexpectedly, when the glanders data were compared with a previous data set from B. pseudomallei infections, there were only two highly increased antibodies shared between these two infections. These findings have implications in the diagnosis and treatment of B. mallei and B. pseudomallei infections.

  19. Systematic review and consensus guidelines for environmental sampling of Burkholderia pseudomallei.

    Directory of Open Access Journals (Sweden)

    Direk Limmathurotsakul

    Full Text Available BACKGROUND: Burkholderia pseudomallei, a Tier 1 Select Agent and the cause of melioidosis, is a Gram-negative bacillus present in the environment in many tropical countries. Defining the global pattern of B. pseudomallei distribution underpins efforts to prevent infection, and is dependent upon robust environmental sampling methodology. Our objective was to review the literature on the detection of environmental B. pseudomallei, update the risk map for melioidosis, and propose international consensus guidelines for soil sampling. METHODS/PRINCIPAL FINDINGS: An international working party (Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP was formed during the VIth World Melioidosis Congress in 2010. PubMed (January 1912 to December 2011 was searched using the following MeSH terms: pseudomallei or melioidosis. Bibliographies were hand-searched for secondary references. The reported geographical distribution of B. pseudomallei in the environment was mapped and categorized as definite, probable, or possible. The methodology used for detecting environmental B. pseudomallei was extracted and collated. We found that global coverage was patchy, with a lack of studies in many areas where melioidosis is suspected to occur. The sampling strategies and bacterial identification methods used were highly variable, and not all were robust. We developed consensus guidelines with the goals of reducing the probability of false-negative results, and the provision of affordable and 'low-tech' methodology that is applicable in both developed and developing countries. CONCLUSIONS/SIGNIFICANCE: The proposed consensus guidelines provide the basis for the development of an accurate and comprehensive global map of environmental B. pseudomallei.

  20. Quantitative proteomic analysis of Burkholderia pseudomallei Bsa type III secretion system effectors using hypersecreting mutants.

    Science.gov (United States)

    Vander Broek, Charles W; Chalmers, Kevin J; Stevens, Mark P; Stevens, Joanne M

    2015-04-01

    Burkholderia pseudomallei is an intracellular pathogen and the causative agent of melioidosis, a severe disease of humans and animals. One of the virulence factors critical for early stages of infection is the Burkholderia secretion apparatus (Bsa) Type 3 Secretion System (T3SS), a molecular syringe that injects bacterial proteins, called effectors, into eukaryotic cells where they subvert cellular functions to the benefit of the bacteria. Although the Bsa T3SS itself is known to be important for invasion, intracellular replication, and virulence, only a few genuine effector proteins have been identified and the complete repertoire of proteins secreted by the system has not yet been fully characterized. We constructed a mutant lacking bsaP, a homolog of the T3SS "gatekeeper" family of proteins that exert control over the timing and magnitude of effector protein secretion. Mutants lacking BsaP, or the T3SS translocon protein BipD, were observed to hypersecrete the known Bsa effector protein BopE, providing evidence of their role in post-translational control of the Bsa T3SS and representing key reagents for the identification of its secreted substrates. Isobaric Tags for Relative and Absolute Quantification (iTRAQ), a gel-free quantitative proteomics technique, was used to compare the secreted protein profiles of the Bsa T3SS hypersecreting mutants of B. pseudomallei with the isogenic parent strain and a bsaZ mutant incapable of effector protein secretion. Our study provides one of the most comprehensive core secretomes of B. pseudomallei described to date and identified 26 putative Bsa-dependent secreted proteins that may be considered candidate effectors. Two of these proteins, BprD and BapA, were validated as novel effector proteins secreted by the Bsa T3SS of B. pseudomallei.

  1. Revised structures for the predominant O-polysaccharides expressed by Burkholderia pseudomallei and Burkholderia mallei

    OpenAIRE

    Heiss, Christian; Burtnick, Mary N.; Roberts, Rosemary A.; Black, Ian; Azadi, Parastoo; Brett, Paul J.

    2013-01-01

    O-Polysaccharides (OPS) were isolated from purified Burkholderia pseudomallei and Burkholderia mallei lipopolysaccharides by mild-acid hydrolysis and gel-permeation chromatography. 1-D and 2-D 1H and 13C NMR spectroscopy experiments revealed that the OPS antigens were unbranched heteropolymers with the following structures:

  2. Volatile-Sulfur-Compound Profile Distinguishes Burkholderia pseudomallei from Burkholderia thailandensis

    OpenAIRE

    Inglis, Timothy J J; Hahne, Dorothee R.; Merritt, Adam J.; Clarke, Michael W.

    2015-01-01

    Solid-phase microextraction gas chromatography-mass spectrometry (SPME-GCMS) was used to show that dimethyl sulfide produced by Burkholderia pseudomallei is responsible for its unusual truffle-like smell and distinguishes the species from Burkholderia thailandensis. SPME-GCMS can be safely used to detect dimethyl sulfide produced by agar-grown B. pseudomallei.

  3. rpsU-based discrimination within the genus Burkholderia

    OpenAIRE

    Frickmann, H.; Neubauer, H.; Loderstaedt, U.; Derschum, H.; Hagen, R. M.

    2014-01-01

    Sequencing of the gene rpsU reliably delineates saprophytic Burkholderia (B.) thailandensis from highly pathogenic B. mallei and B. pseudomallei. We analyzed the suitability of this technique for the delineation of the B. pseudomallei complex from other Burkholderia species.

  4. Novel Selective Medium for Isolation of Burkholderia pseudomallei

    OpenAIRE

    Howard, K; Inglis, T. J. J.

    2003-01-01

    Isolation of Burkholderia pseudomallei currently relies on the use of Ashdown's selective agar (ASA). We designed a new selective agar (Burkholderia pseudomallei selective agar [BPSA]) to improve recovery of the more easily inhibited strains of B. pseudomallei. B. pseudomallei, Burkholderia cepacia, and Pseudomonas aeruginosa were used to determine the selectivity and sensitivity of BPSA. BPSA was more inhibitory to P. aeruginosa and B. cepacia and should make recognition of Burkholderia spec...

  5. RNA-dependent RNA polymerases from cowpea mosaic virus-infected cowpea leaves

    NARCIS (Netherlands)

    Dorssers, L.C.J.

    1983-01-01

    The aim of the research described in this thesis was the purification and identification of the RNA-dependent RNA polymerase engaged in replicating viral RNA in cowpea mosaic virus (CPMV)- infected cowpea leaves.Previously, an RNA-dependent RNA polymerase produced upon infection of Vigna unguiculata

  6. Study of class I integron in a Burkholderia cepacia complex strain isolated from blood colture

    Directory of Open Access Journals (Sweden)

    Linda Furlanis

    2011-06-01

    Full Text Available The Burkholderia cepacia complex (Bcc consists of several species that cause lung infections in patients with cystic fibrosis but are also capable to colonize immunocompromised patients. Once established, the infection is usually difficult to eradicate, as Bcc is intrinsically resistant to many antibiotics. Besides, the acquisition of additional resistance determinants by horizontal gene transfer makes very difficult the therapeutic approach to these infections. Among horizontally acquired DNAs, integrons have been frequently reported in many Gramnegative bacteria that affect human health, but they have not been found frequently in Burkholderia isolates until now. In the present work we report on a Bcc isolate, recovered from the blood of an immunocompromised patient, that carries a 2.3 kb class I integron already described in a Salmonella enterica isolate eight years ago, coding for aacA4, aadA1 and catB2 in its cassette array.

  7. 40 CFR 725.1075 - Burkholderia cepacia complex.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Burkholderia cepacia complex. 725.1075... Specific Microorganisms § 725.1075 Burkholderia cepacia complex. (a) Microorganism and significant new uses subject to reporting. (1) The microorganisms identified as the Burkholderia cepacia complex defined...

  8. Influenza infection suppresses NADPH oxidase-dependent phagocytic bacterial clearance and enhances susceptibility to secondary MRSA infection

    Science.gov (United States)

    Sun, Keer; Metzger, Dennis W.

    2014-01-01

    Methicillin-resistant S. aureus (MRSA) has emerged as a leading contributor to mortality during recent influenza pandemics. The mechanism for this influenza-induced susceptibility to secondary S. aureus infection is poorly understood. Here we show that innate antibacterial immunity was significantly suppressed during the recovery stage of influenza infection, despite the fact that MRSA super-infection had no significant effect on viral burdens. Compared to mice infected with bacteria alone, post-influenza MRSA infected mice exhibited impaired bacterial clearance, which was not due to defective phagocyte recruitment, but rather coincided with reduced intracellular reactive oxygen species (ROS) levels in alveolar macrophages and neutrophils. NADPH oxidase is responsible for ROS production during phagocytic bacterial killing, a process also known as oxidative burst. We found that gp91phox-containing NADPH oxidase activity in macrophages and neutrophils was essential for optimal bacterial clearance during respiratory MRSA infections. In contrast to WT animals, gp91phox−/− mice exhibited similar defects in MRSA clearance before and after influenza infection. Using gp91phox+/− mosaic mice, we further demonstrate that influenza infection inhibits a cell-intrinsic contribution of NADPH oxidase to phagocyte bactericidal activity. Together, our results establish that influenza infection suppresses NADPH oxidase-dependent bacterial clearance and leads to susceptibility to secondary MRSA infection. PMID:24563256

  9. Eradication and phenotypic tolerance of Burkholderia cenocepacia biofilms exposed to atmospheric pressure non-thermal plasma.

    Science.gov (United States)

    Alshraiedeh, Nida H; Higginbotham, Sarah; Flynn, Padrig B; Alkawareek, Mahmoud Y; Tunney, Michael M; Gorman, Sean P; Graham, William G; Gilmore, Brendan F

    2016-06-01

    Chronic lung infection with bacteria from the Burkholderia cepacia complex (BCC), and in particular B. cenocepacia, is associated with significant morbidity and mortality in patients with cystic fibrosis (CF). B. cenocepacia can spread from person to person and exhibits intrinsic broad-spectrum antibiotic resistance. Recently, atmospheric pressure non-thermal plasmas (APNTPs) have gained increasing attention as a novel approach to the prevention and treatment of a variety of hospital-acquired infections. In this study, we evaluated an in-house-designed kHz-driven plasma source for the treatment of biofilms of a number of clinical CF B. cenocepacia isolates. The results demonstrated that APNTP is an effective and efficient tool for the eradication of B. cenocepacia biofilms but that efficacy is highly variable across different isolates. Determination of phenotypic differences between isolates in an attempt to understand variability in plasma tolerance revealed that isolates which are highly tolerant to APNTP typically produce biofilms of greater biomass than their more sensitive counterparts. This indicates a potential role for biofilm matrix components in biofilm tolerance to APNTP exposure. Furthermore, significant isolate-dependent differences in catalase activity in planktonic bacteria positively correlated with phenotypic resistance to APNTP by isolates grown in biofilms. PMID:27179816

  10. Brucella infection inhibits macrophages apoptosis via Nedd4-dependent degradation of calpain2.

    Science.gov (United States)

    Cui, Guimei; Wei, Pan; Zhao, Yuxi; Guan, Zhenhong; Yang, Li; Sun, Wanchun; Wang, Shuangxi; Peng, Qisheng

    2014-11-01

    The calcium-dependent protease calpain2 is involved in macrophages apoptosis. Brucella infection-induced up-regulation of intracellular calcium level is an essential factor for the intracellular survival of Brucella within macrophages. Here, we hypothesize that calcium-dependent E3 ubiquitin ligase Nedd4 ubiquitinates calpain2 and inhibits Brucella infection-induced macrophage apoptosis via degradation of calpain2.Our results reveal that Brucella infection induces increases in Nedd4 activity in an intracellular calcium dependent manner. Furthermore, Brucella infection-induced degradation of calpain2 is mediated by Nedd4 ubiquitination of calpain2. Brucella infection-induced calpain2 degradation inhibited macrophages apoptosis. Treatment of Brucella infected macrophages with calcium chelator BAPTA or Nedd4 knock-down decreased Nedd4 activity, prevented calpain2 degradation, and resulted in macrophages apoptosis.

  11. Polyphasic characterisation of Burkholderia cepacia complex species isolated from children with cystic fibrosis

    Science.gov (United States)

    Vicenzi, Fernando José; Pillonetto, Marcelo; de Souza, Helena Aguilar Peres Homem de Mello; Palmeiro, Jussara Kasuko; Riedi, Carlos Antônio; Rosario-Filho, Nelson Augusto; Dalla-Costa, Libera Maria

    2016-01-01

    Cystic fibrosis (CF) patients with Burkholderia cepacia complex (Bcc) pulmonary infections have high morbidity and mortality. The aim of this study was to compare different methods for identification of Bcc species isolated from paediatric CF patients. Oropharyngeal swabs from children with CF were used to obtain isolates of Bcc samples to evaluate six different tests for strain identification. Conventional (CPT) and automatised (APT) phenotypic tests, polymerase chain reaction (PCR)-recA, restriction fragment length polymorphism-recA, recAsequencing, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) were applied. Bacterial isolates were also tested for antimicrobial susceptibility. PCR-recA analysis showed that 36 out of the 54 isolates were Bcc. Kappa index data indicated almost perfect agreement between CPT and APT, CPT and PCR-recA, and APT and PCR-recA to identify Bcc, and MALDI-TOF and recAsequencing to identify Bcc species. The recAsequencing data and the MALDI-TOF data agreed in 97.2% of the isolates. Based on recA sequencing, the most common species identified were Burkholderia cenocepacia IIIA (33.4%),Burkholderia vietnamiensis (30.6%), B. cenocepaciaIIIB (27.8%), Burkholderia multivorans (5.5%), and B. cepacia (2.7%). MALDI-TOF proved to be a useful tool for identification of Bcc species obtained from CF patients, although it was not able to identify B. cenocepacia subtypes. PMID:26814642

  12. The symbiotic role of O-antigen of Burkholderia symbiont in association with host Riptortus pedestris.

    Science.gov (United States)

    Kim, Jiyeun Kate; Park, Ha Young; Lee, Bok Luel

    2016-07-01

    Riptortus pedestris harboring Burkholderia symbiont is a useful symbiosis model to study the molecular interactions between insects and bacteria. We recently reported that the lipopolysaccharide O-antigen is absent in the Burkholderia symbionts isolated from Riptortus guts. Here, we investigated the symbiotic role of O-antigen comprehensively in the Riptortus-Burkholderia model. Firstly, Burkholderia mutant strains deficient of O-antigen biosynthesis genes were generated and confirmed for their different patterns of the lipopolysaccharide by electrophoretic analysis. The O-antigen-deficient mutant strains initially exhibited a reduction of infectivity, having significantly lower level of symbiont population at the second-instar stage. However, both the wild-type and O-antigen mutant symbionts exhibited a similar level of symbiont population from the third-instar stage, indicating that the O-antigen deficiency did not affect the bacterial persistence in the host midgut. Taken together, we showed that the lipopolysaccharide O-antigen of gut symbiont plays an exclusive role in the initial symbiotic association. PMID:26875632

  13. Burkholderia mallei and Burkholderia pseudomallei stimulate differential inflammatory responses from human alveolar type II cells (ATII and macrophages.

    Directory of Open Access Journals (Sweden)

    Richard eLu

    2012-12-01

    Full Text Available Alveolar type II pneumocytes (ATII and alveolar macrophages (AM play a crucial role in the lung’s innate immune response. Burkholderia pseudomallei (BP and Burkholderia mallei (BM are facultative Gram-negative bacilli that cause melioidosis and glanders, respectively. The inhalation of these pathogens can cause lethal disease and death in humans. We sought to compare the pathogenesis of and host responses to BP and BM through contact with human primary ATII cells and monocytes-derived macrophages (MDM. We hypothesized that because BP and BM induce different disease outcomes, each pathogen would induce distinct, unique host immune responses from resident pulmonary cells. Our findings showed that BP adhered readily to ATII cells compared to BM. BP, but not BM, was rapidly internalized by macrophages where it replicated to high numbers. Further, BP induced significantly higher levels of pro-inflammatory cytokine secretion from ATII cells (IL-6, IL-8 and macrophages (IL-6, TNFα at 6h post-infection compared to BM (p<0.05. Interestingly, BM induced the anti-inflammatory cytokine, IL-10, in ATII cells and macrophages at 6h post-infection, with delayed induction of inflammatory cytokines at 24h post-infection. Because BP is flagellated and produces LPS, we confirmed that it stimulated both Toll-like receptor (TLR 4 and TLR5 via NF-κb activation while the non-flagellated BM stimulated only TLR4. These data show the differences in BP and BM pathogenicity in the lung when infecting human ATII cells and macrophages and demonstrate the ability of these pathogens to elicit distinct immune responses from resident lung cells which may open new targets for therapeutic intervention to fight against these pathogens.

  14. Effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl

    International Nuclear Information System (INIS)

    This study evaluated the effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D10 values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased (P10 values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

  15. Evaluation of a latex agglutination assay for the identification of Burkholderia pseudomallei and Burkholderia mallei.

    Science.gov (United States)

    Duval, Brea D; Elrod, Mindy G; Gee, Jay E; Chantratita, Narisara; Tandhavanant, Sarunporn; Limmathurotsakul, Direk; Hoffmaster, Alex R

    2014-06-01

    Cases of melioidosis and glanders are rare in the United States, but the etiologic agents of each disease (Burkholderia pseudomallei and Burkholderia mallei, respectively) are classified as Tier 1 select agents because of concerns about their potential use as bioterrorism agents. A rapid, highly sensitive, and portable assay for clinical laboratories and field use is required. Our laboratory has further evaluated a latex agglutination assay for its ability to identify B. pseudomallei and B. mallei isolates. This assay uses a monoclonal antibody that specifically recognizes the capsular polysaccharide produced by B. pseudomallei and B. mallei, but is absent in closely related Burkholderia species. A total of 110 B. pseudomallei and B. mallei were tested, and 36 closely related Burkholderia species. The latex agglutination assay was positive for 109 of 110 (99.1% sensitivity) B. pseudomallei and B. mallei isolates tested.

  16. Autotransporters and Their Role in the Virulence of Burkholderia pseudomallei and Burkholderia mallei

    OpenAIRE

    Adler, Natalie R. Lazar; Stevens, Joanne M; Stevens, Mark P.; Galyov, Edouard E.

    2011-01-01

    Burkholderia pseudomallei and Burkholderia mallei are closely related Gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. Autotransporters (ATs) comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases, and actin-nucleating factors. The B. pseudomallei K96243 genome contains 11 predicted ATs, eight of which share homologs in the B. mallei ATCC 23344 genome. Th...

  17. In Vitro Activity of Tigecycline against Burkholderia pseudomallei and Burkholderia thailandensis

    OpenAIRE

    Thamlikitkul, Visanu; Trakulsomboon, Suwanna

    2006-01-01

    Investigation of the in vitro activity of tigecycline against Burkholderia pseudomallei and Burkholderia thailandensis revealed that the inhibition zone diameters of tigecycline against all isolates were ≥20 mm and that the MIC50 values were 0.5 and 1 μg/ml and the MIC90 values were 2 and 1.5 μg/ml for B. pseudomallei and B. thailandensis, respectively.

  18. Autotransporters and their role in the virulence of Burkholderia pseudomallei and Burkholderia mallei

    OpenAIRE

    Lazar Adler, N.; Stevens, J; STEVENS, M.; Galyov, E

    2011-01-01

    Burkholderia pseudomallei and Burkholderia mallei are closely related Gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. Autotransporters (ATs) comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases and actin-nucleating factors. The B. pseudomallei K96243 genome contains eleven predicted ATs, eight of which share homologues in the B. mallei ATCC 23344 genom...

  19. Profiling of Burkholderia cepacia secretome at mid-logarithmic and early-stationary phases of growth.

    Directory of Open Access Journals (Sweden)

    Vanitha Mariappan

    Full Text Available BACKGROUND: Burkholderia cepacia is a Gram-negative pathogen that causes serious respiratory infections in immunocompromised patients and individuals with cystic fibrosis. This bacterium is known to release extracellular proteins that may be involved in virulence. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, B. cepacia grown to mid-logarithmic and early-stationary phases were investigated on their ability to invade and survive intracellularly in A549 lung epithelial cells in order to discern the fate of these bacteria in the pathogenesis of B. cepacia lung infections in in vitro condition. The early-stationary phase B. cepacia was demonstrated to be more invasive than mid-logarithmic phase. In addition, culture supernatants of B. cepacia obtained from these phases of growth were also demonstrated to cause different cytotoxic potency on the A549 human lung epithelial cells. Profiling of the supernatants using the gel-based proteomics approach identified 43 proteins that were commonly released in both the growth phases and 40 proteins newly-released at the early-stationary phase. The latter proteins may account for the higher cytotoxic activity of the early-stationary culture supernatant compared to that obtained at the mid-logarithmic phase. Among the newly-released proteins in the early-stationary phase supernatant were flagellar hook-associated domain protein (FliD, flagellar hook-associated protein (FlgK, TonB-dependent siderophore (Fiu, Elongation factor G (FusA, phosphoglycerate kinase (Pgk and sulfatase (AslA which are known for their virulence. CONCLUSION/SIGNIFICANCE: Differences in the ability of B. cepacia to invade and survive intracellularly inside the epithelial cells at different phases of growth may improve our understanding of the varied disease progressions associated with B. cepacia infections. In addition, the identified culture supernatant proteins may be used as targets for the development of new strategies to

  20. An objective approach for Burkholderia pseudomallei strain selection as challenge material for medical countermeasures efficacy testing

    OpenAIRE

    Kristopher E Van Zandt; Apichai eTuanyok; Paul eKeim; Warren, Richard L.; H. Carl eGelhaus

    2012-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs), the high mortality rate...

  1. An Objective Approach for Burkholderia pseudomallei Strain Selection as Challenge Material for Medical Countermeasures Efficacy Testing

    OpenAIRE

    Kristopher E Van Zandt; Tuanyok, Apichai; Paul S Keim; Warren, Richard L.; Gelhaus, H. Carl

    2012-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs), the high mortality rate...

  2. Identification of a LolC Homologue in Burkholderia pseudomallei, a Novel Protective Antigen for Melioidosis▿

    OpenAIRE

    Harland, David N; Chu, Karen; Haque, Ashraful; Nelson, Michelle; Walker, Nicola J.; Sarkar-Tyson, Mitali; Atkins, Timothy P.; Moore, Benjamin; Brown, Katherine A.; Bancroft, Gregory; Titball, Richard W.; Atkins, Helen S.

    2007-01-01

    Melioidosis is an emerging disease of humans in Southeast Asia and tropical Australia. The bacterium causing this disease, Burkholderia pseudomallei, is also considered a bioterrorism agent, and as yet there is no licensed vaccine for preventing B. pseudomallei infection. In this study, we evaluated selected proteins (LolC, PotF, and OppA) of the ATP-binding cassette systems of B. pseudomallei as candidate vaccine antigens. Nonmembrane regions of the B. pseudomallei proteins were expressed an...

  3. An Effect of Biofield Treatment on Multidrug-resistant Burkholderia cepacia: A Multihost Pathogen

    OpenAIRE

    Trivedi, Mahendra Kumar

    2015-01-01

    Burkholderia cepacia (B. cepacia) is an opportunistic, Gram negative pathogen which causes infection mainly in immunocompromised population and associated with high rate of morbidity and mortality in cystic fibrosis patients. Aim of the present study was to analyze the impact of biofield treatment on multidrug resistant B. cepacia. Clinical sample of B. cepacia was divided into two groups i.e. control and biofield treated. The analysis was done after 10 days of treatment and compared with con...

  4. Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

    Directory of Open Access Journals (Sweden)

    Dina A Moustafa

    Full Text Available Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

  5. Recombinant Salmonella Expressing Burkholderia mallei LPS O Antigen Provides Protection in a Murine Model of Melioidosis and Glanders.

    Science.gov (United States)

    Moustafa, Dina A; Scarff, Jennifer M; Garcia, Preston P; Cassidy, Sara K B; DiGiandomenico, Antonio; Waag, David M; Inzana, Thomas J; Goldberg, Joanna B

    2015-01-01

    Burkholderia pseudomallei and Burkholderia mallei are the etiologic agents of melioidosis and glanders, respectively. These bacteria are highly infectious via the respiratory route and can cause severe and often fatal diseases in humans and animals. Both species are considered potential agents of biological warfare; they are classified as category B priority pathogens. Currently there are no human or veterinary vaccines available against these pathogens. Consequently efforts are directed towards the development of an efficacious and safe vaccine. Lipopolysaccharide (LPS) is an immunodominant antigen and potent stimulator of host immune responses. B. mallei express LPS that is structurally similar to that expressed by B. pseudomallei, suggesting the possibility of constructing a single protective vaccine against melioidosis and glanders. Previous studies of others have shown that antibodies against B. mallei or B. pseudomallei LPS partially protect mice against subsequent lethal virulent Burkholderia challenge. In this study, we evaluated the protective efficacy of recombinant Salmonella enterica serovar Typhimurium SL3261 expressing B. mallei O antigen against lethal intranasal infection with Burkholderia thailandensis, a surrogate for biothreat Burkholderia spp. in a murine model that mimics melioidosis and glanders. All vaccine-immunized mice developed a specific antibody response to B. mallei and B. pseudomallei O antigen and to B. thailandensis and were significantly protected against challenge with a lethal dose of B. thailandensis. These results suggest that live-attenuated SL3261 expressing B. mallei O antigen is a promising platform for developing a safe and effective vaccine.

  6. GENOME ANALYSIS OF BURKHOLDERIA CEPACIA AC1100

    Science.gov (United States)

    Burkholderia cepacia is an important organism in bioremediation of environmental pollutants and it is also of increasing interest as a human pathogen. The genomic organization of B. cepacia is being studied in order to better understand its unusual adaptive capacity and genome pl...

  7. Burkholderia pseudomallei Antibodies in Children, Cambodia

    OpenAIRE

    Wuthiekanun, Vanaporn; Pheaktra, Ngoun; Putchhat, Hor; Sin, Lina; Sen, Bun; Kumar, Varun; Langla, Sayan; Peacock, Sharon J.; Nicholas P. Day

    2008-01-01

    Antibodies to Burkholderia pseudomallei were detected in 16% of children in Siem Reap, Cambodia. This organism was isolated from 30% of rice paddies in the surrounding vicinity. Despite the lack of reported indigenous cases, melioidosis is likely to occur in Cambodia.

  8. Eradication of Burkholderia cepacia Using Inhaled Aztreonam Lysine in Two Patients with Bronchiectasis

    Directory of Open Access Journals (Sweden)

    A. Iglesias

    2014-01-01

    Full Text Available There are not many articles about the chronic bronchial infection/colonization in patients with underlying lung disease other than cystic fibrosis (CF, especially with non-CF bronchiectasis (NCFBQ. The prevalence of B. cepacia complex is not well known in NCFBQ. The vast majority of published clinical data on Burkholderia infection in individuals with CF is comprised of uncontrolled, anecdotal, and/or single center experiences, and no consensus has emerged regarding treatment. We present two cases diagnosed with bronchiectasis (BQ of different etiology, with early pulmonary infection by B. cepacia complex, which was eradicated with inhaled aztreonam lysine.

  9. Isolation and Identification of Burkholderia glumae from Symptomless Rice Seeds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A survey on isolation and detection of the casual organism of bacterial grain rot of rice was conducted during 1997-2006.In 2006,six pathogenic bacterial strains were isolated from two symptomiess seed samples of rice (Oryza sativa L.) originally produced in Hainan Province and then planted in Zhejiang Province,China.They were identified as Burkholderia glumae which is the causal organism of bacterial grain rot of rice by physiological characteristics,colony morphology,pathogenicity test,Biolog,fatty acid methyl ester (FAME) analysis and RAPD-PCR compared with the four standard reference strains.It is confirmed that there is the infection of B.glumae in so-called 'health looking seeds'.

  10. Infected Cell Killing by HIV-1 Protease Promotes NF-κB Dependent HIV-1 Replication

    OpenAIRE

    Bren, Gary D.; Joe Whitman; Nathan Cummins; Brett Shepard; Rizza, Stacey A; Trushin, Sergey A.; Badley, Andrew D

    2008-01-01

    Acute HIV-1 infection of CD4 T cells often results in apoptotic death of infected cells, yet it is unclear what evolutionary advantage this offers to HIV-1. Given the independent observations that acute T cell HIV-1 infection results in (1) NF-kappaB activation, (2) caspase 8 dependent apoptosis, and that (3) caspase 8 directly activates NF-kappaB, we questioned whether these three events might be interrelated. We first show that HIV-1 infected T cell apoptosis, NF-kappaB activation, and casp...

  11. Use of a Real-Time PCR TaqMan Assay for Rapid Identification and Differentiation of Burkholderia pseudomallei and Burkholderia mallei

    OpenAIRE

    U'Ren, Jana M.; Matthew N. Van Ert; James M Schupp; Easterday, W. Ryan; Simonson, Tatum S.; Okinaka, Richard T; Pearson, Talima; Keim, Paul

    2005-01-01

    A TaqMan allelic-discrimination assay designed around a synonymous single-nucleotide polymorphism was used to genotype Burkholderia pseudomallei and Burkholderia mallei isolates. The assay rapidly identifies and discriminates between these two highly pathogenic bacteria and does not cross-react with genetic near neighbors, such as Burkholderia thailandensis and Burkholderia cepacia.

  12. Combining functional and structural genomics to sample the essential Burkholderia structome.

    Directory of Open Access Journals (Sweden)

    Loren Baugh

    Full Text Available The genus Burkholderia includes pathogenic gram-negative bacteria that cause melioidosis, glanders, and pulmonary infections of patients with cancer and cystic fibrosis. Drug resistance has made development of new antimicrobials critical. Many approaches to discovering new antimicrobials, such as structure-based drug design and whole cell phenotypic screens followed by lead refinement, require high-resolution structures of proteins essential to the parasite.We experimentally identified 406 putative essential genes in B. thailandensis, a low-virulence species phylogenetically similar to B. pseudomallei, the causative agent of melioidosis, using saturation-level transposon mutagenesis and next-generation sequencing (Tn-seq. We selected 315 protein products of these genes based on structure-determination criteria, such as excluding very large and/or integral membrane proteins, and entered them into the Seattle Structural Genomics Center for Infection Disease (SSGCID structure determination pipeline. To maximize structural coverage of these targets, we applied an "ortholog rescue" strategy for those producing insoluble or difficult to crystallize proteins, resulting in the addition of 387 orthologs (or paralogs from seven other Burkholderia species into the SSGCID pipeline. This structural genomics approach yielded structures from 31 putative essential targets from B. thailandensis, and 25 orthologs from other Burkholderia species, yielding an overall structural coverage for 49 of the 406 essential gene families, with a total of 88 depositions into the Protein Data Bank. Of these, 25 proteins have properties of a potential antimicrobial drug target i.e., no close human homolog, part of an essential metabolic pathway, and a deep binding pocket. We describe the structures of several potential drug targets in detail.This collection of structures, solubility and experimental essentiality data provides a resource for development of drugs against

  13. Inflammation in Achromobacter xylosoxidans infected cystic fibrosis patients

    DEFF Research Database (Denmark)

    Hansen, C. R.; Pressler, T.; Nielsen, K. G.;

    2010-01-01

    BACKGROUND: Achromobacter xylosoxidans infection may cause conspicuous chronic pulmonary inflammation in cystic fibrosis (CF) patients similar to Pseudomonas aeruginosa and the Burkholderia cepacia complex (Bcc). Evolution in lung function was compared in chronically infected patients. Cytokine...

  14. The Multiplicity of Cellular Infection Changes Depending on the Route of Cell Infection in a Plant Virus

    Science.gov (United States)

    Gutiérrez, Serafín; Pirolles, Elodie; Yvon, Michel; Baecker, Volker; Michalakis, Yannis

    2015-01-01

    ABSTRACT The multiplicity of cellular infection (MOI) is the number of virus genomes of a given virus species that infect individual cells. This parameter chiefly impacts the severity of within-host population bottlenecks as well as the intensity of genetic exchange, competition, and complementation among viral genotypes. Only a few formal estimations of the MOI currently are available, and most theoretical reports have considered this parameter as constant within the infected host. Nevertheless, the colonization of a multicellular host is a complex process during which the MOI may dramatically change in different organs and at different stages of the infection. We have used both qualitative and quantitative approaches to analyze the MOI during the colonization of turnip plants by Turnip mosaic virus. Remarkably, different MOIs were observed at two phases of the systemic infection of a leaf. The MOI was very low in primary infections from virus circulating within the vasculature, generally leading to primary foci founded by a single genome. Each lineage then moved from cell to cell at a very high MOI. Despite this elevated MOI during cell-to-cell progression, coinfection of cells by lineages originating in different primary foci is severely limited by the rapid onset of a mechanism inhibiting secondary infection. Thus, our results unveil an intriguing colonization pattern where individual viral genomes initiate distinct lineages within a leaf. Kin genomes then massively coinfect cells, but coinfection by two distinct lineages is strictly limited. IMPORTANCE The MOI is the size of the viral population colonizing cells and defines major phenomena in virus evolution, like the intensity of genetic exchange and the size of within-host population bottlenecks. However, few studies have quantified the MOI, and most consider this parameter as constant during infection. Our results reveal that the MOI can depend largely on the route of cell infection in a systemically

  15. Sero-characterization of lipopolysaccharide from Burkholderia thailandensis

    OpenAIRE

    Qazi, Omar; Prior, Joann L.; Judy, Barbara M; Whitlock, Gregory C.; Kitto, G. Barrie; Torres, Alfredo G.; Estes, D. Mark; Brown, Katherine A

    2008-01-01

    We report the successful purification of lipopolysaccharide (LPS) from Burkholderia thailandesis, a Gram-negative bacterium, closely related to the highly pathogenic organisms Burkholderia pseudomallei and Burkholderia mallei. B. thailandensis LPS is shown to cross-react with rabbit and mouse sera obtained from inoculation with B. pseudomallei or B. mallei, respectively. These data suggest that B. thailandensis LPS shares similar structural features with LPS molecules from highly pathogenic B...

  16. Low cost antiviral activity of Plodia interpunctella haemolymph in vivo demonstrated by dose dependent infection.

    Science.gov (United States)

    Saejeng, A; Siva-Jothy, M T; Boots, M

    2011-02-01

    Given the ubiquity of infectious disease it is important to understand the way in which hosts defend themselves and any costs that they may pay for this defence. Despite this, we know relatively little about insect immune responses to viruses when compared to their well-characterized responses to other pathogens. In particular it is unclear whether there is significant haemocoelic response to viral infection. Here we directly examine this question by examining whether there is a dose-dependency in infection risk when a DNA virus is injected directly into the haemocoel. Infection from direct injection into the haemocoel showed a clear dose dependency that is indicative of an active intrahaemocoelic immune response to DNA viruses in insects. In contrast to the natural oral infection route, we found no measurable sublethal effects in the survivors from direct injection. This suggests that the immune responses in the haemocoel are less costly than those that occur earlier.

  17. The New World arenavirus Tacaribe virus induces caspase-dependent apoptosis in infected cells.

    Science.gov (United States)

    Wolff, Svenja; Groseth, Allison; Meyer, Bjoern; Jackson, David; Strecker, Thomas; Kaufmann, Andreas; Becker, Stephan

    2016-04-01

    The Arenaviridae is a diverse and growing family of viruses that already includes more than 25 distinct species. While some of these viruses have a significant impact on public health, others appear to be non-pathogenic. At present little is known about the host cell responses to infection with different arenaviruses, particularly those found in the New World; however, apoptosis is known to play an important role in controlling infection of many viruses. Here we show that infection with Tacaribe virus (TCRV), which is widely considered the prototype for non-pathogenic arenaviruses, leads to stronger induction of apoptosis than does infection with its human-pathogenic relative Junín virus. TCRV-induced apoptosis occurred in several cell types during late stages of infection and was shown to be caspase-dependent, involving the activation of caspases 3, 7, 8 and 9. Further, UV-inactivated TCRV did not induce apoptosis, indicating that the activation of this process is dependent on active viral replication/transcription. Interestingly, when apoptosis was inhibited, growth of TCRV was not enhanced, indicating that apoptosis does not have a direct negative effect on TCRV infection in vitro. Taken together, our data identify and characterize an important virus-host cell interaction of the prototypic, non-pathogenic arenavirus TCRV, which provides important insight into the growing field of arenavirus research aimed at better understanding the diversity in responses to different arenavirus infections and their functional consequences.

  18. Expression of bovine vitamin K-dependent carboxylase activity in baculovirus-infected insect cells.

    Science.gov (United States)

    Roth, D A; Rehemtulla, A; Kaufman, R J; Walsh, C T; Furie, B; Furie, B C

    1993-09-15

    A vitamin K-dependent carboxylase has recently been purified from bovine liver microsomes and candidate cDNA clones have been isolated. Definitive identification of the carboxylase remains circumstantial since expression of candidate carboxylase cDNAs in mammalian cells is confounded by the presence of endogenous carboxylase activity. To overcome this problem, a recombinant strain of baculovirus (Autographa california nuclear polyhedrosis virus, AcMNPV) encoding a putative carboxylase (vbCbx/AcMNPV) was used to infect Sf9 insect cells, which we demonstrate have no endogenous carboxylase activity. Infection with vbCbx/AcMNPV conferred vitamin K-dependent carboxylase activity to Sf9 insect cells. Carboxylase activity was demonstrated to peak 2-3 days after infection with vbCbx/AcMNPV. Metabolic radiolabeling with L-[35S]methionine revealed that the 90-kDa recombinant protein is the major protein synthesized at the time of peak activity after infection. An anti-peptide antibody directed against residues 86-99 reacted with bovine liver carboxylase on Western blot analysis and immunoprecipitated recombinant carboxylase from infected Sf9 microsomal protein preparations. Since Sf9 insect cells lack endogenous vitamin K-dependent carboxylase activity, expression of carboxylase activity in Sf9 insect cells with recombinant baculovirus demonstrates that the protein encoded by this cDNA is a vitamin K-dependent gamma-glutamyl carboxylase. PMID:8378308

  19. Burkholderia pseudomallei induces IL-23 production in primary human monocytes.

    Science.gov (United States)

    Kulsantiwong, Panthong; Pudla, Matsayapan; Boondit, Jitrada; Wikraiphat, Chanthiwa; Dunachie, Susanna J; Chantratita, Narisara; Utaisincharoen, Pongsak

    2016-06-01

    Burkholderia pseudomallei, a gram-negative intracellular bacterium, is a causative agent of melioidosis. The bacterium has been shown to induce the innate immune response, particularly pro-inflammatory cytokine production in several of both mouse and human cell types. In the present study, we investigate host immune response in B. pseudomallei-infected primary human monocytes. We discover that wild-type B. pseudomallei is able to survive and multiply inside the primary human monocytes. In contrast, B. pseudomallei LPS mutant, a less virulent strain, is susceptible to host killing during bacterial infection. Moreover, microarray result showed that wild-type B. pseudomallei but not B. pseudomallei LPS mutant is able to activate gene expression of IL-23 as demonstrated by the up-regulation of p19 and p40 subunit expression. Consistent with gene expression analysis, the secretion of IL-23 analyzed by ELISA also showed that wild-type B. pseudomallei induces a significantly higher level of IL-23 secretion than that of B. pseudomallei LPS mutant. These results implied that IL-23 may be an important cytokine for the innate immune response during B. pseudomallei infection. The regulation of IL-23 production may drive the different host innate immune responses between patients and may relate to the severity of melioidosis. PMID:26563410

  20. [Pharyngitis due to Burkholderia cepacia. Person-to-person transmission].

    Science.gov (United States)

    Fajardo Olivares, M; Cordero Carrasco, J L; Beteta López, A; Escobar Izquierdo, A B; Sacristán Enciso, B

    2004-06-01

    Burkholderia cepacia is a Gram-negative bacillus that is widely distributed in nature; it is isolated from the ground, water, plants and vegetables. Generally, it produces nosocomial infection due to contamination of disinfectants, medical equipment, prosthetic material and drugs, such as anesthetics or liquids used in urological irrigation. The most probable mechanism of transmission is through hospital material or through fomites among people after contact for several weeks or months. Recently, it has been considered as an important pathogen in immunocompromised patients, or in those with significant underlying diseases, such as chronic granulomastosis or cystic fibrosis. We present a case of pharyngitis due to B. cepacia and its transmission within a few days in two immunocompetent twin siblings without previous underlying diseases. The infection disappeared after specific treatment for this microorganism was started. We believe that samples should be taken from the pharynx and nasal pits in patients with acute upper respiratory tract processes that do not respond to empiric antibiotic treatment, before classifying them as viral infection without etiologic diagnosis.

  1. Molecular Characterization of Putative Virulence Determinants in Burkholderia pseudomallei

    Directory of Open Access Journals (Sweden)

    Suat Moi Puah

    2014-01-01

    Full Text Available The Gram-negative saprophyte Burkholderia pseudomallei is the causative agent of melioidosis, an infectious disease which is endemic in Southeast Asia and northern Australia. This bacterium possesses many virulence factors which are thought to contribute to its survival and pathogenicity. Using a virulent clinical isolate of B. pseudomallei and an attenuated strain of the same B. pseudomallei isolate, 6 genes BPSL2033, BP1026B_I2784, BP1026B_I2780, BURPS1106A_A0094, BURPS1106A_1131, and BURPS1710A_1419 were identified earlier by PCR-based subtractive hybridization. These genes were extensively characterized at the molecular level, together with an additional gene BPSL3147 that had been identified by other investigators. Through a reverse genetic approach, single-gene knockout mutants were successfully constructed by using site-specific insertion mutagenesis and were confirmed by PCR. BPSL2033::Km and BURPS1710A_1419::Km mutants showed reduced rates of survival inside macrophage RAW 264.7 cells and also low levels of virulence in the nematode infection model. BPSL2033::Km demonstrated weak statistical significance (P=0.049 at 8 hours after infection in macrophage infection study but this was not seen in BURPS1710A_1419::Km. Nevertheless, complemented strains of both genes were able to partially restore the gene defects in both in vitro and in vivo studies, thus suggesting that they individually play a minor role in the virulence of B. pseudomallei.

  2. Burkholderia mallei and Burkholderia pseudomallei: the causative micro-organisms of glanders and melioidosis.

    Science.gov (United States)

    Gilad, Jacob

    2007-11-01

    Burkholderia mallei and Burkholderia pseudomallei are the causative micro-organisms of Glanders and Melioidosis, respectively. Although now rare in Western countries, both micro-organisms have recently gained much interest because of their unique potential as bioterrorism agents. This paper reviews the epidemiology, pathogenesis, diagnosis and treatment of Melioidosis and Glanders. Recent patents relating to these micro-organisms, especially potential vaccines, are presented. Continued research and development is urgently needed, especially in regard to rapid and accurate diagnosis of melioidosis and glanders, efficacious therapy and primary and secondary prevention.

  3. CD4+ T cell immunity to the Burkholderia pseudomallei ABC transporter LolC in melioidosis

    OpenAIRE

    Chu, Karen K.; Tippayawat, Patcharaporn; Walker, Nicola J.; Harding, Sarah V.; Atkins, Helen S.; Maillere, Bernard; Bancroft, Gregory J; Lertmemongkolchai, Ganjana; Altmann, Daniel M

    2010-01-01

    Burkholderia pseudomallei (Bp) causes melioidosis, a disease with a wide range of possible outcomes, from seroconversion and dormancy to sepsis and death. This spectrum of host-pathogen interactions poses challenging questions about heterogeneity in immunity to Bp. Models show protection to be dependent on CD4+ cells and IFNγ, but little is known about specific target antigens. Having previously implicated the ABC transporter, LolC, in protective immunity, we here use epitope prediction, HLA ...

  4. Antibody-dependent enhancement of dengue virus infection is inhibited by SA-17, a doxorubicin derivative.

    Science.gov (United States)

    Ayala-Nuñez, Nilda V; Jarupathirun, Patsaporn; Kaptein, Suzanne J F; Neyts, Johan; Smit, Jolanda M

    2013-10-01

    Antibody-dependent enhancement (ADE) is thought to play a critical role in the exacerbation of dengue virus (DENV)-induced disease during a heterologous re-infection. Despite ADE's clinical impact, only a few antiviral compounds have been assessed for their anti-ADE activity. We reported earlier that SA-17, a doxorubicin derivative, efficiently inhibits the in vitro infection of DENV and yellow fever virus. Here we explored SA-17's mechanism of inhibition and investigated if the compound is active against ADE of DENV infection. Since enhanced infectivity stimulated by antibodies has been observed with standard and immature DENV, both types of virions were included in the study. We observed that SA-17 (i) inhibits DENV infection by preventing binding/entry to the cell and (ii) interferes with antibody-mediated infection of both standard and immature DENV2. SA-17 markedly reduced the infectivity of DENV2 in ADE conditions, with IC50s ranging from 0.26 to 2.89μM. The compound exerted its activity when added before, during, and after antibody-opsonization of standard and immature virus. Thus, molecules with the characteristics of SA-17 may be attractive antiviral agents since they can be used both to block DENV2 entry during primary and secondary infection and to inhibit ADE of standard and immature virus. PMID:23994499

  5. Actin-binding proteins from Burkholderia mallei and Burkholderia thailandensis can functionally compensate for the actin-based motility defect of a Burkholderia pseudomallei bimA mutant

    OpenAIRE

    Stevens, J. M.; Ulrich, R L; Taylor, L A; Wood, M W; DeShazer, D; M.P. Stevens; Galyov, E. E.

    2005-01-01

    Recently we identified a bacterial factor (BimA) required for actin-based motility of Burkholderia pseudomallei. Here we report that Burkholderia mallei and Burkholderia thailandensis are capable of actin-based motility in J774.2 cells and that BimA homologs of these bacteria can restore the actin-based motility defect of a B. pseudomallei bimA mutant. While the BimA homologs differ in their amino-terminal sequence, they interact directly with actin in vitro and vary in their ability to bind ...

  6. Actin-Binding Proteins from Burkholderia mallei and Burkholderia thailandensis Can Functionally Compensate for the Actin-Based Motility Defect of a Burkholderia pseudomallei bimA Mutant

    OpenAIRE

    Stevens, Joanne M; Ulrich, Ricky L.; Taylor, Lowrie A.; Wood, Michael W.; DeShazer, David; Stevens, Mark P.; Galyov, Edouard E.

    2005-01-01

    Recently we identified a bacterial factor (BimA) required for actin-based motility of Burkholderia pseudomallei. Here we report that Burkholderia mallei and Burkholderia thailandensis are capable of actin-based motility in J774.2 cells and that BimA homologs of these bacteria can restore the actin-based motility defect of a B. pseudomallei bimA mutant. While the BimA homologs differ in their amino-terminal sequence, they interact directly with actin in vitro and vary in their ability to bind ...

  7. Draft Genomes for Eight Burkholderia mallei Isolates from Turkey

    Science.gov (United States)

    Daligault, H. E.; Davenport, K. W.; Minogue, T. D.; Bishop-Lilly, K. A.; Broomall, S. M.; Bruce, D. C.; Coyne, S. R.; Frey, K. G.; Gibbons, H. S.; Jaissle, J.; Koroleva, G. I.; Ladner, J. T.; Lo, C.-C.; Munk, C.; Wolcott, M. J.; Palacios, G. F.; Redden, C. L.; Rosenzweig, C. N.; Scholz, M. B.; Chain, P. S.

    2016-01-01

    Burkholderia mallei, the etiologic agent of glanders, is a Gram-negative, nonmotile, facultative intracellular pathogen. Although glanders has been eradicated from many parts of the world, the threat of B. mallei being used as a weapon is very real. Here we present draft genome assemblies of 8 Burkholderia mallei strains that were isolated in Turkey. PMID:26744368

  8. Complete Genome Sequence of the Fenitrothion-Degrading Burkholderia sp. Strain YI23

    OpenAIRE

    Lim, Jong Sung; Choi, Beom Soon; Choi, Ah Young; Kim, Kyung Duk; Kim, Dong In; Choi, Ik Young; Ka, Jong-Ok

    2012-01-01

    Burkholderia species are ubiquitous in soil environments. Many Burkholderia species isolated from various environments have the potential to biodegrade man-made chemicals. Burkholderia sp. strain YI23 was isolated from a golf course soil and identified as a fenitrothion-degrading bacterium. In this study, we report the complete genome sequence of Burkholderia sp. strain YI23.

  9. Complete Genome Sequences for 59 Burkholderia Isolates, Both Pathogenic and Near Neighbor

    OpenAIRE

    Johnson, S. L.; Bishop-Lilly, Kimberly A.; Ladner, Jason T.; Daligault, Hajnalka E.; Davenport, Karen W.; Jaissle, James; Frey, Kenneth G.; Koroleva, Galina I.; Bruce, David C.; Coyne, Susan R.; Broomall, Stacey M.; Li, Po-E; Teshima, Hazuki; Gibbons, Henry S.; Palacios, Gustavo F.

    2015-01-01

    The genus Burkholderia encompasses both pathogenic (including Burkholderia mallei and Burkholderia pseudomallei, U.S. Centers for Disease Control and Prevention Category B listed), and nonpathogenic Gram-negative bacilli. Here we present full genome sequences for a panel of 59 Burkholderia strains, selected to aid in detection assay development.

  10. Antibody-dependent enhancement of dengue virus infection is inhibited by SA-17, a doxorubicin derivative

    NARCIS (Netherlands)

    Ayala Nunez, Vanesa; Jarupathirun, Patsaporn; Kaptein, Suzanne; Neyts, Johan; Smit, Jolanda

    2013-01-01

    Antibody-dependent enhancement (ADE) is thought to play a critical role in the exacerbation of dengue virus (DENV)-induced disease during a heterologous re-infection. Despite ADE's clinical impact, only a few antiviral compounds have been assessed for their anti-ADE activity. We reported earlier tha

  11. Genomic Sequence of Burkholderia multivorans NKI379, a Soil Bacterium That Inhibits the Growth of Burkholderia pseudomallei

    OpenAIRE

    Hsueh, Pei-Tan; Liu, Jong-Kang; Chen, Ya-Lei; Liu, Pei-Ju; Ni, Wen-Fan; Chen, Yao-Shen; Wu, Keh-Ming; Lin, Hsi-Hsun

    2015-01-01

    Burkholderia multivorans NKI379 is a soil bacterium that exhibits an antagonistic effect against the growth of Burkholderia pseudomallei, the causative agent of the infectious disease melioidosis. We report the draft genomic sequence of B. multivorans NKI379, which has a G+C content of 67% and 5,203 candidate protein-encoding genes.

  12. Influence of neutrophil defects on Burkholderia cepacia complex pathogenesis

    Directory of Open Access Journals (Sweden)

    Laura A. Porter

    2011-11-01

    Full Text Available The Burkholderia cepacia complex (Bcc is a group of Gram-negative bacteria that are ubiquitous in the environment and have emerged as opportunistic pathogens in immunocompromised patients. The primary patient populations infected with Bcc include individuals with cystic fibrosis (CF, as well as those with chronic granulomatous disease (CGD. While Bcc infection in CF is better characterized than in CGD, these two genetic diseases are not obviously similar and it is currently unknown if there is any commonality in host immune defects that is responsible for the susceptibility to Bcc. CF is caused by mutations in the CF transmembrane conductance regulator, resulting in manifestations in various organ systems, however the major cause of morbidity and mortality is currently due to bacterial respiratory infections. CGD, on the other hand, is a genetic disorder that is caused by defects in phagocyte NADPH oxidase. Because of the defect in CGD, phagocytes in these patients are unable to produce reactive oxygen species, which results in increased susceptibility to bacterial and fungal infections. Despite this significant defect in microbial clearance, the spectrum of pathogens frequently implicated in infections in CGD is relatively narrow and includes some bacterial species that are considered almost pathognomonic for this disorder. Very little is known about the cause of the specific susceptibility to Bcc over other potential pathogens more prevalent in the environment, and a better understanding of specific mechanisms required for bacterial virulence has become a high priority. This review will summarize both the current knowledge and future directions related to Bcc virulence in immunocompromised individuals with a focus on the roles of bacterial factors and neutrophil defects in pathogenesis.

  13. Mouse model of sublethal and lethal intraperitoneal glanders (Burkholderia mallei).

    Science.gov (United States)

    Fritz, D L; Vogel, P; Brown, D R; Deshazer, D; Waag, D M

    2000-11-01

    Sixty male BALB/c mice were inoculated intraperitoneally with either a sublethal or a lethal dose of Burkholderia mallei China 7 strain, then killed at multiple time points postinoculation. Histopathologic changes were qualitatively similar in both groups and consisted of pyogranulomatous inflammation. In sublethal study mice, changes were first seen at 6 hours in mediastinal lymph nodes, then in spleen, liver, peripheral lymph nodes, and bone marrow at day 3. These changes generally reached maximal incidence and severity by day 4 but decreased by comparison in all tissues except the liver. Changes were first seen in lethal study mice also at 6 hours in mediastinal lymph nodes and in spleens. At day 1, changes were present in liver, peripheral lymph nodes, and bone marrow. The incidence and severity of these changes were maximal at day 2. In contrast to sublethal study mice, the incidence and severity of the changes did not decrease through the remainder of the study. The most significant difference between the two groups was the rapid involvement of the spleen in the lethal study mice. Changes indicative of impaired vascular perfusion were more frequently seen in the sublethal study mice. Our findings indicate that mice are susceptible to B. mallei infection and may serve as an appropriate model for glanders infection in a resistant host such as human beings. Additionally, by immunoelectron microscopy, we showed the presence of type I O-antigenic polysaccharide (capsular) antigen surrounding B. mallei.

  14. Differentiation-Dependent KLF4 Expression Promotes Lytic Epstein-Barr Virus Infection in Epithelial Cells.

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    Dhananjay M Nawandar

    2015-10-01

    Full Text Available Epstein-Barr virus (EBV is a human herpesvirus associated with B-cell and epithelial cell malignancies. EBV lytically infects normal differentiated oral epithelial cells, where it causes a tongue lesion known as oral hairy leukoplakia (OHL in immunosuppressed patients. However, the cellular mechanism(s that enable EBV to establish exclusively lytic infection in normal differentiated oral epithelial cells are not currently understood. Here we show that a cellular transcription factor known to promote epithelial cell differentiation, KLF4, induces differentiation-dependent lytic EBV infection by binding to and activating the two EBV immediate-early gene (BZLF1 and BRLF1 promoters. We demonstrate that latently EBV-infected, telomerase-immortalized normal oral keratinocyte (NOKs cells undergo lytic viral reactivation confined to the more differentiated cell layers in organotypic raft culture. Furthermore, we show that endogenous KLF4 expression is required for efficient lytic viral reactivation in response to phorbol ester and sodium butyrate treatment in several different EBV-infected epithelial cell lines, and that the combination of KLF4 and another differentiation-dependent cellular transcription factor, BLIMP1, is highly synergistic for inducing lytic EBV infection. We confirm that both KLF4 and BLIMP1 are expressed in differentiated, but not undifferentiated, epithelial cells in normal tongue tissue, and show that KLF4 and BLIMP1 are both expressed in a patient-derived OHL lesion. In contrast, KLF4 protein is not detectably expressed in B cells, where EBV normally enters latent infection, although KLF4 over-expression is sufficient to induce lytic EBV reactivation in Burkitt lymphoma cells. Thus, KLF4, together with BLIMP1, plays a critical role in mediating lytic EBV reactivation in epithelial cells.

  15. Genomic Characterization of Burkholderia pseudomallei Isolates Selected for Medical Countermeasures Testing: Comparative Genomics Associated with Differential Virulence

    OpenAIRE

    Sahl, Jason W.; Allender, Christopher J.; Colman, Rebecca E.; Califf, Katy J.; Schupp, James M.; Currie, Bart J.; Van Zandt, Kristopher E.; H Carl Gelhaus; Paul Keim; Apichai Tuanyok

    2015-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis and a potential bioterrorism agent. In the development of medical countermeasures against B. pseudomallei infection, the US Food and Drug Administration (FDA) animal Rule recommends using well-characterized strains in animal challenge studies. In this study, whole genome sequence data were generated for 6 B. pseudomallei isolates previously identified as candidates for animal challenge studies; an additional 5 isolates were seque...

  16. Role for the Burkholderia pseudomallei Type Three Secretion System Cluster 1 bpscN Gene in Virulence ▿

    OpenAIRE

    D'Cruze, Tanya; Gong, Lan; Treerat, Puthayalai; Ramm, Georg; John D Boyce; Prescott, Mark; Adler, Ben; Rodney J. Devenish

    2011-01-01

    Burkholderia pseudomallei, the causal agent of melioidosis, employs a number of virulence factors during its infection of mammalian cells. One such factor is the type three secretion system (TTSS), which is proposed to mediate the transport and secretion of bacterial effector molecules directly into host cells. The B. pseudomallei genome contains three TTSS gene clusters (designated TTSS1, TTSS2, and TTSS3). Previous research has indicated that neither TTSS1 nor TTSS2 is involved in B. pseudo...

  17. Comparative analysis of two phenotypically-similar but genomically-distinct Burkholderia cenocepacia-specific bacteriophages

    Directory of Open Access Journals (Sweden)

    Lynch Karlene H

    2012-06-01

    Full Text Available Abstract Background Genomic analysis of bacteriophages infecting the Burkholderia cepacia complex (BCC is an important preliminary step in the development of a phage therapy protocol for these opportunistic pathogens. The objective of this study was to characterize KL1 (vB_BceS_KL1 and AH2 (vB_BceS_AH2, two novel Burkholderia cenocepacia-specific siphoviruses isolated from environmental samples. Results KL1 and AH2 exhibit several unique phenotypic similarities: they infect the same B. cenocepacia strains, they require prolonged incubation at 30°C for the formation of plaques at low titres, and they do not form plaques at similar titres following incubation at 37°C. However, despite these similarities, we have determined using whole-genome pyrosequencing that these phages show minimal relatedness to one another. The KL1 genome is 42,832 base pairs (bp in length and is most closely related to Pseudomonas phage 73 (PA73. In contrast, the AH2 genome is 58,065 bp in length and is most closely related to Burkholderia phage BcepNazgul. Using both BLASTP and HHpred analysis, we have identified and analyzed the putative virion morphogenesis, lysis, DNA binding, and MazG proteins of these two phages. Notably, MazG homologs identified in cyanophages have been predicted to facilitate infection of stationary phase cells and may contribute to the unique plaque phenotype of KL1 and AH2. Conclusions The nearly indistinguishable phenotypes but distinct genomes of KL1 and AH2 provide further evidence of both vast diversity and convergent evolution in the BCC-specific phage population.

