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Burkholderia species infections in patients with cystic fibrosis in British Columbia, Canada. 30 years' experience. Ann Am Thorac Soc 2015; 12:70-8. [PMID: 25474359 DOI: 10.1513/annalsats.201408-395oc] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE We have been collecting Burkholderia species bacteria from patients with cystic fibrosis (CF) for the last 30 years. During this time, our understanding of their multispecies taxonomy and infection control has evolved substantially. OBJECTIVES To evaluate the long-term (30 year) epidemiology and clinical outcome of Burkholderia infection in CF, and fully define the risks associated with infection by each species. METHODS Isolates from Burkholderia-positive patients (n=107) were speciated and typed annually for each infected patient. Microbiological and clinical data were evaluated by thorough review of patient charts, and statistical analyses performed to define significant epidemiological factors. MEASUREMENTS AND MAIN RESULTS Before 1995, the majority of new Burkholderia infections were caused by epidemic clones of Burkholderia cenocepacia. After implementation of new infection control measures in 1995, Burkholderia multivorans became the most prevalent species. Survival analysis showed that patients with CF infected with B. cenocepacia had a significantly worse outcome than those with B. multivorans, and a novel finding was that, after Burkholderia infection, the prognosis for females was significantly worse than for males. CONCLUSIONS B. multivorans and B. cenocepacia have been the predominant Burkholderia species infecting people with CF in Vancouver. The implementation of infection control measures were successful in preventing new acquisition of epidemic strains of B. cenocepacia, leaving nonclonal B. multivorans as the most prevalent species. Historically, survival after infection with B. cenocepacia has been significantly worse than B. multivorans infection, and, of new significance, we show that females tend toward worse clinical outcomes.
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Tyrosine Phosphorylation and Dephosphorylation in Burkholderia cenocepacia Affect Biofilm Formation, Growth under Nutritional Deprivation, and Pathogenicity. Appl Environ Microbiol 2015; 82:843-56. [PMID: 26590274 DOI: 10.1128/aem.03513-15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 11/14/2015] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cenocepacia, a member of the B. cepacia complex (Bcc), is an opportunistic pathogen causing serious chronic infections in patients with cystic fibrosis. Tyrosine phosphorylation has emerged as an important posttranslational modification modulating the physiology and pathogenicity of Bcc bacteria. Here, we investigated the predicted bacterial tyrosine kinases BCAM1331 and BceF and the low-molecular-weight protein tyrosine phosphatases BCAM0208, BceD, and BCAL2200 of B. cenocepacia K56-2. We show that BCAM1331, BceF, BCAM0208, and BceD contribute to biofilm formation, while BCAL2200 is required for growth under nutrient-limited conditions. Multiple deletions of either tyrosine kinase or low-molecular-weight protein tyrosine phosphatase genes resulted in the attenuation of B. cenocepacia intramacrophage survival and reduced pathogenicity in the Galleria mellonella larval infection model. Experimental evidence indicates that BCAM1331 displays reduced tyrosine autophosphorylation activity compared to that of BceF. With the artificial substrate p-nitrophenyl phosphate, the phosphatase activities of the three low-molecular-weight protein tyrosine phosphatases demonstrated similar kinetic parameters. However, only BCAM0208 and BceD could dephosphorylate BceF. Further, BCAL2200 became tyrosine phosphorylated in vivo and catalyzed its autodephosphorylation. Together, our data suggest that despite having similar biochemical activities, low-molecular-weight protein tyrosine phosphatases and tyrosine kinases have both overlapping and specific roles in the physiology of B. cenocepacia.
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Gonyar LA, Fankhauser SC, Goldberg JB. Single amino acid substitution in homogentisate 1,2-dioxygenase is responsible for pigmentation in a subset of Burkholderia cepacia complex isolates. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:180-187. [PMID: 25294803 PMCID: PMC4560265 DOI: 10.1111/1758-2229.12217] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 09/13/2014] [Indexed: 06/03/2023]
Abstract
The Burkholderia cepacia complex (Bcc) is a group of Gram-negative bacilli that are ubiquitous in the environment and have emerged over the past 30 years as opportunistic pathogens in immunocompromised populations, specifically individuals with cystic fibrosis (CF) and chronic granulomatous disease. This complex of at least 18 distinct species is phenotypically and genetically diverse. One phenotype observed in a subset of Burkholderia cenocepacia (a prominent Bcc pathogen) isolates is the ability to produce a melanin-like pigment. Melanins have antioxidant properties and have been shown to act as virulence factors allowing pathogens to resist killing by the host immune system. The melanin-like pigment expressed by B. cenocepacia is produced through tyrosine catabolism, specifically through the autoxidation and polymerization of homogentisate. Burkholderia cenocepacia J2315 is a CF clinical isolate that displays a pigmented phenotype when grown under normal laboratory conditions. We examined the amino acid sequences of critical enzymes in the melanin synthesis pathway in pigmented and non-pigmented Bcc isolates, and found that an amino acid substitution of glycine for arginine at amino acid 378 in homogentisate 1,2-dioxygenase correlated with pigment production; we identify this as one mechanism for expression of pigment in Bcc isolates.