  18. TLR-dependent control of Francisella tularensis infection and host inflammatory responses.

    Directory of Open Access Journals (Sweden)

    Allison L Abplanalp

    Full Text Available BACKGROUND: Francisella tularensis is the causative agent of tularemia and is classified as a Category A select agent. Recent studies have implicated TLR2 as a critical element in the host protective response to F. tularensis infection, but questions remain about whether TLR2 signaling dominates the response in all circumstances and with all species of Francisella and whether F. tularensis PAMPs are predominantly recognized by TLR2/TLR1 or TLR2/TLR6. To address these questions, we have explored the role of Toll-like receptors (TLRs in the host response to infections with F. tularensis Live Vaccine Strain (LVS and F. tularensis subspecies (subsp. novicida in vivo. METHODOLOGY/PRINCIPAL FINDINGS: C57BL/6 (B6 control mice and TLR- or MyD88-deficient mice were infected intranasally (i.n. or intradermally (i.d. with F. tularensis LVS or with F. tularensis subsp. novicida. B6 mice survived >21 days following infection with LVS by both routes and survival of TLR1(-/-, TLR4(-/-, and TLR6(-/- mice infected i.n. with LVS was equivalent to controls. Survival of TLR2(-/- and MyD88(-/- mice, however, was significantly reduced compared to B6 mice, regardless of the route of infection or the subspecies of F. tularensis. TLR2(-/- and MyD88(-/- mice also showed increased bacterial burdens in lungs, liver, and spleen compared to controls following i.n. infection. Primary macrophages from MyD88(-/- and TLR2(-/- mice were significantly impaired in the ability to secrete TNF and other pro-inflammatory cytokines upon ex vivo infection with LVS. TNF expression was also impaired in vivo as demonstrated by analysis of bronchoalveolar lavage fluid and by in situ immunofluorescent staining. CONCLUSIONS/SIGNIFICANCE: We conclude from these studies that TLR2 and MyD88, but not TLR4, play critical roles in the innate immune response to F. tularensis infection regardless of the route of infection or the subspecies. Moreover, signaling through TLR2 does not depend exclusively

  19. Role of phages in the pathogenesis of Burkholderia or “Where are the toxin genes in Burkholderia phages?”

    OpenAIRE

    Summer, Elizabeth J.; Gill, Jason J.; Upton, Chris; Gonzalez, Carlos F.; Young, Ry

    2007-01-01

    Most bacteria of the genus Burkholderia are soil- and rhizosphere- associated, noted for their metabolic plasticity in the utilization of a wide range of organic compounds as carbon sources. Many Burkholderia species are also opportunistic human and plant pathogens and the distinction between environmental, plant, and human pathogens is not always clear. Burkholderia phages are not uncommon and multiple cryptic prophages are identifiable in the sequenced Burkholderia genomes. Phages have play...

  20. Septin-Dependent Assembly of the Exocyst Is Essential for Plant Infection by Magnaporthe oryzae.

    Science.gov (United States)

    Gupta, Yogesh K; Dagdas, Yasin F; Martinez-Rocha, Ana-Lilia; Kershaw, Michael J; Littlejohn, George R; Ryder, Lauren S; Sklenar, Jan; Menke, Frank; Talbot, Nicholas J

    2015-11-01

    Magnaporthe oryzae is the causal agent of rice blast disease, the most devastating disease of cultivated rice (Oryza sativa) and a continuing threat to global food security. To cause disease, the fungus elaborates a specialized infection cell called an appressorium, which breaches the cuticle of the rice leaf, allowing the fungus entry to plant tissue. Here, we show that the exocyst complex localizes to the tips of growing hyphae during vegetative growth, ahead of the Spitzenkörper, and is required for polarized exocytosis. However, during infection-related development, the exocyst specifically assembles in the appressorium at the point of plant infection. The exocyst components Sec3, Sec5, Sec6, Sec8, and Sec15, and exocyst complex proteins Exo70 and Exo84 localize specifically in a ring formation at the appressorium pore. Targeted gene deletion, or conditional mutation, of genes encoding exocyst components leads to impaired plant infection. We demonstrate that organization of the exocyst complex at the appressorium pore is a septin-dependent process, which also requires regulated synthesis of reactive oxygen species by the NoxR-dependent Nox2 NADPH oxidase complex. We conclude that septin-mediated assembly of the exocyst is necessary for appressorium repolarization and host cell invasion. PMID:26566920

  1. Vpr Promotes Macrophage-Dependent HIV-1 Infection of CD4+ T Lymphocytes.

    Directory of Open Access Journals (Sweden)

    David R Collins

    2015-07-01

    Full Text Available Vpr is a conserved primate lentiviral protein that promotes infection of T lymphocytes in vivo by an unknown mechanism. Here we demonstrate that Vpr and its cellular co-factor, DCAF1, are necessary for efficient cell-to-cell spread of HIV-1 from macrophages to CD4+ T lymphocytes when there is inadequate cell-free virus to support direct T lymphocyte infection. Remarkably, Vpr functioned to counteract a macrophage-specific intrinsic antiviral pathway that targeted Env-containing virions to LAMP1+ lysosomal compartments. This restriction of Env also impaired virological synapses formed through interactions between HIV-1 Env on infected macrophages and CD4 on T lymphocytes. Treatment of infected macrophages with exogenous interferon-alpha induced virion degradation and blocked synapse formation, overcoming the effects of Vpr. These results provide a mechanism that helps explain the in vivo requirement for Vpr and suggests that a macrophage-dependent stage of HIV-1 infection drives the evolutionary conservation of Vpr.

  2. Context-Dependent Effects of Ranaviral Infection on Northern Leopard Frog Life History Traits

    OpenAIRE

    Pierre Echaubard; Kevin Little; Bruce Pauli; David Lesbarrères

    2010-01-01

    Pathogens have important effects on host life-history traits, but the magnitude of these effects is often strongly context-dependent. The outcome of an interaction between a host and an infectious agent is often associated with the level of stress experienced by the host. Ranavirus causes disease and mortality in amphibian populations in various locations around the world, but most known cases of ranaviral infection have occurred in North America and the United Kingdom. While Ranavirus virule...

  3. Carotenoid-dependent coloration of male American kestrels predicts ability to reduce parasitic infections

    Science.gov (United States)

    Dawson, Russell D.; Bortolotti, Gary R.

    2006-12-01

    The signaling function of sexually selected traits, such as carotenoid-dependent avian plumage coloration, has received a great deal of recent attention especially with respect to parasitism and immunocompetence. We argue that parasite-mediated models of sexual selection may have an implicit temporal component that many researchers have ignored. For example, previous studies have demonstrated that carotenoid-dependent traits can signal past parasite exposure, current levels of parasitism, or the ability of individuals to manage parasitic infections in the future. We examined repeated measures of carotenoid-dependent skin color and blood parasitism in American kestrels ( Falco sparverius) to distinguish whether coloration might signal current parasitism or the potential to deal with infections in the future. We found no evidence that coloration was related to current levels of parasitism in either sex. However, coloration of males significantly predicted their response to parasitism; males with bright orange coloration during prelaying, when mate choice is occurring, were more likely than dull yellow males to reduce their levels of infection by the time incubation began. Coloration during prelaying may advertise a male’s health later in the breeding season. For kestrels, the ability to predict future health would be highly beneficial given the male’s role in providing food to his mate and offspring. Coloration of females was not a significant predictor of parasitism in the future, and we provide several possible explanations for this result.

  4. Age-Dependent Susceptibility to Enteropathogenic Escherichia coli (EPEC Infection in Mice.

    Directory of Open Access Journals (Sweden)

    Aline Dupont

    2016-05-01

    Full Text Available Enteropathogenic Escherichia coli (EPEC represents a major causative agent of infant diarrhea associated with significant morbidity and mortality in developing countries. Although studied extensively in vitro, the investigation of the host-pathogen interaction in vivo has been hampered by the lack of a suitable small animal model. Using RT-PCR and global transcriptome analysis, high throughput 16S rDNA sequencing as well as immunofluorescence and electron microscopy, we characterize the EPEC-host interaction following oral challenge of newborn mice. Spontaneous colonization of the small intestine and colon of neonate mice that lasted until weaning was observed. Intimate attachment to the epithelial plasma membrane and microcolony formation were visualized only in the presence of a functional bundle forming pili (BFP and type III secretion system (T3SS. Similarly, a T3SS-dependent EPEC-induced innate immune response, mediated via MyD88, TLR5 and TLR9 led to the induction of a distinct set of genes in infected intestinal epithelial cells. Infection-induced alterations of the microbiota composition remained restricted to the postnatal period. Although EPEC colonized the adult intestine in the absence of a competing microbiota, no microcolonies were observed at the small intestinal epithelium. Here, we introduce the first suitable mouse infection model and describe an age-dependent, virulence factor-dependent attachment of EPEC to enterocytes in vivo.

  5. Spinal cord injury-induced immune deficiency syndrome enhances infection susceptibility dependent on lesion level.

    Science.gov (United States)

    Brommer, Benedikt; Engel, Odilo; Kopp, Marcel A; Watzlawick, Ralf; Müller, Susanne; Prüss, Harald; Chen, Yuying; DeVivo, Michael J; Finkenstaedt, Felix W; Dirnagl, Ulrich; Liebscher, Thomas; Meisel, Andreas; Schwab, Jan M

    2016-03-01

    Pneumonia is the leading cause of death after acute spinal cord injury and is associated with poor neurological outcome. In contrast to the current understanding, attributing enhanced infection susceptibility solely to the patient's environment and motor dysfunction, we investigate whether a secondary functional neurogenic immune deficiency (spinal cord injury-induced immune deficiency syndrome, SCI-IDS) may account for the enhanced infection susceptibility. We applied a clinically relevant model of experimental induced pneumonia to investigate whether the systemic SCI-IDS is functional sufficient to cause pneumonia dependent on spinal cord injury lesion level and investigated whether findings are mirrored in a large prospective cohort study after human spinal cord injury. In a mouse model of inducible pneumonia, high thoracic lesions that interrupt sympathetic innervation to major immune organs, but not low thoracic lesions, significantly increased bacterial load in lungs. The ability to clear the bacterial load from the lung remained preserved in sham animals. Propagated immune susceptibility depended on injury of central pre-ganglionic but not peripheral postganglionic sympathetic innervation to the spleen. Thoracic spinal cord injury level was confirmed as an independent increased risk factor of pneumonia in patients after motor complete spinal cord injury (odds ratio = 1.35, P paralysis, spinal cord injury also induces a functional SCI-IDS ('immune paralysis'), sufficient to propagate clinically relevant infection in an injury level dependent manner. PMID:26754788

  6. Identification of an OmpW homologue in Burkholderia pseudomallei, a protective vaccine antigen against melioidosis.

    Science.gov (United States)

    Casey, William T; Spink, Natasha; Cia, Felipe; Collins, Cassandra; Romano, Maria; Berisio, Rita; Bancroft, Gregory J; McClean, Siobhán

    2016-05-17

    Burkholderia pseudomallei is the causative agent of melioidosis, which is associated with a range of clinical manifestations, including sepsis and fatal pneumonia and is endemic in Southeast Asia and Northern Australia. Treatment can be challenging and control of infection involves prolonged antibiotic therapy, yet there are no approved vaccines available to prevent infection. Our aim was to develop and assess the potential of a prophylactic vaccine candidate targeted against melioidosis. The identified candidate is the 22kDa outer membrane protein, OmpW. We previously demonstrated that this protein was immunoprotective in mouse models of Burkholderia cepacia complex (Bcc) infections. We cloned Bp_ompW in Escherichia coli, expressed and purified the protein. Endotoxin free protein administered with SAS adjuvant protected Balb/C mice (75% survival) relative to controls (25% survival) (p<0.05). A potent serological response was observed with IgG2a to IgG1 ratio of 6.0. Furthermore C57BL/6 mice were protected for up to 80 days against a lethal dose of B. pseudomallei and surpassed the efficacy of the live attenuated 2D2 positive control. BpompW is homologous across thirteen sequenced B. pseudomallei strains, indicating that it should be broadly protective against B. pseudomallei. In conclusion, we have demonstrated that BpOmpW is able to induce protective immunity against melioidosis and is likely to be an effective vaccine antigen, possibly in combination with other subunit antigens. PMID:27091689

  7. Burkholderia glumae ToxA Is a Dual-Specificity Methyltransferase That Catalyzes the Last Two Steps of Toxoflavin Biosynthesis.

    Science.gov (United States)

    Fenwick, Michael K; Philmus, Benjamin; Begley, Tadhg P; Ealick, Steven E

    2016-05-17

    Toxoflavin is a major virulence factor of the rice pathogen Burkholderia glumae. The tox operon of B. glumae contains five putative toxoflavin biosynthetic genes toxABCDE. ToxA is a predicted S-adenosylmethionine-dependent methyltransferase, and toxA knockouts of B. glumae are less virulent in plant infection models. In this study, we show that ToxA performs two consecutive methylations to convert the putative azapteridine intermediate, 1,6-didemethyltoxoflavin, to toxoflavin. In addition, we report a series of crystal structures of ToxA complexes that reveals the molecular basis of the dual methyltransferase activity. The results suggest sequential methylations with initial methylation at N6 of 1,6-didemethyltoxoflavin followed by methylation at N1. The two azapteridine orientations that position N6 or N1 for methylation are coplanar with a 140° rotation between them. The structure of ToxA contains a class I methyltransferase fold having an N-terminal extension that either closes over the active site or is largely disordered. The ordered conformation places Tyr7 at a position of a structurally conserved tyrosine site of unknown function in various methyltransferases. Crystal structures of ToxA-Y7F consistently show a closed active site, whereas structures of ToxA-Y7A consistently show an open active site, suggesting that the hydroxyl group of Tyr7 plays a role in opening and closing the active site during the multistep reaction. PMID:27070241

  8. PREVALENCE OF HEPATITIS C VIRUS INFECTION IN NON INSULIN DEPENDENT DIABETIC PATIENTS (NIDDM

    Directory of Open Access Journals (Sweden)

    Sreedhara

    2015-08-01

    Full Text Available AIM : The present study was done to evaluate the prevalence of hepatitis C virus (HCV infection in non - insulin dependent diabetic patients (NIDDM and to investigate influence of HCV seropositivity on several factors such as age of onset of diabetes, complicat ions and mode of treatment. METHODS: The study is prospective, hospital based case - control study done over a period of 3 years. A total of 428 diabetic patients were compared with 1800 voluntary blood donors for the presence of HCV infection. Serological testing for anti HCV was done by using commercial enzyme linked immunosorbent assay (ELISA. Data about various variables were collected from diabetic patients using a structured questionnaire after taking informed consent. RESULTS: Higher prevalence of H CV (7.71% infection rate observed in NIDDM patients in comparison with blood donors (1.1%. In our study, HCV seropositivity is highest (11.81% in 40 - 50 years age group followed by (8.57% 30 - 40 years age and least (2.43% in age > 61 years. Mean age of onset of diabetes mellitus (DM is 39 years in HCV +ve patients in comparison with 46 years in non - reactors. Proportion of seropositive cases among male and female diabetic cases did not show significant difference. Out of 33 HCV seropositive cases, 63.64% managed with insulin and 48.49% oral hypoglycemic drugs with insulin supplement. Ten out of 33 (30.30% HCV seropositive cases presented with one or more late diabetic complications compared to 78 out of 395 (19.75% seronegative cases, with diabetic neph ropathy being commonest one. CONCLUSION: Although, HCV infection is more common among adults with type 2 diabetes, it is uncertain whether HCV infection precedes the development of diabetes. Hence, there is a need to perform a prospective analysis to inves tigate, in persons who acquire type 2 diabetes whether they are more likely to have had antecedent HCV infection

  9. Antibacterial activity of a lectin-like Burkholderia cenocepacia protein

    OpenAIRE

    Ghequire, Maarten; De Canck, Evelien; Wattiau, Pierre; Van Winge, Iris; Loris, Remy; Coenye, Tom; De Mot, René

    2013-01-01

    Abstract Bacteriocins of the LlpA family have previously been characterized in the γ-proteobacteria Pseudomonas and Xanthomonas. These proteins are composed of two MMBL (monocot mannose-binding lectin) domains, a module predominantly and abundantly found in lectins from monocot plants. Genes encoding four different types of LlpA-like proteins were identified in genomes from strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. A selected recombin...

  10. Characterization of the Burkholderia mallei tonB Mutant and Its Potential as a Backbone Strain for Vaccine Development.

    Directory of Open Access Journals (Sweden)

    Tiffany M Mott

    Full Text Available In this study, a Burkholderia mallei tonB mutant (TMM001 deficient in iron acquisition was constructed, characterized, and evaluated for its protective properties in acute inhalational infection models of murine glanders and melioidosis.Compared to the wild-type, TMM001 exhibits slower growth kinetics, siderophore hyper-secretion and the inability to utilize heme-containing proteins as iron sources. A series of animal challenge studies showed an inverse correlation between the percentage of survival in BALB/c mice and iron-dependent TMM001 growth. Upon evaluation of TMM001 as a potential protective strain against infection, we found 100% survival following B. mallei CSM001 challenge of mice previously receiving 1.5 x 10(4 CFU of TMM001. At 21 days post-immunization, TMM001-treated animals showed significantly higher levels of B. mallei-specific IgG1, IgG2a and IgM when compared to PBS-treated controls. At 48 h post-challenge, PBS-treated controls exhibited higher levels of serum inflammatory cytokines and more severe pathological damage to target organs compared to animals receiving TMM001. In a cross-protection study of acute inhalational melioidosis with B. pseudomallei, TMM001-treated mice were significantly protected. While wild type was cleared in all B. mallei challenge studies, mice failed to clear TMM001.Although further work is needed to prevent chronic infection by TMM001 while maintaining immunogenicity, our attenuated strain demonstrates great potential as a backbone strain for future vaccine development against both glanders and melioidosis.

  11. Effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yohan; Kim, Jae-Hun; Byun, Myung-Woo [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeollabuk 580-185 (Korea, Republic of); Choi, Kyoung-Hee [Department of Oral Microbiology, College of Dentistry, Wonkwang University, Iksan, Jeollabuk 570-749 (Korea, Republic of); Lee, Ju-Woon, E-mail: sjwlee@kaeri.re.k [Team for Radiation Food Science and Biotechnology, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Jeollabuk 580-185 (Korea, Republic of)

    2010-04-15

    This study evaluated the effect of gamma irradiation on Burkholderia thailandensis (Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D{sub 10} values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased (P<0.05) as irradiation dose increased, and no differences (P>=0.05) in cell counts of the bacteria were observed among different levels of NaCl and pH. D{sub 10} values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

  12. Effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate) survival under combinations of pH and NaCl

    Science.gov (United States)

    Yoon, Yohan; Kim, Jae-Hun; Byun, Myung-Woo; Choi, Kyoung-Hee; Lee, Ju-Woon

    2010-04-01

    This study evaluated the effect of gamma irradiation on Burkholderia thailandensis ( Burkholderia pseudomallei surrogate; potential bioterrorism agent) survival under different levels of NaCl and pH. B. thailandensis in Luria Bertani broth supplemented with NaCl (0-3%), and pH-adjusted to 4-7 was treated with gamma irradiation (0-0.5 kGy). Surviving cell counts of bacteria were then enumerated on tryptic soy agar. Data for the cell counts were also used to calculate D10 values (the dose required to reduce 1 log CFU/mL of B. thailandensis). Cell counts of B. thailandensis were decreased ( Pbacteria were observed among different levels of NaCl and pH. D10 values ranged from 0.04 to 0.07 kGy, regardless of NaCl and pH level. These results indicate that low doses of gamma irradiation should be a useful treatment in decreasing the potential bioterrorism bacteria, which may possibly infect humans through foods.

  13. A prospective study on TT virus infection in transfusion-dependent patients with beta-thalassemia.

    Science.gov (United States)

    Prati, D; Lin, Y H; De Mattei, C; Liu, J K; Farma, E; Ramaswamy, L; Zanella, A; Lee, H; Rebulla, P; Allain, J P; Sirchia, G; Chen, B

    1999-03-01

    A novel DNA virus designated TT virus (TTV) has been reported to be involved in the development of posttransfusion non-A-C hepatitis. We evaluated the frequency and natural course of TTV infection in a cohort of transfusion-dependent thalassemic patients in a 3-year follow-up study. Ninety-three serum hepatitis C virus (HCV) antibody-negative patients (median age of 8 years; range, 0 to 25) from eight centers were studied. Of them, 34 (37%) had an abnormal alanine-aminotransferase (ALT) baseline pattern, and the other 12 (13%) showed ALT flare-ups during the follow-up. TTV DNA in patient sera collected at the time of enrollment and at the end of follow-up was determined by polymerase chain reaction (PCR). In parallel, serum samples from 100 healthy blood donors were also tested. At baseline, 87 patient sera (93.5%) tested positive for the TTV DNA. Of these TTV DNA-positive patients, 84 (96.5%) remained viremic at the end of the study period. Of the 6 TTV DNA-negative patients, 3 acquired TTV infection during follow-up. However, no definite relation was observed between the results of TTV DNA determination and ALT patterns. TTV viremia was also detectable in 22% of blood donors. In conclusion, TTV infection is frequent and persistent among Italian transfusion-dependent patients. The high rate of viremia observed in healthy donors indicates that the parenteral route is not the only mode of TTV spread.

  14. 洋葱伯克霍尔德菌污染肝素钠封管液致血管导管相关血流感染暴发%Vascular catheter-related bloodstream infection outbreak due to the contamination of heparin sodium sealing solution by Burkholderia cepacia

    Institute of Scientific and Technical Information of China (English)

    李静

    2013-01-01

    目的 调查某院肿瘤病房一起由洋葱伯克霍尔德菌(BC)引起的血管导管相关血流感染(CRBSI)暴发的原因,为预防和控制医院感染提供依据.方法 采用临床资料调查和现场采样检测相结合的方法,对此次医院感染的暴发进行流行病学调查.结果 11例次BC引起的 CRBSI发生时间集中,分别为2008年2月18日(1例)、19日(1例)、20日(6例)、21日(1例)、22日(2例);均为股静脉置管患者,均从患者血液中培养出BC,均使用了同一袋肝素钠封管液.环境卫生学调查,患者所使用的液体、一次性注射器材、环境物品细菌学检测均合格,仅在1份剩余肝素钠封管液中(患者共用此封管液)培养出1株BC,其药敏结果与患者血液培养菌株一致.立即采取措施,拔除患者深静脉置管,并抗感染治疗.11例患者7 d后血培养均无细菌生长,该病区再无相同病例出现.结论 BC污染肝素钠封管液是此次CRBSI暴发的原因,经积极采取措施,感染得到有效控制.%Objective To investigate the causes of an outbreak of Burkholderia cepacia (B. cepacia) vascular catheter-related bloodstream infection(CRBSI) in an oncology department, and provide the basis for the prevention and control of health care-associated infection. Methods Epidemiological investigation was performed by combination of clinical data analysis and on-site sampling . Results The occurrence time of 11 B. cepacia CRBSf cases concentrated on February 18(1 case) , 19 (1 case) , 20 (6 cases) , 21 (1 case) , and 22 (2 cases) of 2008, respectively ; all patients were intubated in the femoral vein, isolated B. cepacia from blood cultures ,and used the same bag of heparin sodium sealing solution. Bacterial culture results of heparin sodium sealing solution , disposable syringes, and environmental samples were all qualified, only 1 tube of used heparin sodium sealing solution (all patients shared this tube) isolated B. cepacia, antimicrobial susceptibility

  15. Environmental Transmission of the Gut Symbiont Burkholderia to Phloem-Feeding Blissus insularis

    Science.gov (United States)

    Xu, Yao; Buss, Eileen A.; Boucias, Drion G.

    2016-01-01

    The plant-phloem-feeding Blissus insularis possesses specialized midgut crypts, which harbor a dense population of the exocellular bacterial symbiont Burkholderia. Most individual B. insularis harbor a single Burkholderia ribotype in their midgut crypts; however, a diverse Burkholderia community exists within a host population. To understand the mechanism underlying the consistent occurrence of various Burkholderia in B. insularis and their specific association, we investigated potential gut symbiont transmission routes. PCR amplification detected a low titer of Burkholderia in adult reproductive tracts; however, fluorescence in situ hybridization assays failed to produce detectable signals in these tracts. Furthermore, no Burkholderia-specific PCR signals were detected in eggs and neonates, suggesting that it is unlikely that B. insularis prenatally transmits gut symbionts via ovarioles. In rearing experiments, most nymphs reared on St. Augustinegrass treated with cultured Burkholderia harbored the cultured Burkholderia strains. Burkholderia was detected in the untreated host grass of B. insularis, and most nymphs reared on untreated grass harbored a Burkholderia ribotype that was closely related to a plant-associated Burkholderia strain. These findings revealed that B. insularis neonates acquired Burkholderia primarily from the environment (i.e., plants and soils), even though the possibility of acquisition via egg surface cannot be excluded. In addition, our study explains how the diverse Burkholderia symbiont community in B. insularis populations can be maintained. PMID:27548682

  16. Environmental Transmission of the Gut Symbiont Burkholderia to Phloem-Feeding Blissus insularis.

    Science.gov (United States)

    Xu, Yao; Buss, Eileen A; Boucias, Drion G

    2016-01-01

    The plant-phloem-feeding Blissus insularis possesses specialized midgut crypts, which harbor a dense population of the exocellular bacterial symbiont Burkholderia. Most individual B. insularis harbor a single Burkholderia ribotype in their midgut crypts; however, a diverse Burkholderia community exists within a host population. To understand the mechanism underlying the consistent occurrence of various Burkholderia in B. insularis and their specific association, we investigated potential gut symbiont transmission routes. PCR amplification detected a low titer of Burkholderia in adult reproductive tracts; however, fluorescence in situ hybridization assays failed to produce detectable signals in these tracts. Furthermore, no Burkholderia-specific PCR signals were detected in eggs and neonates, suggesting that it is unlikely that B. insularis prenatally transmits gut symbionts via ovarioles. In rearing experiments, most nymphs reared on St. Augustinegrass treated with cultured Burkholderia harbored the cultured Burkholderia strains. Burkholderia was detected in the untreated host grass of B. insularis, and most nymphs reared on untreated grass harbored a Burkholderia ribotype that was closely related to a plant-associated Burkholderia strain. These findings revealed that B. insularis neonates acquired Burkholderia primarily from the environment (i.e., plants and soils), even though the possibility of acquisition via egg surface cannot be excluded. In addition, our study explains how the diverse Burkholderia symbiont community in B. insularis populations can be maintained. PMID:27548682

  17. Exploitation of host cells by Burkholderia pseudomallei.

    Science.gov (United States)

    Stevens, Mark P; Galyov, Edouard E

    2004-04-01

    Intracellular bacterial pathogens have evolved mechanisms to enter and exit eukaryotic cells using the power of actin polymerisation and to subvert the activity of cellular enzymes and signal transduction pathways. The proteins deployed by bacteria to subvert cellular processes often mimic eukaryotic proteins in their structure or function. Studies on the exploitation of host cells by the facultative intracellular pathogen Burkholderia pseudomallei are providing novel insights into the pathogenesis of melioidosis, a serious invasive disease of animals and humans that is endemic in tropical and subtropical areas. B. pseudomallei can invade epithelial cells, survive and proliferate inside phagocytes, escape from endocytic vesicles, form actin-based membrane protrusions and induce host cell fusion. Here we review current understanding of the molecular mechanisms underlying these processes.

  18. Comparison of the in vitro and in vivo susceptibilities of Burkholderia mallei to Ceftazidime and Levofloxacin

    Directory of Open Access Journals (Sweden)

    Torres Alfredo G

    2009-05-01

    Full Text Available Abstract Background Burkholderia mallei is a zoonotic Gram negative bacterium which primarily infects solipeds but can cause lethal disease in humans if left untreated. The effect of two antibiotics with different modes of action on Burkholderia mallei strain ATCC23344 was investigated by using in vitro and in vivo studies. Results Determination of minimal inhibitory concentrations (MICs in vitro was done by the agar diffusion method and the dilution method. The MICs of levofloxacin and ceftazidime were in the similar range, 2.5 and 5.0 μg/ml, respectively. Intracellular susceptibility of the bacterium to these two antibiotics in J774A.1 mouse macrophages in vitro was also investigated. Macrophages treated with antibiotics demonstrated uptake of the drugs and reduced bacterial loads in vitro. The efficacy of ceftazidime and levofloxacin were studied in BALB/c mice as post-exposure treatment following intranasal B. mallei infection. Intranasal infection with 5 × 105 CFUs of B. mallei resulted in 90% death in non-treated control mice. Antibiotic treatments 10 days post-infection proved to be effective in vivo with all antibiotic treated mice surviving to day 34 post-infection. The antibiotics did not result in complete clearance of the bacterial infection and presence of the bacteria was found in lungs and spleens of the survivors, although bacterial burden recovered from levofloxacin treated animals appeared reduced compared to ceftazidime. Conclusion Both antibiotics demonstrated utility for the treatment of glanders, including the ability for intracellular penetration and clearance of organisms in vitro.

  19. Host and parasite thermal acclimation responses depend on the stage of infection.

    Science.gov (United States)

    Altman, Karie A; Paull, Sara H; Johnson, Pieter T J; Golembieski, Michelle N; Stephens, Jeffrey P; LaFonte, Bryan E; Raffel, Thomas R

    2016-07-01

    Global climate change is expected to alter patterns of temperature variability, which could influence species interactions including parasitism. Species interactions can be difficult to predict in variable-temperature environments because of thermal acclimation responses, i.e. physiological changes that allow organisms to adjust to a new temperature following a temperature shift. The goal of this study was to determine how thermal acclimation influences host resistance to infection and to test for parasite acclimation responses, which might differ from host responses in important ways. We tested predictions of three, non-mutually exclusive hypotheses regarding thermal acclimation effects on infection of green frog tadpoles (Lithobates clamitans) by the trematode parasite Ribeiroia ondatrae with fully replicated controlled-temperature experiments. Trematodes or tadpoles were independently acclimated to a range of 'acclimation temperatures' prior to shifting them to new 'performance temperatures' for experimental infections. Trematodes that were acclimated to intermediate temperatures (19-22 °C) had greater encystment success across temperatures than either cold- or warm-acclimated trematodes. However, host acclimation responses varied depending on the stage of infection (encystment vs. clearance): warm- (22-28 °C) and cold-acclimated (13-19 °C) tadpoles had fewer parasites encyst at warm and cold performance temperatures, respectively, whereas intermediate-acclimated tadpoles (19-25 °C) cleared the greatest proportion of parasites in the week following exposure. These results suggest that tadpoles use different immune mechanisms to resist different stages of trematode infection, and that each set of mechanisms has unique responses to temperature variability. Our results highlight the importance of considering thermal responses of both parasites and hosts when predicting disease patterns in variable-temperature environments. PMID:27040618

  20. A Burkholderia Type VI Effector Deamidates Rho GTPases to Activate the Pyrin Inflammasome and Trigger Inflammation.

    Science.gov (United States)

    Aubert, Daniel F; Xu, Hao; Yang, Jieling; Shi, Xuyan; Gao, Wenqing; Li, Lin; Bisaro, Fabiana; Chen, She; Valvano, Miguel A; Shao, Feng

    2016-05-11

    Burkholderia cenocepacia is an opportunistic pathogen of the cystic fibrosis lung that elicits a strong inflammatory response. B. cenocepacia employs a type VI secretion system (T6SS) to survive in macrophages by disarming Rho-type GTPases, causing actin cytoskeletal defects. Here, we identified TecA, a non-VgrG T6SS effector responsible for actin disruption. TecA and other bacterial homologs bear a cysteine protease-like catalytic triad, which inactivates Rho GTPases by deamidating a conserved asparagine in the GTPase switch-I region. RhoA deamidation induces caspase-1 inflammasome activation, which is mediated by the familial Mediterranean fever disease protein Pyrin. In mouse infection, the deamidase activity of TecA is necessary and sufficient for B. cenocepacia-triggered lung inflammation and also protects mice from lethal B. cenocepacia infection. Therefore, Burkholderia TecA is a T6SS effector that modifies a eukaryotic target through an asparagine deamidase activity, which in turn elicits host cell death and inflammation through activation of the Pyrin inflammasome. PMID:27133449

  1. The Madagascar hissing cockroach as a novel surrogate host for Burkholderia pseudomallei, B. mallei and B. thailandensis

    Directory of Open Access Journals (Sweden)

    Fisher Nathan A

    2012-06-01

    Full Text Available Abstract Background Burkholderia pseudomallei and Burkholderia mallei are gram-negative pathogens responsible for the diseases melioidosis and glanders, respectively. Both species cause disease in humans and animals and have been designated as category B select agents by the Centers for Disease Control and Prevention (CDC. Burkholderia thailandensis is a closely related bacterium that is generally considered avirulent for humans. While it can cause disease in rodents, the B. thailandensis 50% lethal dose (LD50 is typically ≥ 104-fold higher than the B. pseudomallei and B. mallei LD50 in mammalian models of infection. Here we describe an alternative to mammalian hosts in the study of virulence and host-pathogen interactions of these Burkholderia species. Results Madagascar hissing cockroaches (MH cockroaches possess a number of qualities that make them desirable for use as a surrogate host, including ease of breeding, ease of handling, a competent innate immune system, and the ability to survive at 37°C. MH cockroaches were highly susceptible to infection with B. pseudomallei, B. mallei and B. thailandensis and the LD50 was 50 for Escherichia coli in MH cockroaches was >105 cfu. B. pseudomallei, B. mallei, and B. thailandensis cluster 1 type VI secretion system (T6SS-1 mutants were all attenuated in MH cockroaches, which is consistent with previous virulence studies conducted in rodents. B. pseudomallei mutants deficient in the other five T6SS gene clusters, T6SS-2 through T6SS-6, were virulent in both MH cockroaches and hamsters. Hemocytes obtained from MH cockroaches infected with B. pseudomallei harbored numerous intracellular bacteria, suggesting that this facultative intracellular pathogen can survive and replicate inside of MH cockroach phagocytic cells. The hemolymph extracted from these MH cockroaches also contained multinuclear giant cells (MNGCs with intracellular B. pseudomallei, which indicates that infected hemocytes can

  2. Resolution of acute malarial infections by T cell-dependent non-antibody-mediated mechanisms of immunity.

    OpenAIRE

    Cavacini, L A; Parke, L A; Weidanz, W P

    1990-01-01

    While it is generally accepted that acute blood stage malarial infections are resolved through the actions of protective antibodies, we observed that resistance to acute infection with Plasmodium chabaudi adami was mediated by T cell-dependent cellular immune mechanisms independent of antibody. We now report that acute blood stage infections caused by three additional murine hemoprotozoan parasites, Plasmodium vinckei petteri, Plasmodium chabaudi chabaudi, and Babesia microti, appear to be co...

  3. Versatility of the Burkholderia cepacia complex for the biosynthesis of exopolysaccharides: a comparative structural investigation.

    Directory of Open Access Journals (Sweden)

    Bruno Cuzzi

    Full Text Available The Burkholderia cepacia Complex assembles at least eighteen closely related species that are ubiquitous in nature. Some isolates show beneficial potential for biocontrol, bioremediation and plant growth promotion. On the contrary, other strains are pathogens for plants and immunocompromised individuals, like cystic fibrosis patients. In these subjects, they can cause respiratory tract infections sometimes characterised by fatal outcome. Most of the Burkholderia cepacia Complex species are mucoid when grown on a mannitol rich medium and they also form biofilms, two related characteristics, since polysaccharides are important component of biofilm matrices. Moreover, polysaccharides contribute to bacterial survival in a hostile environment by inhibiting both neutrophils chemotaxis and antimicrobial peptides activity, and by scavenging reactive oxygen species. The ability of these microorganisms to produce exopolysaccharides with different structures is testified by numerous articles in the literature. However, little is known about the type of polysaccharides produced in biofilms and their relationship with those obtained in non-biofilm conditions. The aim of this study was to define the type of exopolysaccharides produced by nine species of the Burkholderia cepacia Complex. Two isolates were then selected to compare the polysaccharides produced on agar plates with those formed in biofilms developed on cellulose membranes. The investigation was conducted using NMR spectroscopy, high performance size exclusion chromatography, and gas chromatography coupled to mass spectrometry. The results showed that the Complex is capable of producing a variety of exopolysaccharides, most often in mixture, and that the most common exopolysaccharide is always cepacian. In addition, two novel polysaccharide structures were determined: one composed of mannose and rhamnose and another containing galactose and glucuronic acid. Comparison of exopolysaccharides obtained

  4. Saturation mutagenesis of a CepR binding site as a means to identify new quorum-regulated promoters in Burkholderia cenocepacia

    Science.gov (United States)

    Burkholderia cenocepacia, an opportunistic pathogen of humans, encodes the CepI and CepR proteins, which resemble the LuxI and LuxR quorum sensing proteins of Vibrio fischeri. CepI directs the synthesis of octanoylhomoserine lactone (OHL), while CepR is an OHL dependent transcription factor. In pr...

  5. Context-dependent effects of ranaviral infection on northern leopard frog life history traits.

    Directory of Open Access Journals (Sweden)

    Pierre Echaubard

    Full Text Available Pathogens have important effects on host life-history traits, but the magnitude of these effects is often strongly context-dependent. The outcome of an interaction between a host and an infectious agent is often associated with the level of stress experienced by the host. Ranavirus causes disease and mortality in amphibian populations in various locations around the world, but most known cases of ranaviral infection have occurred in North America and the United Kingdom. While Ranavirus virulence has been investigated, the outcome of Ranavirus infection has seldom been related to the host environment. In a factorial experiment, we exposed Northern leopard frog (Lithobates pipiens, formerly Rana pipiens tadpoles to different concentrations of Ranavirus and investigated the effect of host density on certain life-history traits, namely survival, growth rate, developmental stage and number of days from virus exposure to death. Our results suggest a prominent role of density in driving the direction of the interaction between L. pipiens tadpoles and Ranavirus. We showed that increasing animal holding density is detrimental for host fitness as mortality rate is higher, day of death earlier, development longer and growth rate significantly lower in high-density tanks. We observed a linear increase of detrimental effects when Ranavirus doses increased in low-density conditions, with control tadpoles having a significantly higher overall relative fitness. However, this pattern was no longer observed in high-density conditions, where the effects of increasing Ranavirus dose were limited. Infected and control animals fitness were consequently similar. We speculate that the host may eventually diverts the energy required for a metabolic/immune response triggered by the infection (i.e., direct costs of the infection to better cope with the increase in environmental "stress" associated with high density (i.e., indirect benefits of the infection. Our results

  6. Ligation of Fc gamma receptor IIB inhibits antibody-dependent enhancement of dengue virus infection.

    Science.gov (United States)

    Chan, Kuan Rong; Zhang, Summer Li-Xin; Tan, Hwee Cheng; Chan, Ying Kai; Chow, Angelia; Lim, Angeline Pei Chiew; Vasudevan, Subhash G; Hanson, Brendon J; Ooi, Eng Eong

    2011-07-26

    The interaction of antibodies, dengue virus (DENV), and monocytes can result in either immunity or enhanced virus infection. These opposing outcomes of dengue antibodies have hampered dengue vaccine development. Recent studies have shown that antibodies neutralize DENV by either preventing virus attachment to cellular receptors or inhibiting viral fusion intracellularly. However, whether the antibody blocks attachment or fusion, the resulting immune complexes are expected to be phagocytosed by Fc gamma receptor (FcγR)-bearing cells and cleared from circulation. This suggests that only antibodies that are able to block fusion intracellularly would be able to neutralize DENV upon FcγR-mediated uptake by monocytes whereas other antibodies would have resulted in enhancement of DENV replication. Using convalescent sera from dengue patients, we observed that neutralization of the homologous serotypes occurred despite FcγR-mediated uptake. However, FcγR-mediated uptake appeared to be inhibited when neutralized heterologous DENV serotypes were used instead. We demonstrate that this inhibition occurred through the formation of viral aggregates by antibodies in a concentration-dependent manner. Aggregation of viruses enabled antibodies to cross-link the inhibitory FcγRIIB, which is expressed at low levels but which inhibits FcγR-mediated phagocytosis and hence prevents antibody-dependent enhancement of DENV infection in monocytes. PMID:21746897

  7. Diagnostically and Experimentally Useful Panel of Strains from the Burkholderia cepacia Complex

    OpenAIRE

    Mahenthiralingam, Eshwar; Coenye, Tom; Chung, Jacqueline W.; Speert, David P.; Govan, John R. W.; Taylor, Peter; Vandamme, Peter

    2000-01-01

    Two new species, Burkholderia multivorans and Burkholderia vietnamiensis, and three genomovars (genomovars I, III, and IV) currently constitute the Burkholderia cepacia complex. A panel of 30 well-characterized strains representative of each genomovar and new species was assembled to assist with identification, epidemiological analysis, and virulence studies on this important group of opportunistic pathogens.

  8. The stimulated innate resistance event in Bordetella pertussis infection is dependent on reactive oxygen species production.

    Science.gov (United States)

    Zurita, E; Moreno, G; Errea, A; Ormazabal, M; Rumbo, M; Hozbor, D

    2013-07-01

    The exacerbated induction of innate immune responses in airways can abrogate diverse lung infections by a phenomenon known as stimulated innate resistance (StIR). We recently demonstrated that the enhancement of innate response activation can efficiently impair Bordetella pertussis colonization in a Toll-like receptor 4 (TLR4)-dependent manner. The aim of this work was to further characterize the effect of lipopolysaccharide (LPS) on StIR and to identify the mechanisms that mediate this process. Our results showed that bacterial infection was completely abrogated in treated mice when the LPS of B. pertussis (1 μg) was added before (48 h or 24 h), after (24 h), or simultaneously with the B. pertussis challenge (10(7) CFU). Moreover, we detected that LPS completely cleared bacterial infection as soon as 2 h posttreatment. This timing suggests that the observed StIR phenomenon should be mediated by fast-acting antimicrobial mechanisms. Although neutrophil recruitment was already evident at this time point, depletion assays using an anti-GR1 antibody showed that B. pertussis clearance was achieved even in the absence of neutrophils. To evaluate the possible role of free radicals in StIR, we performed animal assays using the antioxidant N-acetyl cysteine (NAC), which is known to inactivate oxidant species. NAC administration blocked the B. pertussis clearance induced by LPS. Nitrite concentrations were also increased in the LPS-treated mice; however, the inhibition of nitric oxide synthetases did not suppress the LPS-induced bacterial clearance. Taken together, our results show that reactive oxygen species (ROS) play an essential role in the TLR4-dependent innate clearance of B. pertussis.

  9. Integrative functional genomics of hepatitis C virus infection identifies host dependencies in complete viral replication cycle.

    Directory of Open Access Journals (Sweden)

    Qisheng Li

    2014-05-01

    Full Text Available Recent functional genomics studies including genome-wide small interfering RNA (siRNA screens demonstrated that hepatitis C virus (HCV exploits an extensive network of host factors for productive infection and propagation. How these co-opted host functions interact with various steps of HCV replication cycle and exert pro- or antiviral effects on HCV infection remains largely undefined. Here we present an unbiased and systematic strategy to functionally interrogate HCV host dependencies uncovered from our previous infectious HCV (HCVcc siRNA screen. Applying functional genomics approaches and various in vitro HCV model systems, including HCV pseudoparticles (HCVpp, single-cycle infectious particles (HCVsc, subgenomic replicons, and HCV cell culture systems (HCVcc, we identified and characterized novel host factors or pathways required for each individual step of the HCV replication cycle. Particularly, we uncovered multiple HCV entry factors, including E-cadherin, choline kinase α, NADPH oxidase CYBA, Rho GTPase RAC1 and SMAD family member 6. We also demonstrated that guanine nucleotide binding protein GNB2L1, E2 ubiquitin-conjugating enzyme UBE2J1, and 39 other host factors are required for HCV RNA replication, while the deubiquitinating enzyme USP11 and multiple other cellular genes are specifically involved in HCV IRES-mediated translation. Families of antiviral factors that target HCV replication or translation were also identified. In addition, various virologic assays validated that 66 host factors are involved in HCV assembly or secretion. These genes included insulin-degrading enzyme (IDE, a proviral factor, and N-Myc down regulated Gene 1 (NDRG1, an antiviral factor. Bioinformatics meta-analyses of our results integrated with literature mining of previously published HCV host factors allows the construction of an extensive roadmap of cellular networks and pathways involved in the complete HCV replication cycle. This comprehensive study

  10. Colonization or spontaneous resolution:Expanding the role for Burkholderia pseudomallei

    Institute of Scientific and Technical Information of China (English)

    Kushal Naha; Barkur Ananthakrishna Shastry; Kavitha Saravu

    2014-01-01

    A 19-year-old Asian Indian female presented with productive cough since the past one month and low grade fever since the past two weeks. She was diagnosed with pulmonary tuberculosis and treated with antitubercular drugs. Subsequently, delayed cultures of bronchoalveolar lavage fluid grewBurkholderia pseudomallei (B. pseudomallei). On follow up the patient reported significant subjective improvement and ESR progressively returned to normal. In summary, this case report raises two distinct and equally intriguing roles forB. pseudomallei,i.e. respiratory colonization and spontaneously resolving pulmonary infection. The pathogenic potential ofB. pseudomallei, the etiologic agent of melioidosis, is well known. Confirmation of either colonization or spontaneous resolution, would potentially spare many patients unnecessary and expensive therapy with broad-spectrum antibiotics, and contribute to more rational usage of antibiotics, especially in co-infection withMycobacterium tuberculosis andB. pseudomallei-two bacterial diseases with closely similar clinical, radiologic and histopathologic features.

  11. Differentiation of Species Combined into the Burkholderia cepacia Complex and Related Taxa on the Basis of Their Fatty Acid Patterns

    OpenAIRE

    Krejčí, Eva; Kroppenstedt, Reiner M.

    2006-01-01

    Using the established commercial system Sherlock (MIDI, Inc.), cellular fatty acid methyl ester analysis for differentiation among Burkholderia cepacia complex species was proven. The identification key based on the diagnostic fatty acids is able to discern phenotypically related Ralstonia pickettii and Pandoraea spp. and further distinguish Burkholderia pyrrocinia, Burkholderia ambifaria, and Burkholderia vietnamiensis.

  12. Epigenetic alterations in the brain associated with HIV-1 infection and methamphetamine dependence.

    Science.gov (United States)

    Desplats, Paula; Dumaop, Wilmar; Cronin, Peter; Gianella, Sara; Woods, Steven; Letendre, Scott; Smith, David; Masliah, Eliezer; Grant, Igor

    2014-01-01

    HIV involvement of the CNS continues to be a significant problem despite successful use of combination antiretroviral therapy (cART). Drugs of abuse can act in concert with HIV proteins to damage glia and neurons, worsening the neurotoxicity caused by HIV alone. Methamphetamine (METH) is a highly addictive psychostimulant drug, abuse of which has reached epidemic proportions and is associated with high-risk sexual behavior, increased HIV transmission, and development of drug resistance. HIV infection and METH dependence can have synergistic pathological effects, with preferential involvement of frontostriatal circuits. At the molecular level, epigenetic alterations have been reported for both HIV-1 infection and drug abuse, but the neuropathological pathways triggered by their combined effects are less known. We investigated epigenetic changes in the brain associated with HIV and METH. We analyzed postmortem frontal cortex tissue from 27 HIV seropositive individuals, 13 of which had a history of METH dependence, in comparison to 14 cases who never used METH. We detected changes in the expression of DNMT1, at mRNA and protein levels, that resulted in the increase of global DNA methylation. Genome-wide profiling of DNA methylation in a subset of cases, showed differential methylation on genes related to neurodegeneration; dopamine metabolism and transport; and oxidative phosphorylation. We provide evidence for the synergy of HIV and METH dependence on the patterns of DNA methylation on the host brain, which results in a distinctive landscape for the comorbid condition. Importantly, we identified new epigenetic targets that might aid in understanding the aggravated neurodegenerative, cognitive, motor and behavioral symptoms observed in persons living with HIV and addictions. PMID:25054922

  13. Epigenetic alterations in the brain associated with HIV-1 infection and methamphetamine dependence.

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    Paula Desplats

    Full Text Available HIV involvement of the CNS continues to be a significant problem despite successful use of combination antiretroviral therapy (cART. Drugs of abuse can act in concert with HIV proteins to damage glia and neurons, worsening the neurotoxicity caused by HIV alone. Methamphetamine (METH is a highly addictive psychostimulant drug, abuse of which has reached epidemic proportions and is associated with high-risk sexual behavior, increased HIV transmission, and development of drug resistance. HIV infection and METH dependence can have synergistic pathological effects, with preferential involvement of frontostriatal circuits. At the molecular level, epigenetic alterations have been reported for both HIV-1 infection and drug abuse, but the neuropathological pathways triggered by their combined effects are less known. We investigated epigenetic changes in the brain associated with HIV and METH. We analyzed postmortem frontal cortex tissue from 27 HIV seropositive individuals, 13 of which had a history of METH dependence, in comparison to 14 cases who never used METH. We detected changes in the expression of DNMT1, at mRNA and protein levels, that resulted in the increase of global DNA methylation. Genome-wide profiling of DNA methylation in a subset of cases, showed differential methylation on genes related to neurodegeneration; dopamine metabolism and transport; and oxidative phosphorylation. We provide evidence for the synergy of HIV and METH dependence on the patterns of DNA methylation on the host brain, which results in a distinctive landscape for the comorbid condition. Importantly, we identified new epigenetic targets that might aid in understanding the aggravated neurodegenerative, cognitive, motor and behavioral symptoms observed in persons living with HIV and addictions.

  14. Recovery efficiencies for Burkholderia thailandensis from various aerosol sampling media

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    Paul eDabisch

    2012-06-01

    Full Text Available Burkholderia thailandensis is used in the laboratory as a surrogate of the more virulent B. pseudomallei. Since inhalation is believed to be a natural route of infection for B. pseudomallei, many animal studies with B. pseudomallei and B. thailandensis utilize the inhalation route of exposure. The aim of the present study was to quantify the recovery efficiency of culturable B. thailandensis from several common aerosol sampling devices to ensure that collected microorganisms could be reliably recovered post-collection. The sampling devices tested included 25-mm gelatin filters, 25-mm stainless steel disks used in Mercer cascade impactors, and two types of glass impingers. The results demonstrate that while several processing methods tested resulted in significantly lower physical recovery efficiencies than other methods, it was possible to obtain culturable recovery efficiencies for B. thailandensis and physical recovery efficiencies for 1 μm fluorescent spheres of at least 0.95 from all of the sampling media tested given an appropriate sample processing procedure. The results of the present study also demonstrated that the bubbling action of liquid media in all-glass impingers (AGIs can result in physical loss of material from the collection medium, although additional studies are needed to verify the exact mechanisms involved. Overall, the results of this study demonstrate that the collection mechanism as well as the post-collection processing method can significantly affect the recovery from and retention of culturable microorganisms in sampling media, potentially affecting the calculated airborne concentration and any subsequent estimations of risk or dose derived from such data.

  15. Burkholderia rhizoxinica sp. nov. and Burkholderia endofungorum sp. nov., bacterial endosymbionts of the plant-pathogenic fungus Rhizopus microsporus.

    Science.gov (United States)

    Partida-Martinez, Laila P; Groth, Ingrid; Schmitt, Imke; Richter, Walter; Roth, Martin; Hertweck, Christian

    2007-11-01

    Several strains of the fungus Rhizopus microsporus harbour endosymbiotic bacteria for the production of the causal agent of rice seedling blight, rhizoxin, and the toxic cyclopeptide rhizonin. R. microsporus and isolated endobacteria were selected for freeze-fracture electron microscopy, which allowed visualization of bacterial cells within the fungal cytosol by their two parallel-running envelope membranes and by the fine structure of the lipopolysaccharide layer of the outer membrane. Two representatives of bacterial endosymbionts were chosen for phylogenetic analyses on the basis of full 16S rRNA gene sequences, which revealed that the novel fungal endosymbionts formed a monophyletic group within the genus Burkholderia. Inter-sequence similarities ranged from 98.94 to 100%, and sequence similarities to members of the Burkholderia pseudomallei group, the closest neighbours, were 96.74-97.38%. In addition, the bacterial strains were distinguished from their phylogenetic neighbours by their fatty acid profiles and other biochemical characteristics. The phylogenetic studies based on 16S rRNA gene sequence data, together with conclusive DNA-DNA reassociation experiments, strongly support the proposal that these strains represent two novel species within the genus Burkholderia, for which the names Burkholderia rhizoxinica sp. nov. (type strain, HKI 454T=DSM 19002T=CIP 109453T) and Burkholderia endofungorum sp. nov. (type strain, HKI 456T=DSM 19003T=CIP 109454T) are proposed. PMID:17978222

  16. Prevalence of Burkholderia pseudomallei in Guangxi, China.

    Science.gov (United States)

    Ma, G; Zheng, D; Cai, Q; Yuan, Z

    2010-01-01

    Melioidosis, an infectious disease caused by the Gram-negative bacterium Burkholderia pseudomallei, is now recognized as an important public health problem in Southeast Asia and tropical northern Australia. Although B. pseudomallei has been detected in various water and soil samples in southeast China, the enviromental distribution of B. pseudomallei in China is unclear. In the winter months of 2007, 154 and 130 soil and water samples, respectively, were collected from several locations in Guangxi, China. The samples were screened for B. pseudomallei by bacterial culture and identification and confirmed by PCR for species-specific 16S rDNA and flagellin genes. B. pseudomallei was detected in 8.4% of the soil samples but in none of the water samples. All positive samples were confined to a single low-lying region from rice paddy fields. Counts of B. pseudomallei ranged from 23 to 521 c.f.u./g soil. This is the first geographical distribution survey of B. pseudomallei in soil in Guangxi, China, and the data are of importance for further evaluating the impact of this pathogen on melioidosis in this region. PMID:19538822

  17. Inhibition of Burkholderia multivorans Adhesion to Lung Epithelial Cells by Bivalent Lactosides

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    Trinidad Velasco-Torrijos

    2012-08-01

    Full Text Available Burkholderia cepacia complex (Bcc is an opportunistic pathogen in cystic fibrosis patients which is inherently resistant to antimicrobial agents. The mechanisms of attachment and pathogenesis of Bcc, a group of 17 species, are poorly understood. The most commonly identified Bcc species in newly colonised patients, Burkholderia multivorans, continues to be acquired from the environment. Development of therapies which can prevent or reduce the risk of colonization on exposure to Bcc in the environment would be a better alternative to antimicrobial agents. Previously, it has been shown that Bcc strains bound to many glycolipid receptors on lung epithelia. Using a real-time PCR method to quantify the levels of binding of B. multivorans to the lung epithelial cells, we have examined glycoconjugate derivatives for their potential to inhibit host cell attachment. Bivalent lactosides previously shown to inhibit galectin binding significantly reduced the attachment of B. multivorans to CF lung epithelial cells at micromolar concentrations. This was in contrast to monosaccharides and lactose, which were only effective in the millimolar range. Development of glycoconjugate therapies such as these, which inhibit attachment to lung epithelial cells, represent an alternative means of preventing infection with inherently antimicrobially resistant pathogens such as B. multivorans.

  18. The physical relationship between infectivity and prion protein aggregates is strain-dependent.

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    Philippe Tixador

    2010-04-01

    Full Text Available Prions are unconventional infectious agents thought to be primarily composed of PrP(Sc, a multimeric misfolded conformer of the ubiquitously expressed host-encoded prion protein (PrP(C. They cause fatal neurodegenerative diseases in both animals and humans. The disease phenotype is not uniform within species, and stable, self-propagating variations in PrP(Sc conformation could encode this 'strain' diversity. However, much remains to be learned about the physical relationship between the infectious agent and PrP(Sc aggregation state, and how this varies according to the strain. We applied a sedimentation velocity technique to a panel of natural, biologically cloned strains obtained by propagation of classical and atypical sheep scrapie and BSE infectious sources in transgenic mice expressing ovine PrP. Detergent-solubilized, infected brain homogenates were used as starting material. Solubilization conditions were optimized to separate PrP(Sc aggregates from PrP(C. The distribution of PrP(Sc and infectivity in the gradient was determined by immunoblotting and mouse bioassay, respectively. As a general feature, a major proteinase K-resistant PrP(Sc peak was observed in the middle part of the gradient. This population approximately corresponds to multimers of 12-30 PrP molecules, if constituted of PrP only. For two strains, infectivity peaked in a markedly different region of the gradient. This most infectious component sedimented very slowly, suggesting small size oligomers and/or low density PrP(Sc aggregates. Extending this study to hamster prions passaged in hamster PrP transgenic mice revealed that the highly infectious, slowly sedimenting particles could be a feature of strains able to induce a rapidly lethal disease. Our findings suggest that prion infectious particles are subjected to marked strain-dependent variations, which in turn could influence the strain biological phenotype, in particular the replication dynamics.

  19. Temperature dependent bacteriophages of a tropical bacterial pathogen

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    Martha Rebecca Jane Clokie

    2014-11-01

    Full Text Available There is an increasing awareness of the multiple ways that bacteriophages (phages influence bacterial evolution, population dynamics, physiology and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model Burkholderia thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C, the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C, the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial life, and on our ability to culture and correctly enumerate viable bacteria.

  20. Burkholderia dabaoshanensis sp. nov., a heavy-metal-tolerant bacteria isolated from Dabaoshan mining area soil in China.

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    Honghui Zhu

    Full Text Available Heavy-metal-tolerant bacteria, GIMN1.004(T, was isolated from mine soils of Dabaoshan in South China, which were acidic (pH 2-4 and polluted with heavy metals. The isolation was Gram-negative, aerobic, non-spore-forming, and rod-shaped bacteria having a cellular width of 0.5-0.6 µm and a length of 1.3-1.8 µm. They showed a normal growth pattern at pH 4.0-9.0 in a temperature ranging from 5 °C to 40 °C.The organism contained ubiquinone Q-8 as the predominant isoprenoid quinine, and C(16:0, summed feature 8 (C(18:1ω7c and C(18:1ω6c, C(18:0, summed feature 3 (C(16:1ω7c or iso-C(15:0 2-OH, C(17:0 cyclo, C(18:1ω9c, C(19:0 cyclo ω8c, C(14:0 as major fatty acid. These profiles were similar to those reported for Burkholderia species. The DNA G+C % of this strain was 61.6%. Based on the similarity to 16S rRNA gene sequence, GIMN1.004(T was considered to be in the genus Burkholderia. The similarities of 16S rRNA gene sequence between strain GIMN1.004(T and members of the genus Burkholderia were 96-99.4%, indicating that this novel strain was phylogenetically related to members of that genus. The novel strain showed the highest sequence similarities to Burkholderia soli DSM 18235(T (99.4%; Levels of DNA-DNA hybridization with DSM 18235(T was 25%. Physiological and biochemical tests including cell wall composition analysis, differentiated phenotype of this strain from that closely related Burkholderia species. The isolation had great tolerance to cadmium with MIC of 22 mmol/L, and adsorbability of 144.94 mg/g cadmium,and it was found to exhibit antibiotic resistance characteristics. The adsorptive mechanism of GIMN1.004(T for cadmium depended on the action of the amide,carboxy and phosphate of cell surface and producing low-molecular-weight (LMW organic acids to complex or chelated Cd(2+.Therefore, the strain GIMN1.004(T represented a new cadmium resistance species, which was tentatively named as Burkholderia dabaoshanensis sp. nov. The strain type

  1. Dengue virus sero-cross-reactivity drives antibody-dependent enhancement of infection with zika virus.

    Science.gov (United States)

    Dejnirattisai, Wanwisa; Supasa, Piyada; Wongwiwat, Wiyada; Rouvinski, Alexander; Barba-Spaeth, Giovanna; Duangchinda, Thaneeya; Sakuntabhai, Anavaj; Cao-Lormeau, Van-Mai; Malasit, Prida; Rey, Felix A; Mongkolsapaya, Juthathip; Screaton, Gavin R

    2016-09-01

    Zika virus (ZIKV) was discovered in 1947 and was thought to lead to relatively mild disease. The recent explosive outbreak of ZIKV in South America has led to widespread concern, with reports of neurological sequelae ranging from Guillain Barré syndrome to microcephaly. ZIKV infection has occurred in areas previously exposed to dengue virus (DENV), a flavivirus closely related to ZIKV. Here we investigated the serological cross-reaction between the two viruses. Plasma immune to DENV showed substantial cross-reaction to ZIKV and was able to drive antibody-dependent enhancement (ADE) of ZIKV infection. Using a panel of human monoclonal antibodies (mAbs) to DENV, we showed that most antibodies that reacted to DENV envelope protein also reacted to ZIKV. Antibodies to linear epitopes, including the immunodominant fusion-loop epitope, were able to bind ZIKV but were unable to neutralize the virus and instead promoted ADE. Our data indicate that immunity to DENV might drive greater ZIKV replication and have clear implications for disease pathogenesis and future vaccine programs for ZIKV and DENV. PMID:27339099

  2. Variable selection in covariate dependent random partition models: an application to urinary tract infection.

    Science.gov (United States)

    Barcella, William; Iorio, Maria De; Baio, Gianluca; Malone-Lee, James

    2016-04-15

    Lower urinary tract symptoms can indicate the presence of urinary tract infection (UTI), a condition that if it becomes chronic requires expensive and time consuming care as well as leading to reduced quality of life. Detecting the presence and gravity of an infection from the earliest symptoms is then highly valuable. Typically, white blood cell (WBC) count measured in a sample of urine is used to assess UTI. We consider clinical data from 1341 patients in their first visit in which UTI (i.e. WBC ≥ 1) is diagnosed. In addition, for each patient, a clinical profile of 34 symptoms was recorded. In this paper, we propose a Bayesian nonparametric regression model based on the Dirichlet process prior aimed at providing the clinicians with a meaningful clustering of the patients based on both the WBC (response variable) and possible patterns within the symptoms profiles (covariates). This is achieved by assuming a probability model for the symptoms as well as for the response variable. To identify the symptoms most associated to UTI, we specify a spike and slab base measure for the regression coefficients: this induces dependence of symptoms selection on cluster assignment. Posterior inference is performed through Markov Chain Monte Carlo methods. PMID:26536840

  3. Collagen arrangement in hepatic granuloma in mice infected with Schistosoma mansoni: dependence on fiber radiation centers

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    H.L. Lenzi

    1999-05-01

    Full Text Available The collagen structure of isolated and in situ liver granuloma from Swiss Webster mice infected with Schistosoma mansoni was sequentially and three-dimensionally analyzed during different times of infection (early acute, acute, transitional acute-chronic, and chronic phases by laser scanning confocal microscopy and electron scanning variable vacuum microscopy. The initial granuloma structure is characterized by vascular collagen residues and by anchorage points (or fiber radiation centers, from where collagenous fibers are angularly shed and self-assembled. During the exudative-productive stage, the self-assembly of these fibers minimizes energy and mass through continuous tension and focal compression. The curvature or angles between collagen fibers probably depends on the fibroblastic or myofibroblastic organization of stress fibers. Gradually, the loose unstable lattice of the exudative-productive stage transforms into a highly packed and stable architecture as a result of progressive compactness. The three-dimensional architecture of granulomas provides increased tissue integrity, efficient distribution of soluble compounds and a haptotactic background to the cells.

  4. Strain-Dependent Effect of Macroautophagy on Abnormally Folded Prion Protein Degradation in Infected Neuronal Cells.

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    Daisuke Ishibashi

    Full Text Available Prion diseases are neurodegenerative disorders caused by the accumulation of abnormal prion protein (PrPSc in the central nervous system. With the aim of elucidating the mechanism underlying the accumulation and degradation of PrPSc, we investigated the role of autophagy in its degradation, using cultured cells stably infected with distinct prion strains. The effects of pharmacological compounds that inhibit or stimulate the cellular signal transduction pathways that mediate autophagy during PrPSc degradation were evaluated. The accumulation of PrPSc in cells persistently infected with the prion strain Fukuoka-1 (FK, derived from a patient with Gerstmann-Sträussler-Scheinker syndrome, was significantly increased in cultures treated with the macroautophagy inhibitor 3-methyladenine (3MA but substantially reduced in those treated with the macroautophagy inducer rapamycin. The decrease in FK-derived PrPSc levels was mediated, at least in part, by the phosphatidylinositol 3-kinase/MEK signalling pathway. By contrast, neither rapamycin nor 3MA had any apparently effect on PrPSc from either the 22L or the Chandler strain, indicating that the degradation of PrPSc in host cells might be strain-dependent.

  5. Characterization of the Poly-β-1,6-N-Acetylglucosamine Polysaccharide Component of Burkholderia Biofilms ▿

    OpenAIRE

    Yakandawala, Nandadeva; Gawande, Purushottam V.; LoVetri, Karen; Cardona, Silvia T.; Romeo, Tony; Nitz, Mark; Madhyastha, Srinivasa

    2011-01-01

    We demonstrated the production of poly-β-1,6-N-acetylglucosamine (PNAG) polysaccharide in the biofilms of Burkholderia multivorans, Burkholderia vietnamiensis, Burkholderia ambifaria, Burkholderia cepacia, and Burkholderia cenocepacia using an immunoblot assay for PNAG. These results were confirmed by further studies, which showed that the PNAG hydrolase, dispersin B, eliminated immunoreactivity of extracts from the species that were tested (B. cenocepacia and B. multivorans). Dispersin B als...

  6. Burkholderia mallei and Burkholderia pseudomallei cluster 1 type VI secretion system gene expression is negatively regulated by iron and zinc.

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    Mary N Burtnick

    Full Text Available Burkholderia mallei is a facultative intracellular pathogen that causes glanders in humans and animals. Previous studies have demonstrated that the cluster 1 type VI secretion system (T6SS-1 expressed by this organism is essential for virulence in hamsters and is positively regulated by the VirAG two-component system. Recently, we have shown that T6SS-1 gene expression is up-regulated following internalization of this pathogen into phagocytic cells and that this system promotes multinucleated giant cell formation in infected tissue culture monolayers. In the present study, we further investigated the complex regulation of this important virulence factor. To assess T6SS-1 expression, B. mallei strains were cultured in various media conditions and Hcp1 production was analyzed by Western immunoblotting. Transcript levels of several VirAG-regulated genes (bimA, tssA, hcp1 and tssM were also determined using quantitative real time PCR. Consistent with previous observations, T6SS-1 was not expressed during growth of B. mallei in rich media. Curiously, growth of the organism in minimal media (M9G or minimal media plus casamino acids (M9CG facilitated robust expression of T6SS-1 genes whereas growth in minimal media plus tryptone (M9TG did not. Investigation of this phenomenon confirmed a regulatory role for VirAG in this process. Additionally, T6SS-1 gene expression was significantly down-regulated by the addition of iron and zinc to M9CG. Other genes under the control of VirAG did not appear to be as tightly regulated by these divalent metals. Similar results were observed for B. pseudomallei, but not for B. thailandensis. Collectively, our findings indicate that in addition to being positively regulated by VirAG, B. mallei and B. pseudomallei T6SS-1 gene expression is negatively regulated by iron and zinc.

  7. Infection

    Science.gov (United States)

    ... Potential Hazards Exposure of employees to community and nosocomial infections, e.g., Methicillin-resistant Staphylococcus aureus (MRSA) . Nosocomial infections are infections that occur from exposure to infectious ...

  8. Recent Advances in Burkholderia mallei and B. pseudomallei Research

    Science.gov (United States)

    Hatcher, Christopher L.; Muruato, Laura A.

    2015-01-01

    Burkholderia mallei and Burkholderia pseudomallei are Gram-negative organisms, which are etiological agents of glanders and melioidosis, respectively. Although only B. pseudomallei is responsible for a significant number of human cases, both organisms are classified as Tier 1 Select Agents and their diseases lack effective diagnosis and treatment. Despite a recent resurgence in research pertaining to these organisms, there are still a number of knowledge gaps. This article summarizes the latest research progress in the fields of B. mallei and B. pseudomallei pathogenesis, vaccines, and diagnostics. PMID:25932379

  9. Treatment of urodelans based on temperature dependent infection dynamics of Batrachochytrium salamandrivorans.

    Science.gov (United States)

    Blooi, M; Martel, A; Haesebrouck, F; Vercammen, F; Bonte, D; Pasmans, F

    2015-01-27

    The recently emerged chytrid fungus Batrachochytrium salamandrivorans currently causes amphibian population declines. We hypothesized that temperature dictates infection dynamics of B. salamandrivorans, and that therefore heat treatment may be applied to clear animals from infection. We examined the impact of environmental temperature on B. salamandrivorans infection and disease dynamics in fire salamanders (Salamandra salamandra). Colonization of salamanders by B. salamandrivorans occurred at 15°C and 20°C but not at 25°C, with a significantly faster buildup of infection load and associated earlier mortality at 15°C. Exposing B. salamandrivorans infected salamanders to 25°C for 10 days resulted in complete clearance of infection and clinically cured all experimentally infected animals. This treatment protocol was validated in naturally infected wild fire salamanders. In conclusion, we show that B. salamandrivorans infection and disease dynamics are significantly dictated by environmental temperature, and that heat treatment is a viable option for clearing B. salamandrivorans infections.

  10. Antibody-Dependent Enhancement of Dengue Virus Infection in Primary Human Macrophages; Balancing Higher Fusion against Antiviral Responses.

    Science.gov (United States)

    Flipse, Jacky; Diosa-Toro, Mayra A; Hoornweg, Tabitha E; van de Pol, Denise P I; Urcuqui-Inchima, Silvio; Smit, Jolanda M

    2016-01-01

    The dogma is that the human immune system protects us against pathogens. Yet, several viruses, like dengue virus, antagonize the hosts' antibodies to enhance their viral load and disease severity; a phenomenon called antibody-dependent enhancement of infection. This study offers novel insights in the molecular mechanism of antibody-mediated enhancement (ADE) of dengue virus infection in primary human macrophages. No differences were observed in the number of bound and internalized DENV particles following infection in the absence and presence of enhancing concentrations of antibodies. Yet, we did find an increase in membrane fusion activity during ADE of DENV infection. The higher fusion activity is coupled to a low antiviral response early in infection and subsequently a higher infection efficiency. Apparently, subtle enhancements early in the viral life cycle cascades into strong effects on infection, virus production and immune response. Importantly, and in contrast to other studies, the antibody-opsonized virus particles do not trigger immune suppression and remain sensitive to interferon. Additionally, this study gives insight in how human macrophages interact and respond to viral infections and the tight regulation thereof under various conditions of infection. PMID:27380892

  11. Antibody-Dependent Enhancement of Dengue Virus Infection in Primary Human Macrophages; Balancing Higher Fusion against Antiviral Responses

    Science.gov (United States)

    Flipse, Jacky; Diosa-Toro, Mayra A.; Hoornweg, Tabitha E.; van de Pol, Denise P. I.; Urcuqui-Inchima, Silvio; Smit, Jolanda M.

    2016-01-01

    The dogma is that the human immune system protects us against pathogens. Yet, several viruses, like dengue virus, antagonize the hosts’ antibodies to enhance their viral load and disease severity; a phenomenon called antibody-dependent enhancement of infection. This study offers novel insights in the molecular mechanism of antibody-mediated enhancement (ADE) of dengue virus infection in primary human macrophages. No differences were observed in the number of bound and internalized DENV particles following infection in the absence and presence of enhancing concentrations of antibodies. Yet, we did find an increase in membrane fusion activity during ADE of DENV infection. The higher fusion activity is coupled to a low antiviral response early in infection and subsequently a higher infection efficiency. Apparently, subtle enhancements early in the viral life cycle cascades into strong effects on infection, virus production and immune response. Importantly, and in contrast to other studies, the antibody-opsonized virus particles do not trigger immune suppression and remain sensitive to interferon. Additionally, this study gives insight in how human macrophages interact and respond to viral infections and the tight regulation thereof under various conditions of infection. PMID:27380892

  12. Postinfection Biological Control of Oomycete Pathogens of Pea by Burkholderia cepacia AMMDR1.

    Science.gov (United States)

    Heungens, K; Parke, J L

    2001-04-01

    ABSTRACT Burkholderia cepacia AMMDR1 is a biocontrol agent that reduces Pythium damping-off and Aphanomyces root rot severity on peas in the field. We studied the effect of B. cepacia AMMDR1 on post-infection stages in the life cycles of these pathogens, including mycelial colonization of the host, production of oogonia, and production of secondary zoospore inoculum. We used Burkholderia cepacia 1324, a seed and rootcolonizing but antibiosis-deficient Tn5 mutant of B. cepacia AMMDR1, to study mechanisms of biological control other than antibiosis. B. cepacia AMMDR1 significantly reduced Pythium aphanidermatum postinfection colonization and damping-off of pea seeds, even when the bacteria were applied 12 h after zoospore inoculation. B. cepacia AMMDR1 also significantly reduced colonization of taproots by Aphanomyces euteiches mycelium, but only when the bacteria were applied at high population densities at the site of zoospore inoculation. The antibiosisdeficient mutant, B. cepacia 1324, had no effect on mycelial colonization of seeds or roots by Pythium aphanidermatum nor A. euteiches, suggesting that antibiosis is the primary mechanism of biological control. B. cepacia AMMDR1, but not B. cepacia 1324, reduced production of A. euteiches oogonia. This effect occurred even when the population size of B. cepacia AMMDR1 was too small to cause a reduction in lesion length early on in the infection process and may result from in situ antibiotic production. B. cepacia AMMDR1 had no effect on the production of secondary zoospores of A. euteiches from infected roots. The main effects of B. cepacia AMMDR1 on postinfection stages in the life cycles of these pathogens therefore were reductions in mycelial colonization by Pythium aphanidermatum and in formation of oogonia by A. euteiches. No mechanism other than antibiosis could be identified. PMID:18943851

  13. Burkholderia cenocepacia Differential Gene Expression during Host–Pathogen Interactions and Adaptation to the Host Environment

    Science.gov (United States)

    O’Grady, Eoin P.; Sokol, Pamela A.

    2011-01-01

    Members of the Burkholderia cepacia complex (Bcc) are important in medical, biotechnological, and agricultural disciplines. These bacteria naturally occur in soil and water environments and have adapted to survive in association with plants and animals including humans. All Bcc species are opportunistic pathogens including Burkholderia cenocepacia that causes infections in cystic fibrosis and chronic granulomatous disease patients. The adaptation of B. cenocepacia to the host environment was assessed in a rat chronic respiratory infection model and compared to that of high cell-density in vitro grown cultures using transcriptomics. The distribution of genes differentially expressed on chromosomes 1, 2, and 3 was relatively proportional to the size of each genomic element, whereas the proportion of plasmid-encoded genes differentially expressed was much higher relative to its size and most genes were induced in vivo. The majority of genes encoding known virulence factors, components of types II and III secretion systems and chromosome 2-encoded type IV secretion system were similarly expressed between in vitro and in vivo environments. Lower expression in vivo was detected for genes encoding N-acyl-homoserine lactone synthase CepI, orphan LuxR homolog CepR2, zinc metalloproteases ZmpA and ZmpB, LysR-type transcriptional regulator ShvR, nematocidal protein AidA, and genes associated with flagellar motility, Flp type pilus formation, and type VI secretion. Plasmid-encoded type IV secretion genes were markedly induced in vivo. Additional genes induced in vivo included genes predicted to be involved in osmotic stress adaptation or intracellular survival, metal ion, and nutrient transport, as well as those encoding outer membrane proteins. Genes identified in this study are potentially important for virulence during host–pathogen interactions and may be associated with survival and adaptation to the host environment during chronic lung infections. PMID:22919581

  14. Beclin 1 Is Required for Starvation-Enhanced, but Not Rapamycin-Enhanced, LC3-Associated Phagocytosis of Burkholderia pseudomallei in RAW 264.7 Cells

    OpenAIRE

    Li, Xuelei; Prescott, Mark; Adler, Ben; John D Boyce; Rodney J. Devenish

    2013-01-01

    LC3-associated phagocytosis (LAP) of Burkholderia pseudomallei by murine macrophage (RAW 264.7) cells is an intracellular innate defense mechanism. Beclin 1, a protein with several roles in autophagic processes, is known to be recruited to phagosomal membranes as a very early event in LAP. We sought to determine whether knockdown of Beclin 1 by small interfering RNA (siRNA) would affect recruitment of LC3 and subsequent LAP of infecting B. pseudomallei. Both starvation and rapamycin treatment...

  15. Survival of Burkholderia pseudomallei in Water

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    Woods Donald E

    2008-05-01

    Full Text Available Abstract Background The ability of Burkholderia pseudomallei to survive in water likely contributes to its environmental persistence in endemic regions. To determine the physiological adaptations which allow B. pseudomallei to survive in aqueous environments, we performed microarray analyses of B. pseudomallei cultures transferred from Luria broth (LB to distilled water. Findings Increased expression of a gene encoding for a putative membrane protein (BPSL0721 was confirmed using a lux-based transcriptional reporter system, and maximal expression was noted at approximately 6 hrs after shifting cells from LB to water. A BPSL0721 deficient mutant of B. pseudomallei was able to survive in water for at least 90 days indicating that although involved, BPSL0721 was not essential for survival. BPSL2961, a gene encoding a putative phosphatidylglycerol phosphatase (PGP, was also induced when cells were shifted to water. This gene is likely involved in cell membrane biosynthesis. We were unable to construct a PGP mutant suggesting that the gene is not only involved in survival in water but is essential for cell viability. We also examined mutants of polyhydroxybutyrate synthase (phbC, lipopolysaccharide (LPS oligosaccharide and capsule synthesis, and these mutations did not affect survival in water. LPS mutants lacking outer core were found to lose viability in water by 200 days indicating that an intact LPS core provides an outer membrane architecture which allows prolonged survival in water. Conclusion The results from these studies suggest that B. pseudomallei survival in water is a complex process that requires an LPS molecule which contains an intact core region.

  16. Burkholderia type VI secretion systems have distinct roles in eukaryotic and bacterial cell interactions.

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    Sandra Schwarz

    Full Text Available Bacteria that live in the environment have evolved pathways specialized to defend against eukaryotic organisms or other bacteria. In this manuscript, we systematically examined the role of the five type VI secretion systems (T6SSs of Burkholderia thailandensis (B. thai in eukaryotic and bacterial cell interactions. Consistent with phylogenetic analyses comparing the distribution of the B. thai T6SSs with well-characterized bacterial and eukaryotic cell-targeting T6SSs, we found that T6SS-5 plays a critical role in the virulence of the organism in a murine melioidosis model, while a strain lacking the other four T6SSs remained as virulent as the wild-type. The function of T6SS-5 appeared to be specialized to the host and not related to an in vivo growth defect, as ΔT6SS-5 was fully virulent in mice lacking MyD88. Next we probed the role of the five systems in interbacterial interactions. From a group of 31 diverse bacteria, we identified several organisms that competed less effectively against wild-type B. thai than a strain lacking T6SS-1 function. Inactivation of T6SS-1 renders B. thai greatly more susceptible to cell contact-induced stasis by Pseudomonas putida, Pseudomonas fluorescens and Serratia proteamaculans-leaving it 100- to 1000-fold less fit than the wild-type in competition experiments with these organisms. Flow cell biofilm assays showed that T6S-dependent interbacterial interactions are likely relevant in the environment. B. thai cells lacking T6SS-1 were rapidly displaced in mixed biofilms with P. putida, whereas wild-type cells persisted and overran the competitor. Our data show that T6SSs within a single organism can have distinct functions in eukaryotic versus bacterial cell interactions. These systems are likely to be a decisive factor in the survival of bacterial cells of one species in intimate association with those of another, such as in polymicrobial communities present both in the environment and in many infections.

  17. Stress conditions triggering mucoid morphotype variation in Burkholderia species and effect on virulence in Galleria mellonella and biofilm formation in vitro.

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    Inês N Silva

    Full Text Available Burkholderia cepacia complex (Bcc bacteria are opportunistic pathogens causing chronic respiratory infections particularly among cystic fibrosis patients. During these chronic infections, mucoid-to-nonmucoid morphotype variation occurs, with the two morphotypes exhibiting different phenotypic properties. Here we show that in vitro, the mucoid clinical isolate Burkholderia multivorans D2095 gives rise to stable nonmucoid variants in response to prolonged stationary phase, presence of antibiotics, and osmotic and oxidative stresses. Furthermore, in vitro colony morphotype variation within other members of the Burkholderia genus occurred in Bcc and non-Bcc strains, irrespectively of their clinical or environmental origin. Survival to starvation and iron limitation was comparable for the mucoid parental isolate and the respective nonmucoid variant, while susceptibility to antibiotics and to oxidative stress was increased in the nonmucoid variants. Acute infection of Galleria mellonella larvae showed that, in general, the nonmucoid variants were less virulent than the respective parental mucoid isolate, suggesting a role for the exopolysaccharide in virulence. In addition, most of the tested nonmucoid variants produced more biofilm biomass than their respective mucoid parental isolate. As biofilms are often associated with increased persistence of pathogens in the CF lungs and are an indicative of different cell-to-cell interactions, it is possible that the nonmucoid variants are better adapted to persist in this host environment.

  18. Screening a mushroom extract library for activity against Acinetobacter baumannii and Burkholderia cepacia and the identification of a compound with anti-Burkholderia activity

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    Rott Marc

    2010-01-01

    Full Text Available Abstract Background Acinetobacter baumannii and species within the Burkholderia cepacia complex (BCC are significant opportunistic bacterial pathogens of humans. These species exhibit a high degree of antibiotic resistance, and some clinical isolates are resistant to all currently available antimicrobial drugs used for treatment. Thus, new drugs are needed to treat infections by these species. Mushrooms could be a potential source for new drugs to treat A. baumannii and BCC infections. Methods The aim of this study was to screen a library of crude extracts from 330 wild mushrooms by disk diffusion assays for antibacterial activity against A. baumannii and Burkholderia cepacia in the hope of identifying a novel natural drug that could be used to treat infections caused by these species. Once positive hits were identified, the extracts were subjected to bioassay-guided separations to isolate and identify the active drug molecules. MICs were performed to gauge the in vitro activity of the purified compounds. Results Only three crude extracts (0.9% had activity against A. baumannii and B. cepacia. Compounds from two of these extracts had MICs greater than 128 μg/ml, and further analyses were not performed. From the third extract, prepared from Leucopaxillus albissimus, 2-aminoquinoline (2-AQ was isolated. This compound exhibited a modest MIC in vitro against strains from nine different BCC species, including multi-drug resistant clinical isolates (MIC = 8-64 μg/ml, and a weak MIC (128 μg/ml against A baumannii. The IC50 against a murine monocyte line was 1.5 mg/ml. Conclusion The small number of positive hits in this study suggests that finding a new drug from mushrooms to treat Gram-negative bacterial infections may be difficult. Although 2-AQ was identified in one mushroom, and it was shown to inhibit the growth of multi-drug resistant BCC isolates, the relatively high MICs (8-128 μg/ml for both A. baumannii and BCC strains suggests that 2-AQ

  19. Symbiotic ß-proteobacteria beyond legumes: Burkholderia in Rubiaceae.

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    Brecht Verstraete

    Full Text Available Symbiotic ß-proteobacteria not only occur in root nodules of legumes but are also found in leaves of certain Rubiaceae. The discovery of bacteria in plants formerly not implicated in endosymbiosis suggests a wider occurrence of plant-microbe interactions. Several ß-proteobacteria of the genus Burkholderia are detected in close association with tropical plants. This interaction has occurred three times independently, which suggest a recent and open plant-bacteria association. The presence or absence of Burkholderia endophytes is consistent on genus level and therefore implies a predictive value for the discovery of bacteria. Only a single Burkholderia species is found in association with a given plant species. However, the endophyte species are promiscuous and can be found in association with several plant species. Most of the endophytes are part of the plant-associated beneficial and environmental group, but others are closely related to B. glathei. This soil bacteria, together with related nodulating and non-nodulating endophytes, is therefore transferred to a newly defined and larger PBE group within the genus Burkholderia.

  20. Severe bacterial infections in patients with non-transfusion-dependent thalassemia: prevalence and clinical risk factors

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    Nattiya Teawtrakul

    2015-10-01

    Conclusion: The prevalence of bacterial infection in patients with NTDT was found to be moderate. Time after splenectomy >10 years, deferoxamine therapy, and iron overload may be clinical risk factors for severe bacterial infection in patients with NTDT. Bacterial infection should be recognized in splenectomized patients with NTDT, particularly those who have an iron overload.

  1. Production and characterization of chimeric monoclonal antibodies against Burkholderia pseudomallei and B. mallei using the DHFR expression system.

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    Hyung-Yong Kim

    Full Text Available Burkholderia pseudomallei (BP and B. mallei (BM are closely related gram-negative, facultative anaerobic bacteria which cause life-threatening melioidosis in human and glanders in horse, respectively. Our laboratory has previously generated and characterized more than 100 mouse monoclonal antibodies (MAbs against BP and BM, according to in vitro and in vivo assay. In this study, 3 MAbs (BP7 10B11, BP7 2C6, and BP1 7F7 were selected to develop into chimeric mouse-human monoclonal antibodies (cMAbs against BP and/or BM. For the stable production of cMAbs, we constructed 4 major different vector systems with a dihydrofolate reductase (DHFR amplification marker, and optimized transfection/selection conditions in mammalian host cells with the single-gene and/or double-gene expression system. These 3 cMAbs were stably produced by the DHFR double mutant Chinese hamster ovarian (CHO-DG44 cells. By ELISA and Western blot analysis using whole bacterial antigens treated by heat (65°C/90 min, sodium periodate, and proteinase K, the cMAb BP7 10B11 (cMAb CK1 reacted with glycoproteins (34, 38, 48 kDa in BP; 28, 38, 48 kDa in BM. The cMAb BP7 2C6 (cMAb CK2 recognized surface-capsule antigens with molecular sizes of 38 to 52 kDa, and 200 kDa in BM. The cMAb CK2 was weakly reactive to 14∼28, 200 kDa antigens in BP. The cMAb BP1 7F7 (cMAb CK3 reacted with lipopolysaccharides (38∼52 kDa in BP; 38∼60 kDa in B. thailandensis. Western blot results with the outer surface antigens of the 3 Burkholderia species were consistent with results with the whole Burkholderia cell antigens, suggesting that these immunodominant antigens reacting with the 3 cMAbs were primarily present on the outer surface of the Burkholderia species. These 3 cMAbs would be useful for analyzing the role of the major outer surface antigens in Burkholderia infection.

  2. Research Status and Prospect ofBurkholderia glumae, the Pathogen Causing Bacterial Panicle Blight

    Institute of Scientific and Technical Information of China (English)

    CUI Zhou-qi; ZHU Bo; XIE Guan-lin; LI Bin; HUANG Shi-wen

    2016-01-01

    Bacterial panicle blight caused by Burkholderia glumae is one of the most severe seed-borne bacterial diseases of rice in the world. Currently, this disease has affected many countries of Asia, Africa, South and North America. It is a typical example of the shifting from minor plant disease to major disease due to the changes of environmental conditions. Some virulent factors of B. glumae have been identified, including toxoflavins and lipases, whose productions are dependent on the TofI/TofR quorum-sensing system, and type III effectors. In spite of its economic significance, neither effective control measure for this disease nor resistant rice variety is currently available. In recent years, genomics, transcriptomics and other molecular methods have provided useful information for better understanding the molecular mechanisms underlyingB. glumaevirulence and the rice defence mechanisms against pathogens. For the prevention of this pathogen, our laboratory has developed a rapid and sensitive multiplex PCR assay for detecting and distinguishingB. glumae from otherBurkholderia species. This improved understanding ofB. glumae will shed new light on bacterial panicle blight disease management.

  3. Mycotic aneurysm caused by Burkholderia pseudomallei in a previously healthy returning traveller

    Science.gov (United States)

    Bodilsen, Jacob; Vammen, Sten; Fuursted, Kurt; Hjort, Ulla

    2014-01-01

    Burkholderia pseudomallei is a common cause of serious, difficult to treat infections in South-East Asia and Northern Australia, but is a rare imported pathogen in the USA and Europe. We report a case of a patient with a mycotic aneurysm caused by B. pseudomallei in a previously healthy returning traveller. The patient presented with 4 weeks of abdominal pain and intermittent fever after a brief vacation in Thailand. The aneurysm was excised and replaced by an autologous deep vein graft, and the patient was treated for 6 months with antibiotics adjusted according to postoperative renal impairment. Twenty-four months after surgery the patient is well and without relapse. PMID:25246454

  4. Burkholderia pseudomallei Type III Secretion System Cluster 3 ATPase BsaS, a Chemotherapeutic Target for Small-Molecule ATPase Inhibitors

    OpenAIRE

    Gong, Lan; Lai, Shu-Chin; Treerat, Puthayalai; Prescott, Mark; Adler, Ben; John D Boyce; Rodney J. Devenish

    2015-01-01

    Melioidosis is an infectious disease of high mortality for humans and other animal species; it is prevalent in tropical regions worldwide. The pathogenesis of melioidosis depends on the ability of its causative agent, the Gram-negative bacterium Burkholderia pseudomallei, to enter and survive in host cells. B. pseudomallei can escape from the phagosome into the cytosol of phagocytic cells where it replicates and acquires actin-mediated motility, avoiding killing by the autophagy-dependent pro...

  5. Extensive complement-dependent enhancement of HIV-1 by autologous non-neutralising antibodies at early stages of infection

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    Williams Ian

    2011-03-01

    Full Text Available Abstract Background Non-neutralising antibodies to the envelope glycoprotein are elicited during acute HIV-1 infection and are abundant throughout the course of disease progression. Although these antibodies appear to have negligible effects on HIV-1 infection when assayed in standard neutralisation assays, they have the potential to exert either inhibitory or enhancing effects through interactions with complement and/or Fc receptors. Here we report that non-neutralising antibodies produced early in response to HIV-1 infection can enhance viral infectivity. Results We investigated this complement-mediated antibody-dependent enhancement (C'-ADE of early HIV infection by carrying out longitudinal studies with primary viruses and autologous sera derived sequentially from recently infected individuals, using a T cell line naturally expressing the complement receptor 2 (CR2; CD21. The C'-ADE was consistently observed and in some cases achieved infection-enhancing levels of greater than 350-fold, converting a low-level infection to a highly destructive one. C'-ADE activity declined as a neutralising response to the early virus emerged, but later virus isolates that had escaped the neutralising response demonstrated an increased capacity for enhanced infection by autologous antibodies. Moreover, sera with autologous enhancing activity were capable of C'ADE of heterologous viral isolates, suggesting the targeting of conserved epitopes on the envelope glycoprotein. Ectopic expression of CR2 on cell lines expressing HIV-1 receptors was sufficient to render them sensitive to C'ADE. Conclusions Taken together, these results suggest that non-neutralising antibodies to the HIV-1 envelope that arise during acute infection are not 'passive', but in concert with complement and complement receptors may have consequences for HIV-1 dissemination and pathogenesis.

  6. Retromer Is Essential for Autophagy-Dependent Plant Infection by the Rice Blast Fungus

    Science.gov (United States)

    He, Yunlong; Xie, Qiurong; Chen, Ahai; Zheng, Huawei; Shi, Lei; Zhao, Xu; Zhang, Chengkang; Huang, Qingping; Fang, Kunhai; Lu, Guodong; Ebbole, Daniel J.; Li, Guangpu; Naqvi, Naweed I.; Wang, Zonghua

    2015-01-01

    The retromer mediates protein trafficking through recycling cargo from endosomes to the trans-Golgi network in eukaryotes. However, the role of such trafficking events during pathogen-host interaction remains unclear. Here, we report that the cargo-recognition complex (MoVps35, MoVps26 and MoVps29) of the retromer is essential for appressorium-mediated host penetration by Magnaporthe oryzae, the causal pathogen of the blast disease in rice. Loss of retromer function blocked glycogen distribution and turnover of lipid bodies, delayed nuclear degeneration and reduced turgor during appressorial development. Cytological observation revealed dynamic MoVps35-GFP foci co-localized with autophagy-related protein RFP-MoAtg8 at the periphery of autolysosomes. Furthermore, RFP-MoAtg8 interacted with MoVps35-GFP in vivo, RFP-MoAtg8 was mislocalized to the vacuole and failed to recycle from the autolysosome in the absence of the retromer function, leading to impaired biogenesis of autophagosomes. We therefore conclude that retromer is essential for autophagy-dependent plant infection by the rice blast fungus. PMID:26658729

  7. Removal of Burkholderia cepacia biofilms with oxidants

    Science.gov (United States)

    Koenig, D. W.; Mishra, S. K.; Pierson, D. L.

    1995-01-01

    Iodine is used to disinfect the water system aboard US space shuttles and is the anticipated biocide for the international space station. Water quality on spacecraft must be maintained at the highest possible levels for the safety of the crew. Furthermore, the treatment process used to maintain the quality of water on research must be robust and operate for long periods with minimal crew intervention. Biofilms are recalcitrant and pose a major threat with regard to chronic contamination of spacecraft water systems. We measured the effectiveness of oxidizing biocides on the removal and regrowth of Burkholderia (Pseudomonas) cepacia biofilms. B. cepacia, isolated from the water distribution system of the space shuttle Discovery, was grown in continuous culture to produce a bacterial contamination source for biofilm formation and removal studies. A 10(7) CFU ml-1 B. cepacia suspension, in distilled water, was used to form biofilms on 3000 micrometers2 glass surfaces. Rates of attachment were measured directly with image analysis and were found to be 7.8, 15.2, and 22.8 attachment events h-1 for flow rates of 20.7, 15.2, and 9.8 ml min-1, respectively. After 18 h of formation, the B. cepacia biofilms were challenged with oxidants (ozone, chlorine, and iodine) and the rates of biofilm removal determined by image analysis. Fifty percent of the biofilm material was removed in the first hour of continous treatment with 24 mg l-1 chlorine or 2 mg l-1 ozone. Iodine (48 mg l-1) did not remove any measurable cellular material after 6 h continuous contact. After this first removal of biofilms by the oxidants, the surface was allowed to refoul and was again treated with the biocide. Iodine was the only compound that was unable to remove cellular debris from either primary or secondary biofilms. Moreover, treating primary biofilms with iodine increased the rate of formation of secondary biofilms, from 4.4 to 5.8 attachment events h-1. All the oxidants tested inactivated the B

  8. Gram-Negative Bacterial Infection in Thigh Abscess Can Migrate to Distant Burn Depending on Burn Depth

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    Victoria Hamrahi

    2012-01-01

    Full Text Available Sepsis remains the major cause of death in patients with major burn injuries. In the present investigation we evaluated the interaction between burn injuries of varying severity and preexisting distant infection. We used Gram-negative bacteria (Pseudomonas aeruginosa and Proteus mirabilis that were genetically engineered to be bioluminescent, which allowed for noninvasive, sequential optical imaging of the extent and severity of the infection. The bioluminescent bacteria migrated from subcutaneous abscesses in the leg to distant burn wounds on the back depending on the severity of the burn injury, and this migration led to increased mortality of the mice. Treatment with ciprofloxacin, injected either in the leg with the bacterial infection or into the burn eschar, prevented this colonization of the wound and decreased mortality. The present data suggest that burn wounds can readily become colonized by infections distant from the wound itself.

  9. Burkholderia: an update on taxonomy and biotechnological potential as antibiotic producers.

    Science.gov (United States)

    Depoorter, Eliza; Bull, Matt J; Peeters, Charlotte; Coenye, Tom; Vandamme, Peter; Mahenthiralingam, Eshwar

    2016-06-01

    Burkholderia is an incredibly diverse and versatile Gram-negative genus, within which over 80 species have been formally named and multiple other genotypic groups likely represent new species. Phylogenetic analysis based on the 16S rRNA gene sequence and core genome ribosomal multilocus sequence typing analysis indicates the presence of at least three major clades within the genus. Biotechnologically, Burkholderia are well-known for their bioremediation and biopesticidal properties. Within this review, we explore the ability of Burkholderia to synthesise a wide range of antimicrobial compounds ranging from historically characterised antifungals to recently described antibacterial antibiotics with activity against multiresistant clinical pathogens. The production of multiple Burkholderia antibiotics is controlled by quorum sensing and examples of quorum sensing pathways found across the genus are discussed. The capacity for antibiotic biosynthesis and secondary metabolism encoded within Burkholderia genomes is also evaluated. Overall, Burkholderia demonstrate significant biotechnological potential as a source of novel antibiotics and bioactive secondary metabolites. PMID:27115756

  10. [Long-term HIV infection and dialysis dependent renal failure in analgesic nephropathy].

    Science.gov (United States)

    Müller, V; Opravil, M

    1998-09-01

    We report a case of advanced human immundeficiency virus infection and relapsing urinary tract infections due to analgesic nephropathy. The patient developed an urosepsis with multiorgan dysfunction syndrome and required dialysis. Inspite of this complicated course, for the first time thirteen years after diagnosis of the HIV-infection, an antiretroviral treatment was started, followed by an impressive improvement of quality of life, physical activity and psychological stabilization.

  11. Lack of MyD88 protects the immunodeficient host against fatal lung inflammation triggered by the opportunistic bacteria Burkholderia cenocepacia.

    Science.gov (United States)

    Ventura, Grasiella M de C; Balloy, Viviane; Ramphal, Reuben; Khun, Huot; Huerre, Michel; Ryffel, Bernhard; Plotkowski, Maria-Cristina M; Chignard, Michel; Si-Tahar, Mustapha

    2009-07-01

    Burkholderia cenocepacia is an opportunistic pathogen of major concern for cystic fibrosis patients as well as immunocompromised cancer patients and transplant recipients. The mechanisms by which B. cenocepacia triggers a rapid health deterioration of the susceptible host have yet to be characterized. TLR and their key signaling intermediate MyD88 play a central role in the detection of microbial molecular patterns and in the initiation of an effective immune response. We performed a study to better understand the role of TLR-MyD88 signaling in B. cenocepacia-induced pathogenesis in the immunocompromised host, using an experimental murine model. The time-course of several dynamic parameters, including animal survival, bacterial load, and secretion of critical inflammatory mediators, was compared in infected and immunosuppressed wild-type and MyD88(-/-) mice. Notably, when compared with wild-type mice, infected MyD88(-/-) animals displayed significantly reduced levels of inflammatory mediators (including KC, TNF-alpha, IL-6, MIP-2, and G-CSF) in blood and lung airspaces. Moreover, despite a higher transient bacterial load in the lungs, immunosuppressed mice deficient in MyD88 had an unexpected survival advantage. Finally, we showed that this B. cenocepacia-induced life-threatening infection of wild-type mice involved the proinflammatory cytokine TNF-alpha and could be prevented by corticosteroids. Altogether, our findings demonstrate that a MyD88-dependent pathway can critically contribute to a detrimental host inflammatory response that leads to fatal pneumonia. PMID:19535624

  12. Host immunity in the protective response to vaccination with heat-killed Burkholderia mallei

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    Paessler Slobodan

    2008-09-01

    Full Text Available Abstract Background We performed initial cell, cytokine and complement depletion studies to investigate the possible role of these effectors in response to vaccination with heat-killed Burkholderia mallei in a susceptible BALB/c mouse model of infection. Results While protection with heat-killed bacilli did not result in sterilizing immunity, limited protection was afforded against an otherwise lethal infection and provided insight into potential host protective mechanisms. Our results demonstrated that mice depleted of either B cells, TNF-α or IFN-γ exhibited decreased survival rates, indicating a role for these effectors in obtaining partial protection from a lethal challenge by the intraperitoneal route. Additionally, complement depletion had no effect on immunoglobulin production when compared to non-complement depleted controls infected intranasally. Conclusion The data provide a basis for future studies of protection via vaccination using either subunit or whole-organism vaccine preparations from lethal infection in the experimental BALB/c mouse model. The results of this study demonstrate participation of B220+ cells and pro-inflammatory cytokines IFN-γ and TNF-α in protection following HK vaccination.

  13. Development of a recA Gene-Based Identification Approach for the Entire Burkholderia Genus

    OpenAIRE

    Payne, George W.; Vandamme, Peter; Morgan, Sara H.; LiPuma, John J.; Coenye, Tom; Weightman, Andrew J.; Jones, T. Hefin; Mahenthiralingam, Eshwar

    2005-01-01

    Burkholderia is an important bacterial genus containing species of ecological, biotechnological, and pathogenic interest. With their taxonomy undergoing constant revision and the phenotypic similarity of several species, correct identification of Burkholderia is difficult. A genetic scheme based on the recA gene has greatly enhanced the identification of Burkholderia cepacia complex species. However, the PCR developed for the latter approach was limited by its specificity for the complex. By ...

  14. Species Distribution and Ribotype Diversity of Burkholderia cepacia Complex Isolates from French Patients with Cystic Fibrosis

    OpenAIRE

    Brisse, Sylvain; Cordevant, Christophe; Vandamme, Peter; Bidet, Philippe; Loukil, Chawki; Chabanon, Gérard; Lange, Marc; Bingen, Edouard

    2004-01-01

    A total of 153 Burkholderia cepacia strains obtained from 153 French patients with cystic fibrosis were identified as Burkholderia multivorans (51.6%) or Burkholderia cenocepacia (45.1%). Eighty-two genotypes were identified using PvuII and EcoRI ribotyping. B. multivorans genotype A (found in 32 French patients) and two other genotypes were also identified among isolates from Austrian, German, Italian, and Canadian patients.

  15. Molecular Method To Assess the Diversity of Burkholderia Species in Environmental Samples

    OpenAIRE

    Salles, J; Souza, de, H.R.; Elsas, van, J.D.

    2002-01-01

    In spite of the importance of many members of the genus Burkholderia in the soil microbial community, no direct method to assess the diversity of this genus has been developed so far. The aim of this work was the development of soil DNA-based PCR-denaturing gradient gel electrophoresis (DGGE), a powerful tool for studying the diversity of microbial communities, for detection and analysis of the Burkholderia diversity in soil samples. Primers specific for the genus Burkholderia were developed ...

  16. Members of the genus Burkholderia: good and bad guys [version 1; referees: 3 approved

    OpenAIRE

    Leo Eberl; Peter Vandamme

    2016-01-01

    In the 1990s several biocontrol agents on that contained Burkholderia strains were registered by the United States Environmental Protection Agency (EPA). After risk assessment these products were withdrawn from the market and a moratorium was placed on the registration of Burkholderia-containing products, as these strains may pose a risk to human health. However, over the past few years the number of novel Burkholderia species that exhibit plant-beneficial properties and are normally not isol...

  17. Burkholderia Hep_Hag autotransporter (BuHA proteins elicit a strong antibody response during experimental glanders but not human melioidosis

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    Foster Simon J

    2007-03-01

    Full Text Available Abstract Background The bacterial biothreat agents Burkholderia mallei and Burkholderia pseudomallei are the cause of glanders and melioidosis, respectively. Genomic and epidemiological studies have shown that B. mallei is a recently emerged, host restricted clone of B. pseudomallei. Results Using bacteriophage-mediated immunoscreening we identified genes expressed in vivo during experimental equine glanders infection. A family of immunodominant antigens were identified that share protein domain architectures with hemagglutinins and invasins. These have been designated Burkholderia Hep_Hag autotransporter (BuHA proteins. A total of 110/207 positive clones (53% of a B. mallei expression library screened with sera from two infected horses belonged to this family. This contrasted with 6/189 positive clones (3% of a B. pseudomallei expression library screened with serum from 21 patients with culture-proven melioidosis. Conclusion Members of the BuHA proteins are found in other Gram-negative bacteria and have been shown to have important roles related to virulence. Compared with other bacterial species, the genomes of both B. mallei and B. pseudomallei contain a relative abundance of this family of proteins. The domain structures of these proteins suggest that they function as multimeric surface proteins that modulate interactions of the cell with the host and environment. Their effect on the cellular immune response to B. mallei and their potential as diagnostics for glanders requires further study.

  18. Engagement and Substance Dependence in a Primary Care-Based Addiction Treatment Program for People Infected with HIV and People at High-Risk for HIV Infection.

    Science.gov (United States)

    Walley, Alexander Y; Palmisano, Joseph; Sorensen-Alawad, Amy; Chaisson, Christine; Raj, Anita; Samet, Jeffrey H; Drainoni, Mari-Lynn

    2015-12-01

    To improve outcomes for people with substance dependence and HIV infection or at risk for HIV infection, patients were enrolled in a primary care-based addiction treatment program from 2008-2012 that included a comprehensive substance use assessment, individual and group counseling, addiction pharmacotherapy and case management. We examined whether predisposing characteristics (depression, housing status, polysubstance use) and an enabling resource (buprenorphine treatment) were associated with engagement in the program and persistent substance dependence at 6 months. At program enrollment 61% were HIV-infected, 53% reported heroin use, 46% reported alcohol use, 37% reported cocaine use, and 28% reported marijuana use in the past 30 days, 72% reported depression, 19% were homeless, and 53% had polysubstance use. Within 6-months 60% had been treated with buprenorphine. Engagement (defined as 2 visits in first 14 days and 2 additional visits in next 30 days) occurred in 64%; 49% had substance dependence at 6-months. Receipt of buprenorphine treatment was associated with engagement (Adjusted Odds Ratio (AOR) 8.32 95% CI: 4.13-16.77). Self-reported depression at baseline was associated with substance dependence at 6-months (AOR 3.30 95% CI: 1.65-6.61). Neither housing status nor polysubstance use was associated with engagement or substance dependence. The FAST PATH program successfully engaged and treated patients in a primary care-based addiction treatment program. Buprenorphine, a partial opioid agonist, was a major driver of addiction treatment engagement. Given depression's association with adverse outcomes in this clinical population, including mental health treatment as part of integrated care holds potential to improve addiction treatment outcomes. PMID:26298399

  19. Age-Dependent Cell Trafficking Defects in Draining Lymph Nodes Impair Adaptive Immunity and Control of West Nile Virus Infection.

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    Justin M Richner

    2015-07-01

    Full Text Available Impaired immune responses in the elderly lead to reduced vaccine efficacy and increased susceptibility to viral infections. Although several groups have documented age-dependent defects in adaptive immune priming, the deficits that occur prior to antigen encounter remain largely unexplored. Herein, we identify novel mechanisms for compromised adaptive immunity that occurs with aging in the context of infection with West Nile virus (WNV, an encephalitic flavivirus that preferentially causes disease in the elderly. An impaired IgM and IgG response and enhanced vulnerability to WNV infection during aging was linked to delayed germinal center formation in the draining lymph node (DLN. Adoptive transfer studies and two-photon intravital microscopy revealed a decreased trafficking capacity of donor naïve CD4+ T cells from old mice, which manifested as impaired T cell diapedesis at high endothelial venules and reduced cell motility within DLN prior to antigen encounter. Furthermore, leukocyte accumulation in the DLN within the first few days of WNV infection or antigen-adjuvant administration was diminished more generally in old mice and associated with a second aging-related defect in local cytokine and chemokine production. Thus, age-dependent cell-intrinsic and environmental defects in the DLN result in delayed immune cell recruitment and antigen recognition. These deficits compromise priming of early adaptive immune responses and likely contribute to the susceptibility of old animals to acute WNV infection.

  20. Association with Soil Bacteria Enhances p38-Dependent Infection Resistance in Caenorhabditis elegans

    Science.gov (United States)

    Montalvo-Katz, Sirena; Huang, Hao; Appel, Michael David; Berg, Maureen

    2013-01-01

    The importance of our inner microbial communities for proper immune responses against invading pathogens is now well accepted, but the mechanisms underlying this protection are largely unknown. In this study, we used Caenorhabditis elegans to investigate such mechanisms. Since very little is known about the microbes interacting with C. elegans in its natural environment, we began by taking the first steps to characterize the C. elegans microbiota. We established a natural-like environment in which initially germfree, wild-type larvae were grown on enriched soil. Bacterial members of the adult C. elegans microbiota were isolated by culture and identified using 16S rRNA gene sequencing. Using pure cultures of bacterial isolates as food, we identified two, Bacillus megaterium and Pseudomonas mendocina, that enhanced resistance to a subsequent infection with the Gram-negative pathogen Pseudomonas aeruginosa. Whereas protection by B. megaterium was linked to impaired egg laying, corresponding to a known trade-off between fecundity and resistance, the mechanism underlying protection conferred by P. mendocina depended on weak induction of immune genes regulated by the p38 MAPK pathway. Disruption of the p38 ortholog, pmk-1, abolished protection. P. mendocina enhanced resistance to P. aeruginosa but not to the Gram-positive pathogen Enterococcus faecalis. Furthermore, protection from P. aeruginosa was similarly induced by a P. aeruginosa gacA mutant with attenuated virulence but not by a different C. elegans-associated Pseudomonas sp. isolate. Our results support a pivotal role for the conserved p38 pathway in microbiota-initiated immune protection and suggest that similarity between microbiota members and pathogens may play a role in such protection. PMID:23230286

  1. Identification of Burkholderia mallei and Burkholderia pseudomallei adhesins for human respiratory epithelial cells

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    Hogan Robert J

    2010-09-01

    Full Text Available Abstract Background Burkholderia pseudomallei and Burkholderia mallei cause the diseases melioidosis and glanders, respectively. A well-studied aspect of pathogenesis by these closely-related bacteria is their ability to invade and multiply within eukaryotic cells. In contrast, the means by which B. pseudomallei and B. mallei adhere to cells are poorly defined. The purpose of this study was to identify adherence factors expressed by these organisms. Results Comparative sequence analyses identified a gene product in the published genome of B. mallei strain ATCC23344 (locus # BMAA0649 that resembles the well-characterized Yersinia enterocolitica autotransporter adhesin YadA. The gene encoding this B. mallei protein, designated boaA, was expressed in Escherichia coli and shown to significantly increase adherence to human epithelial cell lines, specifically HEp2 (laryngeal cells and A549 (type II pneumocytes, as well as to cultures of normal human bronchial epithelium (NHBE. Consistent with these findings, disruption of the boaA gene in B. mallei ATCC23344 reduced adherence to all three cell types by ~50%. The genomes of the B. pseudomallei strains K96243 and DD503 were also found to contain boaA and inactivation of the gene in DD503 considerably decreased binding to monolayers of HEp2 and A549 cells and to NHBE cultures. A second YadA-like gene product highly similar to BoaA (65% identity was identified in the published genomic sequence of B. pseudomallei strain K96243 (locus # BPSL1705. The gene specifying this protein, termed boaB, appears to be B. pseudomallei-specific. Quantitative attachment assays demonstrated that recombinant E. coli expressing BoaB displayed greater binding to A549 pneumocytes, HEp2 cells and NHBE cultures. Moreover, a boaB mutant of B. pseudomallei DD503 showed decreased adherence to these respiratory cells. Additionally, a B. pseudomallei strain lacking expression of both boaA and boaB was impaired in its ability to

  2. Identification of CD4-Binding Site Dependent Plasma Neutralizing Antibodies in an HIV-1 Infected Indian Individual.

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    Lubina Khan

    Full Text Available Dissecting antibody specificities in the plasma of HIV-1 infected individuals that develop broadly neutralizing antibodies (bNAbs is likely to provide useful information for refining target epitopes for vaccine design. Several studies have reported CD4-binding site (CD4bs antibodies as neutralization determinants in the plasma of subtype B-infected individuals; however there is little information on the prevalence of CD4bs specificities in HIV-infected individuals in India. Here, we report on the presence of CD4bs antibodies and their contribution to virus neutralization in the plasma from a cohort of HIV-1 infected Indian individuals. Plasma from 11 of the 140 HIV-1 infected individuals (7.9% studied here exhibited cross-neutralization activity against a panel of subtype B and C viruses. Analyses of these 11 plasma samples for the presence of CD4bs antibodies using two CD4bs-selective probes (antigenically resurfaced HXB2gp120 core protein RSC3 and hyperglycosylated JRFLgp120 mutant ΔN2mCHO revealed that five (AIIMS 617, 619, 627, 642, 660 contained RSC3-reactive plasma antibodies and only one (AIIMS 660 contained ΔN2mCHO-reactive antibodies. Plasma antibody depletion and competition experiments confirmed that the neutralizing activity in the AIIMS 660 plasma was dependent on CD4bs antibodies. To the best of our knowledge, this is the first study to report specifically on the presence of CD4bs antibodies in the plasma of a cohort of HIV-1 infected Indian donors. The identification of CD4bs dependent neutralizing antibodies in an HIV-1 infected Indian donor is a salient finding of this study and is supportive of ongoing efforts to induce similar antibodies by immunization.

  3. Human glial chimeric mice reveal astrocytic dependence of JC virus infection

    DEFF Research Database (Denmark)

    Kondo, Yoichi; Windrem, Martha S; Zou, Lisa;

    2014-01-01

    with humanized white matter by engrafting human glial progenitor cells (GPCs) into neonatal immunodeficient and myelin-deficient mice. Intracerebral delivery of JCV resulted in infection and subsequent demyelination of these chimeric mice. Human GPCs and astrocytes were infected more readily than...... oligodendrocytes, and viral replication was noted primarily in human astrocytes and GPCs rather than oligodendrocytes, which instead expressed early viral T antigens and exhibited apoptotic death. Engraftment of human GPCs in normally myelinated and immunodeficient mice resulted in humanized white matter...... that was chimeric for human astrocytes and GPCs. JCV effectively propagated in these mice, which indicates that astroglial infection is sufficient for JCV spread. Sequencing revealed progressive mutation of the JCV capsid protein VP1 after infection, suggesting that PML may evolve with active infection...

  4. Analysis of host- and strain-dependent cell death responses during infectious salmon anemia virus infection in vitro

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    Mjaaland Siri

    2009-07-01

    Full Text Available Abstract Background Infectious salmon anemia virus (ISAV is an aquatic orthomyxovirus and the causative agent of infectious salmon anemia (ISA, a disease of great importance in the Atlantic salmon farming industry. In vitro, ISAV infection causes cytophatic effect (CPE in cell lines from Atlantic salmon, leading to rounding and finally detachment of the cells from the substratum. In this study, we investigated the mode of cell death during in vitro ISAV infection in different Atlantic salmon cell lines, using four ISAV strains causing different mortality in vivo. Results The results show that caspase 3/7 activity increased during the course of infection in ASK and SHK-1 cells, infected cells showed increased surface expression of phosphatidylserine and increased PI uptake, compared to mock infected cells; and morphological alterations of the mitochondria were observed. Expression analysis of immune relevant genes revealed no correlation between in vivo mortality and expression, but good correlation in expression of interferon genes. Conclusion Results from this study indicate that there is both strain and cell type dependent differences in the virus-host interaction during ISAV infection. This is important to bear in mind when extrapolating in vitro findings to the in vivo situation.

  5. ICP34.5-Dependent and –Independent Activities of Salubrinal in Herpes Simplex Virus-1 Infected Cells

    OpenAIRE

    Bryant, Kevin F.; Macari, Elizabeth R.; Malik, Natasha; Boyce, Michael; Yuan, Junying; Coen, Donald M.

    2008-01-01

    The small molecule salubrinal has antiviral activity against herpes simplex virus-1 (HSV-1) and inhibits dephosphorylation of eIF2α mediated by the HSV-1 protein ICP34.5. We investigated whether salubrinal's activities in infected cells depend on ICP34.5. An ICP34.5 deletion mutant was as sensitive as wild type HSV-1 to salubrinal inhibition of plaque formation in Vero cells. However, salubrinal induced formation of syncytia in infected Vero cells, which was enhanced by ICP34.5 mutations. Exp...

  6. IL-33-Dependent Endothelial Activation Contributes to Apoptosis and Renal Injury in Orientia tsutsugamushi-Infected Mice

    Science.gov (United States)

    Shelite, Thomas R.; Liang, Yuejin; Wang, Hui; Mendell, Nicole L.; Trent, Brandon J.; Sun, Jiaren; Gong, Bin; Xu, Guang; Hu, Haitao; Bouyer, Donald H.; Soong, Lynn

    2016-01-01

    Endothelial cells (EC) are the main target for Orientia tsutsugamushi infection and EC dysfunction is a hallmark of severe scrub typhus in patients. However, the molecular basis of EC dysfunction and its impact on infection outcome are poorly understood. We found that C57BL/6 mice that received a lethal dose of O. tsutsugamushi Karp strain had a significant increase in the expression of IL-33 and its receptor ST2L in the kidneys and liver, but a rapid reduction of IL-33 in the lungs. We also found exacerbated EC stress and activation in the kidneys of infected mice, as evidenced by elevated angiopoietin (Ang) 2/Ang1 ratio, increased endothelin 1 (ET-1) and endothelial nitric oxide synthase (eNOS) expression. Such responses were significantly attenuated in the IL-33-/- mice. Importantly, IL-33-/- mice also had markedly attenuated disease due to reduced EC stress and cellular apoptosis. To confirm the biological role of IL-33, we challenged wild-type (WT) mice with a sub-lethal dose of O. tsutsugamushi and gave mice recombinant IL-33 (rIL-33) every 2 days for 10 days. Exogenous IL-33 significantly increased disease severity and lethality, which correlated with increased EC stress and activation, increased CXCL1 and CXCL2 chemokines, but decreased anti-apoptotic gene BCL-2 in the kidneys. To further examine the role of EC stress, we infected human umbilical vein endothelial cells (HUVEC) in vitro. We found an infection dose-dependent increase in the expression of IL-33, ST2L soluble ST2 (sST2), and the Ang2/Ang1 ratio at 24 and 48 hours post-infection. This study indicates a pathogenic role of alarmin IL-33 in a murine model of scrub typhus and highlights infection-triggered EC damage and IL-33-mediated pathological changes during the course of Orientia infection. PMID:26943125

  7. IL-33-Dependent Endothelial Activation Contributes to Apoptosis and Renal Injury in Orientia tsutsugamushi-Infected Mice.