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Affiliation(s)
- Laura A. Gonyar
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
| | - Sarah C. Fankhauser
- Department of Pediatrics, Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA
| | - Joanna B. Goldberg
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA, USA
- Department of Pediatrics, Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, GA, USA
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Chmiel JF, Aksamit TR, Chotirmall SH, Dasenbrook EC, Elborn JS, LiPuma JJ, Ranganathan SC, Waters VJ, Ratjen FA. Antibiotic management of lung infections in cystic fibrosis. II. Nontuberculous mycobacteria, anaerobic bacteria, and fungi. Ann Am Thorac Soc 2014; 11:1298-306. [PMID: 25167882 PMCID: PMC5469357 DOI: 10.1513/annalsats.201405-203as] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 08/07/2014] [Indexed: 01/05/2023] Open
Abstract
Airway infections are a key component of cystic fibrosis (CF) lung disease. Whereas the approach to common pathogens such as Pseudomonas aeruginosa is guided by a significant body of evidence, other infections often pose a considerable challenge to treating physicians. In Part I of this series on the antibiotic management of difficult lung infections, we discussed bacterial organisms including methicillin-resistant Staphylococcus aureus, gram-negative bacterial infections, and treatment of multiple bacterial pathogens. Here, we summarize the approach to infections with nontuberculous mycobacteria, anaerobic bacteria, and fungi. Nontuberculous mycobacteria can significantly impact the course of lung disease in patients with CF, but differentiation between colonization and infection is difficult clinically as coinfection with other micro-organisms is common. Treatment consists of different classes of antibiotics, varies in intensity, and is best guided by a team of specialized clinicians and microbiologists. The ability of anaerobic bacteria to contribute to CF lung disease is less clear, even though clinical relevance has been reported in individual patients. Anaerobes detected in CF sputum are often resistant to multiple drugs, and treatment has not yet been shown to positively affect patient outcome. Fungi have gained significant interest as potential CF pathogens. Although the role of Candida is largely unclear, there is mounting evidence that Scedosporium species and Aspergillus fumigatus, beyond the classical presentation of allergic bronchopulmonary aspergillosis, can be relevant in patients with CF and treatment should be considered. At present, however there remains limited information on how best to select patients who could benefit from antifungal therapy.
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Affiliation(s)
- James F. Chmiel
- Department of Pediatrics, Case Western Reserve University School of Medicine and Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Timothy R. Aksamit
- Division of Pulmonary Disease and Critical Care Medicine, Department of Medicine, Mayo Clinic, Rochester, Minnesota
| | - Sanjay H. Chotirmall
- Department of Respiratory Medicine, Beaumont Hospital, Dublin, Republic of Ireland and Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Elliott C. Dasenbrook
- Departments of Medicine and Pediatrics, Case Western Reserve University School of Medicine and University Hospitals Case Medical Center, Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - J. Stuart Elborn
- Medicine and Surgery, Queens University Belfast and Belfast City Hospital, Belfast, Northern Ireland, United Kingdom
| | - John J. LiPuma
- Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan
| | - Sarath C. Ranganathan
- Department of Respiratory Medicine, Royal Children’s Hospital, Infection and Immunity Theme, Murdoch Children’s Research Institute, and Department of Pediatrics, University of Melbourne, Melbourne, Australia; and
| | | | - Felix A. Ratjen
- Division of Respiratory Medicine, Department of Pediatrics, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
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Eradication of Burkholderia cepacia Using Inhaled Aztreonam Lysine in Two Patients with Bronchiectasis. Case Rep Pulmonol 2014; 2014:192146. [PMID: 25295210 PMCID: PMC4175385 DOI: 10.1155/2014/192146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 08/01/2014] [Indexed: 11/18/2022] Open
Abstract
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.
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Andrade A, Valvano MA. A Burkholderia cenocepacia gene encoding a non-functional tyrosine phosphatase is required for the delayed maturation of the bacteria-containing vacuoles in macrophages. Microbiology (Reading) 2014; 160:1332-1345. [DOI: 10.1099/mic.0.077206-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Burkholderia cenocepacia infects patients with cystic fibrosis. We have previously shown that B. cenocepacia can survive in macrophages within membrane vacuoles [B. cenocepacia-containing vacuoles (BcCVs)] that preclude fusion with the lysosome. The bacterial factors involved in B. cenocepacia intracellular survival are not fully elucidated. We report here that deletion of BCAM0628, encoding a predicted low molecular weight protein tyrosine phosphatase (LMW-PTP) that is restricted to B. cenocepacia strains of the transmissible ET-12 clone, accelerates the maturation of the BcCVs. Compared to the parental strain and deletion mutants in other LMW-PTPs that are widely conserved in Burkholderia species, a greater proportion of BcCVs containing the ΔBCAM0628 mutant were targeted to the lysosome. Accelerated BcCV maturation was not due to reduced intracellular viability since ΔBCAM0628 survived and replicated in macrophages similarly to the parental strain. Therefore, BCAM0628 was referred to as dpm (delayed phagosome maturation). We provide evidence that the Dpm protein is secreted during growth in vitro and upon macrophage infection. Dpm secretion requires an N-terminal signal peptide. Heterologous expression of Dpm in Burkholderia multivorans confers to this bacterium a similar phagosomal maturation delay to that found with B. cenocepacia. We demonstrate that Dpm is an inactive phosphatase, suggesting that its contribution to phagosomal maturation arrest must be unrelated to tyrosine phosphatase activity.
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Affiliation(s)
- Angel Andrade
- Centre for Human Immunology and Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
| | - Miguel A. Valvano
- Centre for Infection and Immunity, Queen's University Belfast, Belfast BT9 5AE, UK
- Centre for Human Immunology and Department of Microbiology and Immunology, University of Western Ontario, London, ON N6A 5C1, Canada
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Costello A, Reen FJ, O'Gara F, Callaghan M, McClean S. Inhibition of co-colonizing cystic fibrosis-associated pathogens by Pseudomonas aeruginosa and Burkholderia multivorans. MICROBIOLOGY-SGM 2014; 160:1474-1487. [PMID: 24790091 DOI: 10.1099/mic.0.074203-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cystic fibrosis (CF) is a recessive genetic disease characterized by chronic respiratory infections and inflammation causing permanent lung damage. Recurrent infections are caused by Gram-negative antibiotic-resistant bacterial pathogens such as Pseudomonas aeruginosa, Burkholderia cepacia complex (Bcc) and the emerging pathogen genus Pandoraea. In this study, the interactions between co-colonizing CF pathogens were investigated. Both Pandoraea and Bcc elicited potent pro-inflammatory responses that were significantly greater than Ps. aeruginosa. The original aim was to examine whether combinations of pro-inflammatory pathogens would further exacerbate inflammation. In contrast, when these pathogens were colonized in the presence of Ps. aeruginosa the pro-inflammatory response was significantly decreased. Real-time PCR quantification of bacterial DNA from mixed cultures indicated that Ps. aeruginosa significantly inhibited the growth of Burkholderia multivorans, Burkholderia cenocepacia, Pandoraea pulmonicola and Pandoraea apista, which may be a factor in its dominance as a colonizer of CF patients. Ps. aeruginosa cell-free supernatant also suppressed growth of these pathogens, indicating that inhibition was innate rather than a response to the presence of a competitor. Screening of a Ps. aeruginosa mutant library highlighted a role for quorum sensing and pyoverdine biosynthesis genes in the inhibition of B. cenocepacia. Pyoverdine was confirmed to contribute to the inhibition of B. cenocepacia strain J2315. B. multivorans was the only species that could significantly inhibit Ps. aeruginosa growth. B. multivorans also inhibited B. cenocepacia and Pa. apista. In conclusion, both Ps. aeruginosa and B. multivorans are capable of suppressing growth and virulence of co-colonizing CF pathogens.
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Affiliation(s)
- Anne Costello
- Centre of Microbial Host Interactions, Centre of Applied Science for Health, Institute of Technology Tallaght, Old Blessington Road, Tallaght, Dublin 24, Ireland
| | - F Jerry Reen
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - Fergal O'Gara
- Curtin University, School of Biomedical Sciences, Perth, WA 6845, Australia.,BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - Máire Callaghan
- Centre of Microbial Host Interactions, Centre of Applied Science for Health, Institute of Technology Tallaght, Old Blessington Road, Tallaght, Dublin 24, Ireland
| | - Siobhán McClean
- Centre of Microbial Host Interactions, Centre of Applied Science for Health, Institute of Technology Tallaght, Old Blessington Road, Tallaght, Dublin 24, Ireland
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Mogayzel PJ, Dunitz J, Marrow LC, Hazle LA. Improving chronic care delivery and outcomes: the impact of the cystic fibrosis Care Center Network. BMJ Qual Saf 2014; 23 Suppl 1:i3-8. [DOI: 10.1136/bmjqs-2013-002363] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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59
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Denman CC, Robinson MT, Sass AM, Mahenthiralingam E, Brown AR. Growth on mannitol-rich media elicits a genome-wide transcriptional response in Burkholderia multivorans that impacts on multiple virulence traits in an exopolysaccharide-independent manner. MICROBIOLOGY-SGM 2013; 160:187-197. [PMID: 24196427 DOI: 10.1099/mic.0.072975-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In common with other members of the Burkholderia cepacia complex (BCC), Burkholderia multivorans is capable of producing exopolysaccharide (EPS) when grown on certain mannitol-rich media. The significance of the resulting mucoid phenotype and the genome-wide response to mannitol has never been characterized despite its clinical relevance following the approval of a dried-powder preparation of mannitol as an inhaled osmolyte therapy for cystic fibrosis (CF) patients. In the present study we defined the transcriptional response of B. multivorans ATCC 17616, a model genome-sequenced strain of environmental origin, to growth on mannitol-rich yeast extract media (MYEM). EPS-dependent and -independent impact of MYEM on virulence-associated traits was assessed in both strain ATCC 17616 and the CF isolate B. multivorans C1576. Our studies revealed a significant transcriptional response to MYEM encompassing approximately 23 % of predicted genes within the genome. Strikingly, this transcriptional response identified that EPS induction occurs in ATCC 17616 without the upregulation of the bce-I and bce-II EPS gene clusters, despite their pivotal role in EPS biosynthesis. Of approximately 20 differentially expressed putative virulence factors, 16 exhibited upregulation including flagella, ornibactin, oxidative stress proteins and phospholipases. MYEM-grown B. multivorans also exhibited enhanced motility, biofilm formation and epithelial cell invasion. In contrast to these potential virulence enhancements, MYEM-grown B. multivorans C1576 showed attenuated virulence in the Galleria mellonella infection model. All of the observed phenotypic responses occurred independently of EPS production, highlighting the profound impact that mannitol-based growth has on the physiology and virulence of B. multivorans.
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Affiliation(s)
- Carmen C Denman
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Matthew T Robinson
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Andrea M Sass
- Organisms & Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Eshwar Mahenthiralingam
- Organisms & Environment Division, Cardiff School of Biosciences, Cardiff University, Cardiff, UK
| | - Alan R Brown
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
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Inhaled aztreonam for chronic Burkholderia infection in cystic fibrosis: a placebo-controlled trial. J Cyst Fibros 2013; 13:296-305. [PMID: 24176390 DOI: 10.1016/j.jcf.2013.08.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 11/24/2022]
Abstract
BACKGROUND Individuals with Burkholderia spp. infection have historically been excluded from efficacy trials of inhaled antibiotics, including aztreonam for inhalation solution (AZLI). METHODS A double-blind, placebo-controlled, 24-week trial of continuous AZLI/placebo treatment was undertaken in individuals with cystic fibrosis (CF) and chronic Burkholderia spp. infection. All subjects also received usual medical care (determined by their physicians). Additional antibiotic use was not restricted. RESULTS Baseline FEV1% predicted values ranged from 15.8% to 114.6%. No significant treatment differences (AZLI vs. placebo) were observed at week 24 for any endpoints, including FEV1% predicted, number of respiratory exacerbations requiring systemic/inhaled antibiotics, or hospitalizations. Continuous AZLI administration was well tolerated. Burkholderia spp. susceptibility to antibiotics commonly used in CF therapy showed little change. CONCLUSIONS 24-weeks of continuous AZLI treatment did not significantly improve lung function in CF subjects with chronic Burkholderia spp. infection. Non-study antibiotic use may have confounded any potential AZLI effects.