    Directory of Open Access Journals (Sweden)

    Thomas R Shelite

    2016-03-01

    Full Text Available Endothelial cells (EC are the main target for Orientia tsutsugamushi infection and EC dysfunction is a hallmark of severe scrub typhus in patients. However, the molecular basis of EC dysfunction and its impact on infection outcome are poorly understood. We found that C57BL/6 mice that received a lethal dose of O. tsutsugamushi Karp strain had a significant increase in the expression of IL-33 and its receptor ST2L in the kidneys and liver, but a rapid reduction of IL-33 in the lungs. We also found exacerbated EC stress and activation in the kidneys of infected mice, as evidenced by elevated angiopoietin (Ang 2/Ang1 ratio, increased endothelin 1 (ET-1 and endothelial nitric oxide synthase (eNOS expression. Such responses were significantly attenuated in the IL-33-/- mice. Importantly, IL-33-/- mice also had markedly attenuated disease due to reduced EC stress and cellular apoptosis. To confirm the biological role of IL-33, we challenged wild-type (WT mice with a sub-lethal dose of O. tsutsugamushi and gave mice recombinant IL-33 (rIL-33 every 2 days for 10 days. Exogenous IL-33 significantly increased disease severity and lethality, which correlated with increased EC stress and activation, increased CXCL1 and CXCL2 chemokines, but decreased anti-apoptotic gene BCL-2 in the kidneys. To further examine the role of EC stress, we infected human umbilical vein endothelial cells (HUVEC in vitro. We found an infection dose-dependent increase in the expression of IL-33, ST2L soluble ST2 (sST2, and the Ang2/Ang1 ratio at 24 and 48 hours post-infection. This study indicates a pathogenic role of alarmin IL-33 in a murine model of scrub typhus and highlights infection-triggered EC damage and IL-33-mediated pathological changes during the course of Orientia infection.

  8. Life cycle-dependent cytoskeletal modifications in Plasmodium falciparum infected erythrocytes.

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    Hui Shi

    Full Text Available Plasmodium falciparum infection of human erythrocytes is known to result in the modification of the host cell cytoskeleton by parasite-coded proteins. However, such modifications and corresponding implications in malaria pathogenesis have not been fully explored. Here, we probed the gradual modification of infected erythrocyte cytoskeleton with advancing stages of infection using atomic force microscopy (AFM. We reported a novel strategy to derive accurate and quantitative information on the knob structures and their connections with the spectrin network by performing AFM-based imaging analysis of the cytoplasmic surface of infected erythrocytes. Significant changes on the red cell cytoskeleton were observed from the expansion of spectrin network mesh size, extension of spectrin tetramers and the decrease of spectrin abundance with advancing stages of infection. The spectrin network appeared to aggregate around knobs but also appeared sparser at non-knob areas as the parasite matured. This dramatic modification of the erythrocyte skeleton during the advancing stage of malaria infection could contribute to the loss of deformability of the infected erythrocyte.

  9. Molecular Signatures and Phylogenomic Analysis of the Genus Burkholderia: Proposal for Division of this Genus into the Emended Genus Burkholderia Containing Pathogenic Organisms and a New Genus Paraburkholderia gen. nov. Harboring Environmental Species

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    Aman eSawana

    2014-12-01

    Full Text Available The genus Burkholderia contains large number of diverse species which are not reliably distinguished by the available biochemical or molecular characteristics. We report here results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concatenated sequences for 21 conserved proteins as well as 16S rRNA gene sequences, Burkholderia species grouped into two major clades. Within these main clades a number of smaller clades were also clearly distinguished. Our comparative analysis of protein sequences from Burkholderia spp. has identified 42 highly specific molecular markers in the form of conserved sequence indels (CSIs that are uniquely found in different clades of Burkholderia spp. Six of these CSIs are specific for a group of Burkholderia spp. (referred to as Clade I which contains all clinically relevant members of the genus as well as the phytopathogenic Burkholderia species. The second main clade (Clade II composed of the environmental Burkholderia species, is also distinguished by 2 of the identified CSIs. Additionally, our work has also identified 3 CSIs that are specific for the Burkholderia cepacia complex, 4 CSIs that are uniquely found in the Burkholderia pseudomallei group, 5 CSIs that are specific for the phytopathogenic Burkholderia spp. and 22 other CSI that distinguish two groups within Clade II. The described molecular markers provide highly specific means for the demarcation of different groups of Burkholderia spp. and for development of novel diagnostic assays for the clinically important members of the group. Based upon the results from different lines of studies, a division of the genus Burkholderia into two genera is proposed. In this new proposal, the emended genus Burkholderia will contain only the clinically relevant and phytopathogenic Burkholderia species, whereas all other Burkholderia spp. are transferred to a new genus

  10. Activation and inflammation markers in HIV-1-infected patients in dependency of treatment strategies

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    R Ehret

    2012-11-01

    Full Text Available Purpose of the study: HIV-1-infected patients have elevated levels of immune activation and systemic inflammatory markers which are partially strong predictors of disease progression or are associated with increased cardiovascular risk. The dependency of anti-retroviral treatment (ART, the usage of NNRTI or PI-based and the application of non-nuc regimens is analysed here on the basis of a dataset (Chronic Inflammation Dependency on TREatment: CIDRE cohort from 1500 patients in Berlin. Methods: In a retrospective analysis we compared relative CD4+ cell counts, viral load, relative CD8+CD38+DR-and CD3+DR+cells, concentration of high-sensitivity C-reactive protein (hsCRP and interleukin-6 (IL-6 in therapy-naïve or treated patients dependent on usage or non-usage of NUCs, PI or NNRTI. Statistics were performed with R (R Core Team; 2012; R: A language and environment for statistical computing using Wilcoxon rank sum test in two-sided analysis. Summary of results: As to expect, ART-naïve patients (n=190 had significantly higher viral loads and lower CD4+cell counts (p: both<0.05 and showed higher activation levels than treated patient (CD8+CD38+DR- and CD3+DR+both<0.05. But no significant difference was calculated for hsCRP or IL-6. Nuc-sparing regimen (n=46 did not show any distinction compared to nuc-containing therapies (n=1249 for the analysed parameters. Significant differences were detected for PI-regimen (n=711 with lower CD4+ cell counts and higher activation (CD8+38+DR-, CD3+DR+ and IL-6 (p: all<0.05 but not for hsCRP (p=0.39. The opposite was true for NNRTI-based therapies (n=445 with higher CD4+ cell percentages and lower activation and inflammation markers (p: all<0.05 and as well no difference in hsCRP (p=0.97 compared with all other treated patients. Conclusions: The lack of differences between therapy-naïve patients and patients on ART for inflammation markers may be due to the relative good immunological state of the first group

  11. Melioidosis: an emerging infection in Taiwan?

    OpenAIRE

    Hsueh, P. R.; Teng, L J; Lee, L N; Yu, C. J.; Yang, P. C.; Ho, S W; Luh, K. T.

    2001-01-01

    From January 1982 to May 2000, 17 infections caused by Burkholderia pseudomallei were diagnosed in 15 patients in Taiwan; almost all the infections were diagnosed from 1994 to May 2000. Of the 15 patients, 9 (60%) had underlying diseases, and 10 (67%) had bacteremic pneumonia. Thirteen (76%) episodes of infection were considered indigenous. Four patients died of melioidosis. Seventeen B. pseudomallei isolates, recovered from eight patients from November 1996 to May 2000, were analyzed to dete...

  12. Specific elimination of HIV-1 infected cells using Tat/Rev-dependent circuit

    OpenAIRE

    Perdigão, Pedro Ricardo Lucas, 1987-

    2011-01-01

    Tese de mestrado. Biologia (Biologia Molecular e Genética). Universidade de Lisboa, Faculdade de Ciências, 2011 Despite the success of antiretroviral cocktails, a cure for HIV-1 remains elusive. This is mainly due to the existence of persistent cellular reservoirs infected with non-transcriptional, latent HIV-1. An effective treatment against HIV-1 would target both active and latent HIV-1-infected cells, and eliminate them without harming non-infected cells. In order to achieve this, we h...

  13. Understanding the Pathogenicity of Burkholderia contaminans, an Emerging Pathogen in Cystic Fibrosis

    Science.gov (United States)

    Nunvar, Jaroslav; Kalferstova, Lucie; Bloodworth, Ruhi A. M.; Kolar, Michal; Degrossi, Jose; Lubovich, Silvina; Cardona, Silvia T.; Drevinek, Pavel

    2016-01-01

    Several bacterial species from the Burkholderia cepacia complex (Bcc) are feared opportunistic pathogens that lead to debilitating lung infections with a high risk of developing fatal septicemia in cystic fibrosis (CF) patients. However, the pathogenic potential of other Bcc species is yet unknown. To elucidate clinical relevance of Burkholderia contaminans, a species frequently isolated from CF respiratory samples in Ibero-American countries, we aimed to identify its key virulence factors possibly linked with an unfavorable clinical outcome. We performed a genome-wide comparative analysis of two isolates of B. contaminans ST872 from sputum and blood culture of a female CF patient in Argentina. RNA-seq data showed significant changes in expression for quorum sensing-regulated virulence factors and motility and chemotaxis. Furthermore, we detected expression changes in a recently described low-oxygen-activated (lxa) locus which encodes stress-related proteins, and for two clusters responsible for the biosynthesis of antifungal and hemolytic compounds pyrrolnitrin and occidiofungin. Based on phenotypic assays that confirmed changes in motility and in proteolytic, hemolytic and antifungal activities, we were able to distinguish two phenotypes of B. contaminans that coexisted in the host and entered her bloodstream. Whole genome sequencing revealed that the sputum and bloodstream isolates (each representing a distinct phenotype) differed by over 1,400 mutations as a result of a mismatch repair-deficient hypermutable state of the sputum isolate. The inferred lack of purifying selection against nonsynonymous mutations and the high rate of pseudogenization in the derived isolate indicated limited evolutionary pressure during evolution in the nutrient-rich, stable CF sputum environment. The present study is the first to examine the genomic and transcriptomic differences between longitudinal isolates of B. contaminans. Detected activity of a number of putative virulence

  14. The multiple roles of hypothetical gene BPSS1356 in Burkholderia pseudomallei.

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    Hokchai Yam

    Full Text Available Burkholderia pseudomallei is an opportunistic pathogen and the causative agent of melioidosis. It is able to adapt to harsh environments and can live intracellularly in its infected hosts. In this study, identification of transcriptional factors that associate with the β' subunit (RpoC of RNA polymerase was performed. The N-terminal region of this subunit is known to trigger promoter melting when associated with a sigma factor. A pull-down assay using histidine-tagged B. pseudomallei RpoC N-terminal region as bait showed that a hypothetical protein BPSS1356 was one of the proteins bound. This hypothetical protein is conserved in all B. pseudomallei strains and present only in the Burkholderia genus. A BPSS1356 deletion mutant was generated to investigate its biological function. The mutant strain exhibited reduced biofilm formation and a lower cell density during the stationary phase of growth in LB medium. Electron microscopic analysis revealed that the ΔBPSS1356 mutant cells had a shrunken cytoplasm indicative of cell plasmolysis and a rougher surface when compared to the wild type. An RNA microarray result showed that a total of 63 genes were transcriptionally affected by the BPSS1356 deletion with fold change values of higher than 4. The expression of a group of genes encoding membrane located transporters was concurrently down-regulated in ΔBPSS1356 mutant. Amongst the affected genes, the putative ion transportation genes were the most severely suppressed. Deprivation of BPSS1356 also down-regulated the transcriptions of genes for the arginine deiminase system, glycerol metabolism, type III secretion system cluster 2, cytochrome bd oxidase and arsenic resistance. It is therefore obvious that BPSS1356 plays a multiple regulatory roles on many genes.

  15. The Impact of Ly49-NK Cell-Dependent Recognition of MCMV Infection on Innate and Adaptive Immune Responses

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    Michal Pyzik

    2011-01-01

    Full Text Available Clinical and experimental data indicate that a subset of innate lymphocytes, natural killer (NK cells, plays a crucial role in the response against herpesviruses, especially cytomegaloviruses (CMV. Indeed, in mice, NK cells, due to the expression of germline encoded Ly49 receptors, possess multiple mechanisms to recognize CMV infection. Classically, this results in NK cell activation and the destruction of the infected cells. More recently, however, this unique host-pathogen interaction has permitted the discovery of novel aspects of NK cell biology, implicating them in the regulation of adaptive immune responses as well as in the development of immunological memory. Here, we will concisely review the newly acquired evidence pertaining to NK cell Ly49-dependent recognition of MCMV-infected cell and the ensuing NK cell regulatory responses.

  16. The Burkholderia Genome Database: facilitating flexible queries and comparative analyses

    OpenAIRE

    Winsor, Geoffrey L.; Khaira, Bhavjinder; Van Rossum, Thea; Lo, Raymond; Whiteside, Matthew D.; Fiona S.L. Brinkman

    2008-01-01

    Summary: As the genome sequences of multiple strains of a given bacterial species are obtained, more generalized bacterial genome databases may be complemented by databases that are focused on providing more information geared for a distinct bacterial phylogenetic group and its associated research community. The Burkholderia Genome Database represents a model for such a database, providing a powerful, user-friendly search and comparative analysis interface that contains features not found in ...

  17. Burkholderia pseudomallei Capsular Polysaccharide Conjugates Provide Protection against Acute Melioidosis

    OpenAIRE

    Scott, Andrew E.; Mary N Burtnick; Stokes, Margaret G. M.; Whelan, Adam O.; Williamson, E. Diane; Atkins, Timothy P.; Prior, Joann L.; Brett, Paul J

    2014-01-01

    Burkholderia pseudomallei, the etiologic agent of melioidosis, is a CDC tier 1 select agent that causes severe disease in both humans and animals. Diagnosis and treatment of melioidosis can be challenging, and in the absence of optimal chemotherapeutic intervention, acute disease is frequently fatal. Melioidosis is an emerging infectious disease for which there are currently no licensed vaccines. Due to the potential malicious use of B. pseudomallei as well as its impact on public health in r...

  18. Dissecting novel virulent determinants in the Burkholderia cepacia complex

    OpenAIRE

    George P Tegos; Haynes, Mark K.; Schweizer, Herbert P.

    2012-01-01

    Prevention and control of infectious diseases remains a major public health challenge and a number of highly virulent pathogens are emerging both in and beyond the hospital setting. Despite beneficial aspects such as use in biocontrol and bioremediation exhibited by members of the Burkholderia cepacia complex (Bcc) some members of this group have recently gained attention as significant bacterial pathogens due to their high levels of intrinsic antibiotic resistance, transmissibility in nosoco...

  19. Symbiotic ß-Proteobacteria beyond Legumes: Burkholderia in Rubiaceae

    OpenAIRE

    Brecht Verstraete; Steven Janssens; Erik Smets; Steven Dessein

    2013-01-01

    Symbiotic ß-proteobacteria not only occur in root nodules of legumes but are also found in leaves of certain Rubiaceae. The discovery of bacteria in plants formerly not implicated in endosymbiosis suggests a wider occurrence of plant-microbe interactions. Several ß-proteobacteria of the genus Burkholderia are detected in close association with tropical plants. This interaction has occurred three times independently, which suggest a recent and open plant-bacteria association. The presence or a...

  20. Burkholderia pseudomallei: Its Detection in Soil and Seroprevalence in Bangladesh

    OpenAIRE

    Jilani, Md. Shariful Alam; Robayet, Jamshedul Alam Mohammad; Mohiuddin, Md.; Hasan, Md. Rokib; Ahsan, Chowdhury Rafiqul; Haq, Jalaluddin Ashraful

    2016-01-01

    Background Melioidosis, caused by Burkholderia pseudomallei, is an endemic disease in Bangladesh. No systematic study has yet been done to detect the environmental source of the organism and its true extent in Bangladesh. The present study attempted to isolate B. pseudomallei in soil samples and to determine its seroprevalence in several districts in Bangladesh. Methodology and Results Soil samples were collected from rural areas of four districts of Bangladesh from where culture confirmed me...

  1. Clearance of Pneumocystis murina infection is not dependent on MyD88.

    Science.gov (United States)

    Ripamonti, Chiara; Bishop, Lisa R; Yang, Jun; Lempicki, Richard A; Kovacs, Joseph A

    2014-06-01

    To determine if myeloid differentiation factor 88 (MyD88), which is necessary for signaling by most TLRs and IL-1Rs, is necessary for control of Pneumocystis infection, MyD88-deficient and wild-type mice were infected with Pneumocystis by exposure to infected seeder mice and were followed for up to 106 days. MyD88-deficient mice showed clearance of Pneumocystis and development of anti-Pneumocystis antibody responses with kinetics similar to wild-type mice. Based on expression levels of select genes, MyD88-deficient mice developed immune responses similar to wild-type mice. Thus, MyD88 and the upstream pathways that rely on MyD88 signaling are not required for control of Pneumocystis infection. PMID:24680862

  2. Burkholderia type VI secretion systems have distinct roles in eukaryotic and bacterial cell interactions

    DEFF Research Database (Denmark)

    Schwarz, Sandra; West, T Eoin; Boyer, Frédéric;

    2010-01-01

    Bacteria that live in the environment have evolved pathways specialized to defend against eukaryotic organisms or other bacteria. In this manuscript, we systematically examined the role of the five type VI secretion systems (T6SSs) of Burkholderia thailandensis (B. thai) in eukaryotic and bacterial....... From a group of 31 diverse bacteria, we identified several organisms that competed less effectively against wild-type B. thai than a strain lacking T6SS-1 function. Inactivation of T6SS-1 renders B. thai greatly more susceptible to cell contact-induced stasis by Pseudomonas putida, Pseudomonas...... fluorescens and Serratia proteamaculans-leaving it 100- to 1000-fold less fit than the wild-type in competition experiments with these organisms. Flow cell biofilm assays showed that T6S-dependent interbacterial interactions are likely relevant in the environment. B. thai cells lacking T6SS-1 were rapidly...

  3. Proteasome- and Ethanol-Dependent Regulation of HCV-Infection Pathogenesis

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    Natalia A. Osna

    2014-09-01

    Full Text Available This paper reviews the role of the catabolism of HCV and signaling proteins in HCV protection and the involvement of ethanol in HCV-proteasome interactions. HCV specifically infects hepatocytes, and intracellularly expressed HCV proteins generate oxidative stress, which is further exacerbated by heavy drinking. The proteasome is the principal proteolytic system in cells, and its activity is sensitive to the level of cellular oxidative stress. Not only host proteins, but some HCV proteins are degraded by the proteasome, which, in turn, controls HCV propagation and is crucial for the elimination of the virus. Ubiquitylation of HCV proteins usually leads to the prevention of HCV propagation, while accumulation of undegraded viral proteins in the nuclear compartment exacerbates infection pathogenesis. Proteasome activity also regulates both innate and adaptive immunity in HCV-infected cells. In addition, the proteasome/immunoproteasome is activated by interferons, which also induce “early” and “late” interferon-sensitive genes (ISGs with anti-viral properties. Cleaving viral proteins to peptides in professional immune antigen presenting cells and infected (“target” hepatocytes that express the MHC class I-antigenic peptide complex, the proteasome regulates the clearance of infected hepatocytes by the immune system. Alcohol exposure prevents peptide cleavage by generating metabolites that impair proteasome activity, thereby providing escape mechanisms that interfere with efficient viral clearance to promote the persistence of HCV-infection.

  4. Investigation into the susceptibility of Burkholderia cepacia complex isolates to photodynamic antimicrobial chemotherapy (PACT)

    Science.gov (United States)

    Cassidy, C. M.; Watters, A. L.; Donnelly, R. F.; Tunney, M. M.

    2009-06-01

    The main cause of morbidity and mortality in cystic fibrosis (CF) sufferers is progressive pulmonary damage caused by recurrent and often unremitting respiratory tract infection. Causative organisms include Pseudomonas aeruginosa and Haemophilus influenzae, but in recent years the Burkholderia cepacia complex has come to the fore. This group of highly drug-resistant Gram-negative bacteria are associated with a rapid decline in lung function and the often fatal cepacia syndrome, with treatment limited to patient segregation and marginally effective antibacterial regimens. Thus, development of an effective treatment is of the upmost importance. PACT, a non-target specific therapy, has proven successful in killing both Gram-positive and Gram-negative bacteria. In this study, planktonic cultures of six strains of the B. cepacia complex were irradiated (635 nm, 200 J cm-2,10 minutes irradiation) following 30 seconds incubation with methylene blue (MB) or meso-tetra (N-methyl-4-pyridyl) porphine tetra tosylate (TMP). Rates of kill of > 99 % were achieved with MB- and TMP-PACT. A MB concentration of 50 μg ml-1 and TMP concentration of 500 μg ml-1 were associated with highest percentage kills for each photosensitizer. PACT is an attractive option for treatment of B.cepacia complex infection. Further study, involving biofilm culture susceptibility, delivery of light to the target and in vivo testing will be necessary before it PACT becomes a viable treatment option for CF patients who are colonised or infected with B. cepacia complex.

  5. Burkholderia cenocepacia J2315 escapes to the cytosol and actively subverts autophagy in human macrophages.

    Science.gov (United States)

    Al-Khodor, Souhaila; Marshall-Batty, Kimberly; Nair, Vinod; Ding, Li; Greenberg, David E; Fraser, Iain D C

    2014-03-01

    Selective autophagy functions to specifically degrade cellular cargo tagged by ubiquitination, including bacteria. Strains of the Burkholderia cepacia complex (Bcc) are opportunistic pathogens that cause life-threatening infections in patients with cystic fibrosis (CF) and chronic granulomatous disease (CGD). While there is evidence that defective macrophage autophagy in a mouse model of CF can influence B. cenocepacia susceptibility, there have been no comprehensive studies on how this bacterium is sensed and targeted by the host autophagy response in human macrophages. Here, we describe the intracellular life cycle of B. cenocepacia J2315 and its interaction with the autophagy pathway in human cells. Electron and confocal microscopy analyses demonstrate that the invading bacteria interact transiently with the endocytic pathway before escaping to the cytosol. This escape triggers theselective autophagy pathway, and the recruitment of ubiquitin, the ubiquitin-binding adaptors p62 and NDP52 and the autophagosome membrane-associated protein LC3B, to the bacterial vicinity. However, despite recruitment of these key autophagy pathway effectors, B. cenocepacia blocks autophagosome completion and replicates in the host cytosol. We find that a pre-infection increase in cellular autophagy flux can significantly inhibit B. cenocepacia replication and that lower autophagy flux in macrophages from immunocompromised CGD patients could contribute to increased B. cenocepacia susceptibility, identifying autophagy manipulation as a potential therapeutic approach to reduce bacterial burden in B. cenocepacia infections. PMID:24119232

  6. Vaccination with non-toxic mutant toxic shock syndrome toxin-1 induces IL-17-dependent protection against Staphylococcus aureus infection.

    Science.gov (United States)

    Narita, Kouji; Hu, Dong-Liang; Asano, Krisana; Nakane, Akio

    2015-06-01

    Toxic shock syndrome toxin-1 (TSST-1) is one of superantigens produced by Staphylococcus aureus. We have previously demonstrated that vaccination with non-toxic mutant TSST-1 (mTSST-1) develops host protection to lethal S. aureus infection in mice. However, the detailed mechanism underlying this protection is necessary to elucidate because the passive transfer of antibodies against TSST-1 fails to provide complete protection against S. aureus infection. In this study, the results showed that interleukin-17A (IL-17A)-producing cells were increased in the spleen cells of mTSST-1-vaccinated mice. The main source of IL-17A in mTSST-1-vaccinated mice was T-helper 17 (Th17) cells. The protective effect of vaccination was induced when the vaccinated wild type but not IL-17A-deficient mice were challenged with S. aureus. Gene expression of chemokines, CCL2 and CXCL1, and infiltration of neutrophils and macrophages were increased in spleens and livers of vaccinated mice after infection. The IL-17A-dependent immune response was TSST-1 specific because TSST-1-deficient S. aureus failed to induce the response. The present study suggests that mTSST-1 vaccination is able to provide the IL-17A-dependent host defense against S. aureus infection which promotes chemokine-mediated infiltration of phagocytes into the infectious foci.

  7. Draft Genome Sequence of the Organophosphorus Compound-Degrading Burkholderia zhejiangensis Strain CEIB S4-3

    OpenAIRE

    Hernández-Mendoza, Armando; Martínez-Ocampo, Fernando; Lozano-Aguirre Beltrán, Luis Fernando; Popoca-Ursino, Elida Carolina; Ortiz-Hernández, Laura; Sánchez-Salinas, Enrique; Dantán-González, Edgar

    2014-01-01

    Burkholderia species are widely distributed in the environment. A Burkholderia zhejiangensis strain was isolated from pesticide-contaminated soil from an agricultural field in Mexico and identified as an organophosphorus compound-degrading bacterium. In this study, we report the draft genome sequence of Burkholderia zhejiangensis strain CEIB S4-3.

  8. Draft Genome Sequence of the Lignin-Degrading Burkholderia sp. Strain LIG30, Isolated from Wet Tropical Forest Soil

    OpenAIRE

    Woo, Hannah L.; Utturkar, Sagar; Klingeman, Dawn; Simmons, Blake A.; DeAngelis, Kristen M; Brown, Steven D.; Hazen, Terry C.

    2014-01-01

    Burkholderia species are common soil Betaproteobacteria capable of degrading recalcitrant aromatic compounds and xenobiotics. Burkholderia sp. strain LIG30 was isolated from wet tropical forest soil and is capable of utilizing lignin as a sole carbon source. Here we report the draft genome sequence of Burkholderia sp. strain LIG30.

  9. Leukotriene B4 Enhances NOD2-Dependent Innate Response against Influenza Virus Infection.

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    Manon Le Bel

    Full Text Available Leukotriene B4 (LTB4, a central mediator of inflammation, is well known for its chemoattractant properties on effectors cells of the immune system. LTB4 also has the ability to control microbial infection by improving host innate defenses through the release of antimicrobial peptides and modulation of intracellular Toll-like receptors (TLRs expression in response to agonist challenge. In this report, we provide evidences that LTB4 acts on nucleotide-binging oligomerization domain 2 (NOD2 pathway to enhance immune response against influenza A infection. Infected mice receiving LTB4 show improved survival, lung architecture and reduced lung viral loads as compared to placebo-treated animals. NOD2 and its downstream adaptor protein IPS-1 have been found to be essential for LTB4-mediated effects against IAV infection, as absence of NOD2 or IPS-1 diminished its capacity to control viral infection. Treatment of IAV-infected mice with LTB4 induces an increased activation of IPS-1-IRF3 axis leading to an enhanced production of IFNβ in lungs of infected mice. LTB4 also has the ability to act on the RICK-NF-κB axis since administration of LTB4 to mice challenged with MDP markedly increases the secretion of IL-6 and TNFα in lungs of mice. TAK1 appears to be essential to the action of LTB4 on NOD2 pathway since pretreatment of MEFs with TAK1 inhibitor prior stimulation with IAV or MDP strongly abrogated the potentiating effects of LTB4 on both IFNβ and cytokine secretion. Together, our results demonstrate that LTB4, through its ability to activate TAK1, potentiates both IPS-1 and RICK axis of the NOD2 pathway to improve host innate responses.

  10. Switch from cap- to factorless IRES-dependent 0 and +1 frame translation during cellular stress and dicistrovirus infection.

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    Qing S Wang

    Full Text Available Internal ribosome entry sites (IRES are utilized by a subset of cellular and viral mRNAs to initiate translation during cellular stress and virus infection when canonical cap-dependent translation is compromised. The intergenic region (IGR IRES of the Dicistroviridae uses a streamlined mechanism in which it can directly recruit the ribosome in the absence of initiation factors and initiates translation using a non-AUG codon. A subset of IGR IRESs including that from the honey bee viruses can also direct translation of an overlapping +1 frame gene. In this study, we systematically examined cellular conditions that lead to IGR IRES-mediated 0 and +1 frame translation in Drosophila S2 cells. Towards this, a novel bicistronic reporter that exploits the 2A "stop-go" peptide was developed to allow the detection of IRES-mediated translation in vivo. Both 0 and +1 frame translation by the IGR IRES are stimulated under a number of cellular stresses and in S2 cells infected by cricket paralysis virus, demonstrating a switch from cap-dependent to IRES-dependent translation. The regulation of the IGR IRES mechanism ensures that both 0 frame viral structural proteins and +1 frame ORFx protein are optimally expressed during virus infection.

  11. Intranasal infection with Chlamydia abortus induces dose-dependent latency and abortion in sheep.

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    David Longbottom

    Full Text Available BACKGROUND: Latency is a key feature of the animal pathogen Chlamydia abortus, where infection remains inapparent in the non-pregnant animal and only becomes evident during a subsequent pregnancy. Often the first sign that an animal is infected is abortion occurring late in gestation. Despite this, little is understood of the underlying mechanisms that control latency or the recrudescence of infection that occurs during subsequent pregnancy. The aim of this study was to develop an experimental model of latency by mimicking the natural route of infection through the intranasal inoculation of non-pregnant sheep with C. abortus. METHODOLOGY/PRINCIPAL FINDINGS: Three groups of sheep (groups 1, 2 and 3 were experimentally infected with different doses of C. abortus (5×10(3, 5×10(5 and 5×10(7 inclusion forming units (IFU, respectively prior to mating and monitored over 2 breeding cycles for clinical, microbiological, pathological, immunological and serological outcomes. Two further groups received either negative control inoculum (group 4a,b or were inoculated subcutaneously on day 70 of gestation with 2×10(6 IFU C. abortus (group 5. Animals in groups 1, 2 and 5 experienced an abortion rate of 50-67%, while only one animal aborted in group 3 and none in group 4a,b. Pathological, microbiological, immunological and serological analyses support the view that the maternal protective immune response is influenced by initial exposure to the bacterium. CONCLUSIONS/SIGNIFICANCE: The results show that intranasal administration of non-pregnant sheep with a low/medium dose of C. abortus results in a latent infection that leads in a subsequent pregnancy to infection of the placenta and abortion. In contrast a high dose stimulates protective immunity, resulting in a much lower abortion rate. This model will be useful in understanding the mechanisms of infection underlying latency and onset of disease, as well as in the development of novel therapeutics and

  12. Age-dependent immune events during HBV infection from birth to adulthood: an alternative interpretation

    Directory of Open Access Journals (Sweden)

    Antonio eBertoletti

    2014-09-01

    Full Text Available Immune responses change during the life of an individual. While this concept has been well accepted for adaptive immunity, only recently it is becoming clear that the innate immune responses also acquire distinct features in different phases of life. We believe that this concept can offer a different interpretation of the pathological manifestations that can be observed in HBV-infected subjects during the patient’s life. Here, we will review the age-related immunopathological features of HBV infection and discuss how the different virological and clinical manifestations might be linked to the developmental pathway of the immune system from newborns to adults. We will discuss how the age of patients can affect the degree of inflammatory responses, but not the levels of antiviral specific immunity. We then propose that the different clinical manifestations occurring during the natural history of HBV infection are related to the host ability to trigger an inflammatory immune response.

  13. Antimicrobial and antibiofilm activity of LL-37 and its truncated variants against Burkholderia pseudomallei

    NARCIS (Netherlands)

    S. Kanthawong; J.G.M. Bolscher; E.C.I. Veerman; J. van Marle; H.J.J. de Soet; K. Nazmi; S. Wongratanacheewin; S. Taweechaisupapong

    2012-01-01

    The Gram-negative bacterium Burkholderia pseudomallei is the aetiological agent of melioidosis, which is an endemic disease in tropical areas of Southeast Asia and Northern Australia. Burkholderia pseudomallei has intrinsic resistance to a number of commonly used antibiotics and has also been report

  14. Draft Genome Sequence of Burkholderia cenocepacia Strain CEIB S5-2, a Methyl Parathion- and p-Nitrophenol-Degrading Bacterium, Isolated from Agricultural Soils in Morelos, Mexico

    OpenAIRE

    Martínez-Ocampo, Fernando; Fernández López, Maikel Gilberto; Lozano-Aguirre Beltrán, Luis Fernando; Popoca-Ursino, Elida Carolina; Ortiz-Hernández, M. Laura; Sánchez-Salinas, Enrique; Ramos Quintana, Fernando; Villalobos-López, Miguel A.; Dantán-González, Edgar

    2016-01-01

    Burkholderia cenocepacia is an opportunistic pathogen that belongs to Burkholderia cepacia complex (BCC). Burkholderia cenocepacia strain CEIB S5-2 was isolated from agricultural soils in Morelos, Mexico, and previously has shown its abilities for bioremediation. In this study, we report the draft genome sequence of Burkholderia cenocepacia strain CEIB S5-2.

  15. Draft Genome Sequence of Burkholderia cenocepacia Strain CEIB S5-2, a Methyl Parathion- and p-Nitrophenol-Degrading Bacterium, Isolated from Agricultural Soils in Morelos, Mexico

    Science.gov (United States)

    Martínez-Ocampo, Fernando; Fernández López, Maikel Gilberto; Lozano-Aguirre Beltrán, Luis Fernando; Popoca-Ursino, Elida Carolina; Ortiz-Hernández, M. Laura; Sánchez-Salinas, Enrique; Ramos Quintana, Fernando; Villalobos-López, Miguel A.

    2016-01-01

    Burkholderia cenocepacia is an opportunistic pathogen that belongs to Burkholderia cepacia complex (BCC). Burkholderia cenocepacia strain CEIB S5-2 was isolated from agricultural soils in Morelos, Mexico, and previously has shown its abilities for bioremediation. In this study, we report the draft genome sequence of Burkholderia cenocepacia strain CEIB S5-2. PMID:27125479

  16. C-reactive protein protects mice against pneumococcal infection via both phosphocholine-dependent and phosphocholine-independent mechanisms.

    Science.gov (United States)

    Gang, Toh B; Hanley, Gregory A; Agrawal, Alok

    2015-05-01

    The mechanism of action of C-reactive protein (CRP) in protecting mice against lethal Streptococcus pneumoniae infection is unknown. The involvement of the phosphocholine (PCh)-binding property of CRP in its antipneumococcal function previously has been explored twice, with conflicting results. In this study, using three different intravenous sepsis mouse models, we investigated the role of the PCh-binding property of CRP by employing a CRP mutant incapable of binding to PCh. The ability of wild-type CRP to protect mice against infection was found to differ in the three models; the protective ability of wild-type CRP decreased when the severity of infection was increased, as determined by measuring mortality and bacteremia. In the first animal model, in which we used 25 μg of CRP and 10(7) CFU of pneumococci, both wild-type and mutant CRP protected mice against infection, suggesting that the protection was independent of the PCh-binding activity of CRP. In the second model, in which we used 25 μg of CRP and 5 × 10(7) CFU of pneumococci, mutant CRP was not protective while wild-type CRP was, suggesting that the protection was dependent on the PCh-binding activity of CRP. In the third model, in which we used 150 μg of CRP and 10(7) CFU of pneumococci, mutant CRP was as protective as wild-type CRP, again indicating that the protection was independent of the PCh-binding activity of CRP. We conclude that both PCh-dependent and PCh-independent mechanisms are involved in the CRP-mediated decrease in bacteremia and the resulting protection of mice against pneumococcal infection.

  17. C-reactive protein protects mice against pneumococcal infection via both phosphocholine-dependent and phosphocholine-independent mechanisms.

    Science.gov (United States)

    Gang, Toh B; Hanley, Gregory A; Agrawal, Alok

    2015-05-01

    The mechanism of action of C-reactive protein (CRP) in protecting mice against lethal Streptococcus pneumoniae infection is unknown. The involvement of the phosphocholine (PCh)-binding property of CRP in its antipneumococcal function previously has been explored twice, with conflicting results. In this study, using three different intravenous sepsis mouse models, we investigated the role of the PCh-binding property of CRP by employing a CRP mutant incapable of binding to PCh. The ability of wild-type CRP to protect mice against infection was found to differ in the three models; the protective ability of wild-type CRP decreased when the severity of infection was increased, as determined by measuring mortality and bacteremia. In the first animal model, in which we used 25 μg of CRP and 10(7) CFU of pneumococci, both wild-type and mutant CRP protected mice against infection, suggesting that the protection was independent of the PCh-binding activity of CRP. In the second model, in which we used 25 μg of CRP and 5 × 10(7) CFU of pneumococci, mutant CRP was not protective while wild-type CRP was, suggesting that the protection was dependent on the PCh-binding activity of CRP. In the third model, in which we used 150 μg of CRP and 10(7) CFU of pneumococci, mutant CRP was as protective as wild-type CRP, again indicating that the protection was independent of the PCh-binding activity of CRP. We conclude that both PCh-dependent and PCh-independent mechanisms are involved in the CRP-mediated decrease in bacteremia and the resulting protection of mice against pneumococcal infection. PMID:25690104

  18. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

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    Hao Shen

    Full Text Available Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources

  19. Growth but not photosynthesis response of a host plant to infection by a holoparasitic plant depends on nitrogen supply.

    Science.gov (United States)

    Shen, Hao; Xu, Shu-Jun; Hong, Lan; Wang, Zhang-Ming; Ye, Wan-Hui

    2013-01-01

    Parasitic plants can adversely influence the growth of their hosts by removing resources and by affecting photosynthesis. Such negative effects depend on resource availability. However, at varied resource levels, to what extent the negative effects on growth are attributed to the effects on photosynthesis has not been well elucidated. Here, we examined the influence of nitrogen supply on the growth and photosynthesis responses of the host plant Mikania micrantha to infection by the holoparasite Cuscuta campestris by focusing on the interaction of nitrogen and infection. Mikania micrantha plants fertilized at 0.2, 1 and 5 mM nitrate were grown with and without C. campestris infection. We observed that the infection significantly reduced M. micrantha growth at each nitrate fertilization and more severely at low than at high nitrate. Such alleviation at high nitrate was largely attributed to a stronger influence of infection on root biomass at low than at high nitrate fertilization. However, although C. campestris altered allometry and inhibited host photosynthesis, the magnitude of the effects was independent of nitrate fertilizations. The infection reduced light saturation point, net photosynthesis at saturating irradiances, apparent quantum yield, CO2 saturated rate of photosynthesis, carboxylation efficiency, the maximum carboxylation rate of Rubisco, and maximum light-saturated rate of electron transport, and increased light compensation point in host leaves similarly across nitrate levels, corresponding to a similar magnitude of negative effects of the parasite on host leaf soluble protein and Rubisco concentrations, photosynthetic nitrogen use efficiency and stomatal conductance across nitrate concentrations. Thus, the more severe inhibition in host growth at low than at high nitrate supplies cannot be attributed to a greater parasite-induced reduction in host photosynthesis, but the result of a higher proportion of host resources transferred to the parasite at

  20. Molecular mechanisms of dengue virus infection : cell tropism, antibody-dependent enhancement, and cytokines

    NARCIS (Netherlands)

    Flipse, Jacobus

    2015-01-01

    Dengue is the most prevalent mosquito-borne viral disease in humans. Although most infections occur in the (sub)tropical areas, recent outbreaks in Italy and Madeira indicate that the virus is spreading into Europe. Despite its relevance, no vaccine or medications are available against this virus. T

  1. Molecular mechanisms involved in antibody-dependent enhancement of dengue virus infection in humans

    NARCIS (Netherlands)

    Flipse, Jacky; Wilschut, Jan; Smit, Jolanda M.

    2013-01-01

    Dengue is the most common arthropod-borne viral infection in humans with similar to 50 million cases annually worldwide. In recent decades, a steady increase in the number of severe dengue cases has been seen. Severe dengue disease is most often observed in individuals that have pre-existing immunit

  2. Development of CD4 T cell dependent immunity against N. brasiliensis infection

    Directory of Open Access Journals (Sweden)

    Marina eHarvie

    2013-03-01

    Full Text Available Of all the microbial infections relevant to mammals the relationship between parasitic worms and what constitutes and regulates a host protective immune response is perhaps the most complex and evolved. Nippostrongylus brasiliensis is a tissue migrating parasitic roundworm of rodents that exemplifies many of the salient features of parasitic worm infection, including parasite development through sequential larval stages as it migrates through specific tissue sites. Immune competent hosts respond to infection by N. brasiliensis with a rapid and selective development of a profound Th2 immune response that appears able to confer life long protective immunity against reinfection. This review details how the lung can be the site of migrating nematode immune killing and the gut a site of rapid immune mediated clearance of worms. Furthermore it appears that N. brasiliensis induced responses in the lung are sufficient for conferring immunity in lung and gut while infection of the gut only confers immunity in the gut. This review also covers the role of IL-4, STAT6 and the innate cytokines IL-25, IL-33 and TSLP in the generation of CD4-mediated immunity against N. brasiliensis reinfection and discusses what cytokines might be involved in mediated killing or expulsion of helminth parasites.

  3. Discrimination of Burkholderia mallei/pseudomallei from Burkholderia thailandensis by sequence comparison of a fragment of the ribosomal protein S21 (rpsU) gene

    OpenAIRE

    Frickmann, H.; Chantratita, N.; Gauthier, Y. P.; Neubauer, H.; Hagen, R. M.

    2012-01-01

    Discrimination of Burkholderia (B.) pseudomallei and B. mallei from environmental B. thailandensis is challenging. We describe a discrimination method based on sequence comparison of the ribosomal protein S21 (rpsU) gene.

  4. The relationship between Helicobacter pylori infection and gastric emptying in patients with non-insulin-dependent diabetes mellitus

    Energy Technology Data Exchange (ETDEWEB)

    Kao Chiahung [Dept. of Nuclear Medicine, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China); Pan Dahyou [Div. of Gastroenterology, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China); Wang Shyhjen [Dept. of Nuclear Medicine, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China); Chen Granhum [Div. of Gastroenterology, Taichung Veterans General Hospital, Taichung (Taiwan, Province of China)

    1995-02-01

    Forty-four patients with non-insulin-dependent diabetes mellitus (NIDDM) were included in this study. Radionuclide-labelled solid meals were used to calculate gastric emptying times (GETs). The carbon-14 urea breath test ({sup 14}C-UBT) was used to diagnose Helicobacter pylori (HP) infection. The patients were separated into groups according to the following two criteria: (1) HP infection was diagnosed on the basis of a {sup 14}C-UBT value of {>=}1.5; (2) the GET was defined as abnormal when it was {>=}117.1 min. The results showed that 61% (27/44) of the NIDDM patients had an HP infection, and 59% (26/44) had an abnormal GET. The incidence of abnormal GET in positive {sup 14}C-UBT patients (62%) was higher than that in negative {sup 14}C-UBT patients (56%). Similarly, the incidence of positive {sup 14}C-UBT in abnormal GET cases (62%) was higher than that in normal GET cases (56%). However, according to chi-square tests the differences were not significant. In conclusion, no significant relationship between HP infection and GET was found in patients with NIDDM. (orig.)

  5. Characterization of the Burkholderia thailandensis SOS response by using whole-transcriptome shotgun sequencing.

    Science.gov (United States)

    Ulrich, Ricky L; Deshazer, David; Kenny, Tara A; Ulrich, Melanie P; Moravusova, Anna; Opperman, Timothy; Bavari, Sina; Bowlin, Terry L; Moir, Donald T; Panchal, Rekha G

    2013-10-01

    The bacterial SOS response is a well-characterized regulatory network encoded by most prokaryotic bacterial species and is involved in DNA repair. In addition to nucleic acid repair, the SOS response is involved in pathogenicity, stress-induced mutagenesis, and the emergence and dissemination of antibiotic resistance. Using high-throughput sequencing technology (SOLiD RNA-Seq), we analyzed the Burkholderia thailandensis global SOS response to the fluoroquinolone antibiotic, ciprofloxacin (CIP), and the DNA-damaging chemical, mitomycin C (MMC). We demonstrate that a B. thailandensis recA mutant (RU0643) is ∼4-fold more sensitive to CIP in contrast to the parental strain B. thailandensis DW503. Our RNA-Seq results show that CIP and MMC treatment (P SOS response were induced and include lexA, uvrA, dnaE, dinB, recX, and recA. At the genome-wide level, we found an overall decrease in gene expression, especially for genes involved in amino acid and carbohydrate transport and metabolism, following both CIP and MMC exposure. Interestingly, we observed the upregulation of several genes involved in bacterial motility and enhanced transcription of a B. thailandensis genomic island encoding a Siphoviridae bacteriophage designated E264. Using B. thailandensis plaque assays and PCR with B. mallei ATCC 23344 as the host, we demonstrate that CIP and MMC exposure in B. thailandensis DW503 induces the transcription and translation of viable bacteriophage in a RecA-dependent manner. This is the first report of the SOS response in Burkholderia spp. to DNA-damaging agents. We have identified both common and unique adaptive responses of B. thailandensis to chemical stress and DNA damage.

  6. Determining the Biochemical Properties of the Oxalate Biosynthetic Component (Obc)1 from Burkholderia mallei.

    Science.gov (United States)

    Lambert, Peter M; Nakata, Paul A

    2016-01-01

    Oxalic acid is produced by a variety of organisms ranging from simple microbes to complex animals. This acid has been proposed to fulfill various physiological and pathological functions which vary between organisms. In bacteria from the Burkholderia genus, oxalate secretion has been shown to be quorum sensing dependent and to support pathogenicity and cell viability. In light of the critical roles of oxalate in Burkholderia as well as other organisms, it is surprising that our understanding of how this simple dicarboxylate is biosynthesized remains incomplete. Here we report the expression, purification, and partial characterization of the first intact bacterial oxalate biosynthetic enzyme, Obc1, from B. mallei. An N-terminal His-tagged Bmobc1 was cloned into pDUET, expressed in E. coli BLR (DE3), and the recombinant enzyme purified by affinity chromatography. Oxalate biosynthetic enzyme assays coupled with HPLC analysis revealed that BmObc1 catalyzed the biosynthesis of oxalate, acetoacetate, and free CoA from oxaloacetate and a short chain acyl-CoA following Michaelis-Menten kinetics. Optimal enzyme activity was measured at pH 8.0 and a temperature around 44°C. Kinetic analysis conducted under conditions of saturating acetyl-CoA and varying oxaloacetate concentrations resulted in a calculated Km value for oxaloacetate of 94.3± 9.2 μM (mean ± SE). Under conditions of saturating oxaloacetate concentration and varying acyl-CoA (acetyl- or propionyl-CoA) concentrations kinetic analysis generated a calculated Km value of 26.8 ± 2.3 μM (mean ± SE) for acetyl-CoA and 104.4 ± 12.7 μM for propionyl-CoA. The significantly lower Km for acetyl-CoA suggests that it is strongly favored as a substrate over propionyl-CoA. PMID:27643499

  7. IL-4 receptor-alpha-dependent control of Cryptococcus neoformans in the early phase of pulmonary infection.

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    Andreas Grahnert

    Full Text Available Cryptococcus neoformans is an opportunistic fungal pathogen that causes lung inflammation and meningoencephalitis in immunocompromised people. Previously we showed that mice succumb to intranasal infection by induction of pulmonary interleukin (IL-4Rα-dependent type 2 immune responses, whereas IL-12-dependent type 1 responses confer resistance. In the experiments presented here, IL-4Rα⁻/⁻ mice unexpectedly show decreased fungal control early upon infection with C. neoformans, whereas wild-type mice are able to control fungal growth accompanied by enhanced macrophage and dendritic cell recruitment to the site of infection. Lower pulmonary recruitment of macrophages and dendritic cells in IL-4Rα⁻/⁻ mice is associated with reduced pulmonary expression of CCL2 and CCL20 chemokines. Moreover, IFN-γ and nitric oxide production are diminished in IL-4Rα⁻/⁻ mice compared to wild-type mice. To directly study the potential mechanism(s responsible for reduced production of IFN-γ, conventional dendritic cells were stimulated with C. neoformans in the presence of IL-4 which results in increased IL-12 production and reduced IL-10 production. Together, a beneficial role of early IL-4Rα signaling is demonstrated in pulmonary cryptococcosis, which contrasts with the well-known IL-4Rα-mediated detrimental effects in the late phase.

  8. Transmission and prevalence of Burkholderia cepacia in Welsh cystic fibrosis patients.

    Science.gov (United States)

    Millar-Jones, L; Ryley, H C; Paull, A; Goodchild, M C

    1998-02-01

    From 1987 to 1994, 16 of 162 cystic fibrosis (CF) patients attending CF clinics at three different hospitals in South Wales, U.K. were found to have respiratory secretions colonized with Burkholderia cepacia (B. cepacia). Bacteriological typing by polymerase chain reaction (PCR) ribotyping demonstrated seven strains of B. cepacia among these 16 CF patients. This typing confirmed that cross-infection was the mechanism of colonization in six of the nine patients who were colonized at the paediatric CF clinic at the University Hospital of Wales in Cardiff, and in three of the six patients who were colonized at the adult CF clinic at Llandough Hospital in Cardiff (cross-infection rate nine of 16 patients or 56%). A search was made for a nosocomial source, with screening of wards and clinics. Swabs from fomites produced four positive cultures for B. cepacia. Two isolates had the same PCR ribotype as that of the previous CF room occupant. To establish prevalence of B. cepacia among CF children living throughout Wales, respiratory secretions were cultured from 151 of 186 CF children (age < 16 years). This failed to demonstrate B. cepacia colonization other than in the CF patients already identified.

  9. Virulent Burkholderia species mimic host actin polymerases to drive actin-based motility

    Science.gov (United States)

    Benanti, Erin L.; Nguyen, Catherine M.; Welch, Matthew D.

    2015-01-01

    Summary Burkholderia pseudomallei and B. mallei are bacterial pathogens that cause melioidosis and glanders, while their close relative B. thailandensis is nonpathogenic. All use the trimeric autotransporter BimA to facilitate actin-based motility, host cell fusion and dissemination. Here, we show that BimA orthologs mimic different host actin-polymerizing proteins. B. thailandensis BimA activates the host Arp2/3 complex. In contrast, B. pseudomallei and B. mallei BimA mimic host Ena/VASP actin polymerases in their ability to nucleate, elongate and bundle filaments by associating with barbed ends, as well as in their use of WH2 motifs and oligomerization for activity. Mechanistic differences among BimA orthologs resulted in distinct actin filament organization and motility parameters, which affected the efficiency of cell fusion during infection. Our results identify bacterial Ena/VASP mimics and reveal that pathogens imitate the full spectrum of host actin-polymerizing pathways, suggesting that mimicry of different polymerization mechanisms influences key parameters of infection. PMID:25860613

  10. Exposure of Thomsen-Friedenreich Antigen in Streptococcus pneumoniae Infection is Dependent on Pneumococcal Neuraminidase A**

    OpenAIRE

    Coats, Mamie T.; Murphy, Trudy; James C Paton; Gray, Barry; Briles, David E.

    2011-01-01

    Pneumococcal hemolytic uremic syndrome is recognized in a small portion of otherwise healthy children who have or have recently had Streptococcus pneumoniae infections, including severe pneumonia, meningitis, and bacteremia. As in other types of hemolytic uremic syndrome (HUS), pneumococcal HUS is characterized by microangiopathic hemolytic anemia, and thrombocytopenia, usually with extensive kidney damage. Although not demonstrated in vivo, the pathogenesis of pneumococcal HUS has been attri...

  11. Viral infection controlled by a calcium-dependent lipid-binding module in ALIX.

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    Bissig, Christin; Lenoir, Marc; Velluz, Marie-Claire; Kufareva, Irina; Abagyan, Ruben; Overduin, Michael; Gruenberg, Jean

    2013-05-28

    ALIX plays a role in nucleocapsid release during viral infection, as does lysobisphosphatidic acid (LBPA). However, the mechanism remains unclear. Here we report that LBPA is recognized within an exposed site in ALIX Bro1 domain predicted by MODA, an algorithm for discovering membrane-docking areas in proteins. LBPA interactions revealed a strict requirement for a structural calcium tightly bound near the lipid interaction site. Unlike other calcium- and phospholipid-binding proteins, the all-helical triangle-shaped fold of the Bro1 domain confers selectivity for LBPA via a pair of hydrophobic residues in a flexible loop, which undergoes a conformational change upon membrane association. Both LBPA and calcium binding are necessary for endosome association and virus infection, as are ALIX ESCRT binding and dimerization capacity. We conclude that LBPA recruits ALIX onto late endosomes via the calcium-bound Bro1 domain, triggering a conformational change in ALIX to mediate the delivery of viral nucleocapsids to the cytosol during infection. PMID:23664863

  12. Burkholderia glumae EN EL CULTIVO DE ARROZ EN COSTA RICA

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    Andrea Quesada-Gonz\\u00E1lez

    2014-01-01

    Full Text Available Burkholderia glumae en el cultivo de arroz en Costa Rica. El objetivo de este trabajo fue determinar la presencia de Burkholderia glumae en arroz en Costa Rica. La bacteria Burkholderia glumae está asociada al cultivo del arroz en el que provoca la enfermedad llamada añublo bacterial. Bajo condiciones ambientales favorables, la densidad bacteriana aumenta, lo que provoca que, bajo un sistema de regulación denominado quorum sensing, se expresen sus mecanismos de virulencia mediante la activación de genes responsables para la síntesis de la toxoflavina, que bloquea el flujo de nutrientes, para la biogénesis de flagelos y la respuesta quimiotáctica, y la producción de la enzima catalasa. Las plantas desarrollan la sintomatología que finalmente conlleva a un vaneamiento del grano provocando pérdidas económicas importantes. Se investigó la situación referente a la contaminación del grano de arroz causado por esta bacteria en Costa Rica durante los años 2009 y 2010, mediante un convenio entre la Corporación Nacional Arrocera y el Laboratorio de Fitopatología del Centro de Investigación en Protección de Cultivos de la Universidad de Costa Rica. Se usó la metodología de PCR de punto final recomendada por investigadores del Centro Internacional de Agricultura Tropical en Colombia y se reforzó la identificación, por medio de técnicas de microbiología convencional. Se obtuvieron resultados que indican la presencia de la bacteria en Costa Rica, la primera información sobre la prevalencia de un fitopatógeno bacteriano de gran importancia para el sector arrocero.

  13. Genomic analysis and relatedness of P2-like phages of the Burkholderia cepacia complex

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    Dennis Jonathan J

    2010-10-01

    Full Text Available Abstract Background The Burkholderia cepacia complex (BCC is comprised of at least seventeen Gram-negative species that cause infections in cystic fibrosis patients. Because BCC bacteria are broadly antibiotic resistant, phage therapy is currently being investigated as a possible alternative treatment for these infections. The purpose of our study was to sequence and characterize three novel BCC-specific phages: KS5 (vB_BceM-KS5 or vB_BmuZ-ATCC 17616, KS14 (vB_BceM-KS14 and KL3 (vB_BamM-KL3 or vB_BceZ-CEP511. Results KS5, KS14 and KL3 are myoviruses with the A1 morphotype. The genomes of these phages are between 32317 and 40555 base pairs in length and are predicted to encode between 44 and 52 proteins. These phages have over 50% of their proteins in common with enterobacteria phage P2 and so can be classified as members of the Peduovirinae subfamily and the "P2-like viruses" genus. The BCC phage proteins similar to those encoded by P2 are predominantly structural components involved in virion morphogenesis. As prophages, KS5 and KL3 integrate into an AMP nucleosidase gene and a threonine tRNA gene, respectively. Unlike other P2-like viruses, the KS14 prophage is maintained as a plasmid. The P2 E+E' translational frameshift site is conserved among these three phages and so they are predicted to use frameshifting for expression of two of their tail proteins. The lysBC genes of KS14 and KL3 are similar to those of P2, but in KS5 the organization of these genes suggests that they may have been acquired via horizontal transfer from a phage similar to λ. KS5 contains two sequence elements that are unique among these three phages: an ISBmu2-like insertion sequence and a reverse transcriptase gene. KL3 encodes an EcoRII-C endonuclease/methylase pair and Vsr endonuclease that are predicted to function during the lytic cycle to cleave non-self DNA, protect the phage genome and repair methylation-induced mutations. Conclusions KS5, KS14 and KL3 are the

  14. Positive Coexistence of Steady States for a Diffusive Ratio-Dependent Predator-Prey Model with an Infected Prey

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    Kwangjoong Kim

    2015-01-01

    Full Text Available We examine a diffusive ratio-dependent predator-prey system with disease in the prey under homogeneous Dirichlet boundary conditions with a hostile environment at its boundary. We investigate the positive coexistence of three interacting species (susceptible prey, infected prey, and predator and provide nonexistence conditions of positive solutions to the system. In addition, the global stability of the trivial and semitrivial solutions to the system is studied. Furthermore, the biological interpretation based on the result is also presented. The methods are employed from a comparison argument for the elliptic problem as well as the fixed-point theory as applied to a positive cone on a Banach space.

  15. Exploring the HME and HAE1 efflux systems in the genus Burkholderia

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    Pasca Maria

    2010-06-01

    Full Text Available Abstract Background The genus Burkholderia includes a variety of species with opportunistic human pathogenic strains, whose increasing global resistance to antibiotics has become a public health problem. In this context a major role could be played by multidrug efflux pumps belonging to Resistance Nodulation Cell-Division (RND family, which allow bacterial cells to extrude a wide range of different substrates, including antibiotics. This study aims to i identify rnd genes in the 21 available completely sequenced Burkholderia genomes, ii analyze their phylogenetic distribution, iii define the putative function(s that RND proteins perform within the Burkholderia genus and iv try tracing the evolutionary history of some of these genes in Burkholderia. Results BLAST analysis of the 21 Burkholderia sequenced genomes, using experimentally characterized ceoB sequence (one of the RND family counterpart in the genus Burkholderia as probe, allowed the assembly of a dataset comprising 254 putative RND proteins. An extensive phylogenetic analysis revealed the occurrence of several independent events of gene loss and duplication across the different lineages of the genus Burkholderia, leading to notable differences in the number of paralogs between different genomes. A putative substrate [antibiotics (HAE1 proteins/heavy-metal (HME proteins] was also assigned to the majority of these proteins. No correlation was found between the ecological niche and the lifestyle of Burkholderia strains and the number/type of efflux pumps they possessed, while a relation can be found with genome size and taxonomy. Remarkably, we observed that only HAE1 proteins are mainly responsible for the different number of proteins observed in strains of the same species. Data concerning both the distribution and the phylogenetic analysis of the HAE1 and HME in the Burkholderia genus allowed depicting a likely evolutionary model accounting for the evolution and spreading of HME and HAE

  16. Gender and Age-Dependent Etiology of Community-Acquired Urinary Tract Infections

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    Enrico Magliano

    2012-01-01

    Full Text Available Urinary tract infections (UTIs are among the most frequent community-acquired infections worldwide. Escherichia coli is the most common UTI pathogen although underlying host factors such as patients’ age and gender may influence prevalence of causative agents. In this study, 61 273 consecutive urine samples received over a 22-month period from outpatients clinics of an urban area of north Italy underwent microbiological culture with subsequent bacterial identification and antimicrobial susceptibility testing of positive samples. A total of 13 820 uropathogens were isolated and their prevalence analyzed according to patient’s gender and age group. Overall Escherichia coli accounted for 67.6% of all isolates, followed by Klebsiella pneumoniae (8.8%, Enterococcus faecalis (6.3%, Proteus mirabilis (5.2%, and Pseudomonas aeruginosa (2.5%. Data stratification according to both age and gender showed E. coli isolation rates to be lower in both males aged ≥60 years (52.2%, E. faecalis and P. aeruginosa being more prevalent in this group (11.6% and 7.8%, resp., as well as in those aged ≤14 years (51.3% in whom P. mirabilis prevalence was found to be as high as 21.2%. Streptococcus agalactiae overall prevalence was found to be 2.3% although it was shown to occur most frequently in women aged between 15 and 59 years (4.1%. Susceptibility of E. coli to oral antimicrobial agents was demonstrated to be as follows: fosfomycin (72.9%, trimethoprim/sulfamethoxazole (72.9%, ciprofloxacin (76.8%, ampicillin (48.0%, and amoxicillin/clavulanate (77.5%. In conclusion, both patients’ age and gender are significant factors in determining UTIs etiology; they can increase accuracy in defining the causative uropathogen as well as providing useful guidance to empiric treatment.