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61
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Factors influencing acquisition of Burkholderia cepacia complex organisms in patients with cystic fibrosis. J Clin Microbiol 2013; 51:3975-80. [PMID: 24048536 DOI: 10.1128/jcm.01360-13] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cepacia complex organisms are important transmissible pathogens found in cystic fibrosis (CF) patients. In recent years, the rates of cross-infection of epidemic strains have declined due to effective infection control efforts. However, cases of sporadic B. cepacia complex infection continue to occur in some centers. The acquisition pathways and clinical outcomes of sporadic B. cepacia complex infection are unclear. We sought to determine the patient clinical characteristics, outcomes, incidence, and genotypic relatedness for all cases of B. cepacia complex infection at two CF centers. We also sought to study the external conditions that influence the acquisition of infection. From 2001 to 2011, 67 individual organisms were cultured from the respiratory samples of 64 patients. Sixty-five percent of the patients were adults, in whom chronic infections were more common (68%) (P = 0.006). The incidence of B. cepacia complex infection increased by a mean of 12% (95% confidence interval [CI], 3 to 23%) per year. The rates of transplantation and death were similar in the incident cases who developed chronic infection compared to those in patients with chronic Pseudomonas aeruginosa infection. Multilocus sequence typing revealed 50 individual strains from 65 isolates. Overall, 85% of the patients were infected with unique strains, suggesting sporadic acquisition of infection. The yearly incidence of nonepidemic B. cepacia complex infection was positively correlated with the amount of rainfall in the two sites examined: subtropical Brisbane (r = 0.65, P = 0.031) and tropical Townsville (r = 0.82, P = 0.002). This study demonstrates that despite strict cohort segregation, new cases of unrelated B. cepacia complex infection continue to occur. These data also support an environmental origin of infection and suggest that climate conditions may be associated with the acquisition of B. cepacia complex infections.
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Waters V, Atenafu EG, Lu A, Yau Y, Tullis E, Ratjen F. Chronic Stenotrophomonas maltophilia infection and mortality or lung transplantation in cystic fibrosis patients. J Cyst Fibros 2013; 12:482-6. [DOI: 10.1016/j.jcf.2012.12.006] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 12/05/2012] [Accepted: 12/11/2012] [Indexed: 11/17/2022]
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Horsley A, Jones AM. Antibiotic treatment for Burkholderia cepacia complex in people with cystic fibrosis experiencing a pulmonary exacerbation. Cochrane Database Syst Rev 2012; 10:CD009529. [PMID: 23076960 DOI: 10.1002/14651858.cd009529.pub2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Chronic pulmonary infection is one of the hallmarks of lung disease in cystic fibrosis. Infections dominated by organisms of the Burkholderia cepacia complex, a group of at least 17 closely-related species of gram-negative bacteria, are particularly difficult to treat. These infections may be associated with a fulminant necrotising pneumonia, and are greatly feared by patients. Burkholderia cepacia bacteria are innately resistant to many common antibiotics and able to acquire resistance against many more. Since strict patient segregation was introduced to cystic fibrosis medical care, the incidence of the more virulent epidemic strains has fallen, and new infections are more likely to be with environmentally-acquired strains which seem to exhibit less virulence. Nonetheless, exacerbations of respiratory symptoms require effective therapy directed against the dominant bacterial species. Although evidence-based guidelines exist for the treatment of respiratory exacerbations involving Pseudomonas aeruginosa, the most common chronic infection in cystic fibrosis, these cannot be directly extended to Burkholderia cepacia complex infections. The aim of this review is to assess the available trial evidence for choice and application of treatments for Burkholderia cepacia complex infections. OBJECTIVES To assess the effectiveness and safety of different antibiotic regimens in people with cystic fibrosis experiencing an exacerbation, who are chronically infected with organisms of the Burkholderia cepacia complex. SEARCH METHODS We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched the reference lists of relevant articles and reviews.Date of latest search: 29 November 2011. SELECTION CRITERIA Randomised and quasi-randomised controlled trials of treatments for exacerbations of pulmonary symptoms in cystic fibrosis patients chronically infected with organisms of the Burkholderia cepacia complex. DATA COLLECTION AND ANALYSIS No relevant trials were identified. MAIN RESULTS No trials were included in this review. AUTHORS' CONCLUSIONS Burkholderia cepacia complex infections present a significant challenge for cystic fibrosis clinicians and patients alike. The incidence is likely to increase as the cystic fibrosis population ages and the problem of how to manage and treat these infections becomes more important. There is a lack of trial evidence to guide decision making and no conclusions can be drawn from this review about the optimal antibiotic regimens for cystic fibrosis patients with chronic Burkholderia cepacia complex infections. Clinicians must continue to assess each patient individually, taking into account in vitro antibiotic susceptibility data, previous clinical responses and their own experience. There is a clear need for multi-centre randomised clinical trials to assess the effectiveness of different antibiotic regimens in cystic fibrosis patients infected with organisms of the Burkholderia cepacia complex.
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Affiliation(s)
- Alex Horsley
- School of Translational Medicine, University Hospital of South Manchester, Manchester, UK.
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64
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Tolman JS, Valvano MA. Global changes in gene expression by the opportunistic pathogen Burkholderia cenocepacia in response to internalization by murine macrophages. BMC Genomics 2012; 13:63. [PMID: 22321740 PMCID: PMC3296584 DOI: 10.1186/1471-2164-13-63] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 02/09/2012] [Indexed: 12/18/2022] Open
Abstract
Background Burkholderia cenocepacia is an opportunistic pathogen causing life-threatening infections in patients with cystic fibrosis. The bacterium survives within macrophages by interfering with endocytic trafficking and delaying the maturation of the B. cenocepacia-containing phagosome. We hypothesize that B. cenocepacia undergoes changes in gene expression after internalization by macrophages, inducing genes involved in intracellular survival and host adaptation. Results We examined gene expression by intracellular B. cenocepacia using selective capture of transcribed sequences (SCOTS) combined with microarray analysis. We identified 767 genes with significantly different levels of expression by intracellular bacteria, of which 330 showed increased expression and 437 showed decreased expression. Affected genes represented all aspects of cellular life including information storage and processing, cellular processes and signaling, and metabolism. In general, intracellular gene expression demonstrated a pattern of environmental sensing, bacterial response, and metabolic adaptation to the phagosomal environment. Deletion of various SCOTS-identified genes affected bacterial entry into macrophages and intracellular replication. We also show that intracellular B. cenocepacia is cytotoxic towards the macrophage host, and capable of spread to neighboring cells, a role dependent on SCOTS-identified genes. In particular, genes involved in bacterial motility, cobalamin biosynthesis, the type VI secretion system, and membrane modification contributed greatly to macrophage entry and subsequent intracellular behavior of B. cenocepacia. Conclusions B. cenocepacia enters macrophages, adapts to the phagosomal environment, replicates within a modified phagosome, and exhibits cytotoxicity towards the host cells. The analysis of the transcriptomic response of intracellular B. cenocepacia reveals that metabolic adaptation to a new niche plays a major role in the survival of B. cenocepacia in macrophages. This adaptive response does not require the expression of any specific virulence-associated factor, which is consistent with the opportunistic nature of this microorganism. Further investigation into the remaining SCOTS-identified genes will provide a more complete picture of the adaptive response of B. cenocepacia to the host cell environment.
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Affiliation(s)
- Jennifer S Tolman
- Infectious Diseases Research Group, Department of Microbiology & Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
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65
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Bedini E, Cirillo L, Parrilli M. Synthesis of the trisaccharide outer core fragment of Burkholderia cepacia pv. vietnamiensis lipooligosaccharide. Carbohydr Res 2012; 349:24-32. [DOI: 10.1016/j.carres.2011.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 11/29/2011] [Accepted: 12/06/2011] [Indexed: 10/14/2022]
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Ganesan S, Sajjan US. Host evasion by Burkholderia cenocepacia. Front Cell Infect Microbiol 2012; 1:25. [PMID: 22919590 PMCID: PMC3417383 DOI: 10.3389/fcimb.2011.00025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 12/22/2011] [Indexed: 11/13/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic respiratory pathogen of individuals with cystic fibrosis (CF). Some strains of B. cenocepacia are highly transmissible and resistant to almost all antibiotics. Approximately one-third of B. cenocepacia infected CF patients go on to develop fatal "cepacia syndrome." During the last two decades, substantial progress has been made with regards to evasion of host innate defense mechanisms by B. cenocepacia. Almost all strains of B. cenocepacia have the capacity to survive and replicate intracellularly in both airway epithelial cells and macrophages, which are primary sentinels of the lung and play a pivotal role in clearance of infecting bacteria. Those strains of B. cenocepacia, which express both cable pili and the associated 22 kDa adhesin are also capable of transmigrating across airway epithelium and persist in mouse models of infection. In this review, we will discuss how this type of interaction between B. cenocepacia and host may lead to persistence of bacteria as well as lung inflammation in CF patients.
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Affiliation(s)
- Shyamala Ganesan
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI, USA
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67
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Horsley A, Webb K, Bright-Thomas R, Govan J, Jones A. Can early Burkholderia cepacia complex infection in cystic fibrosis be eradicated with antibiotic therapy? Front Cell Infect Microbiol 2011; 1:18. [PMID: 22919584 PMCID: PMC3417365 DOI: 10.3389/fcimb.2011.00018] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 11/30/2011] [Indexed: 11/13/2022] Open
Abstract
Introduction: Organisms of the Burkholderia cepacia complex (BCC) are important pathogens in cystic fibrosis (CF). The majority of those who acquire BCC develop chronic infection but it can also result in rapid decline in a significant minority. In addition, chronic infection with Burkholderia cenocepacia in particular is regarded as a contraindication to lung transplantation in many units. Whilst aggressive antibiotic therapy is employed in CF to eradicate Pseudomonas aeruginosa before infection becomes irreversibly established, no formal assessment of such strategies has been previously reported for BCC, despite the apparent widespread adoption of this practice. Methods: UK adult CF centers were surveyed about their current approach to new BCC infection. Outcomes of eradication therapy were assessed in patients attending the Manchester Adult CF Center with new BCC isolates between 1st January 2002 and 1st May 2011. Patients with previous infection with the same strain of BCC were excluded. BCC were identified at the national reference laboratories and confirmed by species-specific PCR and RecA sequencing. Results: Routine use of therapies to attempt eradication of new BCC is commonly used in the UK (12/17 centers who responded). This typically involves a combination of intravenous and nebulised antibiotics. Of 19 eligible cases of new BCC infection, the organism has been eradicated in 7 (37%). Three of these did not receive specific eradication therapy. Of 14 patients who have received eradication therapy and completed follow up, BCC were cleared in only 4 (29%). Conclusions: Attempted eradication of new BCC is a common practice in UK adult CF centers. A minority of patients clear the infection spontaneously and the effects of eradication therapies are at best modest. Early treatment may be associated with better outcomes, though there are insufficient data to support the use of any specific treatment regimen. A prospective, systematic evaluation of treatments and outcomes is required.