  17. Bacterial Superantigens Promote Acute Nasopharyngeal Infection by Streptococcus pyogenes in a Human MHC Class II-Dependent Manner

    Science.gov (United States)

    Kasper, Katherine J.; Zeppa, Joseph J.; Wakabayashi, Adrienne T.; Xu, Stacey X.; Mazzuca, Delfina M.; Welch, Ian; Baroja, Miren L.; Kotb, Malak; Cairns, Ewa; Cleary, P. Patrick; Haeryfar, S. M. Mansour; McCormick, John K.

    2014-01-01

    Establishing the genetic determinants of niche adaptation by microbial pathogens to specific hosts is important for the management and control of infectious disease. Streptococcus pyogenes is a globally prominent human-specific bacterial pathogen that secretes superantigens (SAgs) as ‘trademark’ virulence factors. SAgs function to force the activation of T lymphocytes through direct binding to lateral surfaces of T cell receptors and class II major histocompatibility complex (MHC-II) molecules. S. pyogenes invariably encodes multiple SAgs, often within putative mobile genetic elements, and although SAgs are documented virulence factors for diseases such as scarlet fever and the streptococcal toxic shock syndrome (STSS), how these exotoxins contribute to the fitness and evolution of S. pyogenes is unknown. Here we show that acute infection in the nasopharynx is dependent upon both bacterial SAgs and host MHC-II molecules. S. pyogenes was rapidly cleared from the nasal cavity of wild-type C57BL/6 (B6) mice, whereas infection was enhanced up to ∼10,000-fold in B6 mice that express human MHC-II. This phenotype required the SpeA superantigen, and vaccination with an MHC –II binding mutant toxoid of SpeA dramatically inhibited infection. Our findings indicate that streptococcal SAgs are critical for the establishment of nasopharyngeal infection, thus providing an explanation as to why S. pyogenes produces these potent toxins. This work also highlights that SAg redundancy exists to avoid host anti-SAg humoral immune responses and to potentially overcome host MHC-II polymorphisms. PMID:24875883

  18. Retention on buprenorphine is associated with high levels of maximal viral suppression among HIV-infected opioid dependent released prisoners.

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    Sandra A Springer

    Full Text Available INTRODUCTION: HIV-infected prisoners lose viral suppression within the 12 weeks after release to the community. This prospective study evaluates the use of buprenorphine/naloxone (BPN/NLX as a method to reduce relapse to opioid use and sustain viral suppression among released HIV-infected prisoners meeting criteria for opioid dependence (OD. METHODS: From 2005-2010, 94 subjects meeting DSM-IV criteria for OD were recruited from a 24-week prospective trial of directly administered antiretroviral therapy (DAART for released HIV-infected prisoners; 50 (53% selected BPN/NLX and were eligible to receive it for 6 months; the remaining 44 (47% selected no BPN/NLX therapy. Maximum viral suppression (MVS, defined as HIV-1 RNA<50 copies/mL, was compared for the BPN/NLX and non-BPN/NLX (N = 44 groups. RESULTS: The two groups were similar, except the BPN/NLX group was significantly more likely to be Hispanic (56.0% v 20.4%, from Hartford (74.4% v 47.7% and have higher mean global health quality of life indicator scores (54.18 v 51.40. MVS after 24 weeks of being released was statistically correlated with 24-week retention on BPN/NLX [AOR = 5.37 (1.15, 25.1], having MVS at the time of prison-release [AOR = 10.5 (3.21, 34.1] and negatively with being Black [AOR = 0.13 (0.03, 0.68]. Receiving DAART or methadone did not correlate with MVS. CONCLUSIONS: In recognition that OD is a chronic relapsing disease, strategies that initiate and retain HIV-infected prisoners with OD on BPN/NLX is an important strategy for improving HIV treatment outcomes as a community transition strategy.

  19. Burkholderia cepacia lipase is a promising biocatalyst for biofuel production.

    Science.gov (United States)

    Sasso, Francesco; Natalello, Antonino; Castoldi, Simone; Lotti, Marina; Santambrogio, Carlo; Grandori, Rita

    2016-07-01

    Lipases resistant to inhibition and denaturation by methanol are valuable tools for biotechnological applications, in particular for biofuel production. Microbial lipases have attracted a great deal of interest because of their stability at high concentrations of organic solvents. Burkholderia cepacia lipase (BCL) is tested here for robustness towards methanol in terms of conformational stability and catalytic activity in transesterification assays. This lipase turns out to be even more tolerant than the homologous and better characterized enzyme from Burkholderia glumae. BCL unfolding transition, as monitored by far-UV circular dichroism (CD) and intrinsic fluorescence, displays a Tm above 60°C in the presence of 50% methanol. The protein unfolds at low pH, and the organic solvent affects the nature of the denatured state under acidic conditions. The protein performs well in transesterification assays upon prolonged incubations at high methanol concentrations. BCL is highly tolerant to methanol and displays particularly high conformational stability under conditions employed for transesterification reactions. These features depict BCL as a promising enzyme for biofuel industry. PMID:27067648

  20. Biosynthetic engineering and fermentation media development leads to gram-scale production of spliceostatin natural products in Burkholderia sp.

    Science.gov (United States)

    Eustáquio, Alessandra S; Chang, Li-Ping; Steele, Greg L; O'Donnell, Christopher J; Koehn, Frank E

    2016-01-01

    A key challenge in natural products drug discovery is compound supply. Hundreds of grams of purified material are needed to advance a natural product lead through preclinical development. Spliceostatins are polyketide-nonribosomal peptide natural products that bind to the spliceosome, an emerging target in cancer therapy. The wild-type bacterium Burkholderia sp. FERM BP-3421 produces a suite of spliceostatin congeners with varying biological activities and physiological stabilities. Hemiketal compounds such as FR901464 were the first to be described. Due to its improved properties, we were particularly interested in a carboxylic acid precursor analog that was first reported from Burkholderia sp. MSMB 43 and termed thailanstatin A. Inactivation of the iron/α-ketoglutarate-dependent dioxygenase gene fr9P had been shown to block hemiketal biosynthesis. However, a 4-deoxy congener of thailanstatin A was the main product seen in the dioxygenase mutant. We show here that expression of the cytochrome P450 gene fr9R is a metabolic bottle neck, as use of an l-arabinose inducible system led to nearly complete conversion of the 4-deoxy analog to the target molecule. By integrating fermentation media development approaches with biosynthetic engineering, we were able to improve production titers of the target compound >40-fold, going from the starting ~60 mg/L to 2.5 g/L, and to achieve what is predominantly a single component production profile. These improvements were instrumental in enabling preclinical development of spliceostatin analogs as chemotherapy. PMID:26620532

  1. HIV-1 Infection of T Cells and Macrophages Are Differentially Modulated by Virion-Associated Hck: A Nef-Dependent Phenomenon

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    Gilda Tachedjian

    2013-09-01

    Full Text Available The proline repeat motif (PxxP of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages confirmed the presence of a Nef:Hck complex which was dependent on the Nef proline repeat motif. The proline repeat motif of Nef also enhanced both HIV-1 infection and replication in macrophages, and was required for incorporation of Hck into viral particles. Unexpectedly, wild-type Hck inhibited infection of macrophages, but Hck was shown to enhance infection of primary T lymphocytes. These results indicate that the interaction between Nef and Hck is important for Nef-dependent modulation of viral infectivity. Hck-dependent enhancement of HIV-1 infection of T cells suggests that Nef-Hck interaction may contribute to the spread of HIV-1 infection from macrophages to T cells by modulating events in the producer cell, virion and target cell.

  2. HIV-1 infection of T cells and macrophages are differentially modulated by virion-associated Hck: a Nef-dependent phenomenon.

    Science.gov (United States)

    Cornall, Alyssa; Mak, Johnson; Greenway, Alison; Tachedjian, Gilda

    2013-09-01

    The proline repeat motif (PxxP) of Nef is required for interaction with the SH3 domains of macrophage-specific Src kinase Hck. However, the implication of this interaction for viral replication and infectivity in macrophages and T lymphocytes remains unclear. Experiments in HIV-1 infected macrophages confirmed the presence of a Nef:Hck complex which was dependent on the Nef proline repeat motif. The proline repeat motif of Nef also enhanced both HIV-1 infection and replication in macrophages, and was required for incorporation of Hck into viral particles. Unexpectedly, wild-type Hck inhibited infection of macrophages, but Hck was shown to enhance infection of primary T lymphocytes. These results indicate that the interaction between Nef and Hck is important for Nef-dependent modulation of viral infectivity. Hck-dependent enhancement of HIV-1 infection of T cells suggests that Nef-Hck interaction may contribute to the spread of HIV-1 infection from macrophages to T cells by modulating events in the producer cell, virion and target cell. PMID:24051604

  3. Transport of nanoparticles and tobramycin-loaded liposomes in Burkholderia cepacia complex biofilms.

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    Anne-Sophie Messiaen

    Full Text Available Due to the intrinsic resistance of Burkholderia cepacia complex (Bcc to many antibiotics and the production of a broad range of virulence factors, lung infections by these bacteria, primarily occurring in cystic fibrosis (CF patients, are very difficult to treat. In addition, the ability of Bcc organisms to form biofilms contributes to their persistence in the CF lung. As Bcc infections are associated with poor clinical outcome, there is an urgent need for new effective therapies to treat these infections. In the present study, we investigated whether liposomal tobramycin displayed an increased anti-biofilm effect against Bcc bacteria compared to free tobramycin. Single particle tracking (SPT was used to study the transport of positively and negatively charged nanospheres in Bcc biofilms as a model for the transport of liposomes. Negatively charged nanospheres became immobilized in close proximity of biofilm cell clusters, while positively charged nanospheres interacted with fiber-like structures, probably eDNA. Based on these data, encapsulation of tobramycin in negatively charged liposomes appeared promising for targeted drug delivery. However, the anti-biofilm effect of tobramycin encapsulated into neutral or anionic liposomes did not increase compared to that of free tobramycin. Probably, the fusion of the anionic liposomes with the negatively charged bacterial surface of Bcc bacteria was limited by electrostatic repulsive forces. The lack of a substantial anti-biofilm effect of tobramycin encapsulated in neutral liposomes could be further investigated by increasing the liposomal tobramycin concentration. However, this was hampered by the low encapsulation efficiency of tobramycin in these liposomes.

  4. Genotyping of Burkholderia mallei from an outbreak of glanders in Bahrain suggests multiple introduction events.

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    Holger C Scholz

    2014-09-01

    Full Text Available Glanders, caused by the gram-negative bacterium Burkholderia mallei, is a highly infectious zoonotic disease of solipeds causing severe disease in animals and men. Although eradicated from many Western countries, it recently emerged in Asia, the Middle-East, Africa, and South America. Due to its rareness, little is known about outbreak dynamics of the disease and its epidemiology.We investigated a recent outbreak of glanders in Bahrain by applying high resolution genotyping (multiple locus variable number of tandem repeats, MLVA and comparative whole genome sequencing to B. mallei isolated from infected horses and a camel. These results were compared to samples obtained from an outbreak in the United Arab Emirates in 2004, and further placed into a broader phylogeographic context based on previously published B. mallei data. The samples from the outbreak in Bahrain separated into two distinct clusters, suggesting a complex epidemiological background and evidence for the involvement of multiple B. mallei strains. Additionally, the samples from Bahrain were more closely related to B. mallei isolated from horses in the United Arab Emirates in 2004 than other B. mallei which is suggestive of repeated importation to the region from similar geographic sources.High-resolution genotyping and comparative whole genome analysis revealed the same phylogenetic patterns among our samples. The close relationship of the Dubai/UAE B. mallei populations to each other may be indicative of a similar geographic origin that has yet to be identified for the infecting strains. The recent emergence of glanders in combination with worldwide horse trading might pose a new risk for human infections.

  5. Candidate Essential Genes in Burkholderia cenocepacia J2315 Identified by Genome-Wide TraDIS.

    Science.gov (United States)

    Wong, Yee-Chin; Abd El Ghany, Moataz; Naeem, Raeece; Lee, Kok-Wei; Tan, Yung-Chie; Pain, Arnab; Nathan, Sheila

    2016-01-01

    Burkholderia cenocepacia infection often leads to fatal cepacia syndrome in cystic fibrosis patients. However, antibiotic therapy rarely results in complete eradication of the pathogen due to its intrinsic resistance to many clinically available antibiotics. Recent attention has turned to the identification of essential genes as the proteins encoded by these genes may serve as potential targets for development of novel antimicrobials. In this study, we utilized TraDIS (Transposon Directed Insertion-site Sequencing) as a genome-wide screening tool to facilitate the identification of B. cenocepacia genes essential for its growth and viability. A transposon mutant pool consisting of approximately 500,000 mutants was successfully constructed, with more than 400,000 unique transposon insertion sites identified by computational analysis of TraDIS datasets. The saturated library allowed for the identification of 383 genes that were predicted to be essential in B. cenocepacia. We extended the application of TraDIS to identify conditionally essential genes required for in vitro growth and revealed an additional repertoire of 439 genes to be crucial for B. cenocepacia growth under nutrient-depleted conditions. The library of B. cenocepacia mutants can subsequently be subjected to various biologically related conditions to facilitate the discovery of genes involved in niche adaptation as well as pathogenicity and virulence. PMID:27597847

  6. Aerogenic vaccination with a Burkholderia mallei auxotroph protects against aerosol-initiated glanders in mice.

    Science.gov (United States)

    Ulrich, Ricky L; Amemiya, Kei; Waag, David M; Roy, Chad J; DeShazer, David

    2005-03-14

    Burkholderia mallei is an obligate mammalian pathogen that causes the zoonotic disease glanders. Two live attenuated B. mallei strains, a capsule mutant and a branched-chain amino acid auxotroph, were evaluated for use as vaccines against aerosol-initiated glanders in mice. Animals were aerogenically vaccinated and serum samples were obtained before aerosol challenge with a high-dose (>300 times the LD50) of B. mallei ATCC 23344. Mice vaccinated with the capsule mutant developed a Th2-like Ig subclass antibody response and none survived beyond 5 days. In comparison, the auxotrophic mutant elicited a Th1-like Ig subclass antibody response and 25% of the animals survived for 1 month postchallenge. After a low-dose (5 times the LD50) aerosol challenge, the survival rates of auxotroph-vaccinated and unvaccinated animals were 50 and 0%, respectively. Thus, live attenuated strains that promote a Th1-like Ig response may serve as promising vaccine candidates against aerosol infection with B. mallei.

  7. A Pipeline for Screening Small Molecules with Growth Inhibitory Activity against Burkholderia cenocepacia.

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    Carrie Selin

    Full Text Available Infections with the bacteria Burkholderia cepacia complex (Bcc are very difficult to eradicate in cystic fibrosis patients due the intrinsic resistance of Bcc to most available antibiotics and the emergence of multiple antibiotic resistant strains during antibiotic treatment. In this work, we used a whole-cell based assay to screen a diverse collection of small molecules for growth inhibitors of a relevant strain of Bcc, B. cenocepacia K56-2. The primary screen used bacterial growth in 96-well plate format and identified 206 primary actives among 30,259 compounds. From 100 compounds with no previous record of antibacterial activity secondary screening and data mining selected a total of Bce bioactives that were further analyzed. An experimental pipeline, evaluating in vitro antibacterial and antibiofilm activity, toxicity and in vivo antibacterial activity using C. elegans was used for prioritizing compounds with better chances to be further investigated as potential Bcc antibacterial drugs. This high throughput screen, along with the in vitro and in vivo analysis highlights the utility of this experimental method to quickly identify bioactives as a starting point of antibacterial drug discovery.

  8. A Pipeline for Screening Small Molecules with Growth Inhibitory Activity against Burkholderia cenocepacia.

    Science.gov (United States)

    Selin, Carrie; Stietz, Maria S; Blanchard, Jan E; Gehrke, Sebastian S; Bernard, Sylvain; Hall, Dennis G; Brown, Eric D; Cardona, Silvia T

    2015-01-01

    Infections with the bacteria Burkholderia cepacia complex (Bcc) are very difficult to eradicate in cystic fibrosis patients due the intrinsic resistance of Bcc to most available antibiotics and the emergence of multiple antibiotic resistant strains during antibiotic treatment. In this work, we used a whole-cell based assay to screen a diverse collection of small molecules for growth inhibitors of a relevant strain of Bcc, B. cenocepacia K56-2. The primary screen used bacterial growth in 96-well plate format and identified 206 primary actives among 30,259 compounds. From 100 compounds with no previous record of antibacterial activity secondary screening and data mining selected a total of Bce bioactives that were further analyzed. An experimental pipeline, evaluating in vitro antibacterial and antibiofilm activity, toxicity and in vivo antibacterial activity using C. elegans was used for prioritizing compounds with better chances to be further investigated as potential Bcc antibacterial drugs. This high throughput screen, along with the in vitro and in vivo analysis highlights the utility of this experimental method to quickly identify bioactives as a starting point of antibacterial drug discovery. PMID:26053039

  9. Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo.

    Science.gov (United States)

    Scoffone, Viola C; Chiarelli, Laurent R; Makarov, Vadim; Brackman, Gilles; Israyilova, Aygun; Azzalin, Alberto; Forneris, Federico; Riabova, Olga; Savina, Svetlana; Coenye, Tom; Riccardi, Giovanna; Buroni, Silvia

    2016-01-01

    Burkholderia cenocepacia, an opportunistic respiratory pathogen particularly relevant for cystic fibrosis patients, is difficult to eradicate due to its high level of resistance to most clinically relevant antimicrobials. Consequently, the discovery of new antimicrobials as well as molecules capable of inhibiting its virulence is mandatory. In this regard quorum sensing (QS) represents a good target for anti-virulence therapies, as it has been linked to biofilm formation and is important for the production of several virulence factors, including proteases and siderophores. Here, we report the discovery of new diketopiperazine inhibitors of the B. cenocepacia acyl homoserine lactone synthase CepI, and report their anti-virulence properties. Out of ten different compounds assayed against recombinant CepI, four were effective inhibitors, with IC50 values in the micromolar range. The best compounds interfered with protease and siderophore production, as well as with biofilm formation, and showed good in vivo activity in a Caenorhabditis elegans infection model. These molecules were also tested in human cells and showed very low toxicity. Therefore, they could be considered for in vivo combined treatments with established or novel antimicrobials, to improve the current therapeutic strategies against B. cenocepacia. PMID:27580679

  10. Discovery of new diketopiperazines inhibiting Burkholderia cenocepacia quorum sensing in vitro and in vivo

    Science.gov (United States)

    Scoffone, Viola C.; Chiarelli, Laurent R.; Makarov, Vadim; Brackman, Gilles; Israyilova, Aygun; Azzalin, Alberto; Forneris, Federico; Riabova, Olga; Savina, Svetlana; Coenye, Tom; Riccardi, Giovanna; Buroni, Silvia

    2016-01-01

    Burkholderia cenocepacia, an opportunistic respiratory pathogen particularly relevant for cystic fibrosis patients, is difficult to eradicate due to its high level of resistance to most clinically relevant antimicrobials. Consequently, the discovery of new antimicrobials as well as molecules capable of inhibiting its virulence is mandatory. In this regard quorum sensing (QS) represents a good target for anti-virulence therapies, as it has been linked to biofilm formation and is important for the production of several virulence factors, including proteases and siderophores. Here, we report the discovery of new diketopiperazine inhibitors of the B. cenocepacia acyl homoserine lactone synthase CepI, and report their anti-virulence properties. Out of ten different compounds assayed against recombinant CepI, four were effective inhibitors, with IC50 values in the micromolar range. The best compounds interfered with protease and siderophore production, as well as with biofilm formation, and showed good in vivo activity in a Caenorhabditis elegans infection model. These molecules were also tested in human cells and showed very low toxicity. Therefore, they could be considered for in vivo combined treatments with established or novel antimicrobials, to improve the current therapeutic strategies against B. cenocepacia. PMID:27580679

  11. A new bacterial disease of carnation in Portugal caused by Burkholderia andropogonis

    Directory of Open Access Journals (Sweden)

    Madalena Eloy

    2008-12-01

    Full Text Available The occurrence of a leaf spot disease of carnation caused by Burkholderia andropogonis is recorded for the first time in Portugal. Symptoms consisted of ‘eyespot’ lesions on all aerial plant parts, often bordered by water-soaked halos on the leaves. As the disease progressed lesions became dark brown and affected areas dried out. Phenotypic studies and Polymerase Chain Reaction using specific primers Pf/Pr targeted to 16S rDNA of B. andropogonis were used to identify the pathogen. Pathogenicity tests on china pink plants, re-isolation of the pathogen from inoculated plants and further PCR testing confirmed the identification of the bacterium. Infected plants came from an open air nursery and the whole production was destroyed to avoid dissemination of the pathogen.A ocorrência da mancha bacteriana do craveiro causada por Burkholderia andropogonis é pela primeira vez assinalada em Portugal. Os sintomas observados consistiam em manchas em forma de olho-de-perdiz em todos os órgãos aéreos das plantas afectadas, frequentemente circundadas por halos hidrópicos nas folhas. À medida que a doença progredia, as lesões adquiriam uma coloração castanha escura, acabando os órgãos afectados por secar. A identificação do agente causal da doença baseou-se no estudo dos seus caracteres fenotípicos e na Reacção em Cadeia da Polimerase (PCR, utilizando os iniciadores específicos Pf/Pr dirigidos à região 16S rDNA de B. andropogonis. A identificação foi confirmada por ensaios de patogenicidade em cravinas, reisolamento do agente causal da doença a partir das plantas inoculadas e novos ensaios PCR. As plantas infectadas provinham de um viveiro ao ar livre e toda a produção foi destruída a fim de evitar a disseminação do patogéneo.

  12. TRACKING THE RESPONSE OF BURKHOLDERIA CEPACIA G4 5223-PR1 IN AQUIFER MICROCOSMS

    Science.gov (United States)

    The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of microbial population dynamics to define persistence and activity from both efficacy and risk assessment perspectives, Burkholderia cepacia G4 5223-P...

  13. AQUIFER PROTIST RESPONSE AND THE POTENTIAL FOR TCE BIOREMEDIATION WITH BURKHOLDERIA CEPACIA G4 PR1

    Science.gov (United States)

    The introduction of bacteria into the environment for bioremediation purposes (bioaugmentation) requires analysis and monitoring of the persistence and activity of microbial population for efficacy and risk assessment purposes. Burkholderia cepacia G4 PR123 and PR131 constitutive...

  14. BIOAUGMENTATION WITH BURKHOLDERIA CEPACIA PR1301 FOR IN SITU BIOREMEDIATION OF TRICHLOROETHYLENE CONTAMINATED GROUNDWATER (RESEARCH BRIEF)

    Science.gov (United States)

    A pilot field study was conducted at the Moffett Federal Airfield, Mountain View, California, to determine whether effective in-situ aerobic cometabolic biodegradation of TCE could be accomplished through bioaugmentation with a genetically modified strain of Burkholderia cepacia ...

  15. Interim report on updated microarray probes for the LLNL Burkholderia pseudomallei SNP array

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, S; Jaing, C

    2012-03-27

    The overall goal of this project is to forensically characterize 100 unknown Burkholderia isolates in the US-Australia collaboration. We will identify genome-wide single nucleotide polymorphisms (SNPs) from B. pseudomallei and near neighbor species including B. mallei, B. thailandensis and B. oklahomensis. We will design microarray probes to detect these SNP markers and analyze 100 Burkholderia genomic DNAs extracted from environmental, clinical and near neighbor isolates from Australian collaborators on the Burkholderia SNP microarray. We will analyze the microarray genotyping results to characterize the genetic diversity of these new isolates and triage the samples for whole genome sequencing. In this interim report, we described the SNP analysis and the microarray probe design for the Burkholderia SNP microarray.

  16. Draft Genome Sequence of Burkholderia pseudomallei Strain 350105, Isolated in Hainan, China, in 1976

    OpenAIRE

    Song, Lihua; Yu, Yonghui; Feng, Le; He, Jun; WANG, Tao; Zhu, Hong; Duan, Qing

    2015-01-01

    Burkholderia pseudomallei is the etiological agent of the potentially fatal disease melioidosis. Here, we report the draft genome sequence of a virulent water isolate obtained from the Hainan Province of China in 1976, B. pseudomallei strain 350105.

  17. Molecular signatures and phylogenomic analysis of the genus Burkholderia: proposal for division of this genus into the emended genus Burkholderia containing pathogenic organisms and a new genus Paraburkholderia gen. nov. harboring environmental species

    OpenAIRE

    Sawana, Amandeep; Adeolu, Mobolaji; Gupta, Radhey S.

    2014-01-01

    The genus Burkholderia contains large number of diverse species which include many clinically important organisms, phytopathogens, as well as environmental species. However, currently, there is a paucity of biochemical or molecular characteristics which can reliably distinguish different groups of Burkholderia species. We report here the results of detailed phylogenetic and comparative genomic analyses of 45 sequenced species of the genus Burkholderia. In phylogenetic trees based upon concate...

  18. Burkholderia pseudomallei penetrates the brain via destruction of the olfactory and trigeminal nerves: implications for the pathogenesis of neurological melioidosis.

    Science.gov (United States)

    St John, James A; Ekberg, Jenny A K; Dando, Samantha J; Meedeniya, Adrian C B; Horton, Rachel E; Batzloff, Michael; Owen, Suzzanne J; Holt, Stephanie; Peak, Ian R; Ulett, Glen C; Mackay-Sim, Alan; Beacham, Ifor R

    2014-01-01

    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

  19. Vertical transmission explains the specific Burkholderia pattern in Sphagnum mosses at multi-geographic scale

    OpenAIRE

    AnastasiaBragina; ChristianBerg

    2013-01-01

    The betaproteobacterial genus Burkholderia is known for its versatile interactions with its hosts that can range from beneficial to pathogenic. A plant-beneficial-environmental (PBE) Burkholderia cluster was recently separated from the pathogen cluster, yet still little is known about burkholderial diversity, distribution, colonization, and transmission patterns on plants. In our study, we applied a combination of high-throughput molecular and microscopic methods to examine the aforementioned...

  20. Multivariate Analyses of Burkholderia Species in Soil: Effect of Crop and Land Use History

    OpenAIRE

    Salles, J.F.; Veen, van, R.; Elsas, van, J.D.

    2004-01-01

    The assessment of Burkholderia diversity in agricultural areas is important considering the potential use of this genus for agronomic and environmental applications. Therefore, the aim of this work was to ascertain how plant species and land use management drive the diversity of the genus Burkholderia. In a greenhouse experiment, different crops, i.e., maize, oat, barley, and grass, were planted in pots containing soils with different land use histories, i.e., maize monoculture, crop rotation...

  1. Characterization and Inference of Gene Gain/Loss Along Burkholderia Evolutionary History

    OpenAIRE

    Bo Zhu; Shengli Zhou; Miaomiao Lou; Jun Zhu; Bin Li; Guanlin Xie; GuLei Jin; René De Mot

    2011-01-01

    A comparative analysis of 60 complete Burkholderia genomes was conducted to obtain insight in the evolutionary history behind the diversity and pathogenicity at species level. A concatenated multiprotein phyletic pattern and a dataset with Burkholderia clusters of orthologous genes (BuCOGs) were constructed. The extent of horizontal gene transfer (HGT) was assessed using a Markov based probabilistic method. A reconstruction of the gene gains and losses history shows that more than half of the...

  2. Burkholderia ferrariae sp. nov., a novel bacterium isolated from an iron ore in Brazil.

    OpenAIRE

    Valverde, A; Delvasto, P.; Peix, A.; Velázquez, E; Santa Regina, I.; Ballester, A.; Rodríguez-Barrueco, C.; García-Balboa, C.; Igual, José Mariano

    2006-01-01

    A Gram-negative, non-spore-forming bacterial strain with the ability to solubilize highly insoluble phosphatic minerals was isolated from a high-phosphorous iron ore from Minas Gerais State, Brazil. This strain, designated FeGl01(T), was subjected to a polyphasic; taxonomic investigation. Comparative 16S rRNA gene sequence analysis indicated that it formed a distinct phylogenetic lineage within the genus Burkholderia together with several other species of the genus, e.g. Burkholderia sacchari...

  3. Burkholderia pseudomallei sequencing identifies genomic clades with distinct recombination, accessory, and epigenetic profiles

    OpenAIRE

    Nandi, Tannistha; Holden, Matthew; Didelot, Xavier; Mehershahi, Kurosh; Boddey, Justin A; Beacham, Ifor; Peak, Ian; Harting, John; Baybayan, Primo; Guo, Yan; Wang, Susana; How, Lee Chee; Sim, Bernice; Essex-Lopresti, Angela; Sarkar-Tyson, Mitali

    2015-01-01

    This study was supported by a core grant to P.T. from the GIS, an A-STAR research institute. The sequencing of the Burkholderia pseudomallei strains was supported by Wellcome Trust grant 098051 to J.P. Burkholderia pseudomallei (Bp) is the causative agent of the infectious disease melioidosis. To investigate population diversity, recombination, and horizontal gene transfer in closely related Bp isolates, we performed whole-genome sequencing (WGS) on 106 clinical, animal, and environmental ...

  4. Protective response to subunit vaccination against intranasal Burkholderia mallei and B. pseudomallei challenge

    OpenAIRE

    Whitlock, Gregory C.; Deeraksa, Arpaporn; Qazi, Omar; Judy, Barbara M.; Taylor, Katherine; Propst, Katie L.; Duffy, Angie J.; Johnson, Kate; Kitto, G. Barrie; Brown, Katherine A.; Dow, Steven W.; Torres, Alfredo G.; Estes, D. Mark

    2010-01-01

    Burkholderia mallei and B. pseudomallei are Gram-negative pathogenic bacteria, responsible for the diseases glanders and melioidosis, respectively. Furthermore, there is currently no vaccine available against these Burkholderia species. In this study, we aimed to identify protective proteins against these pathogens. Immunization with recombinant B. mallei Hcp1 (type VI secreted/structural protein), BimA (autotransporter protein), BopA (type III secreted protein), and B. pseudomallei LolC (ABC...

  5. Vpu mediates depletion of interferon regulatory factor 3 during HIV infection by a lysosome-dependent mechanism.

    Science.gov (United States)

    Doehle, Brian P; Chang, Kristina; Rustagi, Arjun; McNevin, John; McElrath, M Juliana; Gale, Michael

    2012-08-01

    HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV.

  6. Both Lewis and Secretor Status Mediate Susceptibility to Rotavirus Infections in a Rotavirus Genotype–Dependent Manner

    Science.gov (United States)

    Nordgren, Johan; Sharma, Sumit; Bucardo, Filemon; Nasir, Waqas; Günaydın, Gökçe; Ouermi, Djeneba; Nitiema, Leon W.; Becker-Dreps, Sylvia; Simpore, Jacques; Hammarström, Lennart; Larson, Göran; Svensson, Lennart

    2014-01-01

    Background. The live oral rotavirus (RV) vaccines have shown a reduced efficacy in Africa. Recent in vitro studies have shown binding of the RV surface protein (VP4) to histo–blood group antigens (HBGAs) in an RV genotype–dependent manner, suggesting them to be putative receptors for RV. The diversity of HBGA phenotypes in different ethnic populations, combined with prevalence/absence of specific RV genotypes, led us to hypothesize whether the genetic variations in HBGAs in a population limit susceptibility to certain RV genotypes, plausibly leading to reduced vaccine efficacy. Methods. Association between HBGAs status and susceptibility to RV P genotypes was investigated in children in Burkina Faso and Nicaragua. In total, 242 children with diarrhea in Burkina Faso and Nicaragua were investigated, 93 of whom were RV positive. Results. In Burkina Faso, the P[8] RV strains (n = 27) infected only Lewis- and secretor-positive children (27/27; P < .0001), but no Lewis-negative children. In contrast, the P[6] strains (n = 27) infected predominantly Lewis-negative children (n = 18; P < .0001) but also Lewis-positive children, irrespective of their secretor status. The results from Nicaragua confirmed that all P[8]-infected children (n = 22) were secretor Lewis positive. Conclusions. As VP4 of genotype P[8] is a component of current RV vaccines, our finding that Lewis-negative children are resistant to P[8] strains provides a plausible explanation for the reduced vaccine efficacy in populations with a high percentage of Lewis-negative individuals, such as in Africa. Furthermore, our findings provide a plausible explanation as to why P[6] RV strains are more common in Africa. PMID:25097083

  7. Characterization of an isotype-dependent monoclonal antibody against linear neutralizing epitope effective for prophylaxis of enterovirus 71 infection.

    Directory of Open Access Journals (Sweden)

    Xiao Fang Lim

    Full Text Available BACKGROUND: Enterovirus 71 (EV71 is the main causative agent of Hand, Foot and Mouth disease (HFMD and is associated with severe neurologic complications and mortalities. At present, there is no vaccine or therapeutic available for treatment. METHODOLOGY/PRINCIPAL FINDING: In this study, we generated two mAbs, denoted as mAb 51 and 53, both targeting the same linear epitope on VP1 capsid protein, spanning amino acids 215-219. In comparison, mAb 51 belonging to isotype IgM possesses neutralizing activity in vitro, whereas, mAb 53 belonging to isotype IgG1 does not have any neutralizing ability, even towards its homologous strain. When mAb 51 at 10 µg/g of body weight was administered to the 2-week-old AG129 mice one day prior to lethal challenge, 100% in vivo passive protection was observed. In contrast, the isotype control group mice, injected with an irrelevant IgM antibody before the challenge, developed limb paralysis as early as day 6 post-infection. Histological examination demonstrated that mAb 51 was able to protect against pathologic changes such as neuropil vacuolation and neuronal loss in the spinal cord, which were typical in unprotected EV-71 infected mice. BLAST analyses of that epitope revealed that it was highly conserved among all EV71 strains, but not coxsachievirus 16 (CA16. CONCLUSION: We have defined a linear epitope within the VP1 protein and demonstrated its neutralizing ability to be isotype dependent. The neutralizing property and highly conserved sequence potentiated the application of mAb 51 and 53 for protection against EV71 infection and diagnosis respectively.

  8. Vpu Mediates Depletion of Interferon Regulatory Factor 3 during HIV Infection by a Lysosome-Dependent Mechanism

    Science.gov (United States)

    Doehle, Brian P.; Chang, Kristina; Rustagi, Arjun; McNevin, John; McElrath, M. Juliana

    2012-01-01

    HIV has evolved sophisticated mechanisms to avoid restriction by intracellular innate immune defenses that otherwise serve to control acute viral infection and virus dissemination. Innate defenses are triggered when pattern recognition receptor (PRR) proteins of the host cell engage pathogen-associated molecule patterns (PAMPs) present in viral products. Interferon regulatory factor 3 (IRF3) plays a central role in PRR signaling of innate immunity to drive the expression of type I interferon (IFN) and interferon-stimulated genes (ISGs), including a variety of HIV restriction factors, that serve to limit viral replication directly and/or program adaptive immunity. Productive infection of T cells by HIV is dependent upon the targeted proteolysis of IRF3 that occurs through a virus-directed mechanism that results in suppression of innate immune defenses. However, the mechanisms by which HIV controls innate immune signaling and IRF3 function are not defined. Here, we examined the innate immune response induced by HIV strains identified through their differential control of PRR signaling. We identified viruses that, unlike typical circulating HIV strains, lack the ability to degrade IRF3. Our studies show that IRF3 regulation maps specifically to the HIV accessory protein Vpu. We define a molecular interaction between Vpu and IRF3 that redirects IRF3 to the endolysosome for proteolytic degradation, thus allowing HIV to avoid the innate antiviral immune response. Our studies reveal that Vpu is an important IRF3 regulator that supports acute HIV infection through innate immune suppression. These observations define the Vpu-IRF3 interface as a novel target for therapeutic strategies aimed at enhancing the immune response to HIV. PMID:22593165

  9. The genetic diversity of Citrus dwarfing viroid populations is mainly dependent on the infected host species.

    Science.gov (United States)

    Tessitori, Matilde; Rizza, Serena; Reina, Antonella; Causarano, Giovanni; Di Serio, Francesco

    2013-03-01

    As with viruses, viroids infect their hosts as polymorphic populations of variants. Identifying possible sources of genetic variability is significant in the case of the species Citrus dwarfing viroid (CDVd) which has been proposed as a dwarfing agent for high-density citrus plantings. Here, a natural CDVd isolate (CMC) was used as an inoculum source for long-term (25 years) and short-term (1 year) bioassays in different citrus host species. Characterization of progenies indicated that the genetic stability of CDVd populations was high in certain hosts (trifoliate orange, Troyer citrange, Etrog citron, Navelina sweet orange), which preserve viroid populations similar to the original CMC isolate even after 25 years. By contrast, CDVd variant populations in Interdonato lemon and Volkamer lemon were completely different to those in the inoculated sources, highlighting how influential the host is on the genetic variability of CDVd populations. Implications for risk assessment of CDVd as a dwarfing agent are discussed. The GenBank/EMBL/DDBJ accession numbers for the complete sequences of the Citrus dwarfing viroid variants are JF970266.1 forH2-2, JF970267.1 for H2-7, EU938647.1 for H6-2, EU938651.1 forH6-10, JF970268.1 for H10-7, EU938652.1 for H14-13, EU938653.1for H14-14, JF970269.1 for H14-16, EU938648.1 for H15-9,EU938649.1 for H16-2, JF970265.1 for H16-9, EU938654.1 forH16-13, EU938650.1 for H20-3, JF970270.1 for H20-7, EU938641.1for PR-1, EU938642.1 for PR-3, EU938643.1 for PR-7, EU938644.1for CR-1, EU938639.1 for VR-4, JF12070.1 for VR-15, JF812069.1LS-4, EU938640.1 for LS-10 and JF970264.1 for LS-11. PMID:23152366

  10. Pivotal role of anthranilate dioxygenase genes in the adaptation of Burkholderia multivorans ATCC 17616 in soil.

    Science.gov (United States)

    Nishiyama, Eri; Ohtsubo, Yoshiyuki; Yamamoto, Yasuhiro; Nagata, Yuji; Tsuda, Masataka

    2012-05-01

    In our recent screen for soil-induced genes, the expression of andA operon (andAcAdAbAa) for anthranilate catabolism in Burkholderia multivorans ATCC 17616 was found to increase dramatically in a soil sample (Nishiyama et al., Environ Microbiol 12: 2539, 2010). The operon was preceded by andR encoding a putative transcriptional regulator for the andA operon. In this study, the andA promoter was induced by tryptophan and anthranilate in an andR-dependent manner. The andA promoter in a deletion mutant lacking tryptophan dioxygenase (one of enzymes for the catabolism of tryptophan to anthranilate) did not respond to tryptophan, indicating that not tryptophan but anthranilate is the effector of AndR. Although both anthranilate and tryptophan were under the detection levels in the soil sample, andA promoter showed higher activity in the soil sample than in a laboratory medium. Such induction required andR and was moderately dependent on the ferric uptake regulator (Fur). The proliferation ability of andAc mutant in the sterile soil was low compared with the co-incubated wild-type cells. These findings suggested that in the soil environment, anthranilate dioxygenase genes are induced by AndR and Fur, and play a pivotal role in the proliferation in the soil environment. PMID:22360670

  11. Pharmacological Inhibition of Host Heme Oxygenase-1 Suppresses Mycobacterium tuberculosis Infection In Vivo by a Mechanism Dependent on T Lymphocytes

    Science.gov (United States)

    Costa, Diego L.; Namasivayam, Sivaranjani; Amaral, Eduardo P.; Arora, Kriti; Chao, Alex; Mittereder, Lara R.; Maiga, Mamoudou; Boshoff, Helena I.; Barry, Clifton E.; Goulding, Celia W.; Andrade, Bruno B.

    2016-01-01

    ABSTRACT Heme oxygenase-1 (HO-1) is a stress response antioxidant enzyme which catalyzes the degradation of heme released during inflammation. HO-1 expression is upregulated in both experimental and human Mycobacterium tuberculosis infection, and in patients it is a biomarker of active disease. Whether the enzyme plays a protective versus pathogenic role in tuberculosis has been the subject of debate. To address this controversy, we administered tin protoporphyrin IX (SnPPIX), a well-characterized HO-1 enzymatic inhibitor, to mice during acute M. tuberculosis infection. These SnPPIX-treated animals displayed a substantial reduction in pulmonary bacterial loads comparable to that achieved following conventional antibiotic therapy. Moreover, when administered adjunctively with antimycobacterial drugs, the HO-1 inhibitor markedly enhanced and accelerated pathogen clearance. Interestingly, both the pulmonary induction of HO-1 expression and the efficacy of SnPPIX treatment in reducing bacterial burden were dependent on the presence of host T lymphocytes. Although M. tuberculosis expresses its own heme-degrading enzyme, SnPPIX failed to inhibit its enzymatic activity or significantly restrict bacterial growth in liquid culture. Together, the above findings reveal mammalian HO-1 as a potential target for host-directed monotherapy and adjunctive therapy of tuberculosis and identify the immune response as a critical regulator of this function.

  12. Complement-Dependent Lysis of Influenza A Virus-Infected Cells by Broadly Cross-Reactive Human Monoclonal Antibodies ▿

    Science.gov (United States)

    Terajima, Masanori; Cruz, John; Co, Mary Dawn T.; Lee, Jane-Hwei; Kaur, Kaval; Wilson, Patrick C.; Ennis, Francis A.

    2011-01-01

    We characterized human monoclonal antibodies (MAbs) cloned from influenza virus-infected patients and from influenza vaccine recipients by complement-dependent lysis (CDL) assay. Most MAbs active in CDL were neutralizing, but not all neutralizing MAbs can mediate CDL. Two of the three stalk-specific neutralizing MAbs tested were able to mediate CDL and were more cross-reactive to temporally distant H1N1 strains than the conventional hemagglutination-inhibiting and neutralizing MAbs. One of the stalk-specific MAbs was subtype cross-reactive to H1 and H2 hemagglutinins, suggesting a role for stalk-specific antibodies in protection against influenza illness, especially by a novel viral subtype which can cause pandemics. PMID:21994454

  13. Molecular mechanisms underlying the close association between soil Burkholderia and fungi.

    Science.gov (United States)

    Stopnisek, Nejc; Zühlke, Daniela; Carlier, Aurélien; Barberán, Albert; Fierer, Noah; Becher, Dörte; Riedel, Katharina; Eberl, Leo; Weisskopf, Laure

    2016-01-01

    Bacterial species belonging to the genus Burkholderia have been repeatedly reported to be associated with fungi but the extent and specificity of these associations in soils remain undetermined. To assess whether associations between Burkholderia and fungi are widespread in soils, we performed a co-occurrence analysis in an intercontinental soil sample collection. This revealed that Burkholderia significantly co-occurred with a wide range of fungi. To analyse the molecular basis of the interaction, we selected two model fungi frequently co-occurring with Burkholderia, Alternaria alternata and Fusarium solani, and analysed the proteome changes caused by cultivation with either fungus in the widespread soil inhabitant B. glathei, whose genome we sequenced. Co-cultivation with both fungi led to very similar changes in the B. glathei proteome. Our results indicate that B. glathei significantly benefits from the interaction, which is exemplified by a lower abundance of several starvation factors that were highly expressed in pure culture. However, co-cultivation also gave rise to stress factors, as indicated by the increased expression of multidrug efflux pumps and proteins involved in oxidative stress response. Our data suggest that the ability of Burkholderia to establish a close association with fungi mainly lies in the capacities to utilize fungal-secreted metabolites and to overcome fungal defense mechanisms. This work indicates that beneficial interactions with fungi might contribute to the survival strategy of Burkholderia species in environments with sub-optimal conditions, including acidic soils. PMID:25989372

  14. Deliberate attenuation of chikungunya virus by adaptation to heparan sulfate-dependent infectivity: a model for rational arboviral vaccine design.

    Science.gov (United States)

    Gardner, Christina L; Hritz, Jozef; Sun, Chengqun; Vanlandingham, Dana L; Song, Timothy Y; Ghedin, Elodie; Higgs, Stephen; Klimstra, William B; Ryman, Kate D

    2014-02-01

    Mosquito-borne chikungunya virus (CHIKV) is a positive-sense, single-stranded RNA virus from the genus Alphavirus, family Togaviridae, which causes fever, rash and severe persistent polyarthralgia in humans. Since there are currently no FDA licensed vaccines or antiviral therapies for CHIKV, the development of vaccine candidates is of critical importance. Historically, live-attenuated vaccines (LAVs) for protection against arthropod-borne viruses have been created by blind cell culture passage leading to attenuation of disease, while maintaining immunogenicity. Attenuation may occur via multiple mechanisms. However, all examined arbovirus LAVs have in common the acquisition of positively charged amino acid substitutions in cell-surface attachment proteins that render virus infection partially dependent upon heparan sulfate (HS), a ubiquitously expressed sulfated polysaccharide, and appear to attenuate by retarding dissemination of virus particles in vivo. We previously reported that, like other wild-type Old World alphaviruses, CHIKV strain, La Réunion, (CHIKV-LR), does not depend upon HS for infectivity. To deliberately identify CHIKV attachment protein mutations that could be combined with other attenuating processes in a LAV candidate, we passaged CHIKV-LR on evolutionarily divergent cell-types. A panel of single amino acid substitutions was identified in the E2 glycoprotein of passaged virus populations that were predicted to increase electrostatic potential. Each of these substitutions was made in the CHIKV-LR cDNA clone and comparisons of the mutant viruses revealed surface exposure of the mutated residue on the spike and sensitivity to competition with the HS analog, heparin, to be primary correlates of attenuation in vivo. Furthermore, we have identified a mutation at E2 position 79 as a promising candidate for inclusion in a CHIKV LAV.

  15. Comparative Genome Sequence Analysis Reveals the Extent of Diversity and Conservation for Glycan-Associated Proteins in Burkholderia spp.

    OpenAIRE

    Ong, Hui San; Mohamed, Rahmah; Firdaus-Raih, Mohd

    2012-01-01

    Members of the Burkholderia family occupy diverse ecological niches. In pathogenic family members, glycan-associated proteins are often linked to functions that include virulence, protein conformation maintenance, surface recognition, cell adhesion, and immune system evasion. Comparative analysis of available Burkholderia genomes has revealed a core set of 178 glycan-associated proteins shared by all Burkholderia of which 68 are homologous to known essential genes. The genome sequence compari...

  16. Prevalence and age-dependent occurrence of intestinal protozoan infections in suckling piglets.

    Science.gov (United States)

    Damriyasa, I Made; Bauer, Christian

    2006-01-01

    A cross-sectional survey was performed on 20 pig breeding farms in southern Hesse, central Germany, to evaluate the prevalence and age-dependent occurrence of intestinal protozoan parasites in unweaned piglets. Faecal samples of 514 clinically unaffected piglets of different age (Balantidium coli (16 of 20 farms), Entamoeba sp. (15), Jodamoeba sp. (14), Isospora (I.) suis (9), Chilomastix sp. (6) and Eimeria spp. (6). The protozoan species differed in the start and course of (oo)cyst excretion. I. suis oocysts and Jodamoeba cysts were detected already in the first week of life whereas shedding of the other parasites started later on. The prevalence of Isospora oocyst excretion increased to a maximum (18%) in 2-3 weeks old animals followed by a sharp decline. The proportion of Balantidium, Entamoeba or Jodamoeba positive suckling piglets continously increased until the age of 5-7 weeks to 60%, 52% and 22%, respectively, whereas that of Chilomastix positive animals remained on a low level of 8-12% independent of the age. Eimeria oocysts were found transiently in the faeces of 1-4 weeks old piglets. PMID:17009710

  17. Rotavirus NSP4: Cell type-dependent transport kinetics to the exofacial plasma membrane and release from intact infected cells

    Directory of Open Access Journals (Sweden)

    Parr Rebecca D

    2011-06-01

    Full Text Available Abstract Background Rotavirus NSP4 localizes to multiple intracellular sites and is multifunctional, contributing to RV morphogenesis, replication and pathogenesis. One function of NSP4 is the induction of early secretory diarrhea by binding surface receptors to initiate signaling events. The aims of this study were to determine the transport kinetics of NSP4 to the exofacial plasma membrane (PM, the subsequent release from intact infected cells, and rebinding to naïve and/or neighboring cells in two cell types. Methods Transport kinetics was evaluated using surface-specific biotinylation/streptavidin pull-downs and exofacial exposure of NSP4 was confirmed by antibody binding to intact cells, and fluorescent resonant energy transfer. Transfected cells similarly were monitored to discern NSP4 movement in the absence of infection or other viral proteins. Endoglycosidase H digestions, preparation of CY3- or CY5- labeled F(ab2 fragments, confocal imaging, and determination of preferential polarized transport employed standard laboratory techniques. Mock-infected, mock-biotinylated and non-specific antibodies served as controls. Results Only full-length (FL, endoglycosidase-sensitive NSP4 was detected on the exofacial surface of two cell types, whereas the corresponding cell lysates showed multiple glycosylated forms. The C-terminus of FL NSP4 was detected on exofacial-membrane surfaces at different times in different cell types prior to its release into culture media. Transport to the PM was rapid and distinct yet FL NSP4 was secreted from both cell types at a time similar to the release of virus. NSP4-containing, clarified media from both cells bound surface molecules of naïve cells, and imaging showed secreted NSP4 from one or more infected cells bound neighboring cell membranes in culture. Preferential sorting to apical or basolateral membranes also was distinct in different polarized cells. Conclusions The intracellular transport of NSP4 to

  18. An objective approach for Burkholderia pseudomallei strain selection as challenge material for medical countermeasures efficacy testing.

    Science.gov (United States)

    Van Zandt, Kristopher E; Tuanyok, Apichai; Keim, Paul S; Warren, Richard L; Gelhaus, H Carl

    2012-01-01

    Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs), the high mortality rates associated with melioidosis raises significant ethical issues concerning treating individuals with new compounds with unknown efficacies. The US Food and Drug Administration (FDA) has formulated a set of guidelines for the licensure of new MCMs to treat diseases in which it would be unethical to test the efficacy of these drugs in humans. The FDA "Animal Rule" 21 CFR 314 calls for consistent, well-characterized B. pseudomallei strains to be used as challenge material in animal models. In order to facilitate the efficacy testing of new MCMs for melioidosis using animal models, we intend to develop a well-characterized panel of strains for use. This panel will comprise of strains that were isolated from human cases, have a low passage history, are virulent in animal models, and are well-characterized phenotypically and genotypically. We have reviewed published and unpublished data on various B. pseudomallei strains to establish an objective method for selecting the strains to be included in the panel of B. pseudomallei strains with attention to five categories: animal infection models, genetic characterization, clinical and passage history, and availability of the strain to the research community. We identified 109 strains with data in at least one of the five categories, scored each strain based on the gathered data and identified six strains as candidate for a B. pseudomallei strain panel. PMID:23057010

  19. An objective approach for Burkholderia pseudomallei strain selection as challenge material for medical countermeasures efficacy testing

    Directory of Open Access Journals (Sweden)

    Kristopher E. Van Zandt

    2012-09-01

    Full Text Available Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs, the high mortality rates associated with melioidosis raises significant ethical issues concerning treating individuals with new compounds with unknown efficacies. The US Food and Drug Administration (FDA has formulated a set of guidelines for the licensure of new MCMs to treat diseases in which it would be unethical to test the efficacy of these drugs in humans. The FDA Animal Rule 21 CFR 314 calls for consistent, well-characterized B. pseudomallei strains to be used as challenge material in animal models. In order to facilitate the efficacy testing of new MCMs for melioidosis using animal models, we intend to develop a well-characterized panel of strains for use. This panel will comprise of strains that were isolated from human cases, have a low passage history, are virulent in animal models, and are well characterized phenotypically and genotypically. We have reviewed published and unpublished data on various B. pseudomallei strains to establish an objective method for selecting the strains to be included in the panel of B. pseudomallei strains with attention to five categories: animal infection models, genetic characterization, clinical and passage history, and availability of the strain to the research community. We identified 109 strains with data in at least one of the five categories, scored each strain based on the gathered data and identified 6 strains as candidate for a B. pseudomallei strain panel.

  20. Molecular determinants of dengue virus 2 envelope protein important for virus entry in FcγRIIA-mediated antibody-dependent enhancement of infection

    International Nuclear Information System (INIS)

    Antibody-dependent enhancement (ADE) of infection may cause severe illness in patients suffering a secondary infection by a heterologous dengue virus (DENV) serotype. During ADE of infection, cross-reactive non- or poorly-neutralizing antibodies form infectious virus-Ab complexes with the newly infecting serotype and enhance virus infection by binding to the Fcγ receptors (FcγR) on FcγR-bearing cells. In this study, we determined that molecular determinants of DENV2 envelope protein critical for virus entry during non-ADE infection are also required for ADE infection mediated by FcγRIIA, and binding of virus-Ab complexes with FcγRIIA alone is not sufficient for ADE of infection. The FcγRIIA mainly plays an auxiliary role in concentrating the virus–Ab complex to the cell surface, and other primary cellular receptors are required for virus entry. Understanding the viral entry pathway in ADE of DENV infection will greatly facilitate rational designs of anti-viral therapeutics against severe dengue disease associated with ADE. - Highlights: • KKK305/307/310 in DENV2 E-DIII is critical for virus attachment in ADE and non-ADE infection. • Binding of DENV2–Ab complex with FcγRII alone is not sufficient for virus entry in ADE infection. • Other primary receptors were required for DENV2 internalization during FcγRII–mediated ADE. • G104 and L135 of DENV2 E are critical for virus-mediated membrane fusion. • DENV2 virus-mediated membrane fusion is required for both ADE and non-ADE infection

  1. Molecular determinants of dengue virus 2 envelope protein important for virus entry in FcγRIIA-mediated antibody-dependent enhancement of infection

    Energy Technology Data Exchange (ETDEWEB)

    Chotiwan, Nunya; Roehrig, John T. [Arboviral Diseases Branch, Division of Vector-Borne Disease, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States); Schlesinger, Jacob J. [Department of Medicine, University of Rochester, Rochester, NY 14642 (United States); Blair, Carol D. [Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523 (United States); Huang, Claire Y.-H., E-mail: yxh0@cdc.gov [Arboviral Diseases Branch, Division of Vector-Borne Disease, Centers for Disease Control and Prevention, Fort Collins, CO 80521 (United States)

    2014-05-15

    Antibody-dependent enhancement (ADE) of infection may cause severe illness in patients suffering a secondary infection by a heterologous dengue virus (DENV) serotype. During ADE of infection, cross-reactive non- or poorly-neutralizing antibodies form infectious virus-Ab complexes with the newly infecting serotype and enhance virus infection by binding to the Fcγ receptors (FcγR) on FcγR-bearing cells. In this study, we determined that molecular determinants of DENV2 envelope protein critical for virus entry during non-ADE infection are also required for ADE infection mediated by FcγRIIA, and binding of virus-Ab complexes with FcγRIIA alone is not sufficient for ADE of infection. The FcγRIIA mainly plays an auxiliary role in concentrating the virus–Ab complex to the cell surface, and other primary cellular receptors are required for virus entry. Understanding the viral entry pathway in ADE of DENV infection will greatly facilitate rational designs of anti-viral therapeutics against severe dengue disease associated with ADE. - Highlights: • KKK305/307/310 in DENV2 E-DIII is critical for virus attachment in ADE and non-ADE infection. • Binding of DENV2–Ab complex with FcγRII alone is not sufficient for virus entry in ADE infection. • Other primary receptors were required for DENV2 internalization during FcγRII–mediated ADE. • G104 and L135 of DENV2 E are critical for virus-mediated membrane fusion. • DENV2 virus-mediated membrane fusion is required for both ADE and non-ADE infection.

  2. Construction and expression of a Rev-dependent TNF-R1 expressing HIV-infected-cell injurious vectors

    Institute of Scientific and Technical Information of China (English)

    SHI Wei-min; Dean Baylis; Damian Purcell; Paul U Cameron

    2005-01-01

    Background Rev is necessary for exporting unspliced and incompletely spliced intron containing HIV mRNAs and for HIV replication. The aim of this study is to develop a kind of selective suicide construct that can specifically and directly induce HIV infected cells into apoptosis based on the high affinity of Rev and Rev response element (RRE). Methods Molecular-cloning technique was used to synthesis Rev dependent TNF-R1 expression construct pDM128-TNF-R1 (pT128) that contains RRE and TNFR1 gene. Restriction digestion, Polymerase Chain Reaction (PCR) and DNA sequencing were processed and the exactness and correctness of the inserted TNF-R1 gene in pT128 were confirmed repeatedly. The expression of pT128 co-transfected with different combination of other plasmids by calcium phosphate-DNA co-precipitation in Helas and by gene gun transfection in keratinocytes was further tested by flow-cytometry and cell counted under microscope. Results The new plasmid specifically expressed TNF-R1 in Helas when co-transfected with pRev but did not when without pRev. Indirect expression of TNF-R1 from pT128 was slower than the direct expression of that from Hu p60 TNFR1 in pDC302 (pT60), but all those pT60 or pT128 transfected cells showed apoptosis at last while TNF-R1 was sufficiently expressed. Other kinds of Rev expression construct such as pAD8 and a chimeric HIV vaccine also can switched on the selective expression of pT128. Not only Rev-dependent expression in Helas, pT128 also normally expressed its TNF-R1 in keratinocytes. Co-transfected with pRev or pAD8 that expressed Rev, pT128 expressed TNF-R1 and induced apoptosis of green fluorescent keratinocytes in skin explant. The number of green fluorescent keratinocytes co-transfected by pT128 plus pRev or pAD8 was gradually outnumbered by that co-transfected by pT128 only. The difference was more significant after culturing for 72 hours. Conclusions Rev dependent pT128 is able to selectively induce apoptosis of HIV-infected or

  3. During acute experimental infection with the reticulotropic Trypanosoma cruzi strain Tulahuen IL-22 is induced IL-23-dependently but is dispensable for protection.

    Science.gov (United States)

    Erdmann, Hanna; Behrends, Jochen; Hölscher, Christoph

    2016-01-01

    Protective immunity against Trypanosoma cruzi, the causative agent of Chagas disease, depends on the activation of macrophages by IFN-γ and IL-17A. In contrast, IL-10 prevents immunopathology. IL-22 belongs to the IL-10 cytokine family and has pleiotropic effects during host defense and immunopathology, however its role in protection and pathology during T. cruzi infection has not been analyzed yet. Therefore, we examined the role of IL-22 in experimental Chagas disease using the reticulotropic Tulahuen strain of T. cruzi. During infection, IL-22 is secreted by CD4-positive cells in an IL-23-dependent fashion. Infected IL-22(-/-) mice exhibited an increased production of IFN-γ and TNF and displayed enhanced numbers of activated IFN-γ-producing T cells in their spleens. Additionally, the production of IL-10 was increased in IL-22(-/-) mice upon infection. Macrophage activation and by association the parasitemia was not affected in the absence of IL-22. Apart from a transient increase in the body weight loss, infected IL-22(-/-) mice did not show any signs for an altered immunopathology during the first fourteen days of infection. Taken together, although IL-22 is expressed, it seems to play a minor role in protection and pathology during the acute systemic infection with the reticulotropic Tulahuen strain of T. cruzi. PMID:27650379

  4. Fucose-binding lectin from opportunistic pathogen Burkholderia ambifaria binds to both plant and human oligosaccharidic epitopes.

    Science.gov (United States)

    Audfray, Aymeric; Claudinon, Julie; Abounit, Saïda; Ruvoën-Clouet, Nathalie; Larson, Göran; Smith, David F; Wimmerová, Michaela; Le Pendu, Jacques; Römer, Winfried; Varrot, Annabelle; Imberty, Anne

    2012-02-01

    Burkholderia ambifaria is generally associated with the rhizosphere of plants where it has biocontrol effects on other microorganisms. It is also a member of the Burkholderia cepacia complex, a group of closely related bacteria that cause lung infections in immunocompromised patients as well as in patients with granulomatous disease or cystic fibrosis. Our previous work indicated that fucose on human epithelia is a frequent target for lectins and adhesins of lung pathogens (Sulák, O., Cioci, G., Lameignère, E., Balloy, V., Round, A., Gutsche, I., Malinovská, L., Chignard, M., Kosma, P., Aubert, D. F., Marolda, C. L., Valvano, M. A., Wimmerová, M., and Imberty, A. (2011) PLoS Pathog. 7, e1002238). Analysis of the B. ambifaria genome identified BambL as a putative fucose-binding lectin. The 87-amino acid protein was produced recombinantly and demonstrated to bind to fucosylated oligosaccharides with a preference for αFuc1-2Gal epitopes. Crystal structures revealed that it associates as a trimer with two fucose-binding sites per monomer. The overall fold is a six-bladed β-propeller formed by oligomerization as in the Ralstonia solanacearum lectin and not by sequential domains like the fungal fucose lectin from Aleuria aurantia. The affinity of BambL for small fucosylated glycans is very high as demonstrated by microcalorimetry (K(D) < 1 μM). Plant cell wall oligosaccharides and human histo-blood group oligosaccharides H-type 2 and Lewis Y are bound with equivalent efficiency. Binding to artificial glycosphingolipid-containing vesicles, human saliva, and lung tissues confirmed that BambL could recognize a wide spectrum of fucosylated epitopes, albeit with a lower affinity for biological material from nonsecretor individuals.

  5. lux-Marking and application of carbofuran degrader Burkholderia cepacia PCL3.

    Science.gov (United States)

    Plangklang, Pensri; Reungsang, Alissara

    2011-10-01

    A luxAB-mutant of the carbofuran degrading bacterium Burkholderia cepacia PCL3 was successfully constructed with the capability to emit a luminescence signal of 1.6×10(-3)RLUcfu(-1). The mutant has a growth pattern and carbofuran degradation ability similar to PCL3 wild-type. The luminescent emission by PCL3:luxAB1 directly correlated with the metabolic activity of the cells. The optimal pH, temperature and n-decanal concentration for luminescence emission are 7.0, 35°C and 0.01%, respectively. PCL3:luxAB1 was used to assess the toxicity of carbofuran and carbofuran phenol in basal salt medium (BSM) in which the different sensitivity of the cells is dependent on the biomass concentration. With the luciferase system, the degradative fraction of the augmented PCL3:luxAB1 and the difference between the active augmented PCL3:luxAB1 and indigenous microorganisms at the contaminated site could be indicated.

  6. Burkholderia Diffusible Signal Factor Signals to Francisella novicida To Disperse Biofilm and Increase Siderophore Production.

    Science.gov (United States)

    Dean, Scott N; Chung, Myung-Chul; van Hoek, Monique L

    2015-10-01

    In many bacteria, the ability to modulate biofilm production relies on specific signaling molecules that are either self-produced or made by neighboring microbes within the ecological niche. We analyzed the potential interspecies signaling effect of the Burkholderia diffusible signal factor (BDSF) on Francisella novicida, a model organism for Francisella tularensis, and demonstrated that BDSF both inhibits the formation and causes the dispersion of Francisella biofilm. Specificity was demonstrated for the cis versus the trans form of BDSF. Using transcriptome sequencing, quantitative reverse transcription-PCR, and activity assays, we found that BDSF altered the expression of many F. novicida genes, including genes involved in biofilm formation, such as chitinases. Using a chitinase inhibitor, the antibiofilm activity of BDSF was also shown to be chitinase dependent. In addition, BDSF caused an increase in RelA expression and increased levels of (p)ppGpp, leading to decreased biofilm production. These results support our observation that exposure of F. novicida to BDSF causes biofilm dispersal. Furthermore, BDSF upregulated the genes involved in iron acquisition (figABCD), increasing siderophore production. Thus, this study provides evidence for a potential role and mechanism of diffusible signal factor (DSF) signaling in the genus Francisella and suggests the possibility of interspecies signaling between Francisella and other bacteria. Overall, this study suggests that in response to the interspecies DSF signal, F. novicida can alter its gene expression and regulate its biofilm formation. PMID:26231649

  7. Rapid Antimicrobial Susceptibility Testing of Bacillus anthracis, Yersinia pestis, and Burkholderia pseudomallei by Use of Laser Light Scattering Technology.

    Science.gov (United States)

    Bugrysheva, Julia V; Lascols, Christine; Sue, David; Weigel, Linda M

    2016-06-01

    Rapid methods to determine antimicrobial susceptibility would assist in the timely distribution of effective treatment or postexposure prophylaxis in the aftermath of the release of bacterial biothreat agents such as Bacillus anthracis, Yersinia pestis, or Burkholderia pseudomallei Conventional susceptibility tests require 16 to 48 h of incubation, depending on the bacterial species. We evaluated a method that is based on laser light scattering technology that measures cell density in real time. We determined that it has the ability to rapidly differentiate between growth (resistant) and no growth (susceptible) of several bacterial threat agents in the presence of clinically relevant antimicrobials. Results were available in 10 h of incubation. Use of laser scattering technology decreased the time required to determine antimicrobial susceptibility by 50% to 75% for B. anthracis, Y. pestis, and B. pseudomallei compared to conventional methods. PMID:26984973

  8. Genetic and phenotypic diversity in Burkholderia: contributions by prophage and phage-like elements

    Directory of Open Access Journals (Sweden)

    Ulrich Ricky L

    2010-07-01

    Full Text Available Abstract Background Burkholderia species exhibit enormous phenotypic diversity, ranging from the nonpathogenic, soil- and water-inhabiting Burkholderia thailandensis to the virulent, host-adapted mammalian pathogen B. mallei. Genomic diversity is evident within Burkholderia species as well. Individual isolates of Burkholderia pseudomallei and B. thailandensis, for example, carry a variety of strain-specific genomic islands (GIs, including putative pathogenicity and metabolic islands, prophage-like islands, and prophages. These GIs may provide some strains with a competitive advantage in the environment and/or in the host relative to other strains. Results Here we present the results of analysis of 37 prophages, putative prophages, and prophage-like elements from six different Burkholderia species. Five of these were spontaneously induced to form bacteriophage particles from B. pseudomallei and B. thailandensis strains and were isolated and fully sequenced; 24 were computationally predicted in sequenced Burkholderia genomes; and eight are previously characterized prophages or prophage-like elements. The results reveal numerous differences in both genome structure and gene content among elements derived from different species as well as from strains within species, due in part to the incorporation of additional DNA, or 'morons' into the prophage genomes. Implications for pathogenicity are also discussed. Lastly, RNAseq analysis of gene expression showed that many of the genes in ϕ1026b that appear to contribute to phage and lysogen fitness were expressed independently of the phage structural and replication genes. Conclusions This study provides the first estimate of the relative contribution of prophages to the vast phenotypic diversity found among the Burkholderiae.

  9. Evidence for Acquisition in Nature of a Chromosomal 2,4-Dichlorophenoxyacetic Acid/(alpha)-Ketoglutarate Dioxygenase Gene by Different Burkholderia spp

    OpenAIRE

    Matheson, V. G.; Forney, L J; Suwa, Y.; Nakatsu, C. H.; A. J. Sexstone; Holben, W E

    1996-01-01

    We characterized the gene required to initiate the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) by the soil bacterium Burkholderia sp. strain TFD6, which hybridized to the tfdA gene of the canonical 2,4-D catabolic plasmid pJP4 under low-stringency conditions. Cleavage of the ether bond of 2,4-D by cell extracts of TFD6 proceeded by an (alpha)-ketoglutarate-dependent reaction, characteristic of TfdA (F. Fukumori and R. P. Hausinger, J. Bacteriol. 175:2083-2086, 1993). The TFD6 tfdA g...

  10. Functional characterization and evaluation of in vitro protective efficacy of murine monoclonal antibodies BURK24 and BURK37 against Burkholderia pseudomallei.

    Directory of Open Access Journals (Sweden)

    Bhavani V Peddayelachagiri

    Full Text Available Burkholderia pseudomallei, the causative agent of melioidosis has been recognized by CDC as a category B select agent. Although substantial efforts have been made for development of vaccine molecules against the pathogen, significant hurdles still remain. With no licensed vaccines available and high relapse rate of the disease, there is a pressing need for development of alternate protection strategies. Antibody-mediated passive protection is promising in this regard and our primary interest was to unravel this frontier of specific mAbs against Burkholderia pseudomallei infections, as functional characterization of antibodies is a pre-requisite to demonstrate them as protective molecules. To achieve this, we designed our study on in vitro-based approach and assessed two mAbs, namely BURK24 and BURK37, reactive with outer membrane proteins and lipopolysaccharide of the pathogen respectively, for their ability to manifest inhibitory effects on the pathogenesis mechanisms of B. pseudomallei including biofilm formation, invasion and induction of apoptosis. The experiments were performed using B. pseudomallei standard strain NCTC 10274 and a clinical isolate, B. pseudomallei 621 recovered from a septicemia patient with diabetic ailment. The growth kinetic studies of the pathogen in presence of various concentrations of each individual mAb revealed their anti-bacterial properties. Minimal inhibitory concentration and minimal bactericidal concentration of both the mAbs were determined by using standards of Clinical and Laboratory Standards Institute (CLSI and experiments were performed using individual mAbs at their respective bacteriostatic concentration. As an outcome, both mAbs exhibited significant anti-Burkholderia pseudomallei properties. They limited the formation of biofilm by the bacterium and completely crippled its invasion into human alveolar adenocarcinoma epithelial cells. Also, the mAbs were appreciably successful in preventing the

  11. Outbreak of Burkholderia cepacia complex bacteremia in a chemotherapy day care unit due to intrinsic contamination of an antiemetic drug

    Directory of Open Access Journals (Sweden)

    T Singhal

    2015-01-01

    Full Text Available Background: In the end of 2009, a large number of patients with cancer undergoing chemotherapy at the day care unit of a private hospital in Mumbai, India developed Burkholderia cepacia complex (BCC blood stream infection (BSI. Objective: The objectives were to identify the source of the outbreak and terminate the outbreak as rapidly as possible. Materials and Methods: All infection control protocols and processes were reviewed. Intensive training was started for all nursing staff involved in patient care. Cultures were sent from the environment (surfaces, water, air, intravenous fluids, disinfectants and antiseptics and opened/unopened medication. Results: A total of 13 patients with cancer with tunneled catheters were affected with BCC BSI. The isolates were of similar antimicrobial sensitivity. No significant breach of infection control protocols could be identified. Cultures from the prepared intravenous medication bags grew BCC. Subsequently, culture from unused vials of the antiemetic granisetron grew BCC, whereas those from the unopened IV fluid bag and chemotherapy medication were negative. On review, it was discovered that the outbreak started when a new brand of granisetron was introduced. The result was communicated to the manufacturer and the brand was withdrawn. There were no further cases. Conclusions: This outbreak was thus linked to intrinsic contamination of medication vials. We acknowledge a delay in identifying the source as we were concentrating more on human errors in medication preparation and less on intrinsic contamination. We recommend that in an event of an outbreak, unopened vials be cultured at the outset.

  12. Genome-wide analysis reveals loci encoding anti-macrophage factors in the human pathogen Burkholderia pseudomallei K96243.

    Directory of Open Access Journals (Sweden)

    Andrea J Dowling

    Full Text Available Burkholderia pseudomallei is an important human pathogen whose infection biology is still poorly understood. The bacterium is endemic to tropical regions, including South East Asia and Northern Australia, where it causes melioidosis, a serious disease associated with both high mortality and antibiotic resistance. B. pseudomallei is a Gram-negative facultative intracellular pathogen that is able to replicate in macrophages. However despite the critical nature of its interaction with macrophages, few anti-macrophage factors have been characterized to date. Here we perform a genome-wide gain of function screen of B. pseudomallei strain K96243 to identify loci encoding factors with anti-macrophage activity. We identify a total of 113 such loci scattered across both chromosomes, with positive gene clusters encoding transporters and secretion systems, enzymes/toxins, secondary metabolite, biofilm, adhesion and signal response related factors. Further phenotypic analysis of four of these regions shows that the encoded factors cause striking cellular phenotypes relevant to infection biology, including apoptosis, formation of actin 'tails' and multi-nucleation within treated macrophages. The detailed analysis of the remaining host of loci will facilitate genetic dissection of the interaction of this important pathogen with host macrophages and thus further elucidate this critical part of its infection cycle.

  13. Respiratory influenza virus infection induces intestinal immune injury via microbiota-mediated Th17 cell–dependent inflammation

    OpenAIRE

    Wang, Jian; Li, Fengqi; Wei, Haiming; Lian, Zhe-Xiong; Sun, Rui; Tian, Zhigang

    2014-01-01

    Influenza in humans is often accompanied by gastroenteritis-like symptoms such as diarrhea, but the underlying mechanism is not yet understood. We explored the occurrence of gastroenteritis-like symptoms using a mouse model of respiratory influenza infection. We found that respiratory influenza infection caused intestinal injury when lung injury occurred, which was not due to direct intestinal viral infection. Influenza infection altered the intestinal microbiota composition, which was mediat...

  14. Cytokine-dependent and–independent gene expression changes and cell cycle block revealed in Trypanosoma cruzi-infected host cells by comparative mRNA profiling

    Directory of Open Access Journals (Sweden)

    Burleigh Barbara A

    2009-05-01

    Full Text Available Abstract Background The requirements for growth and survival of the intracellular pathogen Trypanosoma cruzi within mammalian host cells are poorly understood. Transcriptional profiling of the host cell response to infection serves as a rapid read-out for perturbation of host physiology that, in part, reflects adaptation to the infective process. Using Affymetrix oligonucleotide array analysis we identified common and disparate host cell responses triggered by T. cruzi infection of phenotypically diverse human cell types. Results We report significant changes in transcript abundance in T. cruzi-infected fibroblasts, endothelial cells and smooth muscle cells (2852, 2155 and 531 genes respectively; fold-change ≥ 2, p-value T. cruzi-infected fibroblasts and endothelial cells transwell plates were used to distinguish cytokine-dependent and -independent gene expression profiles. This approach revealed the induction of metabolic and signaling pathways involved in cell proliferation, amino acid catabolism and response to wounding as common themes in T. cruzi-infected cells. In addition, the downregulation of genes involved in mitotic cell cycle and cell division predicted that T. cruzi infection may impede host cell cycle progression. The observation of impaired cytokinesis in T. cruzi-infected cells, following nuclear replication, confirmed this prediction. Conclusion Metabolic pathways and cellular processes were identified as significantly altered at the transcriptional level in response to T. cruzi infection in a cytokine-independent manner. Several of these alterations are supported by previous studies of T. cruzi metabolic requirements or effects on the host. However, our methods also revealed a T. cruzi-dependent block in the host cell cycle, at the level of cytokinesis, previously unrecognized for this pathogen-host cell interaction.

  15. Context-dependent effects of induced resistance under co-infection in a plant-pathogen interaction.

    Science.gov (United States)

    Laine, Anna-Liisa

    2011-09-01

    The ability of a parasite strain to establish and grow on its host may be drastically altered by simultaneous infection by other parasite strains, and dynamics under multiple infection have been suggested to be a major force driving pathogen evolution. Here, I studied whether hosts' induced defenses mediate dynamics of multiple infection of the fungal pathogen, Podosphaera plantaginis, infecting Plantago lanceolata. A laboratory study of sequential infections, where interaction between pathogen strains was prevented, showed that ability to establish remained unaffected, but prior infection elevates the host's resistance to the degree that subsequent infection development is significantly reduced. However, when inoculated plants and their healthy controls were planted back into their natural populations, hosts with prior infection became more heavily infected by the subsequent infections than the initially healthy plants. Hence, a controlled short-term laboratory study is a poor predictor of the host's ability to mediate multiple infection during the course of natural epidemics. These results have applied implications for priming where the plants' defenses are elicited to provide protection against further attack, highlighting the importance of testing priming under natural conditions for relevant time scales. PMID:25568016

  16. Role of an iron-dependent transcriptional regulator in the pathogenesis and host response to infection with Streptococcus pneumoniae.

    Directory of Open Access Journals (Sweden)

    Radha Gupta

    Full Text Available Iron is a critical cofactor for many enzymes and is known to regulate gene expression in many bacterial pathogens. Streptococcus pneumoniae normally inhabits the upper respiratory mucosa but can also invade and replicate in lungs and blood. These anatomic sites vary considerably in both the quantity and form of available iron. The genome of serotype 4 pneumococcal strain TIGR4 encodes a putative iron-dependent transcriptional regulator (IDTR. A mutant deleted at idtr (Δidtr exhibited growth kinetics similar to parent strain TIGR4 in vitro and in mouse blood for up to 48 hours following infection. However, Δidtr was significantly attenuated in a murine model of sepsis. IDTR down-regulates the expression of ten characterized and putative virulence genes in nasopharyngeal colonization and pneumonia. The host cytokine response was significantly suppressed in sepsis with Δidtr. Since an exaggerated inflammatory response is associated with a poor prognosis in sepsis, the decreased inflammatory response could explain the increased survival with Δidtr. Our results suggest that IDTR, which is dispensable for pneumococcal growth in vitro, is associated with regulation of pneumococcal virulence in specific host environments. Additionally, IDTR ultimately modulates the host cytokine response and systemic inflammation that contributes to morbidity and mortality of invasive pneumococcal disease.

  17. Ubiquity of Putative Type III Secretion Genes among Clinical and Environmental Burkholderia pseudomallei Isolates in Northern Australia

    OpenAIRE

    Smith-Vaughan, H C; Gal, D; Lawrie, P. M.; Winstanley, C.; Sriprakash, K S; Currie, B. J.

    2003-01-01

    Horseradish peroxidase-like type III secretion (TTS1) genes were present in all 116 Northern Australian Burkholderia pseudomallei isolates tested but were not detected in other common environmental Burkholderia species. PCR of TTS1 genes may prove valuable as a diagnostic test.

  18. Phylogenetically Diverse Burkholderia Associated with Midgut Crypts of Spurge Bugs, Dicranocephalus spp. (Heteroptera: Stenocephalidae).

    Science.gov (United States)

    Kuechler, Stefan Martin; Matsuura, Yu; Dettner, Konrad; Kikuchi, Yoshitomo

    2016-06-25

    Diverse phytophagous heteropteran insects, commonly known as stinkbugs, are associated with specific gut symbiotic bacteria, which have been found in midgut cryptic spaces. Recent studies have revealed that members of the stinkbug families Coreidae and Alydidae of the superfamily Coreoidea are consistently associated with a specific group of the betaproteobacterial genus Burkholderia, called the "stinkbug-associated beneficial and environmental (SBE)" group, and horizontally acquire specific symbionts from the environment every generation. However, the symbiotic system of another coreoid family, Stenocephalidae remains undetermined. We herein investigated four species of the stenocephalid genus Dicranocephalus. Examinations via fluorescence in situ hybridization (FISH) and transmission electron microscopy (TEM) revealed the typical arrangement and ultrastructures of midgut crypts and gut symbionts. Cloning and molecular phylogenetic analyses of bacterial genes showed that the midgut crypts of all species are colonized by Burkholderia strains, which were further assigned to different subgroups of the genus Burkholderia. In addition to the SBE-group Burkholderia, a number of stenocephalid symbionts belonged to a novel clade containing B. sordidicola and B. udeis, suggesting a specific symbiont clade for the Stenocephalidae. The symbiotic systems of stenocephalid bugs may provide a unique opportunity to study the ongoing evolution of symbiont associations in the stinkbug-Burkholderia interaction. PMID:27265344

  19. Mycobacterium tuberculosis-infected human monocytes down-regulate microglial MMP-2 secretion in CNS tuberculosis via TNFα, NFκB, p38 and caspase 8 dependent pathways

    Directory of Open Access Journals (Sweden)

    Elkington Paul T

    2011-05-01

    Full Text Available Abstract Tuberculosis (TB of the central nervous system (CNS is a deadly disease characterized by extensive tissue destruction, driven by molecules such as Matrix Metalloproteinase-2 (MMP-2 which targets CNS-specific substrates. In a simplified cellular model of CNS TB, we demonstrated that conditioned medium from Mycobacterium tuberculosis-infected primary human monocytes (CoMTb, but not direct infection, unexpectedly down-regulates constitutive microglial MMP-2 gene expression and secretion by 72.8% at 24 hours, sustained up to 96 hours (P M.tb-infected monocyte-dependent networks paradoxically involves the pro-inflammatory mediators TNF-α, p38 MAP kinase and NFκB in addition to a novel caspase 8-dependent pathway.

  20. Toxoplasma gondii is dependent on glutamine and alters migratory profile of infected host bone marrow derived immune cells through SNAT2 and CXCR4 pathways.

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    I-Ping Lee

    Full Text Available The obligate intracellular parasite, Toxoplasma gondii, disseminates through its host inside infected immune cells. We hypothesize that parasite nutrient requirements lead to manipulation of migratory properties of the immune cell. We demonstrate that 1 T. gondii relies on glutamine for optimal infection, replication and viability, and 2 T. gondii-infected bone marrow-derived dendritic cells (DCs display both "hypermotility" and "enhanced migration" to an elevated glutamine gradient in vitro. We show that glutamine uptake by the sodium-dependent neutral amino acid transporter 2 (SNAT2 is required for this enhanced migration. SNAT2 transport of glutamine is also a significant factor in the induction of migration by the small cytokine stromal cell-derived factor-1 (SDF-1 in uninfected DCs. Blocking both SNAT2 and C-X-C chemokine receptor 4 (CXCR4; the unique receptor for SDF-1 blocks hypermotility and the enhanced migration in T. gondii-infected DCs. Changes in host cell protein expression following T. gondii infection may explain the altered migratory phenotype; we observed an increase of CD80 and unchanged protein level of CXCR4 in both T. gondii-infected and lipopolysaccharide (LPS-stimulated DCs. However, unlike activated DCs, SNAT2 expression in the cytosol of infected cells was also unchanged. Thus, our results suggest an important role of glutamine transport via SNAT2 in immune cell migration and a possible interaction between SNAT2 and CXCR4, by which T. gondii manipulates host cell motility.

  1. Molecular and Cellular Basis of Pathogenesis of Burkholderia pseudomallei%类鼻疽伯克霍尔德菌致病机制的分子与细胞基础

    Institute of Scientific and Technical Information of China (English)

    曹旺斌; 贺英

    2012-01-01

    类鼻疽伯克霍尔德菌(Burkholderia pseudomallei)是引起主要发生在东南亚和澳大利亚北部的一种人兽共患病类鼻疽的潜在病原。明确该疾病致病机理及其宿主与病原的互作将加强对该条件致病菌的发病机制的理解。本研究从影响细菌致病性的毒力因子和病原与宿主互作两个方面阐述类鼻疽伯克霍德尔菌的致病机理,为该菌的有效控制提供可能的机制。%Burkholderia pseudomallei is a potential bioterror agent and the causative agent of melioidosis, a se- vere disease that is endemic in areas of Southeast Asia and Northern Australia. Studying how the disease is ac- quired and the host-pathogen interactions involved will underpin understanding of the bacteria, This review presents an overview focused on current knowledge of putative virulence factors and the host-pathogen interac- tions,led to understanding of the infection process of Burkholderia pseudomallei and effective control strategy.

  2. Transcriptional response of Burkholderia cenocepacia J2315 sessile cells to treatments with high doses of hydrogen peroxide and sodium hypochlorite

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    Nelis Hans

    2010-02-01

    Full Text Available Abstract Background Burkholderia cepacia complex bacteria are opportunistic pathogens, which can cause severe respiratory tract infections in patients with cystic fibrosis (CF. As treatment of infected CF patients is problematic, multiple preventive measures are taken to reduce the infection risk. Besides a stringent segregation policy to prevent patient-to-patient transmission, clinicians also advise patients to clean and disinfect their respiratory equipment on a regular basis. However, problems regarding the efficacy of several disinfection procedures for the removal and/or killing of B. cepacia complex bacteria have been reported. In order to unravel the molecular mechanisms involved in the resistance of biofilm-grown Burkholderia cenocepacia cells against high concentrations of reactive oxygen species (ROS, the present study focussed on the transcriptional response in sessile B. cenocepacia J2315 cells following exposure to high levels of H2O2 or NaOCl. Results The exposure to H2O2 and NaOCl resulted in an upregulation of the transcription of 315 (4.4% and 386 (5.4% genes, respectively. Transcription of 185 (2.6% and 331 (4.6% genes was decreased in response to the respective treatments. Many of the upregulated genes in the NaOCl- and H2O2-treated biofilms are involved in oxidative stress as well as general stress response, emphasizing the importance of the efficient neutralization and scavenging of ROS. In addition, multiple upregulated genes encode proteins that are necessary to repair ROS-induced cellular damage. Unexpectedly, a prolonged treatment with H2O2 also resulted in an increased transcription of multiple phage-related genes. A closer inspection of hybridisation signals obtained with probes targeting intergenic regions led to the identification of a putative 6S RNA. Conclusion Our results reveal that the transcription of a large fraction of B. cenocepacia J2315 genes is altered upon exposure of sessile cells to ROS. These

  3. Survey of Bartonella spp. in U.S. bed bugs detects Burkholderia multivorans but not Bartonella.

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    Virna L Saenz

    Full Text Available Bed bugs (Cimex lectularius L. have resurged in the United States and globally. Bed bugs are hematophagous ectoparasites of humans and other animals, including domestic pets, chickens, and bats, and their blood feeding habits contribute to their potential as disease vectors. Several species of Bartonella are re-emergent bacterial pathogens that also affect humans, domestic pets, bats and a number of other wildlife species. Because reports of both bed bugs and Bartonella have been increasing in the U.S., and because their host ranges can overlap, we investigated whether the resurgences of these medically important pathogens and their potential vector might be linked, by screening for Bartonella spp. in bed bugs collected from geographic areas where these pathogens are prevalent and from bed bugs that have been in culture in the laboratory for several years. We screened a total of 331 bed bugs: 316 bed bugs from 36 unique collections in 29 geographic locations in 13 states, 10 bed bugs from two colonies maintained in the laboratory for 3 yr, and 5 bed bugs from a colony that has been in culture since before the recent resurgence of bed bugs. Bartonella spp. DNA was screened using a polymerase chain reaction assay targeting the 16S-23S rRNA intergenic transcribed spacer region. Bartonella DNA was not amplified from any bed bug, but five bed bugs from four different apartments of an elderly housing building in North Carolina contained DNA sequences that corresponded to Burkholderia multivorans, an important pathogen in nosocomial infections that was not previously linked to an arthropod vector.

  4. Characterization of ceftazidime resistance mechanisms in clinical isolates of Burkholderia pseudomallei from Australia.

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    Derek S Sarovich

    Full Text Available 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.

  5. Solution structure of monomeric BsaL, the type III secretion needle protein of Burkholderia pseudomallei.

    Science.gov (United States)

    Zhang, Lingling; Wang, Yu; Picking, Wendy L; Picking, William D; De Guzman, Roberto N

    2006-06-01

    Many gram-negative bacteria that are important human pathogens possess type III secretion systems as part of their required virulence factor repertoire. During the establishment of infection, these pathogens coordinately assemble greater than 20 different proteins into a macromolecular structure that spans the bacterial inner and outer membranes and, in many respects, resembles and functions like a syringe. This type III secretion apparatus (TTSA) is used to inject proteins into a host cell's membrane and cytoplasm to subvert normal cellular processes. The external portion of the TTSA is a needle that is composed of a single type of protein that is polymerized in a helical fashion to form an elongated tube with a central channel of 2-3 nm in diameter. TTSA needle proteins from a variety of bacterial pathogens share sequence conservation; however, no atomic structure for any TTSA needle protein is yet available. Here, we report the structure of a TTSA needle protein called BsaL from Burkholderia pseudomallei determined by nuclear magnetic resonance (NMR) spectroscopy. The central part of the protein assumes a helix-turn-helix core domain with two well-defined alpha-helices that are joined by an ordered, four-residue linker. This forms a two-helix bundle that is stabilized by interhelix hydrophobic contacts. Residues that flank this presumably exposed core region are not completely disordered, but adopt a partial helical conformation. The atomic structure of BsaL and its sequence homology with other TTSA needle proteins suggest potentially unique structural dynamics that could be linked with a universal mechanism for control of type III secretion in diverse gram-negative bacterial pathogens. PMID:16631790

  6. Growing Burkholderia pseudomallei in biofilm stimulating conditions significantly induces antimicrobial resistance.

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    Chakrit Sawasdidoln

    Full Text Available BACKGROUND: Burkholderia pseudomallei, a gram-negative bacterium that causes melioidosis, was reported to produce biofilm. As the disease causes high relapse rate when compared to other bacterial infections, it therefore might be due to the reactivation of the biofilm forming bacteria which also provided resistance to antimicrobial agents. However, the mechanism on how biofilm can provide tolerance to antimicrobials is still unclear. METHODOLOGY/PRINCIPAL FINDINGS: The change in resistance of B. pseudomallei to doxycycline, ceftazidime, imipenem, and trimethoprim/sulfamethoxazole during biofilm formation were measured as minimum biofilm elimination concentration (MBEC in 50 soil and clinical isolates and also in capsule, flagellin, LPS and biofilm mutants. Almost all planktonic isolates were susceptible to all agents studied. In contrast, when they were grown in the condition that induced biofilm formation, they were markedly resistant to all antimicrobial agents even though the amount of biofilm production was not the same. The capsule and O-side chains of LPS mutants had no effect on biofilm formation whereas the flagellin-defective mutant markedly reduced in biofilm production. No alteration of LPS profiles was observed when susceptible form was changed to resistance. The higher amount of N-acyl homoserine lactones (AHLs was detected in the high biofilm-producing isolates. Interestingly, the biofilm mutant which produced a very low amount of biofilm and was sensitive to antimicrobial agents significantly resisted those agents when grown in biofilm inducing condition. CONCLUSIONS/SIGNIFICANCE: The possible drug resistance mechanism of biofilm mutants and other isolates is not by having biofilm but rather from some factors that up-regulated when biofilm formation genes were stimulated. The understanding of genes related to this situation may lead us to prevent B. pseudomallei biofilms leading to the relapse of melioidosis.

  7. Phenotypic and functional characterization of human memory T cell responses to Burkholderia pseudomallei.

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    Patcharaporn Tippayawat

    Full Text Available BACKGROUND: Infection with the Gram-negative bacterium Burkholderia pseudomallei is an important cause of community-acquired lethal sepsis in endemic regions in southeast Asia and northern Australia and is increasingly reported in other tropical areas. In animal models, production of interferon-gamma (IFN-gamma is critical for resistance, but in humans the characteristics of IFN-gamma production and the bacterial antigens that are recognized by the cell-mediated immune response have not been defined. METHODS: Peripheral blood from 133 healthy individuals who lived in the endemic area and had no history of melioidosis, 60 patients who had recovered from melioidosis, and 31 other patient control subjects were stimulated by whole bacteria or purified bacterial proteins in vitro, and IFN-gamma responses were analyzed by ELISPOT and flow cytometry. FINDINGS: B. pseudomallei was a potent activator of human peripheral blood NK cells for innate production of IFN-gamma. In addition, healthy individuals with serological evidence of exposure to B. pseudomallei and patients recovered from active melioidosis developed CD4(+ (and CD8(+ T cells that recognized whole bacteria and purified proteins LolC, OppA, and PotF, members of the B. pseudomallei ABC transporter family. This response was primarily mediated by terminally differentiated T cells of the effector-memory (T(EMRA phenotype and correlated with the titer of anti-B. pseudomallei antibodies in the serum. CONCLUSIONS: Individuals living in a melioidosis-endemic region show clear evidence of T cell priming for the ability to make IFN-gamma that correlates with their serological status. The ability to detect T cell responses to defined B. pseudomallei proteins in large numbers of individuals now provides the opportunity to screen candidate antigens for inclusion in protein or polysaccharide-conjugate subunit vaccines against this important but neglected disease.

  8. The biofilm produced by Burkholderia cepacia complex: molecular aspects and relationship with exopolysaccharides

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    Lucia Corich

    2010-12-01

    Full Text Available Introduction. In cystic fibrosis patients, Burkholderia cepacia complex (Bcc can cause serious pulmonary chronic infections thanks in part to the ability to form biofilm, matrix rich in exopolysaccharides. In Bcc grown in the planktonic state, the main exopolysaccharide is cepacian while in biofilm its presence is controversial. Methods and Results. Two clinical isolates, named BTS7 and BTS2, were studied. BTS7 produces abundant cepacian but not much biofilm (quantified by colorimetric method.At least two of the genes involved in cepacian biosynthesis are not necessary for biofilm production as two BTS7 derivatives, bceB and bceQ knocked out by transposon mutagenesis, produce biofilm levels comparable to the wild-type. BTS2 sinthesyzes cepacian only if cultured on a specific medium. It has been colonizing a patient for almost ten years, showing a significant reduction of biofilm production during this period. This reduction did not appear together with the lack of factors required for the initial adhesion to the surface, or to differences in some of the Bcc genes involved in biofilm formation. Moreover, sequencing of its bce locus revealed a bceX gene, absent in BTS7, coding for a trascriptional regulator. Its product may negatively regulate the production of cepacian but not the one of other polysaccharides, promoting the formation of biofilm. Conclusions. Cepacian seems to be marginal in the production of biofilm.The reduced ability to produce biofilm of BTS2 suggests possible gene mutations occurred over time. Using custom arrays we will compare the gene expression of the BTS2 isolates, to identify the genes responsible for the observed phenotypic changes.

  9. Atrophic gastric changes in both Helicobacter felis and Helicobacter pylori infected mice are host dependent and separate from antral gastritis.

    OpenAIRE

    Sakagami, T; Dixon, M; O'Rourke, J; Howlett, R.; Alderuccio, F; Vella, J; Shimoyama, T; Lee, A.

    1996-01-01

    BACKGROUND/AIMS: The role of host factors has been neglected in studies of the pathogenesis of Helicobacter associated disease. The aim of this study was to assess the response of different mouse strains to infection with a single strain of Helicobacter felis. METHOD: Six strains of inbred mice were infected with the identical H felis culture and were killed at one month, two months, and six months after infection to assess histopathological changes. In addition, two strains of mice were infe...

  10. Infection of XC cells by MLVs and Ebola virus is endosome-dependent but acidification-independent.

    Science.gov (United States)

    Kamiyama, Haruka; Kakoki, Katsura; Yoshii, Hiroaki; Iwao, Masatomo; Igawa, Tsukasa; Sakai, Hideki; Hayashi, Hideki; Matsuyama, Toshifumi; Yamamoto, Naoki; Kubo, Yoshinao

    2011-01-01

    Inhibitors of endosome acidification or cathepsin proteases attenuated infections mediated by envelope proteins of xenotropic murine leukemia virus-related virus (XMRV) and Ebola virus, as well as ecotropic, amphotropic, polytropic, and xenotropic murine leukemia viruses (MLVs), indicating that infections by these viruses occur through acidic endosomes and require cathepsin proteases in the susceptible cells such as TE671 cells. However, as previously shown, the endosome acidification inhibitors did not inhibit these viral infections in XC cells. It is generally accepted that the ecotropic MLV infection in XC cells occurs at the plasma membrane. Because cathepsin proteases are activated by low pH in acidic endosomes, the acidification inhibitors may inhibit the viral infections by suppressing cathepsin protease activation. The acidification inhibitors attenuated the activities of cathepsin proteases B and L in TE671 cells, but not in XC cells. Processing of cathepsin protease L was suppressed by the acidification inhibitor in NIH3T3 cells, but again not in XC cells. These results indicate that cathepsin proteases are activated without endosome acidification in XC cells. Treatment with an endocytosis inhibitor or knockdown of dynamin 2 expression by siRNAs suppressed MLV infections in all examined cells including XC cells. Furthermore, endosomal cathepsin proteases were required for these viral infections in XC cells as other susceptible cells. These results suggest that infections of XC cells by the MLVs and Ebola virus occur through endosomes and pH-independent cathepsin activation induces pH-independent infection in XC cells.

  11. Pathological findings and diagnostic implications of a rhesus macaque (Macacca mulatta) model of aerosol exposure to Burkholderia mallei (glanders).

    Science.gov (United States)

    Yingst, Samuel L; Facemire, Paul; Chuvala, Lara; Norwood, David; Wolcott, Mark; Huzella, Louis

    2015-06-01

    Burkholderia mallei is a Gram-negative bacillus that causes a pneumonic disease known as glanders in equids and humans, and a lymphatic infection known as farcy, primarily in equids. With the potential to infect humans by the respiratory route, aerosol exposure can result in severe, occasionally fatal, pneumonia. Today, glanders infections in humans are rare, likely due to less frequent contact with infected equids than in the past. Acutely ill humans often have non-specific clinical signs and in order to diagnose cases, especially in scenarios of multiple cases in an unexpected setting, rapid diagnostics for B. mallei may be critical. The pathogenesis of acute glanders in the rhesus macaque (Macaca mulatta) was studied as an initial effort to improve diagnostic methods. In the study described here, the diagnostic techniques of PCR, culture and histopathology were compared. The results indicated that PCR may provide rapid, non-invasive diagnosis of glanders in some cases. As expected, PCR results were positive in lung tissue in 11/12 acutely infected rhesus macaques, but more importantly in terms of diagnostic algorithm development, PCR results were frequently positive in non-invasive samples such as broncho-alveolar lavage or nasal swabs (7/12) and occasionally in blood (3/12). However, conventional bacterial culture failed to recover bacteria in many of these samples. The study showed that the clinical presentation of aerosol-exposed rhesus macaques is similar to descriptions of human glanders and that PCR has potential for rapid diagnosis of outbreaks, if not individual cases.

  12. Detection of Burkholderia pseudomallei toxin-mediated inhibition of protein synthesis using a Caenorhabditis elegans ugt-29 biosensor.

    Science.gov (United States)

    Wong, Rui-Rui; Kong, Cin; Lee, Song-Hua; Nathan, Sheila

    2016-01-01

    Toxins are believed to play a crucial role in Burkholderia pseudomallei pathogenicity, however to date, only a few have been identified. The discovery of additional toxic molecules is limited by the lack of a sensitive indicator of B. pseudomallei toxicity. Previously, from a whole genome transcriptome analysis of B. pseudomallei-infected Caenorhabditis elegans, we noted significant overexpression of a number of worm genes encoding detoxification enzymes, indicating the host's attempt to clear bacterial toxic molecules. One of these genes, ugt-29, a family member of UDP-glucuronosyltransferases, was the most robustly induced phase II detoxification gene. In this study, we show that strong induction of ugt-29 is restricted to infections by the most virulent species among the pathogens tested. We also noted that ugt-29 is activated upon disruption of host protein synthesis. Hence, we propose that UGT-29 could be a promising biosensor to detect B. pseudomallei toxins that compromise host protein synthesis. The identification of bactobolin, a polyketide-peptide hybrid molecule, as a toxic molecule of B. pseudomallei further verifies the utilization of this surveillance system to search for bacterial toxins. Hence, a ugt-29 based reporter should be useful in screening for other molecules that inhibit host protein synthesis. PMID:27273550

  13. Detection of Burkholderia pseudomallei toxin-mediated inhibition of protein synthesis using a Caenorhabditis elegans ugt–29 biosensor

    Science.gov (United States)

    Wong, Rui-Rui; Kong, Cin; Lee, Song-Hua; Nathan, Sheila

    2016-01-01

    Toxins are believed to play a crucial role in Burkholderia pseudomallei pathogenicity, however to date, only a few have been identified. The discovery of additional toxic molecules is limited by the lack of a sensitive indicator of B. pseudomallei toxicity. Previously, from a whole genome transcriptome analysis of B. pseudomallei-infected Caenorhabditis elegans, we noted significant overexpression of a number of worm genes encoding detoxification enzymes, indicating the host’s attempt to clear bacterial toxic molecules. One of these genes, ugt–29, a family member of UDP-glucuronosyltransferases, was the most robustly induced phase II detoxification gene. In this study, we show that strong induction of ugt–29 is restricted to infections by the most virulent species among the pathogens tested. We also noted that ugt–29 is activated upon disruption of host protein synthesis. Hence, we propose that UGT–29 could be a promising biosensor to detect B. pseudomallei toxins that compromise host protein synthesis. The identification of bactobolin, a polyketide-peptide hybrid molecule, as a toxic molecule of B. pseudomallei further verifies the utilization of this surveillance system to search for bacterial toxins. Hence, a ugt–29 based reporter should be useful in screening for other molecules that inhibit host protein synthesis. PMID:27273550

  14. Identification of Burkholderia pseudomallei Near-Neighbor Species in the Northern Territory of Australia.

    Directory of Open Access Journals (Sweden)

    Jennifer L Ginther

    Full Text Available Identification and characterization of near-neighbor species are critical to the development of robust molecular diagnostic tools for biothreat agents. One such agent, Burkholderia pseudomallei, a soil bacterium and the causative agent of melioidosis, is lacking in this area because of its genomic diversity and widespread geographic distribution. The Burkholderia genus contains over 60 species and occupies a large range of environments including soil, plants, rhizospheres, water, animals and humans. The identification of novel species in new locations necessitates the need to identify the true global distribution of Burkholderia species, especially the members that are closely related to B. pseudomallei. In our current study, we used the Burkholderia-specific recA sequencing assay to analyze environmental samples from the Darwin region in the Northern Territory of Australia where melioidosis is endemic. Burkholderia recA PCR negative samples were further characterized using 16s rRNA sequencing for species identification. Phylogenetic analysis demonstrated that over 70% of the bacterial isolates were identified as B. ubonensis indicating that this species is common in the soil where B. pseudomallei is endemic. Bayesian phylogenetic analysis reveals many novel branches within the B. cepacia complex, one novel B. oklahomensis-like species, and one novel branch containing one isolate that is distinct from all other samples on the phylogenetic tree. During the analysis with recA sequencing, we discovered 2 single nucleotide polymorphisms in the reverse priming region of B. oklahomensis. A degenerate primer was developed and is proposed for future use. We conclude that the recA sequencing technique is an effective tool to classify Burkholderia and identify soil organisms in a melioidosis endemic area.

  15. XerC Contributes to Diverse Forms of Staphylococcus aureus Infection via agr-Dependent and agr-Independent Pathways.

    Science.gov (United States)

    Atwood, Danielle N; Beenken, Karen E; Loughran, Allister J; Meeker, Daniel G; Lantz, Tamara L; Graham, Justin W; Spencer, Horace J; Smeltzer, Mark S

    2016-04-01

    We demonstrate that mutation of xerC, which reportedly encodes a homologue of an Escherichia coli recombinase, limits biofilm formation in the methicillin-resistant Staphylococcus aureus strain LAC and the methicillin-sensitive strain UAMS-1. This was not due to the decreased production of the polysaccharide intracellular adhesin (PIA) in either strain because the amount of PIA was increased in a UAMS-1xerC mutant and undetectable in both LAC and its isogenic xerC mutant. Mutation of xerC also resulted in the increased production of extracellular proteases and nucleases in both LAC and UAMS-1, and limiting the production of either class of enzymes increased biofilm formation in the isogenic xerC mutants. More importantly, the limited capacity to form a biofilm was correlated with increased antibiotic susceptibility in both strains in the context of an established biofilm in vivo. Mutation of xerC also attenuated virulence in a murine bacteremia model, as assessed on the basis of the bacterial loads in internal organs and overall lethality. It also resulted in the decreased accumulation of alpha toxin and the increased accumulation of protein A. These findings suggest that xerC may impact the functional status of agr. This was confirmed by demonstrating the reduced accumulation of RNAIII and AgrA in LAC and UAMS-1xerC mutants. However, this cannot account for the biofilm-deficient phenotype of xerC mutants because mutation of agr did not limit biofilm formation in either strain. These results demonstrate that xerC contributes to biofilm-associated infections and acute bacteremia and that this is likely due to agr-independent and -dependent pathways, respectively.

  16. Age-dependent differences in cytokine and antibody responses after experimental RSV infection in a bovine model

    DEFF Research Database (Denmark)

    Grell, S.N.; Riber, Ulla; Tjørnehøj, Kirsten;

    2005-01-01

    Respiratory syncytial virus (RSV) causes severe respiratory disease in both infants and calves. As in humans, bovine RSV (BRSV) infections are most severe in the first 6 months of life. In this study, experimental infection with BRSV was performed in calves aged 1-5, 9-16 or 32-37 weeks. Compared...

  17. Delinking CARD9 and IL-17: CARD9 Protects against Candida tropicalis Infection through a TNF-α-Dependent, IL-17-Independent Mechanism.

    Science.gov (United States)

    Whibley, Natasha; Jaycox, Jillian R; Reid, Delyth; Garg, Abhishek V; Taylor, Julie A; Clancy, Cornelius J; Nguyen, M Hong; Biswas, Partha S; McGeachy, Mandy J; Brown, Gordon D; Gaffen, Sarah L

    2015-10-15

    Candida is the third most common cause of bloodstream infections in hospitalized patients. Immunity to C. albicans, the most frequent species to be isolated in candidiasis, involves a well-characterized Dectin-1/caspase-associated recruitment domain adaptor 9 (CARD9)/IL-17 signaling axis. Infections caused by non-albicans Candida species are on the rise, but surprisingly little is known about immunity to these pathogens. In this study, we evaluated a systemic infection model of C. tropicalis, a clinically relevant, but poorly understood, non-albicans Candida. Mice lacking CARD9 were profoundly susceptible to C. tropicalis, displaying elevated fungal burdens in visceral organs and increased mortality compared with wild-type (WT) controls. Unlike C. albicans, IL-17 responses were induced normally in CARD9(-/-) mice following C. tropicalis infection. Moreover, there was no difference in susceptibility to C. tropicalis infection between WT and IL-23p19(-/-), IL-17RA(-/-), or Act1(-/-) mice. However, TNF-α expression was markedly impaired in CARD9(-/-) mice. Consistently, WT mice depleted of TNF-α were more susceptible to C. tropicalis, and CARD9-deficient neutrophils and monocytes failed to produce TNF-α following stimulation with C. tropicalis Ags. Both neutrophils and monocytes were necessary for defense against C. tropicalis, because their depletion in WT mice enhanced susceptibility to C. tropicalis. Disease in CARD9(-/-) mice was not due to defective neutrophil or monocyte recruitment to infected kidneys. However, TNF-α treatment of neutrophils in vitro enhanced their ability to kill C. tropicalis. Thus, protection against systemic C. tropicalis infection requires CARD9 and TNF-α, but not IL-17, signaling. Moreover, CARD9-dependent production of TNF-α enhances the candidacidal capacity of neutrophils, limiting fungal disease during disseminated C. tropicalis infection. PMID:26336150

  18. Interleukin-1 receptor but not Toll-like receptor 2 is essential for MyD88-dependent Th17 immunity to Coccidioides infection.

    Science.gov (United States)

    Hung, Chiung-Yu; Jiménez-Alzate, María del Pilar; Gonzalez, Angel; Wüthrich, Marcel; Klein, Bruce S; Cole, Garry T

    2014-05-01

    Interleukin-17A (IL-17A)-producing CD4(+) T helper (Th17) cells have been shown to be essential for defense against pulmonary infection with Coccidioides species. However, we have just begun to identify the required pattern recognition receptors and understand the signal pathways that lead to Th17 cell activation after fungal infection. We previously reported that Card9(-/-) mice vaccinated with formalin-killed spherules failed to acquire resistance to Coccidioides infection. Here, we report that both MyD88(-/-) and Card9(-/-) mice immunized with a live, attenuated vaccine also fail to acquire protective immunity to this respiratory disease. Like Card9(-/-) mice, vaccinated MyD88(-/-) mice revealed a significant reduction in numbers of both Th17 and Th1 cells in their lungs after Coccidioides infection. Both Toll-like receptor 2 (TLR2) and IL-1 receptor type 1 (IL-1r1) upstream of MyD88 have been implicated in Th17 cell differentiation. Surprisingly, vaccinated TLR2(-/-) and wild-type (WT) mice showed similar outcomes after pulmonary infection with Coccidioides, while vaccinated IL-1r1(-/-) mice revealed a significant reduction in the number of Th17 cells in their infected lungs compared to WT mice. Thus, activation of both IL-1r1/MyD88- and Card9-mediated Th17 immunity is essential for protection against Coccidioides infection. Our data also reveal that the numbers of Th17 cells were reduced in IL-1r1(-/-) mice to a lesser extent than in MyD88(-/-) mice, raising the possibility that other TLRs are involved in MyD88-dependent Th17 immunity to coccidioidomycosis. An antimicrobial action of Th17 cells is to promote early recruitment of neutrophils to infection sites. Our data revealed that neutrophils are required for vaccine immunity to this respiratory disease. PMID:24614655

  19. Temperature dependent bacteriophages of a tropical bacterial pathogen

    Science.gov (United States)

    Shan, Jinyu; Korbsrisate, Sunee; Withatanung, Patoo; Adler, Natalie Lazar; Clokie, Martha R. J.; Galyov, Edouard E.

    2014-01-01

    There is an increasing awareness of the multiple ways that bacteriophages (phages) influence bacterial evolution, population dynamics, physiology, and pathogenicity. By studying a novel group of phages infecting a soil borne pathogen, we revealed a paradigm shifting observation that the phages switch their lifestyle according to temperature. We sampled soil from an endemic area of the serious tropical pathogen Burkholderia pseudomallei, and established that podoviruses infecting the pathogen are frequently present in soil, and many of them are naturally occurring variants of a common virus type. Experiments on one phage in the related model B. thailandensis demonstrated that temperature defines the outcome of phage-bacteria interactions. At higher temperatures (37°C), the phage predominantly goes through a lytic cycle, but at lower temperatures (25°C), the phage remains temperate. This is the first report of a naturally occurring phage that follows a lytic or temperate lifestyle according to temperature. These observations fundamentally alter the accepted views on the abundance, population biology and virulence of B. pseudomallei. Furthermore, when taken together with previous studies, our findings suggest that the phenomenon of temperature dependency in phages is widespread. Such phages are likely to have a profound effect on bacterial biology, and on our ability to culture and correctly enumerate viable bacteria. PMID:25452746

  20. CCR5-Dependent Activation of mTORC1 Regulates Translation of Inducible NO Synthase and COX-2 during Encephalomyocarditis Virus Infection.

    Science.gov (United States)

    Shaheen, Zachary R; Naatz, Aaron; Corbett, John A

    2015-11-01

    Encephalomyocarditis virus (EMCV) infection of macrophages results in the expression of a number of inflammatory and antiviral genes, including inducible NO synthase (iNOS) and cyclooxygenase (COX)-2. EMCV-induced macrophage activation has been shown to require the presence of CCR5 and the activation of PI3K-dependent signaling cascades. The purpose of this study was to determine the role of PI3K in regulating the macrophage responses to EMCV. We show that PI3K regulates EMCV-stimulated iNOS and COX-2 expression by two independent mechanisms. In response to EMCV infection, Akt is activated and regulates the translation of iNOS and COX-2 through the mammalian target of rapamycin complex (mTORC)1. The activation of mTORC1 during EMCV infection is CCR5-dependent and appears to function in a manner that promotes the translation of iNOS and COX-2. CCR5-dependent mTORC1 activation functions as an antiviral response, as mTORC1 inhibition increases the expression of EMCV polymerase. PI3K also regulates the transcriptional induction of iNOS and COX-2 in response to EMCV infection by a mechanism that is independent of Akt and mTORC1 regulation. These findings indicate that macrophage expression of the inflammatory genes iNOS and COX-2 occurs via PI3K- and Akt-dependent translational control of mTORC1 and PI3K-dependent, Akt-independent transcriptional control.

  1. Influenza A virus does not encode a tetherin antagonist with Vpu-like activity and induces IFN-dependent tetherin expression in infected cells.

    Directory of Open Access Journals (Sweden)

    Michael Winkler

    Full Text Available The interferon-induced host cell factor tetherin inhibits release of human immunodeficiency virus (HIV from the plasma membrane of infected cells and is counteracted by the HIV-1 protein Vpu. Influenza A virus (FLUAV also buds from the plasma membrane and is not inhibited by tetherin. Here, we investigated if FLUAV encodes a functional equivalent of Vpu for tetherin antagonism. We found that expression of the FLUAV protein NS1, which antagonizes the interferon (IFN response, did not block the tetherin-mediated restriction of HIV release, which was rescued by Vpu. Similarly, tetherin-mediated inhibition of HIV release was not rescued by FLUAV infection. In contrast, FLUAV infection induced tetherin expression on target cells in an IFN-dependent manner. These results suggest that FLUAV escapes the antiviral effects of tetherin without encoding a tetherin antagonist with Vpu-like activity.

  2. Polar lipids of Burkholderia pseudomallei induce different host immune responses.

    Directory of Open Access Journals (Sweden)

    Mercedes Gonzalez-Juarrero

    Full Text Available Melioidosis is a disease in tropical and subtropical regions of the world that is caused by Burkholderia pseudomallei. In endemic regions the disease occurs primarily in humans and goats. In the present study, we used the goat as a model to dissect the polar lipids of B. pseudomallei to identify lipid molecules that could be used for adjuvants/vaccines or as diagnostic tools. We showed that the lipidome of B. pseudomallei and its fractions contain several polar lipids with the capacity to elicit different immune responses in goats, namely rhamnolipids and ornithine lipids which induced IFN-γ, whereas phospholipids and an undefined polar lipid induced strong IL-10 secretion in CD4(+ T cells. Autologous T cells co-cultured with caprine dendritic cells (cDCs and polar lipids of B. pseudomallei proliferated and up-regulated the expression of CD25 (IL-2 receptor molecules. Furthermore, we demonstrated that polar lipids were able to up-regulate CD1w2 antigen expression in cDCs derived from peripheral blood monocytes. Interestingly, the same polar lipids had only little effect on the expression of MHC class II DR antigens in the same caprine dendritic cells. Finally, antibody blocking of the CD1w2 molecules on cDCs resulted in decreased expression for IFN-γ by CD4(+ T cells. Altogether, these results showed that polar lipids of B. pseudomallei are recognized by the caprine immune system and that their recognition is primarily mediated by the CD1 antigen cluster.

  3. Deciphering the role of RND efflux transporters in Burkholderia cenocepacia.

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    Silvia Bazzini

    Full Text Available Burkholderia cenocepacia J2315 is representative of a highly problematic group of cystic fibrosis (CF pathogens. Eradication of B. cenocepacia is very difficult with the antimicrobial therapy being ineffective due to its high resistance to clinically relevant antimicrobial agents and disinfectants. RND (Resistance-Nodulation-Cell Division efflux pumps are known to be among the mediators of multidrug resistance in gram-negative bacteria. Since the significance of the 16 RND efflux systems present in B. cenocepacia (named RND-1 to -16 has been only partially determined, the aim of this work was to analyze mutants of B. cenocepacia strain J2315 impaired in RND-4 and RND-9 efflux systems, and assess their role in the efflux of toxic compounds. The transcriptomes of mutants deleted individually in RND-4 and RND-9 (named D4 and D9, and a double-mutant in both efflux pumps (named D4-D9, were compared to that of the wild-type B. cenocepacia using microarray analysis. Microarray data were confirmed by qRT-PCR, phenotypic experiments, and by Phenotype MicroArray analysis. The data revealed that RND-4 made a significant contribution to the antibiotic resistance of B. cenocepacia, whereas RND-9 was only marginally involved in this process. Moreover, the double mutant D4-D9 showed a phenotype and an expression profile similar to D4. The microarray data showed that motility and chemotaxis-related genes appeared to be up-regulated in both D4 and D4-D9 strains. In contrast, these gene sets were down-regulated or expressed at levels similar to J2315 in the D9 mutant. Biofilm production was enhanced in all mutants. Overall, these results indicate that in B. cenocepacia RND pumps play a wider role than just in drug resistance, influencing additional phenotypic traits important for pathogenesis.