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Affiliation(s)
- Alex Horsley
- Manchester Adult Cystic Fibrosis Center, University Hospitals South Manchester Manchester, UK; Respiratory Research Group, School of Translational Medicine, University of Manchester, Manchester, UK.
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Kirkby S, Novak K, McCoy K. Aztreonam (for inhalation solution) for the treatment of chronic lung infections in patients with cystic fibrosis: an evidence-based review. CORE EVIDENCE 2011; 6:59-66. [PMID: 22022288 PMCID: PMC3195667 DOI: 10.2147/ce.s11181] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Indexed: 12/04/2022]
Abstract
Cystic fibrosis (CF) is a genetic disease caused by abnormal chloride transport across cellular membranes. In the respiratory tract, this molecular defect causes obstruction of the airways by mucus and chronic endobronchial infection. The majority of patients suffer early death from chronic respiratory disease. Pseudomonas aeruginosa is the predominant chronic airway pathogen in older children and adults with CF and is associated with worse outcomes. However, overall survival in CF has been greatly improved in recent decades due in large part to the aggressive treatment of chronic infections such as P. aeruginosa. While intravenous and oral antibiotics are commonly used in the management of CF respiratory infections, inhaled anti-infective therapies offer the benefit of delivering the drug directly to the site of infection and avoiding potential toxicities associated with systemic absorption. Aztreonam lysine (AZLI) has recently been developed as an inhaled antibiotic for chronic use in CF patients with endobronchial P. aeruginosa infection. This paper reviews background data and the clinical studies which contributed to AZLI’s formal FDA approval and growing role in the management of CF pulmonary disease.
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Affiliation(s)
- Stephen Kirkby
- Section of Pulmonary Medicine, Nationwide Children's Hospital
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69
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Hauser AR, Jain M, Bar-Meir M, McColley SA. Clinical significance of microbial infection and adaptation in cystic fibrosis. Clin Microbiol Rev 2011; 24:29-70. [PMID: 21233507 PMCID: PMC3021203 DOI: 10.1128/cmr.00036-10] [Citation(s) in RCA: 287] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.
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Affiliation(s)
- Alan R Hauser
- Department of Microbiology/Immunology, Northwestern University, 303 E. Chicago Ave., Searle 6-495, Chicago, IL 60611, USA.
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Lynch KH, Stothard P, Dennis JJ. Genomic analysis and relatedness of P2-like phages of the Burkholderia cepacia complex. BMC Genomics 2010; 11:599. [PMID: 20973964 PMCID: PMC3091744 DOI: 10.1186/1471-2164-11-599] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 10/25/2010] [Indexed: 01/24/2023] Open
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 first BCC-specific phages to be identified as P2-like. As KS14 has previously been shown to be active against Burkholderia cenocepacia in vivo, genomic characterization of these phages is a crucial first step in the development of these and similar phages for clinical use against the BCC.
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Affiliation(s)
- Karlene H Lynch
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
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Green DM, McDougal KE, Blackman SM, Sosnay PR, Henderson LB, Naughton KM, Collaco JM, Cutting GR. Mutations that permit residual CFTR function delay acquisition of multiple respiratory pathogens in CF patients. Respir Res 2010; 11:140. [PMID: 20932301 PMCID: PMC2964615 DOI: 10.1186/1465-9921-11-140] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 10/08/2010] [Indexed: 12/22/2022] Open
Abstract
Background Lung infection by various organisms is a characteristic feature of cystic fibrosis (CF). CFTR genotype effects acquisition of Pseudomonas aeruginosa (Pa), however the effect on acquisition of other infectious organisms that frequently precede Pa is relatively unknown. Understanding the role of CFTR in the acquisition of organisms first detected in patients may help guide symptomatic and molecular-based treatment for CF. Methods Lung infection, defined as a single positive respiratory tract culture, was assessed for 13 organisms in 1,381 individuals with CF. Subjects were divided by predicted CFTR function: 'Residual': carrying at least one partial function CFTR mutation (class IV or V) and 'Minimal' those who do not carry a partial function mutation. Kaplan-Meier estimates were created to assess CFTR effect on age of acquisition for each organism. Cox proportional hazard models were performed to control for possible cofactors. A separate Cox regression was used to determine whether defining infection with Pa, mucoid Pa or Aspergillus (Asp) using alternative criteria affected the results. The influence of severity of lung disease at the time of acquisition was evaluated using stratified Cox regression methods by lung disease categories. Results Subjects with 'Minimal' CFTR function had a higher hazard than patients with 'Residual' function for acquisition of 9 of 13 organisms studied (HR ranging from 1.7 to 3.78 based on the organism studied). Subjects with minimal CFTR function acquired infection at a younger age than those with residual function for 12 of 13 organisms (p-values ranging: < 0.001 to 0.017). Minimal CFTR function also associated with younger age of infection when 3 alternative definitions of infection with Pa, mucoid Pa or Asp were employed. Risk of infection is correlated with CFTR function for 8 of 9 organisms in patients with good lung function (>90%ile) but only 1 of 9 organisms in those with poorer lung function (<50%ile). Conclusions Residual CFTR function correlates with later onset of respiratory tract infection by a wide spectrum of organisms frequently cultured from CF patients. The protective effect conferred by residual CFTR function is diminished in CF patients with more advanced lung disease.
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Affiliation(s)
- Deanna M Green
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Greenberg DE, Marshall-Batty KR, Brinster LR, Zarember KA, Shaw PA, Mellbye BL, Iversen PL, Holland SM, Geller BL. Antisense phosphorodiamidate morpholino oligomers targeted to an essential gene inhibit Burkholderia cepacia complex. J Infect Dis 2010; 201:1822-30. [PMID: 20438352 DOI: 10.1086/652807] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Members of the Burkholderia cepacia complex (Bcc) cause considerable morbidity and mortality in patients with chronic granulomatous disease and cystic fibrosis. Many Bcc strains are antibiotic resistant, which requires the exploration of novel antimicrobial approaches, including antisense technologies such as phosphorodiamidate morpholino oligomers (PMOs). METHODS Peptide-conjugated PMOs (PPMOs) were developed to target acpP, which encodes an acyl carrier protein (AcpP) that is thought to be essential for growth. Their antimicrobial activities were tested against different strains of Bcc in vitro and in infection models. RESULTS PPMOs targeting acpP were bactericidal against clinical isolates of Bcc (>4 log reduction), whereas a PPMO with a scrambled base sequence (scrambled PPMO) had no effect on growth. Human neutrophils were infected with Burkholderia multivorans and treated with AcpP PPMO. AcpP PPMO augmented killing, compared with neutrophils alone and compared with neutrophils alone plus scrambled PPMO. Mice with chronic granulomatous disease that were infected with B. multivorans were treated with AcpP PPMO, scrambled PPMO, or water at 0, 3, and 6 h after infection. Compared with water-treated control mice, the AcpP PPMO-treated mice showed an approximately 80% reduction in the risk of dying by day 30 of the experiment and relatively little pathology. CONCLUSION AcpP PPMO is active against Bcc infections in vitro and in vivo.
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Affiliation(s)
- David E Greenberg
- Immunopathogenesis Section, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, Office of Research Services, National Institutes of Health, Bethesda, Maryland, USA.
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A TNF-like trimeric lectin domain from Burkholderia cenocepacia with specificity for fucosylated human histo-blood group antigens. Structure 2010; 18:59-72. [PMID: 20152153 DOI: 10.1016/j.str.2009.10.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/03/2009] [Accepted: 10/22/2009] [Indexed: 11/23/2022]
Abstract
The opportunistic pathogen Burkholderia cenocepacia expresses several soluble lectins, among them BC2L-C. This lectin exhibits two domains: a C-terminal domain with high sequence similarity to the recently described calcium-dependent mannose-binding lectin BC2L-A, and an N-terminal domain of 156 amino acids without similarity to any known protein. The recombinant N-terminal BC2L-C domain is a new lectin with specificity for fucosylated human histo-blood group epitopes H-type 1, Lewis b, and Lewis Y, as determined by glycan array and isothermal titration calorimetry. Methylselenofucoside was used as ligand to solve the crystal structure of the N-terminal BC2L-C domain. Additional molecular modeling studies rationalized the preference for Lewis epitopes. The structure reveals a trimeric jellyroll arrangement with striking similarity to TNF-like proteins, and to BclA, the spore protein from Bacillus anthracis which may play an important role in bioadhesion of anthrax spores in human lungs.
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The Burkholderia cenocepacia K56-2 pleiotropic regulator Pbr, is required for stress resistance and virulence. Microb Pathog 2010; 48:168-77. [PMID: 20206249 DOI: 10.1016/j.micpath.2010.02.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2010] [Revised: 02/22/2010] [Accepted: 02/25/2010] [Indexed: 11/23/2022]
Abstract
Burkholderia cenocepacia is one of the most virulent species of the Burkholderia cepacia complex, a group of bacteria that emerged as important pathogens, especially to cystic fibrosis (CF) patients. In this study, we report the identification and characterization of a mutant strain derived form the CF isolate Burkholderia cenocepacia K56-2, carrying a plasposon insertion in a gene, located in a 3516 bp chromosomal region with an atypical G+C content, encoding a 80 amino acid putative regulatory protein named Pbr. Besides its inability to produce phenazines, the B. cenocepacia K56-2 pbr mutant exhibited a pleiotropic phenotype, including impaired survival to oxidative and osmotic stress, aromatic amino acid and prolonged nutrient starvation periods. In addition, the pbr mutant exhibited decreased virulence the nematode Caenorhabditis elegans. Altogether, our results demonstrate the involvement of Pbr on the regulation of phenazine biosynthesis, and an important role for this regulatory protein on several cellular processes related to stress resistance and virulence.
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Carmody LA, Gill JJ, Summer EJ, Sajjan US, Gonzalez CF, Young RF, LiPuma JJ. Efficacy of bacteriophage therapy in a model of Burkholderia cenocepacia pulmonary infection. J Infect Dis 2010; 201:264-71. [PMID: 20001604 DOI: 10.1086/649227] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The therapeutic potential of bacteriophages (phages) in a mouse model of acute Burkholderia cenocepacia pulmonary infection was assessed. Phage treatment was administered by either intranasal inhalation or intraperitoneal injection. Bacterial density, macrophage inflammatory protein 2 (MIP-2), and tumor necrosis factor alpha (TNF-alpha) levels were significantly reduced in lungs of mice treated with intraperitoneal phages (P < .05). No significant differences in lung bacterial density or MIP-2 levels were found between untreated mice and mice treated with intranasal phages, intraperitoneal ultraviolet-inactivated phages, or intraperitoneal lambda phage control mice. Mock-infected mice treated with phage showed no significant increase in lung MIP-2 or TNF-alpha levels compared with mock-infected/mock-treated mice. We have demonstrated the efficacy of phage therapy in an acute B. cenocepacia lung infection model. Systemic phage administration was more effective than inhalational administration, suggesting that circulating phages have better access to bacteria in lungs than do topical phages.