  4. Efflux pump genes of the resistance-nodulation-division family in Burkholderia cenocepacia genome

    Directory of Open Access Journals (Sweden)

    Manina Giulia

    2006-07-01

    Full Text Available Abstract Background Burkholderia cenocepacia is recognized as opportunistic pathogen that can cause lung infections in cystic fibrosis patients. A hallmark of B. cenocepacia infections is the inability to eradicate the organism because of multiple intrinsic antibiotic resistance. As Resistance-Nodulation-Division (RND efflux systems are responsible for much of the intrinsic multidrug resistance in Gram-negative bacteria, this study aims to identify RND genes in the B. cenocepacia genome and start to investigate their involvement into antimicrobial resistance. Results Genome analysis and homology searches revealed 14 open reading frames encoding putative drug efflux pumps belonging to RND family in B. cenocepacia J2315 strain. By reverse transcription (RT-PCR analysis, it was found that orf3, orf9, orf11, and orf13 were expressed at detectable levels, while orf10 appeared to be weakly expressed in B. cenocepacia. Futhermore, orf3 was strongly induced by chloramphenicol. The orf2 conferred resistance to fluoroquinolones, tetraphenylphosphonium, streptomycin, and ethidium bromide when cloned and expressed in Escherichia coli KAM3, a strain lacking the multidrug efflux pump AcrAB. The orf2-overexpressing E. coli also accumulate low concentrations of ethidium bromide, which was restored to wild type level in the presence of CCCP, an energy uncoupler altering the energy of the drug efflux pump. Conclusion The 14 RND pumps gene we have identified in the genome of B. cenocepacia suggest that active efflux could be a major mechanism underlying antimicrobial resistance in this microorganism. We have characterized the ORF2 pump, one of these 14 potential RND efflux systems. Its overexpression in E. coli conferred resistance to several antibiotics and to ethidium bromide but it remains to be determined if this pump play a significant role in the antimicrobial intrinsic resistance of B. cenocepacia. The characterization of antibiotic efflux pumps in B

  5. Effect of Macrophage Migration Inhibitory Factor (MIF) in Human Placental Explants Infected with Toxoplasma gondii Depends on Gestational Age

    OpenAIRE

    de Oliveira Gomes, Angelica; de Oliveira Silva, Deise Aparecida; Silva, Neide Maria; de Freitas Barbosa, Bellisa; Franco, Priscila Silva; Angeloni, Mariana Bodini; Fermino, Marise Lopes; Roque-Barreira, Maria Cristina; Bechi, Nicoletta; Paulesu, Luana Ricci; dos Santos, Maria Célia; Mineo, José Roberto; Ferro, Eloisa Amália Vieira

    2011-01-01

    Because macrophage migration inhibitory factor (MIF) is a key cytokine in pregnancy and has a role in inflammatory response and pathogen defense, the objective of the present study was to investigate the effects of MIF in first- and third-trimester human placental explants infected with Toxoplasma gondii. Explants were treated with recombinant MIF, IL-12, interferon-γ, transforming growth factor-β1, or IL-10, followed by infection with T. gondii RH strain tachyzoites. Supernatants of cultured...

  6. Oxalotrophy, a widespread trait of plant-associated Burkholderia species, is involved in successful root colonization of lupin and maize by Burkholderia phytofirmans

    OpenAIRE

    Kost, Thomas; Stopnisek, Nejc; Agnoli, Kirsty; Eberl, Leo; Weisskopf, Laure

    2014-01-01

    Plant roots and shoots harbor complex bacterial communities. Early seed and plantlet colonization plays a key role in determining which bacterial populations will successfully invade plant tissues, yet the mechanisms enabling plants to select for beneficial rather than harmful populations are largely unknown. In this study, we demonstrate a role of oxalate as a determinant in this selection process, using members of the genus Burkholderia as model organisms. Oxalotrophy, i.e., the ability to ...

  7. Activation of Langerhans-Type Dendritic Cells Alters Human Cytomegalovirus Infection and Reactivation in a Stimulus-Dependent Manner

    Science.gov (United States)

    Coronel, Roxanne; Jesus, Desyree M.; Dalle Ore, Lucia; Mymryk, Joe S.; Hertel, Laura

    2016-01-01

    Oral mucosal Langerhans cells (LC) are likely to play important roles in host defense against infection by human cytomegalovirus (CMV). We previously showed that in vitro-differentiated immature LC (iLC) populations contain smaller amounts of infected cells but produce higher yields than mature LC (mLC) cultures, obtained by iLC stimulation with fetal bovine serum (FBS), CD40 ligand (CD40L) and lipopolysaccharide (LPS). Here, we sought to determine if exposure to select stimuli can improve LC permissiveness to infection, if specific components of the mLC cocktail are responsible for lowering viral yields, if this is due to defects in progeny production or release, and if these restrictions are also effective against reactivated virus. None of the stimuli tested extended the proportion of infected cells to 100%, suggesting that the block to infection onset cannot be fully removed. While CD40L and FBS exerted positive effects on viral progeny production per cell, stimulation with LPS alone or in combination with CD40L was detrimental. Reductions in viral titers were not due to defects in progeny release, and the permissive or restrictive intracellular environment established upon exposure to each stimulus appeared to act in a somewhat similar way toward lytic and latent infections.

  8. IL-27 receptor signalling restricts the formation of pathogenic, terminally differentiated Th1 cells during malaria infection by repressing IL-12 dependent signals.

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    Ana Villegas-Mendez

    Full Text Available The IL-27R, WSX-1, is required to limit IFN-γ production by effector CD4⁺ T cells in a number of different inflammatory conditions but the molecular basis of WSX-1-mediated regulation of Th1 responses in vivo during infection has not been investigated in detail. In this study we demonstrate that WSX-1 signalling suppresses the development of pathogenic, terminally differentiated (KLRG-1⁺ Th1 cells during malaria infection and establishes a restrictive threshold to constrain the emergent Th1 response. Importantly, we show that WSX-1 regulates cell-intrinsic responsiveness to IL-12 and IL-2, but the fate of the effector CD4⁺ T cell pool during malaria infection is controlled primarily through IL-12 dependent signals. Finally, we show that WSX-1 regulates Th1 cell terminal differentiation during malaria infection through IL-10 and Foxp3 independent mechanisms; the kinetics and magnitude of the Th1 response, and the degree of Th1 cell terminal differentiation, were comparable in WT, IL-10R1⁻/⁻ and IL-10⁻/⁻ mice and the numbers and phenotype of Foxp3⁺ cells were largely unaltered in WSX-1⁻/⁻ mice during infection. As expected, depletion of Foxp3⁺ cells did not enhance Th1 cell polarisation or terminal differentiation during malaria infection. Our results significantly expand our understanding of how IL-27 regulates Th1 responses in vivo during inflammatory conditions and establishes WSX-1 as a critical and non-redundant regulator of the emergent Th1 effector response during malaria infection.

  9. Proof that Burkholderia Strains Form Effective Symbioses with Legumes: a Study of Novel Mimosa-Nodulating Strains from South America

    OpenAIRE

    Chen, Wen-Ming; de Faria, Sergio M.; Straliotto, Rosângela; Pitard, Rosa M.; Simões-Araùjo, Jean L.; Chou, Jui-Hsing; Chou, Yi-Ju; Barrios, Edmundo; Prescott, Alan R; Geoffrey N Elliott; Sprent, Janet I.; J. Peter W. Young; James, Euan K.

    2005-01-01

    Twenty Mimosa-nodulating bacterial strains from Brazil and Venezuela, together with eight reference Mimosa-nodulating rhizobial strains and two other β-rhizobial strains, were examined by amplified rRNA gene restriction analysis. They fell into 16 patterns and formed a single cluster together with the known β-rhizobia, Burkholderia caribensis, Burkholderia phymatum, and Burkholderia tuberum. The 16S rRNA gene sequences of 15 of the 20 strains were determined, and all were shown to belong to t...

  10. The relationship of biofilm production to biocontrol activity of Burkholderia pyrrocinia FP62

    Science.gov (United States)

    Foliar biocontrol agent (BCA) efficacy is often inconsistent due to poor colonization and survival on plant surfaces. Burkholderia pyrrocinia FP62, a superior leaf colonist and BCA of Botrytis cinerea, forms unsaturated biofilms on plant surfaces. To determine the relationship between biocontrol act...

  11. N-acylhomoserine-lactone-mediated communication between Pseudomonas aeruginosa and Burkholderia cepacia in mixed biofilms

    DEFF Research Database (Denmark)

    Riedel, K.; Hentzer, Morten; Geisenberger, O.;

    2001-01-01

    Pseudomonas aeruginosa and Burkholderia cepacia are capable of forming mixed biofilms in the lungs of cystic fibrosis patients. Both bacteria employ quorum-sensing systems, which rely on N-acylhomoserine lactone (AHL) signal molecules, to co- ordinate expression of virulence factors with the...

  12. Interaction of insulin with Burkholderia pseudomallei may be caused by a preservative

    OpenAIRE

    Simpson, A; Wuthiekanun, V

    2000-01-01

    Aim—To re-examine the previously reported in vitro interaction of insulin with Burkholderia pseudomallei, in the light of a suggestion that the interaction may have resulted from the presence of the preservative m-cresol in commercial preparations.

  13. Antimicrobial Properties of an Oxidizer Produced by Burkholderia cenocepacia P525

    Science.gov (United States)

    A compound with both oxidizing properties and antibiotic properties was extracted and purified from broth cultures of Burkholderia cenocepacia strain P525. A four step purification procedure was used to increase its specific activity ~ 400 fold and to yield a HPLC- UV chromatogram containing a sing...

  14. Genome Sequence of the Historical Clinical Isolate Burkholderia pseudomallei PHLS 6.

    Science.gov (United States)

    D'haeseleer, Patrik; Johnson, Shannon L; Davenport, Karen W; Chain, Patrick S; Schoeniger, Joe; Ray, Debjit; Sinha, Anupama; Williams, Kelly P; Peña, José; Branda, Steven S; El-Etr, Sahar

    2016-01-01

    Here, we present the draft genome sequence of Burkholderia pseudomallei PHLS 6, a virulent clinical strain isolated from a melioidosis patient in Bangladesh in 1960. The draft genome consists of 39 contigs and is 7,322,181 bp long. PMID:27365360

  15. NOVEL ORGANIZATION OF THE GENES FOR PHTHALATE DEGRADATION FROM BURKHOLDERIA CEPACIA DBO1

    Science.gov (United States)

    Burkholderia cepacia DBO1 is able to utilize phthalate as the sole source of carbon and energy for growth. Two overlapping cosmid clones containing the genes for phthalate degradation were isolated from this strain. Subcloning and activity analysis localized the genes for phthala...

  16. Draft Genome Sequence of Burkholderia gladioli Strain UCD-UG_CHAPALOTE (Phylum Proteobacteria)

    OpenAIRE

    Ettinger, CL; Shehata, HR; Johnston-Monje, D; Raizada, MN; Eisen, JA

    2015-01-01

    Here, we present the draft genome of Burkholderia gladioli strain UCD-UG_CHAPALOTE. This strain is an endophyte isolated from surface sterilized seeds of an ancient Mexican landrace of corn, Chapalote. The genome contains 8,527,129 bp in 109 scaffolds.

  17. Draft Genome Sequence of the Haloacid-Degrading Burkholderia caribensis Strain MBA4

    OpenAIRE

    Pan, Yanling; Kong, Ka Fai; Tsang, Jimmy S. H.

    2014-01-01

    Burkholderia caribensis MBA4 was isolated from soil for its ability to utilize 2-haloacid. An inducible haloacid operon, encoding for a dehalogenase and a permease, is mainly responsible for the biotransformation. Here, we report the draft genome sequence of this strain.

  18. Draft Genome Sequence of Burkholderia gladioli Strain UCD-UG_CHAPALOTE (Phylum Proteobacteria)

    Science.gov (United States)

    Ettinger, Cassandra L.; Shehata, Hanan R.; Johnston-Monje, David; Raizada, Manish N.

    2015-01-01

    Here, we present the draft genome of Burkholderia gladioli strain UCD-UG_CHAPALOTE. This strain is an endophyte isolated from surface sterilized seeds of an ancient Mexican landrace of corn, Chapalote. The genome contains 8,527,129 bp in 109 scaffolds. PMID:25614570

  19. Molecular method to assess the diversity of Burkholderia species in environmental samples

    NARCIS (Netherlands)

    Salles, J.; Souza, de F.A.; Elsas, van J.D.

    2002-01-01

    In spite of the importance of many members of the genus Burkholderia in the soil microbial community, no direct method to assess the diversity of this genus has been developed so far. The aim of this work was the development of soil DNA-based PCR-denaturing gradient gel electrophoresis (DGGE), a pow

  20. Molecular method to assess the diversity of Burkholderia species in environmental samples

    NARCIS (Netherlands)

    Salles, J.F.; De Souza, F.A.; Van Elsas, J.D.

    2002-01-01

    In spite of the importance of many members of the genus Burkholderia in the soil microbial community, no direct method to assess the diversity of this genus has been developed so far. The aim of this work was the development of soil DNA-based PCR-denaturing gradient get electrophoresis (DGGE), a pow

  1. Study of the mode of action of a polygalacturonase from the phytopathogen Burkholderia cepacia

    DEFF Research Database (Denmark)

    Massa, C.; Clausen, Mads Hartvig; Stojan, J.;

    2007-01-01

    We have recently isolated and heterologously expressed BcPeh28A, an endopolygalacturonase from the phytopathogenic Gram-negative bacterium Burkholderia cepacia. Endopolygalacturonases belong to glycoside hydrolase family 28 and are responsible for the hydrolysis of the non-esterified regions...

  2. Multivariate Analyses of Burkholderia species in soil: effect of crop and land use history.

    NARCIS (Netherlands)

    Salles, J.F.; Veen, van J.A.; Elsas, van J.D.

    2004-01-01

    The assessment of Burkholderia diversity in agricultural areas is important considering the potential use of this genus for agronomic and environmental applications. Therefore, the aim of this work was to ascertain how plant species and land use management drive the diversity of the genus Burkholder

  3. Multivariate analyses of Burkholderia species in soil : Effect of crop and land use history

    NARCIS (Netherlands)

    Salles, JF; van Veen, JA; van Elsas, JD

    2004-01-01

    The assessment of Burkholderia diversity in agricultural areas is important considering the potential use of this genus for agronomic and environmental applications. Therefore, the aim of this work was to ascertain how plant species and land use management drive the diversity of the genus Burkholder

  4. Multivariate analyses of Burkholderia species in soil: effect of crop and land use history

    NARCIS (Netherlands)

    Salles, J.F.; Van Veen, J.A.; van Elsas, J.D.

    2004-01-01

    The assessment of Burkholderia diversity in agricultural areas is important considering the potential use of this genus for agronomic and environmental applications. Therefore, the aim of this work was to ascertain how plant species and land use management drive the diversity of the genus Burkholder

  5. Distribution of Melioidosis Cases and Viable Burkholderia pseudomallei in Soil: Evidence for Emerging Melioidosis in Taiwan▿

    OpenAIRE

    Chen, Yao-Shen; Lin, Hsi-Hsun; Mu, Jung-Jung; Chiang, Chuen-Sheue; Chen, Chang-Hsun; Buu, Leh-Mia; Lin, Yusen E.; Chen, Ya-Lei

    2010-01-01

    A survey for the prevalence if Burkholderia pseudomallei in soil in Taiwan found that its incidence is comparable to that in other regions of the world where melioidosis is endemic. The presence of identical genetic patterns among the clinical and environmental isolates evaluated suggested a link between the pathogens present in contaminated soil and the emergence of indigenous melioidosis.

  6. Changes in agricultural management drive the diversity of Burkholderia species isolated from soil on PLAT medium

    NARCIS (Netherlands)

    Salles, JF; Samyn, E; Vandamme, P; van Veen, JA; van Elsas, JD

    2006-01-01

    In order to assess the diversity of culturable Burkholderia populations in rhizosphere and bulk soil and to evaluate how different agricultural management regimes and land use history affect this diversity, four treatments were evaluated: permanent grassland; grassland converted into maize monocultu

  7. Changes in agricultural management drive the diversity of Burkholderia species isolated from soil on PCAT medium

    NARCIS (Netherlands)

    Salles, J.F.; Samyn, E.; Vandamme, P.; Van Veen, J.A.; van Elsas, J.D.

    2006-01-01

    Abstract In order to assess the diversity of culturable Burkholderia populations in rhizosphere and bulk soil and to evaluate how different agricultural management regimes and land use history affect this diversity, four treatments were evaluated: permanent grassland; grassland converted into maize

  8. Endothelial cell permeability during hantavirus infection involves factor XII-dependent increased activation of the kallikrein-kinin system.

    Science.gov (United States)

    Taylor, Shannon L; Wahl-Jensen, Victoria; Copeland, Anna Maria; Jahrling, Peter B; Schmaljohn, Connie S

    2013-01-01

    Hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS) are diseases caused by hantavirus infections and are characterized by vascular leakage due to alterations of the endothelial barrier. Hantavirus-infected endothelial cells (EC) display no overt cytopathology; consequently, pathogenesis models have focused either on the influx of immune cells and release of cytokines or on increased degradation of the adherens junction protein, vascular endothelial (VE)-cadherin, due to hantavirus-mediated hypersensitization of EC to vascular endothelial growth factor (VEGF). To examine endothelial leakage in a relevant in vitro system, we co-cultured endothelial and vascular smooth muscle cells (vSMC) to generate capillary blood vessel-like structures. In contrast to results obtained in monolayers of cultured EC, we found that despite viral replication in both cell types as well as the presence of VEGF, infected in vitro vessels neither lost integrity nor displayed evidence of VE-cadherin degradation. Here, we present evidence for a novel mechanism of hantavirus-induced vascular leakage involving activation of the plasma kallikrein-kinin system (KKS). We show that incubation of factor XII (FXII), prekallikrein (PK), and high molecular weight kininogen (HK) plasma proteins with hantavirus-infected EC results in increased cleavage of HK, higher enzymatic activities of FXIIa/kallikrein (KAL) and increased liberation of bradykinin (BK). Measuring cell permeability in real-time using electric cell-substrate impedance sensing (ECIS), we identified dramatic increases in endothelial cell permeability after KKS activation and liberation of BK. Furthermore, the alterations in permeability could be prevented using inhibitors that directly block BK binding, the activity of FXIIa, or the activity of KAL. Lastly, FXII binding and autoactivation is increased on the surface of hantavirus-infected EC. These data are the first to demonstrate KKS activation during

  9. Endothelial cell permeability during hantavirus infection involves factor XII-dependent increased activation of the kallikrein-kinin system.

    Directory of Open Access Journals (Sweden)

    Shannon L Taylor

    Full Text Available Hemorrhagic fever with renal syndrome (HFRS and hantavirus pulmonary syndrome (HPS are diseases caused by hantavirus infections and are characterized by vascular leakage due to alterations of the endothelial barrier. Hantavirus-infected endothelial cells (EC display no overt cytopathology; consequently, pathogenesis models have focused either on the influx of immune cells and release of cytokines or on increased degradation of the adherens junction protein, vascular endothelial (VE-cadherin, due to hantavirus-mediated hypersensitization of EC to vascular endothelial growth factor (VEGF. To examine endothelial leakage in a relevant in vitro system, we co-cultured endothelial and vascular smooth muscle cells (vSMC to generate capillary blood vessel-like structures. In contrast to results obtained in monolayers of cultured EC, we found that despite viral replication in both cell types as well as the presence of VEGF, infected in vitro vessels neither lost integrity nor displayed evidence of VE-cadherin degradation. Here, we present evidence for a novel mechanism of hantavirus-induced vascular leakage involving activation of the plasma kallikrein-kinin system (KKS. We show that incubation of factor XII (FXII, prekallikrein (PK, and high molecular weight kininogen (HK plasma proteins with hantavirus-infected EC results in increased cleavage of HK, higher enzymatic activities of FXIIa/kallikrein (KAL and increased liberation of bradykinin (BK. Measuring cell permeability in real-time using electric cell-substrate impedance sensing (ECIS, we identified dramatic increases in endothelial cell permeability after KKS activation and liberation of BK. Furthermore, the alterations in permeability could be prevented using inhibitors that directly block BK binding, the activity of FXIIa, or the activity of KAL. Lastly, FXII binding and autoactivation is increased on the surface of hantavirus-infected EC. These data are the first to demonstrate KKS activation

  10. Multilocus sequence typing and evolutionary relationships among the causative agents of melioidosis and glanders, Burkholderia pseudomallei and Burkholderia mallei.

    Science.gov (United States)

    Godoy, Daniel; Randle, Gaynor; Simpson, Andrew J; Aanensen, David M; Pitt, Tyrone L; Kinoshita, Reimi; Spratt, Brian G

    2003-05-01

    A collection of 147 isolates of Burkholderia pseudomallei, B. mallei, and B. thailandensis was characterized by multilocus sequence typing (MLST). The 128 isolates of B. pseudomallei, the causative agent of melioidosis, were obtained from diverse geographic locations, from humans and animals with disease, and from the environment and were resolved into 71 sequence types. The utility of the MLST scheme for epidemiological investigations was established by analyzing isolates from captive marine mammals and birds and from humans in Hong Kong with melioidosis. MLST gave a level of resolution similar to that given by pulsed-field gel electrophoresis and identified the same three clones causing disease in animals, each of which was also associated with disease in humans. The average divergence between the alleles of B. thailandensis and B. pseudomallei was 3.2%, and there was no sharing of alleles between these species. Trees constructed from differences in the allelic profiles of the isolates and from the concatenated sequences of the seven loci showed that the B. pseudomallei isolates formed a cluster of closely related lineages that were fully resolved from the cluster of B. thailandensis isolates, confirming their separate species status. However, isolates of B. mallei, the causative agent of glanders, recovered from three continents over a 30-year period had identical allelic profiles, and the B. mallei isolates clustered within the B. pseudomallei group of isolates. Alleles at six of the seven loci in B. mallei were also present within B. pseudomallei isolates, and B. mallei is a clone of B. pseudomallei that, on population genetics grounds, should not be given separate species status.

  11. Caracterização fenotípica e molecular de amostras de Burkholderia mallei isoladas na Região Nordeste do Brasil Phenotypic and molecular characterization of Burkholderia mallei isolated in northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Karla P.C. Silva

    2009-05-01

    Full Text Available Objetivou-se com este trabalho realizar o estudo bioquímico e molecular de amostras de Burkholderia mallei isoladas de eqüídeos com diagnóstico clínico e sorológico para o mormo e provenientes da Região Metropolitana do Recife-PE e Zona da Mata dos Estados de Alagoas e Pernambuco. Foram realizadas as técnicas microbiológicas para o isolamento e identificação fenotípica de B. mallei e as técnicas moleculares de ribotipagem-PCR e RAPD-PCR. Das oito amostras estudadas, quatro apresentaram pequenas variações fenotípicas. Nas técnicas moleculares, as amostras formaram quatro grupos de diferentes perfis ribotípicos, demonstrando também quatro perfis genotípicos. Houve associação nos resultados da Ribotipagem-PCR e RAPD-PCR. As variações nos perfis ribotípicos e genotípicos foram associadas às diferentes regiões estudadas. De acordo com os resultados obtidos, conclui-se que as pequenas variações bioquímicas não estão associadas aos diferentes perfis moleculares e que essas diferenças demonstram uma heterogeneidade que está associada à procedência das amostras, indicando que a infecção nos animais ocorre por clones diferentes das amostras analisadas.The objective of this paper was to study the molecular performance and phenotypic characterization of Burkholderia mallei isolated from horses with clinical and serological diagnosis of glanders, originating from the Metropolitan District of Recife and Zona da Mata of Pernambuco and Alagoas. The isolation and biochemical identification of B. mallei was carried out by microbiological and molecular techniques of PCR-fingerprinting and RAPD-PCR. From the eight samples studied, four showed little phenotype variations. In the molecular tests, the samples formed 4 groups of different ribotype profiles and 4 genotype profiles. There was some association of PCR-fingerprinting with RAPD-PCR results. It was concluded that the slight biochemical variations were not associated with

  12. Genetic diversity of Burkholderia (Proteobacteria) species from the Caatinga and Atlantic rainforest biomes in Bahia, Brazil.

    Science.gov (United States)

    Santini, A C; Santos, H R M; Gross, E; Corrêa, R X

    2013-03-11

    The genus Burkholderia (β-Proteobacteria) currently comprises more than 60 species, including parasites, symbionts and free-living organisms. Several new species of Burkholderia have recently been described showing a great diversity of phenotypes. We examined the diversity of Burkholderia spp in environmental samples collected from Caatinga and Atlantic rainforest biomes of Bahia, Brazil. Legume nodules were collected from five locations, and 16S rDNA and recA genes of the isolated microorganisms were analyzed. Thirty-three contigs of 16S rRNA genes and four contigs of the recA gene related to the genus Burkholderia were obtained. The genetic dissimilarity of the strains ranged from 0 to 2.5% based on 16S rDNA analysis, indicating two main branches: one distinct branch of the dendrogram for the B. cepacia complex and another branch that rendered three major groups, partially reflecting host plants and locations. A dendrogram designed with sequences of this research and those designed with sequences of Burkholderia-type strains and the first hit BLAST had similar topologies. A dendrogram similar to that constructed by analysis of 16S rDNA was obtained using sequences of the fragment of the recA gene. The 16S rDNA sequences enabled sufficient identification of relevant similarities and groupings amongst isolates and the sequences that we obtained. Only 6 of the 33 isolates analyzed via 16S rDNA sequencing showed high similarity with the B. cepacia complex. Thus, over 3/4 of the isolates have potential for biotechnological applications.

  13. Antibodies from women urogenitally infected with C. trachomatis predominantly recognized the plasmid protein pgp3 in a conformation-dependent manner

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    Wu Yimou

    2008-06-01

    Full Text Available Abstract Background C. trachomatis organisms carry a cryptic plasmid that encodes 8 open reading frames designated as pORF1 to 8. It is not clear whether all 8 pORFs are expressed during C. trachomatis infection in humans and information on the functionality of the plasmid proteins is also very limited. Results When antibodies from women urogenitally infected with C. trachomatis were reacted with the plasmid proteins, all 8 pORFs were positively recognized by one or more human antibody samples with the recognition of pORF5 protein (known as pgp3 by most antibodies and with the highest titers. The antibody recognition of the pORFs was blocked by C. trachomatis-infected HeLa but not normal HeLa cell lysates. The pgp3 fusion protein-purified human IgG detected the endogenous pgp3 in the cytosol of C. trachomatis-infected cells with an intracellular distribution pattern similar to that of CPAF, a chlamydial genome-encoded protease factor. However, the human antibodies no longer recognized pgp3 but maintained recognition of CPAF when both antigens were linearized or heat-denatured. The pgp3 conformation is likely maintained by the C-terminal 75% amino acid sequence since further deletion blocked the binding by the human antibodies and two conformation-dependent mouse monoclonal antibodies. Conclusion The plasmid-encoded 8 proteins are both expressed and immunogenic with pgp3 as the most immunodominant antigen during chlamydial infection in humans. More importantly, the human anti-pgp3 antibodies are highly conformation-dependent. These observations have provided important information for further understanding the function of the plasmid-encoded proteins and exploring the utility of pgp3 in chlamydial diagnosis and vaccination.

  14. The effect of methanolic extract of Tamarindus indica Linn. on the growth of clinical isolates of Burkholderia pseudomallei.

    Science.gov (United States)

    Muthu, Shankar Esaki; Nandakumar, Subhadra; Rao, Usha Anand

    2005-12-01

    Burkholderia pseudomallei (Pseudomonas pseudomallei) causes melioidosis, a life-threatening infection common among paddy cultivators in Southeast Asian countries. No plant materials have been investigated for its activity against B. pseudomallei. Therefore, a preliminary study was carried out using disc diffusion and minimum inhibitory concentration (MIC) methods to evaluate the anti-B. pseudomallei activity of five Indian medicinal plants documented to have been used for several ailments in the ancient Indian scriptures. The leaf extracts of Tamarindus indica, Lawsonia inermis, and Hibiscus rosa-sinensis, the rhizome extracts of Curcuma longa and the seeds of Vigna radiata were prepared using methanol as solvent. The disc diffusion and MIC methods were used to assess the anti-B. pseudomallei activity of the plants tested. Only methanol leaf extracts of Tamarindus indica exhibited anti-B. pseudomallei activity starting from disc concentrations of 150 mug by the disc diffusion method. The other plants failed to show any zone of inhibition. MIC assay revealed that the MIC and minimum bactericidal concentration (MBC) for B. pseudomallei were 125 mug/ml. Our preliminary finding showed that methanolic extracts of Tamarindus indica has anti-B. pseudomallei inhibitory potentials under in vitro conditions. Extensive animal studies may be required before investigating the role of Tamarindus indica for treating melioidosis.

  15. A genomic survey of positive selection in Burkholderia pseudomallei provides insights into the evolution of accidental virulence.

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    Tannistha Nandi

    2010-04-01

    Full Text Available Certain environmental microorganisms can cause severe human infections, even in the absence of an obvious requirement for transition through an animal host for replication ("accidental virulence". To understand this process, we compared eleven isolate genomes of Burkholderia pseudomallei (Bp, a tropical soil microbe and causative agent of the human and animal disease melioidosis. We found evidence for the existence of several new genes in the Bp reference genome, identifying 282 novel genes supported by at least two independent lines of supporting evidence (mRNA transcripts, database homologs, and presence of ribosomal binding sites and 81 novel genes supported by all three lines. Within the Bp core genome, 211 genes exhibited significant levels of positive selection (4.5%, distributed across many cellular pathways including carbohydrate and secondary metabolism. Functional experiments revealed that certain positively selected genes might enhance mammalian virulence by interacting with host cellular pathways or utilizing host nutrients. Evolutionary modifications improving Bp environmental fitness may thus have indirectly facilitated the ability of Bp to colonize and survive in mammalian hosts. These findings improve our understanding of the pathogenesis of melioidosis, and establish Bp as a model system for studying the genetics of accidental virulence.

  16. Powder formulation of Burkholderia cepacia for control of rape seed damping-off caused by Rhizoctonia solani.

    Science.gov (United States)

    Sharifi-Tehrani, A; Ahmadzadeh, M; Sarani, S; Farzaneh, M

    2007-01-01

    Talc-based formulation of Burkholderia cepaci strain Bu1 was tested as seed and soil drenchs separately for its ability to control Rhizoctonia soloni the causal agent of rape seed damping-off in greenhouse and field trials. In general, the formulated bacteria was more effective to suppress the disease than the suspension of bacteria cells in carboxymethylcellulose solution (1% w/v), in both greenhouse and field trials. The formulation of strain Bul as soil and seed treatments had the greatest effect on reducing the rape seed damping-off in greenhouse and field trials (66.7, 53.3, 64.4 and 40% respectively). The formulation of strain Bu1 as soil and seed treatments were the most effective treatments to increase the root dry weights in the infected soil in greenhouse. The formulation of strain Bul as soil drench had the greatest effect on enhancement of the fresh weight of roots and stem fresh and dry weights. The formulation of strain Bu1 stored at 4 degrees C exhibited better shelf Life and efficacy in vitro than it's counterpart stored at 25 degrees C. PMID:18399433

  17. Induction of IFNα or IL-12 depends on differentiation of THP-1 cells in dengue infections without and with antibody enhancement

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    Chen Rong-Fu

    2012-12-01

    Full Text Available Abstract Background Appropriate induction of the early Th1 cytokine IL-12 is a critical defense directed against viral infection. We have previously shown that different viruses elicited either IL-12 or IFNα dependent Th1 reactions. Using dengue-2 virus, we sought to explore how dengue-2 induced IL-12 or IFNα expression by monocytic and its derived dendritic cells. Methods We employed human monocytic cell line, THP-1, to investigate whether differentiation of monocytic cells is involved in the switch between IFNα and IL-12 induction. Flow cytometry, RT-PCR and ELISA were respectively used to determine cell differentiation, IL-12 and IFNα mRNA expression and protein production. Results THP-1, expressing CD123, which is a plasmacytoid dendritic cell marker, but not CD14, CD11b or CD11c revealed IFNα mRNA expression while stimulated by dengue-2. In contrast, PMA-induced THP-1 differentiation toward monocytic cells expressed CD11b+, and CD14+, but not CD123, and revealed exclusively IL-12 expression while stimulated by dengue-2. Further studies showed that CD123+ expressing THP-1 cells elicited higher IFNα expression in dose and time dependent induction after infection, and PMA-induced monocytic differentiation of THP-1 cells revealed IL-12 expression. Antibody-dependent enhancement of DEN-2 infection significantly suppressed the DEN-2 induced IL-12 p40 expression in monocytic differentiated THP-1 cells. Conclusions Clarification and modulation of the early Th1 reaction in different monocytic cells may change or prevent complication from dengue infection.

  18. HIV-infected CD4+ T Cells Use T-bet-dependent Pathway for Production of IL-10 Upon Antigen Recognition.

    Science.gov (United States)

    Shete, A; Suryawanshi, P; Godbole, S; Pawar, J; Paranjape, R; Thakar, M

    2016-04-01

    Interleukin (IL)-10 has been implicated in persistence of pathogens in a number of chronic infections. Infected CD4+ cells upon reactivation with HIV antigens were also shown to produce IL-10, which might contribute to their persistence. Hence, it is crucial to determine mechanisms regulating IL-10 production after activation with HIV antigens for devising effective blocking strategies. In this study, ERK-, T-bet- and FoxP3-dependent pathways were evaluated for their possible roles in IL-10 production by infected CD4+ cells after reactivation with HIV Env. Intracellular and secreted IL-10 levels were determined by flow cytometry and Bioplex assay after treating PBMCs with PD98059, tipifarnib and cyclosporin A for blocking of ERK-, T-bet-and FoxP3-dependent pathways, respectively. Baseline levels of T-bet, pERK were higher in P24+ CD4+ cells as compared to uninfected CD4+ cells, which increased further after activation with Env. Inhibition of T-bet resulted in 2.3-fold reduction of IL-10 expression whereas ERK and FoxP3 inhibition failed to cause suppression of IL-10 expression. Conversely, IL-10 secreted by PBMCs was inhibited maximally after ERK inhibition suggesting its role in regulation of cytokine secretory pathway. IFN-γ was found to be suppressed after treatment with inhibitors of all these pathways. Thus, the study highlighted need for IL-10 blockade along with the use of antigens for therapeutic vaccinations or latency reversal and identified the T-bet-dependent pathway as an important pathway regulating IL-10 production by infected CD4+ cells. However, simultaneous blockade of IFN-γ precludes use of inhibitor of this pathway as an IL-10 blocking strategy. PMID:27028319

  19. Burkholderia pseudomallei genome plasticity associated with genomic island variation

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    Currie Bart J

    2008-04-01

    Full Text Available Abstract Background Burkholderia pseudomallei is a soil-dwelling saprophyte and the cause of melioidosis. Horizontal gene transfer contributes to the genetic diversity of this pathogen and may be an important determinant of virulence potential. The genome contains genomic island (GI regions that encode a broad array of functions. Although there is some evidence for the variable distribution of genomic islands in B. pseudomallei isolates, little is known about the extent of variation between related strains or their association with disease or environmental survival. Results Five islands from B. pseudomallei strain K96243 were chosen as representatives of different types of genomic islands present in this strain, and their presence investigated in other B. pseudomallei. In silico analysis of 10 B. pseudomallei genome sequences provided evidence for the variable presence of these regions, together with micro-evolutionary changes that generate GI diversity. The diversity of GIs in 186 isolates from NE Thailand (83 environmental and 103 clinical isolates was investigated using multiplex PCR screening. The proportion of all isolates positive by PCR ranged from 12% for a prophage-like island (GI 9, to 76% for a metabolic island (GI 16. The presence of each of the five GIs did not differ between environmental and disease-associated isolates (p > 0.05 for all five islands. The cumulative number of GIs per isolate for the 186 isolates ranged from 0 to 5 (median 2, IQR 1 to 3. The distribution of cumulative GI number did not differ between environmental and disease-associated isolates (p = 0.27. The presence of GIs was defined for the three largest clones in this collection (each defined as a single sequence type, ST, by multilocus sequence typing; these were ST 70 (n = 15 isolates, ST 54 (n = 11, and ST 167 (n = 9. The rapid loss and/or acquisition of gene islands was observed within individual clones. Comparisons were drawn between isolates obtained

  20. HOST RESISTANCE TO TRICHINELLA SPIRALIS INFECTION IN MICE AND RATS: SPECIES-DEPENDENT EFFECTS OF CYCLOPHOSPHAMIDE EXPOSURE

    Science.gov (United States)

    Host resistance to Trichinella spiralis infection was compared in rats (F344) and mice (C57BL/6J) following various cyclophosphamide (CY) treatment schedules. Dozes of CY given to mice were adjusted by body surface area to be comparable to rat doses. dult parasite elimination was...

  1. IFI6 Inhibits Apoptosis via Mitochondrial-Dependent Pathway in Dengue Virus 2 Infected Vascular Endothelial Cells.

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    Yiming Qi

    Full Text Available Dengue hemorrhagic fever (DHF/Dengue shock syndrome (DSS is a fatal infectious disease that demands an effective treatment. Interferon (IFN-stimulated genes (ISGs induced by dengue virus (DENV exert antiviral effects. Among ISGs, IFN-α inducible gene 6 (IFI6 was increased in DENV infected human umbilical vascular endothelial cells (HUVECs by microarray analysis in our previous study. However, its function is incompletely understood. In this study, we confirmed that IFI6 was markedly induced in DENV infection of both primary HUVECs and EA.hy926 cell lines. Recombinant EA.hy926 cell lines in which IFI6 was either over-expressed (IFI6+/+ or knocked-down (IFI6-/- were generated. The activation of caspase-3 and intrinsic apoptosis-related protein caspase-9 were down-regulated in IFI6+/+ but up-regulated in IFI6-/- cells at 24-48 hrs post-infection. After incubation with DENV for 48 hrs, the mitochondrial membrane potential (Δψ(m was more stable in IFI6+/+ cells but reduced in IFI6-/- cells, as assayed by fluorescence staining with JC-1. We observed that Bcl-2 expression was increased in IFI6+/+ and decreased in IFI6-/- cells. By contrast, Bax expression was decreased in IFI6+/+ and increased in IFI6-/- cells. It is presumed that the anti-apoptotic function of IFI6 is expressed by regulating the rheostatic balance between bcl-2/bax expression and inhibition of Δψ(m depolarization during DENV infection of vascular endothelial cells(VECs. In addition, the pro-apoptotic protein X-linked Inhibitor of Apoptosis (XIAP-Associated Factor 1(XAF1 expression had been reported to be up-regulated and led to the induction of apoptosis in DENV2-infected VECs,but the relationship between XAF1 and IFI6 dengue virus-induced apoptosis in VECs warrants further study.

  2. TRIM14 inhibits hepatitis C virus infection by SPRY domain-dependent targeted degradation of the viral NS5A protein

    Science.gov (United States)

    Wang, Shanshan; Chen, Yongzhi; Li, Chunfeng; Wu, Yaoxing; Guo, Lei; Peng, Changwei; Huang, Yueping; Cheng, Genhong; Qin, F. Xiao-Feng

    2016-01-01

    Tripartite motif 14 (TRIM14) was reported to function as a mitochondrial signaling adaptor in mediating innate immune responses. However, the involvement of TRIM14 in host defense against viral infection and molecular mechanisms remain unclear. Here, we demonstrated that enforced expression of TRIM14 could potently inhibit the infection and replication of HCV in hepatocytes, whereas TRIM14 knockout cells became more susceptible to HCV infection. Interestingly, further experiments revealed that such anti-HCV activity was independent of activating the NF-κB or interferon pathways but required the C-terminal SPRY domain of no signaling capacity. In searching for mechanisms how TRIM14 exerts its antiviral function we found that TRIM14 interacted with HCV encoded non-structural protein NS5A and could strongly induce its degradation dependent on the NS5A1 subdomain. Interestingly extensive domain mapping analyses revealed that NS5A degradation was mediated by the highly conserved SPRY domain of TRIM14, which might involve the K48 ubiquitination pathway. Collectively, our work uncovered a new mechanism responsible for host defense against HCV infection, and could potentially aid the development of novel anti-HCV therapeutics. PMID:27578425

  3. Lactobacillus casei triggers a TLR mediated RACK-1 dependent p38 MAPK pathway in Caenorhabditis elegans to resist Klebsiella pneumoniae infection.

    Science.gov (United States)

    Kamaladevi, Arumugam; Balamurugan, Krishnaswamy

    2016-07-13

    In the present study, the effect of Lactic Acid Bacteria (LAB) was investigated at the molecular level using the model organism Caenorhabditis elegans against Klebsiella pneumoniae. Out of the 13 LAB screened, Lactobacillus casei displayed excellent protective efficacy by prolonging the survival of K. pneumoniae-infected nematodes. Pretreatment with L. casei significantly decreased bacterial colonization and rescued K. pneumoniae-infected C. elegans from various physiological impairments. The concomitant upregulation of key immune genes that regulate the TLR, RACK-1 as well as the p38 MAPK pathway rather than the IIS and ERK pathway suggested that the plausible immunomodulatory mechanism of L. casei could be by triggering the TLR, RACK-1 and p38 MAPK pathway. Furthermore, the hyper-susceptibility of L. casei treated loss-of-function mutants of the tol-1, RACK-1 and p38 MAPK pathway (sek-1 and pmk-1) to K. pneumoniae infection and gene expression analysis suggested that L. casei triggered a TLR mediated RACK-1 dependent p38 MAPK pathway to increase host resistance and protect nematodes against K. pneumoniae infection. PMID:27338631

  4. Complement-mediated, antibody-dependent enhancement of HIV-1 infection in vitro is characterized by increased protein and RNA syntheses and infectious virus release.

    Science.gov (United States)

    Robinson, W E; Montefiori, D C; Gillespie, D H; Mitchell, W M

    1989-01-01

    Antibody-dependent enhancement (ADE) of human immunodeficiency virus type 1 (HIV-1) infection in vitro has been described recently and was shown to occur by two mechanisms: either participation of the alternative pathway of complement or to involve an Fc receptor-mediated, complement-independent mechanism. Complement-mediated ADE results in an accelerated cytopathic effect in target cells that can abrogate the protective properties of neutralizing antibodies. This study characterizes the surface antigens of MT-2 cells using flow cytometric analysis and shows that these cells express high levels of both CD4 and complement receptor type 2 (CR2) while several CD4+ cell lines that do not demonstrate complement-mediated ADE lack high levels of complement receptors. Further, utilizing MT-2 cell cultures, it is demonstrated that complement-mediated ADE of HIV-1 infection is conferred by the sera from more than 80% of HIV-1 antibody-positive individuals (N = 85). Complement-mediated ADE of HIV-1 infection causes an acceleration of several parameters indicative of HIV-1 infection in vitro including increased HIV-1 antigen synthesis as detected by indirect immunofluorescence, RNA accumulation as measured by a solution hybridization protocol, reverse transcriptase release, and progeny virus production. PMID:2465404

  5. Direct Detection of Burkholderia cepacia in Susceptible Pharmaceutical Products Using Semi-Nested PCR.

    Science.gov (United States)

    Attia, Mohamed A; Ali, Amal E; Essam, Tamer M; Amin, Magdy A

    2016-01-01

    Burkholderia cepaciahas recently received a considerable attention as one of the major risks in susceptible pharmaceutical products. This microorganism can easily propagate and cause vast and severe contamination, especially to the water supplies for pharmaceutical companies. Moreover, it proliferates within the products and can cause severe infections for humans. Therefore, fast and sensitive detection of these bacteria is of a great demand. The present study introduces improved application of a polymerase chain reaction assay with relatively high sensitivity and specificity for the direct detection ofB. cepaciafrom the aqueous pharmaceutical products. A semi-nested polymerase chain reaction approach using the primer set BCR1/BCR2 followed by BCR1/Mr yielding a 465 bp fragment of the recA gene was applied and tested using both crude lysate from isolated colonies and DNA directly extracted from artificially prepared and spiked reference syrup. The polymerase chain reaction assay showed no interference with other bacterial reference and environmental strains tested, includingStaphylococcus aureusATCC® 6538,Pseudomonas aeruginosaATCC® 9027,Escherichia coliATCC® 8739,Salmonella abonyNCTC® 6017,Bacillus subtilisATCC® 6633,Micrococcus luteus, Staphylococcus warneri, Pseudomonas fluorescens, Pseudomonas putida, andRalstonia pickettii Moreover, this semi-nested assay showed a detection limit of around 10 colony-forming units per sample and could detectB. cepaciastrains isolated from a municipal pre-treated potable water tank. Comparing the results for detection ofB. cepaciain 100 randomly collected commercial syrup preparations using both conventional standard method and polymerase chain reaction assay revealed thatB. cepaciawas detected in two samples using polymerase chain reaction assay while all samples showed negative results by conventional culturing and biochemical methods. These results highlight the advantage of using this polymerase chain reaction assay to

  6. Complete genome sequence of Burkholderia sp. strain PAMC28687, a potential octopine-utilizing bacterium isolated from Antarctica lichen.

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    Han, So-Ra; Yu, Sang-Cheol; Ahn, Do-Hwan; Park, Hyun; Oh, Tae-Jin

    2016-05-20

    We report the complete genome sequence of Burkholderia sp. PAMC28687, which was isolated from the Antarctica lichen Useea sp., for better understanding of its catabolic traits in utilizing octopine as a source of carbon/nitrogen between Burkholderia and lichen. The genome consists of three circular chromosomes with five circular plasmids for the total 6,881,273bp sized genome with a G+C content of 58.14%. PMID:27034021

  7. Uropathogenic Escherichia coli Metabolite-Dependent Quiescence and Persistence May Explain Antibiotic Tolerance during Urinary Tract Infection.

    Science.gov (United States)

    Leatham-Jensen, Mary P; Mokszycki, Matthew E; Rowley, David C; Deering, Robert; Camberg, Jodi L; Sokurenko, Evgeni V; Tchesnokova, Veronika L; Frimodt-Møller, Jakob; Krogfelt, Karen A; Leth Nielsen, Karen; Frimodt-Møller, Niels; Sun, Gongqin; Cohen, Paul S

    2016-01-01

    In the present study, it is shown that although Escherichia coli CFT073, a human uropathogenic (UPEC) strain, grows in liquid glucose M9 minimal medium, it fails to grow on glucose M9 minimal medium agar plates seeded with ≤10(6) CFU. The cells on glucose plates appear to be in a "quiescent" state that can be prevented by various combinations of lysine, methionine, and tyrosine. Moreover, the quiescent state is characteristic of ~80% of E. coli phylogenetic group B2 multilocus sequence type 73 strains, as well as 22.5% of randomly selected UPEC strains isolated from community-acquired urinary tract infections in Denmark. In addition, E. coli CFT073 quiescence is not limited to glucose but occurs on agar plates containing a number of other sugars and acetate as sole carbon sources. It is also shown that a number of E. coli CFT073 mini-Tn5 metabolic mutants (gnd, gdhA, pykF, sdhA, and zwf) are nonquiescent on glucose M9 minimal agar plates and that quiescence requires a complete oxidative tricarboxylic acid (TCA) cycle. In addition, evidence is presented that, although E. coli CFT073 quiescence and persistence in the presence of ampicillin are alike in that both require a complete oxidative TCA cycle and each can be prevented by amino acids, E. coli CFT073 quiescence occurs in the presence or absence of a functional rpoS gene, whereas maximal persistence requires a nonfunctional rpoS. Our results suggest that interventions targeting specific central metabolic pathways may mitigate UPEC infections by interfering with quiescence and persistence. IMPORTANCE Recurrent urinary tract infections (UTIs) affect 10 to 40% of women. In up to 77% of those cases, the recurrent infections are caused by the same uropathogenic E. coli (UPEC) strain that caused the initial infection. Upon infection of urothelial transitional cells in the bladder, UPEC appear to enter a nongrowing quiescent intracellular state that is thought to serve as a reservoir responsible for recurrent

  8. Hydric stress-dependent effects of Plasmodium falciparum infection on the survival of wild-caught Anopheles gambiae female mosquitoes

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    Aboagye-Antwi Fred

    2010-08-01

    Full Text Available Abstract Background Whether Plasmodium falciparum, the agent of human malaria responsible for over a million deaths per year, causes fitness costs in its mosquito vectors is a burning question that has not yet been adequately resolved. Understanding the evolutionary forces responsible for the maintenance of susceptibility and refractory alleles in natural mosquito populations is critical for understanding malaria transmission dynamics. Methods In natural mosquito populations, Plasmodium fitness costs may only be expressed in combination with other environmental stress factors hence this hypothesis was tested experimentally. Wild-caught blood-fed Anopheles gambiae s.s. females of the M and S molecular form from an area endemic for malaria in Mali, West Africa, were brought to the laboratory and submitted to a 7-day period of mild hydric stress or kept with water ad-libitum. At the end of this experiment all females were submitted to intense desiccation until death. The survival of all females throughout both stress episodes, as well as their body size and infection status was recorded. The importance of stress, body size and molecular form on infection prevalence and female survival was investigated using Logistic Regression and Proportional-Hazard analysis. Results Females subjected to mild stress exhibited patterns of survival and prevalence of infection compatible with increased parasite-induced mortality compared to non-stressed females. Fitness costs seemed to be linked to ookinetes and early oocyst development but not the presence of sporozoites. In addition, when females were subjected to intense desiccation stress, those carrying oocysts exhibited drastically reduced survival but those carrying sporozoites were unaffected. No significant differences in prevalence of infection and infection-induced mortality were found between the M and S molecular forms of Anopheles gambiae. Conclusions Because these results suggest that infected

  9. In Vivo Fluorescence Imaging of Bacteriogenic Cyanide in the Lungs of Live Mice Infected with Cystic Fibrosis Pathogens

    OpenAIRE

    Nam, Seong-Won; Chen, Xiaoqiang; Lim, Jeesun; Kim, So Hyun; Kim, Sang-Tae; Cho, You-Hee; Yoon, Juyoung; Park, Sungsu

    2011-01-01

    Background Pseudomonas aeruginosa (PA) and Burkholderia cepacia complex (Bcc), commonly found in the lungs of cystic fibrosis (CF) patients, often produce cyanide (CN), which inhibits cellular respiration. CN in sputa is a potential biomarker for lung infection by CF pathogens. However, its actual concentration in the infected lungs is unknown. Methods and Findings This work reports observation of CN in the lungs of mice infected with cyanogenic PA or Bcc strains using a CN fluorescent chemos...

  10. SLy1 regulates T-cell proliferation during Listeria monocytogenes infection in a Foxo1-dependent manner.

    Science.gov (United States)

    Schäll, Daniel; Schmitt, Fee; Reis, Bernhard; Brandt, Simone; Beer-Hammer, Sandra

    2015-11-01

    Infection of mice with Listeria monocytogenes results in a strong T-cell response that is critical for an efficient defense. Here, we demonstrate that the adapter protein SLy1 (SH3-domain protein expressed in Lymphocytes 1) is essential for the generation of a fully functional T-cell response. The lack of SLy1 leads to reduced survival rates of infected mice. The increased susceptibility of SLy1 knock-out (KO) mice was caused by reduced proliferation of differentiated T cells. Ex vivo analyses of isolated SLy1 KO T cells displayed a dysregulation of Forkhead box protein O1 shuttling after TCR signaling, which resulted in an increased expression of cell cycle inhibiting genes, and therefore, reduced expansion of the T-cell population. Forkhead box protein O1 shuttles to the cytoplasm after phosphorylation in a protein complex including 14-3-3 proteins. Interestingly, we observed a similar regulation for the adapter protein SLy1, where TCR stimulation results in SLy1 phosphorylation and SLy1 export to the cytoplasm. Moreover, immunoprecipitation analyses revealed a binding of SLy1 to 14-3-3 proteins. Altogether, this study describes SLy1 as an immunoregulatory protein, which is involved in the generation of adaptive immune responses during L. monocytogenes infection, and provides a model of how SLy1 regulates T-cell proliferation. PMID:26306874

  11. The role of IgG subclass of mouse monoclonal antibodies in antibody-dependent enhancement of feline infectious peritonitis virus infection of feline macrophages.

    Science.gov (United States)

    Hohdatsu, T; Tokunaga, J; Koyama, H

    1994-01-01

    Antibody-dependent enhancement (ADE) of feline infectious peritonitis virus (FIPV) infection was studied in feline alveolar macrophages and human monocyte cell line U937 using mouse neutralizing monoclonal antibodies (MAbs) directed to the spike protein of FIPV. Even among the MAbs that have been shown to recognize the same antigenic site, IgG 2a MAbs enhanced FIPV infection strongly, whereas IgG 1 MAbs did not. These IgG 2a MAbs enhanced the infection even when macrophages pretreated with the MAb were washed and then inoculated with the virus. Immunofluorescence flow cytometric analysis of the macrophages treated with each of the MAbs showed that the IgG 2a MAbs but not the IgG 1 MAbs bound to feline alveolar macrophages. Treatment of the IgG 2a MAb with protein A decreased the binding to the macrophages and, in parallel, diminished the ADE activity. Although no infection was observed by inoculation of FIPV to human monocyte cell line U937 cells, FIPV complexed with either the IgG 2a MAb or the IgG 1 MAb caused infection in U937 cells which are shown to express Fc gamma receptor (Fc gamma R) I and II that can bind mouse IgG 2a and IgG 1, respectively. These results suggest that the enhancing activity of MAb is closely correlated with IgG subclass and that the correlation is involved in binding of MAb to Fc gamma R on feline macrophage.

  12. Bacterial load and inflammation in fetal tissues is not dependent on IL-17a or IL-22 in 10-14 day pregnant mice infected with Listeria monocytogenes

    Science.gov (United States)

    Poulsen, Keith P.; Faith, Nancy G.; Steinberg, Howard; Czuprynski, Charles J.

    2012-01-01

    In this study, we first assessed the effect of intragastric infection of pregnant mice with Listeria monocytogenes on relative expression of select genes associated with T cell subsets. Relative gene expression was moderately increased in placental tissues for IFNγ, IL-4, IL-17a, IL-22, CD3, and FoxP3. To assess the roles of IL-17a and IL-22 in resistance to listeriosis during pregnancy, we compared the severity of maternal and fetal infection in IL-17a(−/−), IL-22(−/−), and IL-17a(−/−)/IL-22(−/−) mice with that of wild type C57BL/6 mice. Intragastric infection with modest numbers of bacterial cells (105 CFU) caused reproducible maternal and fetal infection in all four mouse strains. We recovered greater numbers of CFU from the bloodstream of pregnant IL-22(−/−) mice than pregnant wild type mice. Otherwise we found no significant difference in bacterial load in maternal or fetal tissues (spleen, liver, fetoplacental units) from pregnant IL-17a(−/−), IL-22(−/−), or IL-17a(−/−)/IL-22(−/−) or wild type mice. Nor did we observe histopathologic differences in severity of inflammation in maternal or fetal tissues from the various groups of mice. Although IL-17a and IL-22 are up-regulated in placental tissue, our study suggests that antibacterial resistance and the host inflammatory response are not dependent on IL-17a or IL-22 during infection of mice with L. monocytogenes at 10-14 days of gestation. PMID:23178254

  13. Changes in IgE- and Antigen-dependent histamine-release in peripheral blood of Schistosoma mansoni-infected Ugandan fishermen after treatment with praziquantel

    Directory of Open Access Journals (Sweden)

    Kazibwe Francis

    2004-04-01

    Full Text Available Abstract Background Parasite-specific IgE levels correlate with human resistance to reinfection with Schistosoma spp. after chemotherapy. Although the role of eosinophils in schistosomiasis has been the focus of a great deal of important research, the involvement of other Fcε receptor-bearing cells, such as mast cells and basophils, has not been investigated in relation to human immunity to schistosomes. Chemotherapy with praziquantel (PZQ kills schistosomes living in an in vivo blood environment rich in IgE, eosinophils and basophils. This releases parasite Ags that have the potential to cross-link cell-bound IgE. However, systemic hypersensitivity reactions are not induced by treatment. Here, we describe the effects of schistosomiasis, and its treatment, on human basophil function by following changes in total cellular histamine and in vitro histamine-release induced by schistosome Ags or anti-IgE, in blood samples from infected Ugandan fishermen, who are continuously exposed to S. mansoni infection, before and 1-day and 21-days after PZQ treatment. Results There was a significant increase in the total cellular histamine in blood samples at 1-day post-treatment, followed by a very significant further increase by 21-days post-treatment. In vitro histamine-release induced by S. mansoni egg (SEA or worm (SWA Ags or anti-IgE antibody, was significantly reduced 1-day post-treatment. The degree of this reduction correlated with pre-treatment infection intensity. Twenty-1-days post-treatment, SEA-induced histamine-release was still significantly lower than at pretreatment. Histamine-release was not correlated to plasma concentrations of total or parasite-specific IgE, nor to specific IgG4 plasma concentrations. Conclusion The biology of human blood basophils is modulated by S. mansoni infection and praziquantel treatment. Infection intensity-dependent suppression of basophil histamine-release, histamine-dependent resistance to infection, and

  14. Adeno-associated virus type 2 infection activates caspase dependent and independent apoptosis in multiple breast cancer lines but not in normal mammary epithelial cells

    Directory of Open Access Journals (Sweden)

    Tandon Apurva

    2011-08-01

    Full Text Available Abstract Background In normal cells proliferation and apoptosis are tightly regulated, whereas in tumor cells the balance is shifted in favor of increased proliferation and reduced apoptosis. Anticancer agents mediate tumor cell death via targeting multiple pathways of programmed cell death. We have reported that the non-pathogenic, tumor suppressive Adeno-Associated Virus Type 2 (AAV2 induces apoptosis in Human Papillomavirus (HPV positive cervical cancer cells, but not in normal keratinocytes. In the current study, we examined the potential of AAV2 to inhibit proliferation of MCF-7 and MDA-MB-468 (both weakly invasive, as well as MDA-MB-231 (highly invasive human breast cancer derived cell lines. As controls, we used normal human mammary epithelial cells (nHMECs isolated from tissue biopsies of patients undergoing breast reduction surgery. Results AAV2 infected MCF-7 line underwent caspase-independent, and MDA-MB-468 and MDA-MB-231 cell lines underwent caspase-dependent apoptosis. Death of MDA-MB-468 cells was marked by caspase-9 activation, whereas death of MDA-MB-231 cells was marked by activation of both caspase-8 and caspase-9, and resembled a mixture of apoptotic and necrotic cell death. Cellular demise was correlated with the ability of AAV2 to productively infect and differentially express AAV2 non-structural proteins: Rep78, Rep68 and Rep40, dependent on the cell line. Cell death in the MCF-7 and MDA-MB-231 lines coincided with increased S phase entry, whereas the MDA-MB-468 cells increasingly entered into G2. AAV2 infection led to decreased cell viability which correlated with increased expression of proliferation markers c-Myc and Ki-67. In contrast, nHMECs that were infected with AAV2 failed to establish productive infection or undergo apoptosis. Conclusion AAV2 regulated enrichment of cell cycle check-point functions in G1/S, S and G2 phases could create a favorable environment for Rep protein expression. Inherent Rep associated

  15. Muramyl dipeptide induces NOD2-dependent Ly6C(high monocyte recruitment to the lungs and protects against influenza virus infection.

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    François Coulombe

    Full Text Available Bacterial peptidoglycan-derived muramyl dipeptide (MDP and derivatives have long-recognized antiviral properties but their mechanism of action remains unclear. In recent years, the pattern-recognition receptor NOD2 has been shown to mediate innate responses to MDP. Here, we show that MDP treatment of mice infected with Influenza A virus (IAV significantly reduces mortality, viral load and pulmonary inflammation in a NOD2-dependent manner. Importantly, the induction of type I interferon (IFN and CCL2 chemokine was markedly increased in the lungs following MDP treatment and correlated with a NOD2-dependent enhancement in circulating monocytes. Mechanistically, the protective effect of MDP could be explained by the NOD2-dependent transient increase in recruitment of Ly6C(high "inflammatory" monocytes and, to a lesser extent, neutrophils to the lungs. Indeed, impairment in both Ly6C(high monocyte recruitment and survival observed in infected Nod2-/- mice treated with MDP was recapitulated in mice deficient for the chemokine receptor CCR2 required for CCL2-mediated Ly6C(high monocyte migration from the bone marrow into the lungs. MDP-induced pulmonary monocyte recruitment occurred normally in IAV-infected and MDP-treated Ips-1-/- mice. However, IPS-1 was required for improved survival upon MDP treatment. Finally, mycobacterial N-glycolyl MDP was more potent than N-acetyl MDP expressed by most bacteria at reducing viral burden while both forms of MDP restored pulmonary function following IAV challenge. Overall, our work sheds light on the antiviral mechanism of a clinically relevant bacterial-derived compound and identifies the NOD2 pathway as a potential therapeutic target against IAV.

  16. Exploring the metabolic network of the epidemic pathogen Burkholderia cenocepacia J2315 via genome-scale reconstruction

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    Panda Gurudutta

    2011-05-01

    Full Text Available Abstract Background Burkholderia cenocepacia is a threatening nosocomial epidemic pathogen in patients with cystic fibrosis (CF or a compromised immune system. Its high level of antibiotic resistance is an increasing concern in treatments against its infection. Strain B. cenocepacia J2315 is the most infectious isolate from CF patients. There is a strong demand to reconstruct a genome-scale metabolic network of B. cenocepacia J2315 to systematically analyze its metabolic capabilities and its virulence traits, and to search for potential clinical therapy targets. Results We reconstructed the genome-scale metabolic network of B. cenocepacia J2315. An iterative reconstruction process led to the establishment of a robust model, iKF1028, which accounts for 1,028 genes, 859 internal reactions, and 834 metabolites. The model iKF1028 captures important metabolic capabilities of B. cenocepacia J2315 with a particular focus on the biosyntheses of key metabolic virulence factors to assist in understanding the mechanism of disease infection and identifying potential drug targets. The model was tested through BIOLOG assays. Based on the model, the genome annotation of B. cenocepacia J2315 was refined and 24 genes were properly re-annotated. Gene and enzyme essentiality were analyzed to provide further insights into the genome function and architecture. A total of 45 essential enzymes were identified as potential therapeutic targets. Conclusions As the first genome-scale metabolic network of B. cenocepacia J2315, iKF1028 allows a systematic study of the metabolic properties of B. cenocepacia and its key metabolic virulence factors affecting the CF community. The model can be used as a discovery tool to design novel drugs against diseases caused by this notorious pathogen.

  17. Assessment of three Resistance-Nodulation-Cell Division drug efflux transporters of Burkholderia cenocepacia in intrinsic antibiotic resistance

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    Venturi Vittorio

    2009-09-01

    Full Text Available Abstract Background Burkholderia cenocepacia are opportunistic Gram-negative bacteria that can cause chronic pulmonary infections in patients with cystic fibrosis. These bacteria demonstrate a high-level of intrinsic antibiotic resistance to most clinically useful antibiotics complicating treatment. We previously identified 14 genes encoding putative Resistance-Nodulation-Cell Division (RND efflux pumps in the genome of B. cenocepacia J2315, but the contribution of these pumps to the intrinsic drug resistance of this bacterium remains unclear. Results To investigate the contribution of efflux pumps to intrinsic drug resistance of B. cenocepacia J2315, we deleted 3 operons encoding the putative RND transporters RND-1, RND-3, and RND-4 containing the genes BCAS0591-BCAS0593, BCAL1674-BCAL1676, and BCAL2822-BCAL2820. Each deletion included the genes encoding the RND transporter itself and those encoding predicted periplasmic proteins and outer membrane pores. In addition, the deletion of rnd-3 also included BCAL1672, encoding a putative TetR regulator. The B. cenocepacia rnd-3 and rnd-4 mutants demonstrated increased sensitivity to inhibitory compounds, suggesting an involvement of these proteins in drug resistance. Moreover, the rnd-3 and rnd-4 mutants demonstrated reduced accumulation of N-acyl homoserine lactones in the growth medium. In contrast, deletion of the rnd-1 operon had no detectable phenotypes under the conditions assayed. Conclusion Two of the three inactivated RND efflux pumps in B. cenocepacia J2315 contribute to the high level of intrinsic resistance of this strain to some antibiotics and other inhibitory compounds. Furthermore, these efflux systems also mediate accumulation in the growth medium of quorum sensing molecules that have been shown to contribute to infection. A systematic study of RND efflux systems in B. cenocepacia is required to provide a full picture of intrinsic antibiotic resistance in this opportunistic

  18. Natural killer function following allogeneic bone marrow transplantation. Very early reemergence but strong dependence of cytomegalovirus infection

    DEFF Research Database (Denmark)

    Hokland, M; Jacobsen, N; Ellegaard, J;

    1988-01-01

    Natural killer (NK) cell function was followed sequentially after allogeneic bone marrow transplantation (BMT) using three approaches: (1) chromium-release assay with purified mononuclear effector cells, (2) chromium-release assay with whole blood effectors, and 3) enumeration of lymphocytes......) infections (primary or reactivated). In contrast, the presence of graft-versus-host (GVH) disease did not associate with consistent changes in the NK parameters measured here. After the first month of increase, NK declined reaching levels near those observed in their respective bone marrow donors at day 90...

  19. Burkholderia pseudomallei Capsule Exacerbates Respiratory Melioidosis but Does Not Afford Protection against Antimicrobial Signaling or Bacterial Killing in Human Olfactory Ensheathing Cells.

    Science.gov (United States)

    Dando, Samantha J; Ipe, Deepak S; Batzloff, Michael; Sullivan, Matthew J; Crossman, David K; Crowley, Michael; Strong, Emily; Kyan, Stephanie; Leclercq, Sophie Y; Ekberg, Jenny A K; St John, James; Beacham, Ifor R; Ulett, Glen C

    2016-07-01

    Melioidosis, caused by the bacterium Burkholderia pseudomallei, is an often severe infection that regularly involves respiratory disease following inhalation exposure. Intranasal (i.n.) inoculation of mice represents an experimental approach used to study the contributions of bacterial capsular polysaccharide I (CPS I) to virulence during acute disease. We used aerosol delivery of B. pseudomallei to establish respiratory infection in mice and studied CPS I in the context of innate immune responses. CPS I improved B. pseudomallei survival in vivo and triggered multiple cytokine responses, neutrophil infiltration, and acute inflammatory histopathology in the spleen, liver, nasal-associated lymphoid tissue, and olfactory mucosa (OM). To further explore the role of the OM response to B. pseudomallei infection, we infected human olfactory ensheathing cells (OECs) in vitro and measured bacterial invasion and the cytokine responses induced following infection. Human OECs killed >90% of the B. pseudomallei in a CPS I-independent manner and exhibited an antibacterial cytokine response comprising granulocyte colony-stimulating factor, tumor necrosis factor alpha, and several regulatory cytokines. In-depth genome-wide transcriptomic profiling of the OEC response by RNA-Seq revealed a network of signaling pathways activated in OECs following infection involving a novel group of 378 genes that encode biological pathways controlling cellular movement, inflammation, immunological disease, and molecular transport. This represents the first antimicrobial program to be described in human OECs and establishes the extensive transcriptional defense network accessible in these cells. Collectively, these findings show a role for CPS I in B. pseudomallei survival in vivo following inhalation infection and the antibacterial signaling network that exists in human OM and OECs.

  20. Burkholderia pseudomallei Capsule Exacerbates Respiratory Melioidosis but Does Not Afford Protection against Antimicrobial Signaling or Bacterial Killing in Human Olfactory Ensheathing Cells.

    Science.gov (United States)

    Dando, Samantha J; Ipe, Deepak S; Batzloff, Michael; Sullivan, Matthew J; Crossman, David K; Crowley, Michael; Strong, Emily; Kyan, Stephanie; Leclercq, Sophie Y; Ekberg, Jenny A K; St John, James; Beacham, Ifor R; Ulett, Glen C

    2016-07-01

    Melioidosis, caused by the bacterium Burkholderia pseudomallei, is an often severe infection that regularly involves respiratory disease following inhalation exposure. Intranasal (i.n.) inoculation of mice represents an experimental approach used to study the contributions of bacterial capsular polysaccharide I (CPS I) to virulence during acute disease. We used aerosol delivery of B. pseudomallei to establish respiratory infection in mice and studied CPS I in the context of innate immune responses. CPS I improved B. pseudomallei survival in vivo and triggered multiple cytokine responses, neutrophil infiltration, and acute inflammatory histopathology in the spleen, liver, nasal-associated lymphoid tissue, and olfactory mucosa (OM). To further explore the role of the OM response to B. pseudomallei infection, we infected human olfactory ensheathing cells (OECs) in vitro and measured bacterial invasion and the cytokine responses induced following infection. Human OECs killed >90% of the B. pseudomallei in a CPS I-independent manner and exhibited an antibacterial cytokine response comprising granulocyte colony-stimulating factor, tumor necrosis factor alpha, and several regulatory cytokines. In-depth genome-wide transcriptomic profiling of the OEC response by RNA-Seq revealed a network of signaling pathways activated in OECs following infection involving a novel group of 378 genes that encode biological pathways controlling cellular movement, inflammation, immunological disease, and molecular transport. This represents the first antimicrobial program to be described in human OECs and establishes the extensive transcriptional defense network accessible in these cells. Collectively, these findings show a role for CPS I in B. pseudomallei survival in vivo following inhalation infection and the antibacterial signaling network that exists in human OM and OECs. PMID:27091931

  1. Properties of Polyhydroxyalkanoate Granules and Bioemulsifiers from Pseudomonas sp. and Burkholderia sp. Isolates Growing on Glucose.

    Science.gov (United States)

    Sacco, Laís Postai; Castellane, Tereza Cristina Luque; Lopes, Erica Mendes; de Macedo Lemos, Eliana Gertrudes; Alves, Lúcia Maria Carareto

    2016-03-01

    A Burkholderia and Pseudomonas species designated as AB4 and AS1, respectively, were isolated from soil containing decomposing straw or sugar cane bagasse collected from Brazil. This study sought to evaluate the capacities of culture media, cell-free medium, and crude lysate preparations (containing PHB inclusion bodies) from bacterial cell cultures to stabilize emulsions with several hydrophobic compounds. Four conditions showed good production of bioemulsifiers (E24 ≥ 50 %), headed by substantially cell-free media from bacterial cell cultures in which bacterial isolates from Burkholderia sp. strain AB4 and Pseudomonas sp. strain AS1 were grown. Our results revealed that the both isolates (AB4 and AS1 strains) exhibited high emulsification indices (indicating usefulness in bioremediation) and good stabilities. PMID:26578147

  2. Quorum Sensing Controls Swarming Motility of Burkholderia glumae through Regulation of Rhamnolipids.

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    Arvin Nickzad

    Full Text Available Burkholderia glumae is a plant pathogenic bacterium that uses an acyl-homoserine lactone-mediated quorum sensing system to regulate protein secretion, oxalate production and major virulence determinants such as toxoflavin and flagella. B. glumae also releases surface-active rhamnolipids. In Pseudomonas aeruginosa and Burkholderia thailandensis, rhamnolipids, along with flagella, are required for the social behavior called swarming motility. In the present study, we demonstrate that quorum sensing positively regulates the production of rhamnolipids in B. glumae and that rhamnolipids are necessary for swarming motility also in this species. We show that a rhlA- mutant, which is unable to produce rhamnolipids, loses its ability to swarm, and that this can be complemented by providing exogenous rhamnolipids. Impaired rhamnolipid production in a quorum sensing-deficient B. glumae mutant is the main factor responsible for its defective swarming motility behaviour.

  3. Quorum Sensing Controls Swarming Motility of Burkholderia glumae through Regulation of Rhamnolipids.

    Science.gov (United States)

    Nickzad, Arvin; Lépine, François; Déziel, Eric

    2015-01-01

    Burkholderia glumae is a plant pathogenic bacterium that uses an acyl-homoserine lactone-mediated quorum sensing system to regulate protein secretion, oxalate production and major virulence determinants such as toxoflavin and flagella. B. glumae also releases surface-active rhamnolipids. In Pseudomonas aeruginosa and Burkholderia thailandensis, rhamnolipids, along with flagella, are required for the social behavior called swarming motility. In the present study, we demonstrate that quorum sensing positively regulates the production of rhamnolipids in B. glumae and that rhamnolipids are necessary for swarming motility also in this species. We show that a rhlA- mutant, which is unable to produce rhamnolipids, loses its ability to swarm, and that this can be complemented by providing exogenous rhamnolipids. Impaired rhamnolipid production in a quorum sensing-deficient B. glumae mutant is the main factor responsible for its defective swarming motility behaviour. PMID:26047513

  4. Enhanced bioconversion of ethylene glycol to glycolic acid by a newly isolated Burkholderia sp. EG13.

    Science.gov (United States)

    Gao, Xiaoxin; Ma, Zhengfei; Yang, Limin; Ma, Jiangquan

    2014-10-01

    Burkholderia sp. EG13 with high ethylene glycol-oxidizing activity was isolated from soil, which could be used for the synthesis of glycolic acid from the oxidation of ethylene glycol. Using the resting cells of Burkholderia sp. EG13 as biocatalysts, the optimum reaction temperature and pH were 30 °C and 6.0, respectively. After 24 h of biotransformation, the yield of glycolic acid from 200 mM ethylene glycol was 98.8 %. Furthermore, an integrated bioprocess for the production of glycolic acid which involved in situ product removal (ISPR) was investigated. Using fed-batch method with ISPR, a total of 793 mM glycolic acid has been accumulated in the reaction mixture after the 4th feed.

  5. Antiretroviral-Related Adipocyte Dysfunction and Lipodystrophy in HIV-Infected Patients: Alteration of the PPARγ-Dependent Pathways

    Directory of Open Access Journals (Sweden)

    Martine Caron

    2009-01-01

    Full Text Available Lipodystrophy and metabolic alterations are major complications of antiretroviral therapy in HIV-infected patients. In vitro studies using cultured murine and human adipocytes revealed that some protease inhibitors (PIs and nucleoside reverse transcriptase inhibitors (NRTIs were implicated to a different extent in adipose cell dysfunction and that a chronic incubation with some PIs decreased mRNA and protein expression of PPARγ. Defective lamin A maturation linked to PI inhibitory activity could impede the nuclear translocation of SREBP1c, therefore, reducing PPARγ expression. Adipose cell function was partially restored by the PPARγ agonists, thiazolidinediones. Adverse effects of PIs and NRTIs have also been reported in macrophages, a cell type that coexists with, and modulates, adipocyte function in fat tissue. In HIV-infected patients under ART, a decreased expression of PPARγ and of PPARγ-related genes was observed in adipose tissue, these anomalies being more severe in patients with ART-induced lipoatrophy. Altered PPARγ expression was reversed in patients stopping PIs. Treatment of patients with agonists of PPARγ could improve, at least partially, the subcutaneous lipoatrophy. These data indicate that decreased PPARγ expression and PPARγ-related function, resulting from ART-induced adipose tissue toxicity, play a central role in HIV-related lipoatrophy and metabolic consequences.

  6. Development of a multiple-locus variable-number tandem-repeat typing scheme for genetic fingerprinting of Burkholderia cenocepacia and application to nationwide epidemiological analysis.

    Science.gov (United States)

    Segonds, Christine; Thouverez, Michelle; Barthe, Antoine; Bossuet-Greif, Nadège; Tisseyre, Lenka; Plésiat, Patrick; Vergnaud, Gilles; Chabanon, Gérard; Pourcel, Christine

    2015-02-01

    Organisms of the Burkholderia cepacia complex are especially important pathogens in cystic fibrosis (CF), with a propensity for patient-to-patient spread and long-term respiratory colonization. B. cenocepacia and Burkholderia multivorans account for the majority of infections in CF, and major epidemic clones have been recognized throughout the world. The aim of the present study was to develop and evaluate a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) scheme for B. cenocepacia. Potential VNTR loci were identified upon analysis of the annotated genome sequences of B. cenocepacia strains AU1054, J2315, and MCO-3, and 10 of them were selected on the basis of polymorphisms and size. A collection of 100 B. cenocepacia strains, including epidemiologically related and unrelated strains, as well as representatives of the major epidemic lineages, was used to evaluate typeability, epidemiological concordance, and the discriminatory power of MLVA-10 compared with those of pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Longitudinal stability was assessed by testing 39 successive isolates from 14 patients. Typeability ranged from 0.91 to 1, except for that of one marker, which was not amplified in 53% of the B. cenocepacia IIIA strains. The MLVA types were shown to be stable in chronically colonized patients and within outbreak-related strains, with excellent epidemiological concordance. Epidemic and/or globally distributed lineages (epidemic Edinburgh-Toronto electrophoretic type 12 [ET-12], sequence type 32 [ST-32], ST-122, ST-234, and ST-241) were successfully identified. Conversely, the discriminatory power of MLVA was lower than that of PFGE or MLST, although PFGE variations within the epidemic lineages sometimes masked their genetic relatedness. In conclusion, MLVA represents a promising cost-effective first-line tool in B. cenocepacia surveillance.

  7. Prevalence and Identification of Burkholderia pseudomallei and Near-Neighbor Species in the Malabar Coastal Region of India

    Science.gov (United States)

    Peddayelachagiri, Bhavani V.; Paul, Soumya; Nagaraj, Sowmya; Gogoi, Madhurjya; Sripathy, Murali H.; Batra, Harsh V.

    2016-01-01

    Accurate identification of pathogens with biowarfare importance requires detection tools that specifically differentiate them from near-neighbor species. Burkholderia pseudomallei, the causative agent of a fatal disease melioidosis, is one such biothreat agent whose differentiation from its near-neighbor species is always a challenge. This is because of its phenotypic similarity with other Burkholderia species which have a wide spread geographical distribution with shared environmental niches. Melioidosis is a major public health concern in endemic regions including Southeast Asia and northern Australia. In India, the disease is still considered to be emerging. Prevalence surveys of this saprophytic bacterium in environment are under-reported in the country. A major challenge in this case is the specific identification and differentiation of B. pseudomallei from the growing list of species of Burkholderia genus. The objectives of this study included examining the prevalence of B. pseudomallei and near-neighbor species in coastal region of South India and development of a novel detection tool for specific identification and differentiation of Burkholderia species. Briefly, we analyzed soil and water samples collected from Malabar coastal region of Kerala, South India for prevalence of B. pseudomallei. The presumptive Burkholderia isolates were identified using recA PCR assay. The recA PCR assay identified 22 of the total 40 presumptive isolates as Burkholderia strains (22.72% and 77.27% B. pseudomallei and non-pseudomallei Burkholderia respectively). In order to identify each isolate screened, we performed recA and 16S rDNA sequencing. This two genes sequencing revealed that the presumptive isolates included B. pseudomallei, non-pseudomallei Burkholderia as well as non-Burkholderia strains. Furthermore, a gene termed D-beta hydroxybutyrate dehydrogenase (bdha) was studied both in silico and in vitro for accurate detection of Burkholderia genus. The optimized bdha

  8. Prevalence and Identification of Burkholderia pseudomallei and Near-Neighbor Species in the Malabar Coastal Region of India.

    Science.gov (United States)

    Peddayelachagiri, Bhavani V; Paul, Soumya; Nagaraj, Sowmya; Gogoi, Madhurjya; Sripathy, Murali H; Batra, Harsh V

    2016-09-01

    Accurate identification of pathogens with biowarfare importance requires detection tools that specifically differentiate them from near-neighbor species. Burkholderia pseudomallei, the causative agent of a fatal disease melioidosis, is one such biothreat agent whose differentiation from its near-neighbor species is always a challenge. This is because of its phenotypic similarity with other Burkholderia species which have a wide spread geographical distribution with shared environmental niches. Melioidosis is a major public health concern in endemic regions including Southeast Asia and northern Australia. In India, the disease is still considered to be emerging. Prevalence surveys of this saprophytic bacterium in environment are under-reported in the country. A major challenge in this case is the specific identification and differentiation of B. pseudomallei from the growing list of species of Burkholderia genus. The objectives of this study included examining the prevalence of B. pseudomallei and near-neighbor species in coastal region of South India and development of a novel detection tool for specific identification and differentiation of Burkholderia species. Briefly, we analyzed soil and water samples collected from Malabar coastal region of Kerala, South India for prevalence of B. pseudomallei. The presumptive Burkholderia isolates were identified using recA PCR assay. The recA PCR assay identified 22 of the total 40 presumptive isolates as Burkholderia strains (22.72% and 77.27% B. pseudomallei and non-pseudomallei Burkholderia respectively). In order to identify each isolate screened, we performed recA and 16S rDNA sequencing. This two genes sequencing revealed that the presumptive isolates included B. pseudomallei, non-pseudomallei Burkholderia as well as non-Burkholderia strains. Furthermore, a gene termed D-beta hydroxybutyrate dehydrogenase (bdha) was studied both in silico and in vitro for accurate detection of Burkholderia genus. The optimized bdha

  9. Purification and characterization of chlorophenol 4-monooxygenase from Burkholderia cepacia AC1100.

    OpenAIRE

    Xun, L

    1996-01-01

    Burkholderia (formerly Pseudomonas) cepacia AC1100 mineralizes the herbicide 2,4,5-trichlorophenoxyacetate (2,4,5-T), and the first intermediate of 2,4,5-T degradation is 2,4,5-trichlorophenol. Chlorophenol 4-monooxygenase activity responsible for 2,4,5-trichlorophenol degradation was detected in the cell extract. The enzyme consisted of two components separated during purification, and both were purified to more than 95% homogeneity. The reconstituted enzyme catalyzed the hydroxylation of se...

  10. Isolation and characterization of Burkholderia sp. strain CCA53 exhibiting ligninolytic potential

    OpenAIRE

    Akita, Hironaga; Kimura, Zen-ichiro; Mohd Yusoff, Mohd Zulkhairi; Nakashima, Nobutaka; Hoshino, Tamotsu

    2016-01-01

    Microbial degradation of lignin releases fermentable sugars, effective utilization of which could support biofuel production from lignocellulosic biomass. In the present study, a lignin-degrading bacterium was isolated from leaf soil and identified as Burkholderia sp. based on 16S rRNA gene sequencing. This strain was named CCA53, and its lignin-degrading capability was assessed by observing its growth on medium containing alkali lignin or lignin-associated aromatic monomers as the sole carbo...

  11. Comparison of different PCR approaches for characterization of Burkholderia (Pseudomonas) cepacia isolates.

    OpenAIRE

    Liu, P. Y.; Shi, Z Y; Lau, Y J; HU, B S; Shyr, J M; Tsai, W S; Lin, Y. H.; Tseng, C Y

    1995-01-01

    In this study, we evaluated three PCR methods for epidemiological typing of Burkholderia (Pseudomonas) cepacia--PCR-ribotyping, arbitrarily primed PCR (AP-PCR) and enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR)--and compared them with pulsed-field gel electrophoresis. The analysis was performed with 31 isolates of B. cepacia, comprising 23 epidemiologically unrelated isolates and 8 isolates collected from the same patient during two episodes of bacteremia. Pulsed-fiel...

  12. In Vitro Antifungal Activity of Burkholderia gladioli pv. agaricicola against Some Phytopathogenic Fungi

    OpenAIRE

    Elshafie, Hazem S.; Ippolito Camele; Rocco Racioppi; Laura Scrano; Iacobellis, Nicola S.; Bufo, Sabino A.

    2012-01-01

    The trend to search novel microbial natural biocides has recently been increasing in order to avoid the environmental pollution from use of synthetic pesticides. Among these novel natural biocides are the bioactive secondary metabolites of Burkholderia gladioli pv. agaricicola (Bga). The aim of this study is to determine antifungal activity of Bga strains against some phytopathogenic fungi. The fungicidal tests were carried out using cultures and cell-free culture filtrates against Botrytis c...

  13. A Burkholderia pseudomallei Toxin Inhibits Helicase Activity of Translation Factor eIF4A

    OpenAIRE

    Cruz, Abimael; Hautbergue, Guillaume M.; Artymiuk, Peter J.; Baker, Patrick J.; Bokori-Brown, Monika; Chang, Chung-Te; Dickman, Mark J.; Essex-Lopresti, Angela; Harding, Sarah V.; Mahadi, Nor Muhammad; Marshall, Laura E.; Mobbs, George W.; Mohamed, Rahmah; Nathan, Sheila; Ngugi, Sarah A.

    2011-01-01

    The structure of BPSL1549, a protein of unknown function from Burkholderia pseudomallei reveals a similarity to E. coli cytotoxic necrotizing factor 1. We found that BPSL1549 acted as a potent cytotoxin against eukaryotic cells and was lethal when administered to mice. Expression levels of bpsl1549 correlate with conditions expected to promote or suppress pathogenicity. BPSL1549 promotes deamidation of Gln339 of the translation initiation factor eIF4A, abolishing its helicase activity and inh...

  14. Purification and sequence analysis of 4-methyl-5-nitrocatechol oxygenase from Burkholderia sp. strain DNT.

    OpenAIRE

    Haigler, B E; Suen, W C; Spain, J C

    1996-01-01

    4-Methyl-5-nitrocatechol (MNC) is an intermediate in the degradation of 2,4-dinitrotoluene by Burkholderia sp. strain DNT. In the presence of NADPH and oxygen, MNC monooxygenase catalyzes the removal of the nitro group from MNC to form 2-hydroxy-5-methylquinone. The gene (dntB) encoding MNC monooxygenase has been previously cloned and characterized. In order to examine the properties of MNC monooxygenase and to compare it with other enzymes, we sequenced the gene encoding the MNC monooxygenas...

  15. Hexadecane and Tween 80 Stimulate Lipase Production in Burkholderia glumae by Different Mechanisms▿

    OpenAIRE

    Boekema, Bouke K. H. L.; Beselin, Anke; Breuer, Michael; Hauer, Bernhard; Koster, Margot; Rosenau, Frank; Jaeger, Karl-Erich; Tommassen, Jan

    2007-01-01

    Burkholderia glumae strain PG1 produces a lipase of biotechnological relevance. Lipase production by this strain and its derivative LU8093, which was obtained through classical strain improvement, was investigated under different conditions. When 10% hexadecane was included in the growth medium, lipolytic activity in both strains could be increased ∼7-fold after 24 h of growth. Hexadecane also stimulated lipase production in a strain containing the lipase gene fused to the tac promoter, indic...

  16. Plant host and sugar alcohol induced exopolysaccharide biosynthesis in the Burkholderia cepacia complex

    OpenAIRE

    Bartholdson, S. Josefin; Brown, Alan R.; Mewburn, Ben R.; Clarke, David J.; Fry, Stephen C; Campopiano, Dominic J.; Govan, John R. W.

    2008-01-01

    The species that presently constitute the Burkholderia cepacia complex (Bcc) have multiple roles; they include soil and water saprophytes, bioremediators, and plant, animal and human pathogens. Since the first description of pathogenicity in the Bcc was based on sour skin rot of onion bulbs, this study returned to this plant host to investigate the onion-associated phenotype of the Bcc. Many Bcc isolates, which were previously considered to be non-mucoid, produced copious amounts of exopolysa...

  17. Burkholderia cepacia and cystic fibrosis: do natural environments present a potential hazard?

    OpenAIRE

    Butler, S. L.; DOHERTY, C.J; Hughes, J. E.; Nelson, J W; Govan, J R

    1995-01-01

    An environmental survey of 55 sites yielded only 12 Burkholderia cepacia isolates, none of which displayed the phenotypic properties of a multiresistant epidemic strain associated with pulmonary colonization in patients with cystic fibrosis. Although the environment probably poses a low risk for patients with cystic fibrosis as a source of B. cepacia, the pathogenic potential of individual environmental strains remains unclear. We advise caution in the development of B. cepacia as a biocontro...

  18. Evaluation of six commercial DNA extraction kits for recovery of Burkholderia pseudomallei DNA.

    Science.gov (United States)

    Marques, Maria Angela de Mello; Zimmermann, Pia; Messelhäußer, Ute; Sing, Andreas

    2012-12-01

    Six commercially available DNA extraction kits, as well as thermal lysis and proteinase K DNA extraction were evaluated regarding bacterial inactivation, DNA yield and purity, and their use in a Burkholderia pseudomallei real-time PCR. While all methods successfully inactivated the bacteria, by measuring DNA purity and the level of detection by real-time PCR, the proteinase K method was the most sensitive.

  19. Bioremediation of refinery wastewater using immobilised Burkholderia cepacia and Corynebacterium sp and their transconjugants

    OpenAIRE

    Abdullahi T. Ajao; Sabo E. Yakubu; Veronica J. Umoh; Joseph B. Ameh

    2013-01-01

    When oil spill occurs, it poses serious toxic hazards to all forms of life. Mixed culture of Burkholderia cepacia and Corynebacterium sp isolated from refinery sludge using selective enrichment technique was used for bioremediation of refinery wastewater in a laboratoryscale bioreactor. Physicochemical parameters of both raw and treated water were as determined and compared with Federal Environ - mental Protection Agency (FEPA-limit, Abuja, Nigeria) to asses the efficiency of the bioremediati...

  20. Draft Genome Sequence of Burkholderia sp. Strain CCA53, Isolated from Leaf Soil

    Science.gov (United States)

    Kimura, Zen-ichiro; Yusoff, Mohd Zulkhairi Mohd; Nakashima, Nobutaka; Hoshino, Tamotsu

    2016-01-01

    Burkholderia sp. strain CCA53 was isolated from leaf soil collected in Higashi-Hiroshima City in Hiroshima Prefecture, Japan. Here, we present a draft genome sequence of this strain, which consists of a total of 4 contigs containing 6,647,893 bp, with a G+C content of 67.0% and comprising 9,329 predicted coding sequences. PMID:27389268

  1. Antimicrobial Drug–Selection Markers for Burkholderia pseudomallei and B. mallei

    OpenAIRE

    Schweizer, Herbert P.; Peacock, Sharon J.

    2008-01-01

    Genetic research into the select agents Burkholderia pseudomallei and B. mallei is currently hampered by a paucity of approved antimicrobial drug–selection markers. The strict regulations imposed on researchers in the United States but not in other parts of the world lead to discrepancies in practice, hinder distribution of genetically modified strains, and impede progress in the field. Deliberation and decisions regarding alternative selection markers (antimicrobial and nonantimicrobial drug...

  2. Survival, Sublethal Injury, and Recovery of Environmental Burkholderia pseudomallei in Soil Subjected to Desiccation

    OpenAIRE

    Larsen, Eloise; Smith, James J.; Norton, Robert; Corkeron, Maree

    2013-01-01

    Environmental Burkholderia pseudomallei isolated from sandy soil at Castle Hill, Townsville, in the dry tropic region of Queensland, Australia, was inoculated into sterile-soil laboratory microcosms subjected to variable soil moisture. Survival and sublethal injury of the B. pseudomallei strain were monitored by recovery using culture-based methods. Soil extraction buffer yielded higher recoveries as an extraction agent than sterile distilled water. B. pseudomallei was not recoverable when in...

  3. Ca2+/calmodulin-dependent kinase II contributes to inhibitor of nuclear factor-kappa B kinase complex activation in Helicobacter pylori infection.

    Science.gov (United States)

    Maubach, Gunter; Sokolova, Olga; Wolfien, Markus; Rothkötter, Hermann-Josef; Naumann, Michael

    2013-09-15

    Helicobacter pylori, a class I carcinogen, induces a proinflammatory response by activating the transcription factor nuclear factor-kappa B (NF-κB) in gastric epithelial cells. This inflammatory condition could lead to chronic gastritis, which is epidemiologically and biologically linked to the development of gastric cancer. So far, there exists no clear knowledge on how H. pylori induces the NF-κB-mediated inflammatory response. In our study, we investigated the role of Ca(2+) /calmodulin-dependent kinase II (CAMKII), calmodulin, protein kinases C (PKCs) and the CARMA3-Bcl10-MALT1 (CBM) complex in conjunction with H. pylori-induced activation of NF-κB via the inhibitor of nuclear factor-kappa B kinase (IKK) complex. We use specific inhibitors and/or RNA interference to assess the contribution of these components. Our results show that CAMKII and calmodulin contribute to IKK complex activation and thus to the induction of NF-κB in response to H. pylori infection, but not in response to TNF-α. Thus, our findings are specific for H. pylori infected cells. Neither the PKCs α, δ, θ, nor the CBM complex itself is involved in the activation of NF-κB by H. pylori. The contribution of CAMKII and calmodulin, but not PKCs/CBM to the induction of an inflammatory response by H. pylori infection augment the understanding of the molecular mechanism involved and provide potential new disease markers for the diagnosis of gastric inflammatory diseases including gastric cancer.

  4. Estrogen-dependent changes in serum iron levels as a translator of the adverse effects of estrogen during infection: a conceptual framework.

    Science.gov (United States)

    Hamad, Mawieh; Awadallah, Samir

    2013-12-01

    Elevated levels of estrogen often associate with increased susceptibility to infection. This has been attributed to the ability of estrogen to concomitantly enhance the growth and virulence of pathogens and suppress host immunity. But the exact mechanism of how estrogen mediates such effects, especially in cases where the pathogen and/or the immune components in question do not express estrogen receptors, has yet to be elucidated. Here we propose that translating the adverse effects of estrogen during infection is dependent to a significant degree upon its ability to manipulate iron homeostasis. For elevated levels of estrogen alter the synthesis and/or activity of several factors involved in iron metabolism including hypoxia inducible factor 1α (HIF-1α) and hepcidin among others. This leads to the inhibition of hepcidin synthesis in hepatocytes and the maintenance of ferroportin (FPN) integrity on the surface of iron-releasing duodenal enterocytes, hepatocytes, and macrophages. Intact FPN permits the continuous efflux of dietary and stored iron into the circulation, which further enhances pathogen growth and virulence on the one hand and suppresses host immunity on the other. This new conceptual framework may help explain a multitude of disparate clinical and experimental observations pertinent to the relationship between estrogen and infection. PMID:24211145

  5. Production of p-hydroxybenzoic acid from p-coumaric acid by Burkholderia glumae BGR1.

    Science.gov (United States)

    Jung, Da-Hye; Kim, Eun-Jung; Jung, Eunok; Kazlauskas, Romas J; Choi, Kwon-Young; Kim, Byung-Gee

    2016-07-01

    p-Coumaric acid (pCA) is abundant in biomass with low lignin content, such as straw and stubble from rye, wheat, and barley. pCA can be isolated from biomass and used for the synthesis of aromatic hydrocarbons. Here, we report engineering of the natural pathway for conversion of pCA into p-hydroxybenzoic acid (pHBA) to increase the amount of pHBA that accumulates more than 100-fold. Burkholderia glumae strain BGR1 (BGR1) grows efficiently on pCA as a sole carbon source via a CoA-dependent non-β-oxidation pathway. This pathway removes two carbons from pCA as acetyl-CoA yielding p-hydroxybenzaldehyde and subsequently oxidizes it to pHBA. To increase the amount of accumulated pHBA in BGR1, we first deleted two genes encoding enzymes that degrade pHBA in the β-ketoadipate pathway. At 10 mM of pCA, the double deletion mutant BGR1_PB4 (Δphb3hΔbcl) accumulated pHBA with 95% conversion, while the control BGR1 accumulated only with 11.2% conversion. When a packed bed reactor containing immobilized BGR1_PB4 cells was operated at a dilution rate 0.2 h(-1) , the productivity of pHBA was achieved at 9.27 mg/L/h for 134 h. However, in a batch reactor at 20 mM pCA, growth of BGR1_PB4 was strongly inhibited, resulting in a low conversion of 19.3%. To further increase the amount of accumulated pCA, we identified the first enzyme in the pathway, p-hydroxcinnmaoyl-CoA synthetase II (phcs II), as the rate-limiting enzyme. Over expression of phcs II using a Palk promoter in a batch reaction at 20 mM of pCA yielded 99.0% conversion to pHBA, which is the highest concentration of pHBA ever reported using a biological process. Biotechnol. Bioeng. 2016;113: 1493-1503. © 2015 Wiley Periodicals, Inc. PMID:26693833

  6. Biodegradation of PAHs by Burkholderia sp. VITRSB1 Isolated from Marine Sediments

    Directory of Open Access Journals (Sweden)

    T. Revathy

    2015-01-01

    Full Text Available The polycyclic aromatic hydrocarbons (PAHs pollution to the environment is a major threat to the living organisms, and hence the degradation of these PAHs is necessary. Studies on PAHs degrading bacteria have focussed on terrestrial microbes and the potential of marine derived microbes is undermined. Herein we report the isolation and characterization of PAHs degrading Burkholderia sp. from lagoon sediments collected at the Southern coast of India. The strain was Gram negative, rod-shaped, motile, and ∼2–5 μm in length. Based on the phylogenetic data the strain was identified as Burkholderia and designated as VITRSB1. Initial PAHs degradation ability of the strain was assessed using basal salt medium supplemented with diesel, kerosene, toluene, aniline, naphthalene, and phenol. The strain was found to be effectively degrading kerosene, diesel, toluene, and aniline even at higher concentration (1%. However, naphthalene and aniline were degraded only at lower concentration (0.1% and phenol, camphor, and DAP inhibited the growth of the strain. Furthermore, the degraded end products of the PAHs were determined using FTIR. Notably, none of the end products were found to be toxic to the biosphere. Our results indicate that the isolated Burkholderia sp. could be a prospective candidate for the effective degradation of selective PAHs.

  7. Biodegradation of PAHs by Burkholderia sp. VITRSB1 Isolated from Marine Sediments.

    Science.gov (United States)

    Revathy, T; Jayasri, M A; Suthindhiran, K

    2015-01-01

    The polycyclic aromatic hydrocarbons (PAHs) pollution to the environment is a major threat to the living organisms, and hence the degradation of these PAHs is necessary. Studies on PAHs degrading bacteria have focussed on terrestrial microbes and the potential of marine derived microbes is undermined. Herein we report the isolation and characterization of PAHs degrading Burkholderia sp. from lagoon sediments collected at the Southern coast of India. The strain was Gram negative, rod-shaped, motile, and ∼2-5 μm in length. Based on the phylogenetic data the strain was identified as Burkholderia and designated as VITRSB1. Initial PAHs degradation ability of the strain was assessed using basal salt medium supplemented with diesel, kerosene, toluene, aniline, naphthalene, and phenol. The strain was found to be effectively degrading kerosene, diesel, toluene, and aniline even at higher concentration (1%). However, naphthalene and aniline were degraded only at lower concentration (0.1%) and phenol, camphor, and DAP inhibited the growth of the strain. Furthermore, the degraded end products of the PAHs were determined using FTIR. Notably, none of the end products were found to be toxic to the biosphere. Our results indicate that the isolated Burkholderia sp. could be a prospective candidate for the effective degradation of selective PAHs. PMID:26605106

  8. Induction of GADD34 is necessary for dsRNA-dependent interferon-β production and participates in the control of Chikungunya virus infection.

    Directory of Open Access Journals (Sweden)

    Giovanna Clavarino

    Full Text Available Nucleic acid sensing by cells is a key feature of antiviral responses, which generally result in type-I Interferon production and tissue protection. However, detection of double-stranded RNAs in virus-infected cells promotes two concomitant and apparently conflicting events. The dsRNA-dependent protein kinase (PKR phosphorylates translation initiation factor 2-alpha (eIF2α and inhibits protein synthesis, whereas cytosolic DExD/H box RNA helicases induce expression of type I-IFN and other cytokines. We demonstrate that the phosphatase-1 cofactor, growth arrest and DNA damage-inducible protein 34 (GADD34/Ppp1r15a, an important component of the unfolded protein response (UPR, is absolutely required for type I-IFN and IL-6 production by mouse embryonic fibroblasts (MEFs in response to dsRNA. GADD34 expression in MEFs is dependent on PKR activation, linking cytosolic microbial sensing with the ATF4 branch of the UPR. The importance of this link for anti-viral immunity is underlined by the extreme susceptibility of GADD34-deficient fibroblasts and neonate mice to Chikungunya virus infection.

  9. Structural stability of Burkholderia cenocepacia biofilms is reliant on eDNA structure and presence of a bacterial nucleic acid binding protein.

    Directory of Open Access Journals (Sweden)

    Laura A Novotny

    Full Text Available Cystic fibrosis (CF is the most common lethal inherited genetic disorder affection Caucasians. Even with medical advances, CF is life-shortening with patients typically surviving only to age 38. Infection of the CF lung by Burkholderia cenocepacia presents exceptional challenges to medical management of these patients as clinically this microbe is resistant to virtually all antibiotics, is highly transmissible and infection of CF patients with this microbe renders them ineligible for lung transplant, often the last lifesaving option. Here we have targeted two abundant components of the B. cenocepacia biofilm for immune intervention: extracellular DNA and DNABII proteins, the latter of which are bacterial nucleic acid binding proteins. Treatment of B. cenocepacia biofilms with antiserum directed at one of these DNABII proteins (integration host factor or IHF resulted in significant disruption of the biofilm. Moreover, when anti-IHF mediated destabilization of a B. cenocepacia biofilm was combined with exposure to traditional antibiotics, B. cenocepacia resident within the biofilm and thereby typically highly resistant to the action of antibiotics, were now rendered susceptible to killing. Pre-incubation of B. cenocepacia with anti-IHF serum prior to exposure to murine CF macrophages, which are normally unable to effectively degrade ingested B. cenocepacia, resulted in a statistically significant increase in killing of phagocytized B. cenocepacia. Collectively, these findings support further development of strategies that target DNABII proteins as a novel approach for treatment of CF patients, particularly those whose lungs are infected with B. cenocepacia.

  10. NF-kappaB p65-dependent transactivation of miRNA genes following Cryptosporidium parvum infection stimulates epithelial cell immune responses.

    Directory of Open Access Journals (Sweden)

    Rui Zhou

    2009-12-01

    Full Text Available Cryptosporidium parvum is a protozoan parasite that infects the gastrointestinal epithelium and causes diarrheal disease worldwide. Innate epithelial immune responses are key mediators of the host's defense to C. parvum. MicroRNAs (miRNAs regulate gene expression at the posttranscriptional level and are involved in regulation of both innate and adaptive immune responses. Using an in vitro model of human cryptosporidiosis, we analyzed C. parvum-induced miRNA expression in biliary epithelial cells (i.e., cholangiocytes. Our results demonstrated differential alterations in the mature miRNA expression profile in cholangiocytes following C. parvum infection or lipopolysaccharide stimulation. Database analysis of C. parvum-upregulated miRNAs revealed potential NF-kappaB binding sites in the promoter elements of a subset of miRNA genes. We demonstrated that mir-125b-1, mir-21, mir-30b, and mir-23b-27b-24-1 cluster genes were transactivated through promoter binding of the NF-kappaB p65 subunit following C. parvum infection. In contrast, C. parvum transactivated mir-30c and mir-16 genes in cholangiocytes in a p65-independent manner. Importantly, functional inhibition of selected p65-dependent miRNAs in cholangiocytes increased C. parvum burden. Thus, we have identified a panel of miRNAs regulated through promoter binding of the NF-kappaB p65 subunit in human cholangiocytes in response to C. parvum infection, a process that may be relevant to the regulation of epithelial anti-microbial defense in general.

  11. NF-kappaB p65-dependent transactivation of miRNA genes following Cryptosporidium parvum infection stimulates epithelial cell immune responses.

    Science.gov (United States)

    Zhou, Rui; Hu, Guoku; Liu, Jun; Gong, Ai-Yu; Drescher, Kristen M; Chen, Xian-Ming

    2009-12-01

    Cryptosporidium parvum is a protozoan parasite that infects the gastrointestinal epithelium and causes diarrheal disease worldwide. Innate epithelial immune responses are key mediators of the host's defense to C. parvum. MicroRNAs (miRNAs) regulate gene expression at the posttranscriptional level and are involved in regulation of both innate and adaptive immune responses. Using an in vitro model of human cryptosporidiosis, we analyzed C. parvum-induced miRNA expression in biliary epithelial cells (i.e., cholangiocytes). Our results demonstrated differential alterations in the mature miRNA expression profile in cholangiocytes following C. parvum infection or lipopolysaccharide stimulation. Database analysis of C. parvum-upregulated miRNAs revealed potential NF-kappaB binding sites in the promoter elements of a subset of miRNA genes. We demonstrated that mir-125b-1, mir-21, mir-30b, and mir-23b-27b-24-1 cluster genes were transactivated through promoter binding of the NF-kappaB p65 subunit following C. parvum infection. In contrast, C. parvum transactivated mir-30c and mir-16 genes in cholangiocytes in a p65-independent manner. Importantly, functional inhibition of selected p65-dependent miRNAs in cholangiocytes increased C. parvum burden. Thus, we have identified a panel of miRNAs regulated through promoter binding of the NF-kappaB p65 subunit in human cholangiocytes in response to C. parvum infection, a process that may be relevant to the regulation of epithelial anti-microbial defense in general.

  12. Shallow Encoding and Forgetting Are Associated with Dependence in Instrumental Activities of Daily Living Among Older Adults Living with HIV Infection

    Science.gov (United States)

    Fazeli, Pariya L.; Doyle, Katie L.; Scott, J. Cobb; Iudicello, Jennifer E.; Casaletto, Kaitlin B.; Weber, Erica; Moore, David J.; Morgan, Erin E.; Grant, Igor; Woods, Steven Paul; Hampton Atkinson, J.; Ellis, Ronald J.; Allen McCutchan, J.; Marcotte, Thomas D.; Marquie-Beck, Jennifer; Sherman, Melanie; Ellis, Ronald J.; Allen McCutchan, J.; Letendre, Scott; Capparelli, Edmund; Schrier, Rachel; Rosario, Debra; LeBlanc, Shannon; Heaton, Robert K.; Woods, Steven Paul; Cherner, Mariana; Moore, David J.; Morgan, Erin E.; Dawson, Matthew; Jernigan, Terry; Fennema-Notestine, Christine; Archibald, Sarah L.; Hesselink, John; Annese, Jacopo; Taylor, Michael J.; Masliah, Eliezer; Achim, Cristian; Everall, Ian; Richman, Douglas; Smith, David M.; Allen McCutchan, J.; Achim, Cristian; Lipton, Stuart; Hampton Atkinson, J.; Gamst, Anthony C.; Cushman, Clint; Abramson, Ian; Vaida, Florin; Deutsch, Reena; Umlauf, Anya

    2014-01-01

    Aging and HIV are both risk factors for memory deficits and declines in real-world functioning. However, we know little about the profile of memory deficits driving instrumental activities of daily living (IADL) declines across the lifespan in HIV. This study examined 145 younger (<50 years) and 119 older (≥50 years) adults with HIV who completed the California Verbal Learning Test-Second Edition (CVLT-II), the Wechsler Memory Scale-Third Edition Logical Memory subtest (WMS-III LM), and a modified Lawton and Brody ADL questionnaire. No memory predictors of IADL dependence emerged in the younger cohort. In the older group, IADL dependence was uniquely associated with worse performance on all primary CVLT-II variables, as well as elevated recency effects. Poorer immediate and delayed recall of the WMS-III LM was also associated with IADL dependence, although recognition was intact. Findings suggest older HIV-infected adults with shallow encoding and forgetting are at risk for IADL dependence. PMID:24695591

  13. Recovering the time-dependent transmission rate from infection data via solution of an inverse ODE problem

    OpenAIRE

    Pollicott, Mark; Wang, Hao; Weiss, Howie

    2009-01-01

    The transmission rate of many acute infectious diseases varies significantly in time, but the underlying mechanisms are usually uncertain. They may include seasonal changes in the environment, contact rate, immune system response, etc. The transmission rate has been thought difficult to measure directly. We present a new algorithm to compute the time-dependent transmission rate directly from prevalence data, which makes no assumptions about the number of susceptibles or vital rates. The algor...

  14. Burkholderia thailandensis harbors two identical rhl gene clusters responsible for the biosynthesis of rhamnolipids

    Directory of Open Access Journals (Sweden)

    Woods Donald E

    2009-12-01

    Full Text Available Abstract Background Rhamnolipids are surface active molecules composed of rhamnose and β-hydroxydecanoic acid. These biosurfactants are produced mainly by Pseudomonas aeruginosa and have been thoroughly investigated since their early discovery. Recently, they have attracted renewed attention because of their involvement in various multicellular behaviors. Despite this high interest, only very few studies have focused on the production of rhamnolipids by Burkholderia species. Results Orthologs of rhlA, rhlB and rhlC, which are responsible for the biosynthesis of rhamnolipids in P. aeruginosa, have been found in the non-infectious Burkholderia thailandensis, as well as in the genetically similar important pathogen B. pseudomallei. In contrast to P. aeruginosa, both Burkholderia species contain these three genes necessary for rhamnolipid production within a single gene cluster. Furthermore, two identical, paralogous copies of this gene cluster are found on the second chromosome of these bacteria. Both Burkholderia spp. produce rhamnolipids containing 3-hydroxy fatty acid moieties with longer side chains than those described for P. aeruginosa. Additionally, the rhamnolipids produced by B. thailandensis contain a much larger proportion of dirhamnolipids versus monorhamnolipids when compared to P. aeruginosa. The rhamnolipids produced by B. thailandensis reduce the surface tension of water to 42 mN/m while displaying a critical micelle concentration value of 225 mg/L. Separate mutations in both rhlA alleles, which are responsible for the synthesis of the rhamnolipid precursor 3-(3-hydroxyalkanoyloxyalkanoic acid, prove that both copies of the rhl gene cluster are functional, but one contributes more to the total production than the other. Finally, a double ΔrhlA mutant that is completely devoid of rhamnolipid production is incapable of swarming motility, showing that both gene clusters contribute to this phenotype. Conclusions Collectively, these

  15. Draft genome sequence of Burkholderia sordidicola S170, a potential plant growth promoter isolated from coniferous forest soil in the Czech Republic

    DEFF Research Database (Denmark)

    Lladó, Salvador; Xu, Zhuofei; Sørensen, Søren Johannes;

    2014-01-01

    Burkholderia species are key players in the accumulation of carbon from cellulose decomposition in coniferous forest ecosystems. We report here the draft genome of Burkholderia sordidicola strain S170, containing features associated with known genes involved in plant growth promotion, the biologi...

  16. Detection of Burkholderia pseudomallei in Sputum using Selective Enrichment Broth and Ashdown’s Medium at Kampong Cham Provincial Hospital, Cambodia [v1; ref status: indexed, http://f1000r.es/4w7

    Directory of Open Access Journals (Sweden)

    Somary Nhem

    2014-12-01

    Full Text Available Melioidosis infection, caused by Burkholderia pseudomallei, is increasingly reported in Cambodia. We hypothesized that implementation of an enhanced sputum testing protocol in a provincial hospital diagnostic microbiology laboratory would increase detection of B. pseudomallei. We tested 241 sputum specimens that were deemed acceptable for culture, comparing culture in selective enrichment broth followed by sub-culture on Ashdown’s medium to standard culture methods. Two specimens (0.8% were positive for B. pseudomallei using the enhanced protocol whereas one specimen (0.4% was positive using standard methods. These findings demonstrate that B. pseudomallei is rarely detected in sputum at this hospital. The low frequency of B. pseudomallei in sputum specimens precludes drawing any conclusions about the relative benefits of an enhanced sputum testing protocol at this site. Promoting clinician awareness of the infection and encouraging utilization of diagnostic microbiology services are likely to be important factors in facilitating identification of melioidosis.

  17. Patent filarial infection modulates malaria-specific type 1 cytokine responses in an IL-10-dependent manner in a filaria/malaria-coinfected population.

    Science.gov (United States)

    Metenou, Simon; Dembélé, Benoit; Konate, Siaka; Dolo, Housseini; Coulibaly, Siaka Y; Coulibaly, Yaya I; Diallo, Abdallah A; Soumaoro, Lamine; Coulibaly, Michel E; Sanogo, Dramane; Doumbia, Salif S; Wagner, Marissa; Traoré, Sekou F; Klion, Amy; Mahanty, Siddhartha; Nutman, Thomas B

    2009-07-15

    The effect of filarial infections on malaria-specific immune responses was investigated in Malian villages coendemic for filariasis (Fil) and malaria. Cytokines were measured from plasma and Ag-stimulated whole blood from individuals with Wuchereria bancrofti and/or Mansonella perstans infections (Fil(+); n = 19) and those without evidence of filarial infection (Fil(-); n = 19). Plasma levels of IL-10 (geometric mean [GM], 22.8 vs 10.4) were higher in Fil(+) compared with Fil(-), whereas levels of IFN-inducible protein (IP)-10 were lower in Fil(+) (GM, 66.3 vs 110.0). Fil(+) had higher levels of spontaneously secreted IL-10 (GM, 59.3 vs 6.8 pg/ml) and lower levels of IL-2 (1.0 vs 1.2 pg/ml) than did Fil(-). Although there were no differences in levels of Staphylococcus aureus enterotoxin B-induced cytokines between the two groups, Fil(+) mounted lower IL-12p70 (GM, 1.11 vs 3.83 pg/ml; p = 0.007), IFN-gamma (GM, 5.44 vs 23.41 pg/ml; p = 0.009), and IP-10 (GM, 29.43 vs 281.7 pg/ml; p = 0.007) responses following malaria Ag (MalAg) stimulation compared with Fil(-). In contrast, Fil(+) individuals had a higher MalAg-specific IL-10 response (GM, 7318 pg/ml vs 3029 pg/ml; p = 0.006) compared with those without filarial infection. Neutralizing Ab to IL-10 (but not to TGFbeta) reversed the down-regulated MalAg-specific IFN-gamma and IP-10 (p < 0.001) responses in Fil(+). Together, these data demonstrate that filarial infections modulate the Plasmodium falciparum-specific IL-12p70/IFN-gamma secretion pathways known to play a key role in resistance to malaria and that they do so in an IL-10-dependent manner. PMID:19561105

  18. Non-medical use of opioids among HIV-infected opioid dependent individuals on opioid maintenance treatment: the need for a more comprehensive approach

    Directory of Open Access Journals (Sweden)

    Roux Perrine

    2011-11-01

    Full Text Available Abstract Background Opioid maintenance treatment (OMT has a positive impact on substance use and health outcomes among HIV-infected opioid dependent patients. The present study investigates non-medical use of opioids by HIV-infected opioid-dependent individuals treated with buprenorphine or methadone. Methods The MANIF 2000 study is a longitudinal study that enrolled a cohort of 476 HIV-infected opioid-dependent individuals. Data were collected in outpatient hospital services delivering HIV care in France. The sample comprised all patients receiving OMT (either methadone or buprenorphine who attended at least one follow-up visit with data on adherence to OMT (N = 235 patients, 1056 visits. Non-medical use of opioids during OMT was defined as having reported use of opioids in a non-medical context, and/or the misuse of the prescribed oral OMT by an inappropriate route of administration (injection or sniffing. After adjusting for the non-random assignment of OMT type, a model based on GEE was then used to identify predictors of non-medical use of opioids. Results Among the 235 patients, 144 (61.3% and 91 (38.9% patients were receiving buprenorphine and methadone, respectively, at baseline. Non-medical use of opioids was found in 41.6% of visits for 83% of individual patients. In the multivariate analysis, predictors of non-medical use of opioids were: cocaine, daily cannabis, and benzodiazepine use, experience of opioid withdrawal symptoms, and less time since OMT initiation. Conclusions Non-medical use of opioids was found to be comparable in OMT patients receiving methadone or buprenorphine. The presence of opioid withdrawal symptoms was a determinant of non-medical use of opioids and may serve as a clinical indicator of inadequate dosage, medication, or type of follow-up. Sustainability and continuity of care with adequate monitoring of withdrawal symptoms and polydrug use may contribute to reduced harms from ongoing non-medical use of opioids.

  19. In Vitro Pharmacodynamics of Levofloxacin and Other Aerosolized Antibiotics under Multiple Conditions Relevant to Chronic Pulmonary Infection in Cystic Fibrosis ▿

    OpenAIRE

    King, Paula; Lomovskaya, Olga; Griffith, David C.; Burns, Jane L.; Dudley, Michael N.

    2009-01-01

    The inhalational administration of antibiotics can provide high concentrations locally in the lungs of cystic fibrosis patients and, thus, can be useful for the treatment of chronic bacterial infections. The present study evaluated the in vitro activities of levofloxacin, ciprofloxacin, tobramycin, amikacin, and aztreonam against clinical isolates of Pseudomonas aeruginosa, Burkholderia cepacia complex, Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and Staphylococcus aureus from cys...

  20. Understanding regulation of the host-mediated gut symbiont population and the symbiont-mediated host immunity in the Riptortus-Burkholderia symbiosis system.

    Science.gov (United States)

    Kim, Jiyeun Kate; Lee, Jun Beom; Jang, Ho Am; Han, Yeon Soo; Fukatsu, Takema; Lee, Bok Luel

    2016-11-01

    Valuable insect models have tremendously contributed to our understanding of innate immunity and symbiosis. Bean bug, Riptortus pedestris, is a useful insect symbiosis model due to harboring cultivable monospecific gut symbiont, genus Burkholderia. Bean bug is a hemimetabolous insect whose immunity is not well-understood. However, we recently identified three major antimicrobial peptides of Riptortus and examined the relationship between gut symbiosis and host immunity. We found that the presence of Burkholderia gut symbiont positively affects Riptortus immunity. From studying host regulation mechanisms of symbiont population, we revealed that the symbiotic Burkholderia cells are much more susceptible to Riptortus immune responses than the cultured cells. We further elucidated that the immune-susceptibility of the Burkholderia gut symbionts is due to the drastic change of bacterial cell envelope. Finally, we show that the immune-susceptible Burkholderia symbionts are able to prosper in host owing to the suppression of immune responses of the symbiotic midgut. PMID:26774501