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Affiliation(s)
- Lisa A Carmody
- Department of Pediatrics and Communicable Disease, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA
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Hansen C, Pressler T, Nielsen K, Jensen P, Bjarnsholt T, Høiby N. Inflammation in Achromobacter xylosoxidans infected cystic fibrosis patients. J Cyst Fibros 2010; 9:51-8. [DOI: 10.1016/j.jcf.2009.10.005] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 10/26/2009] [Accepted: 10/27/2009] [Indexed: 11/26/2022]
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El-Laboudi A, Etherington C, Whitaker P, Clifton I, Conway S, Denton M, Peckham D. Acute Burkholderia cenocepacia pyomyositis in a patient with cystic fibrosis. J Cyst Fibros 2009; 8:273-5. [DOI: 10.1016/j.jcf.2009.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 04/14/2009] [Accepted: 04/26/2009] [Indexed: 10/20/2022]
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Elborn JS, Hodson M, Bertram C. Implementation of European standards of care for cystic fibrosis--control and treatment of infection. J Cyst Fibros 2009; 8:211-7. [PMID: 19372063 DOI: 10.1016/j.jcf.2009.03.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/20/2009] [Accepted: 03/05/2009] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several guidelines on infection control and treatment of infection exist for cystic fibrosis (CF) caregivers, although the extent of implementation is variable. METHODS Adherence to European Consensus Guidelines for CF was studied by sending surveys to named healthcare professionals in 487 European CF centres/units. Qualitative data analysis was performed. RESULTS A total of 177/547 (32%) surveys were returned. Infection control policies were implemented by most (77%) respondents. Separation of patients with Burkholderia cepacia was more common in adults (95%) than children (9%), and was implemented by 53% of respondents for Pseudomonas aeruginosa. Nebulised colistin plus oral ciprofloxacin was the most common (43%) therapy for P. aeruginosa infection. First infections of P. aeruginosa were usually treated with inhaled tobramycin; 41% of repondents did not intervene until lung function deteriorated. Most exacerbations were treated for less than the recommended period. CONCLUSIONS European Consensus Guidelines are widely adhered to. Areas for improvement include: initiating therapy for exacerbations early, separating infected patients and optimising duration of antibiotic therapy.
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Affiliation(s)
- J S Elborn
- Respiratory Medicine Research Group, Queen's University, Belfast City Hospital, Ground Floor, Lisburn Rd, Belfast, BT9 7AB, UK.
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McClean S, Callaghan M. Burkholderia cepacia complex: epithelial cell–pathogen confrontations and potential for therapeutic intervention. J Med Microbiol 2009; 58:1-12. [DOI: 10.1099/jmm.0.47788-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Burkholderia cepaciacomplex (Bcc) is an important and virulent pathogen in cystic fibrosis patients. The interactions between this pathogen and the host lung epithelium are being widely investigated but remain to be elucidated. The complex is very versatile and its interactions with the lung epithelial cells are many and varied. The first steps in the interaction are penetration of the mucosal blanket and subsequent adherence to the epithelial cell surface. A range of epithelial receptors have been reported to bind to Bcc. The next step in pathogenesis is the invasion of the lung epithelial cell and also translocation across the epithelium to the serosal side. Furthermore, pathogenesis is mediated by a range of virulence factors that elicit their effects on the epithelial cells. This review outlines these interactions and examines the therapeutic implications of understanding the mechanisms of pathogenesis of this difficult, antibiotic-resistant, opportunistic pathogen.
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Affiliation(s)
- Siobhán McClean
- Centre of Microbial Host Interactions, Institute of Technology Tallaght Dublin, Dublin 24, Ireland
| | - Máire Callaghan
- Centre of Microbial Host Interactions, Institute of Technology Tallaght Dublin, Dublin 24, Ireland
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80
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Sawicki GS, Rasouliyan L, Pasta DJ, Regelmann WE, Wagener JS, Waltz DA, Ren CL. The impact of incident methicillin resistant Staphylococcus aureus detection on pulmonary function in cystic fibrosis. Pediatr Pulmonol 2008; 43:1117-1123. [PMID: 18846559 DOI: 10.1002/ppul.20914] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The incidence of methicillin resistant Staphylococcus aureus (MRSA) infection is increasing in cystic fibrosis (CF), but the impact of MRSA detection on clinical outcomes is unclear. Our objective was to determine whether incident detection of MRSA is associated with a change in pulmonary function over time in CF patients. We analyzed data from the Epidemiologic Study of Cystic Fibrosis (ESCF), a prospective observational study of CF patients in North America. Multivariable piecewise linear regression was used to model the impact of incident detection of MRSA on pulmonary function over time, measured by percent predicted forced expiratory volume in one second (FEV(1)% predicted), adjusting for potential confounders. There were 5,090 patients >or=6 years old who were MRSA negative for at least 2 calendar years. Five hundred ninety-three (12%) of these patients acquired MRSA during the years 2001-2003, with detection rates of MRSA during those years rising from 4.4% to 6.9%. MRSA positive patients had a lower FEV(1)% predicted and received more antibiotic and other therapies than patients who remained MRSA negative. After adjusting for antibiotic therapy and other potential confounders, MRSA positive patients also had a higher rate of decline in FEV(1)% predicted both before and after the incident culture, although the rate of FEV(1)% predicted decline did not change significantly after MRSA detection. In conclusion, although MRSA in CF was a marker for more aggressive therapy and may reflect increased disease severity, incident MRSA detection was not associated with a changing rate of FEV(1)% predicted decline.
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Affiliation(s)
- Gregory S Sawicki
- Division of Respiratory Diseases, Children's Hospital Boston, Boston, Massachusetts
| | | | | | - Warren E Regelmann
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | | | - David A Waltz
- Division of Respiratory Diseases, Children's Hospital Boston, Boston, Massachusetts.,Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
| | - Clement L Ren
- Department of Pediatrics, University of Rochester, Rochester, New York
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81
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The changing epidemiology of Burkholderia species infection at an adult cystic fibrosis centre. J Cyst Fibros 2008; 7:368-72. [DOI: 10.1016/j.jcf.2008.01.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2007] [Revised: 12/19/2007] [Accepted: 01/11/2008] [Indexed: 11/17/2022]
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Alexander BD, Petzold EW, Reller LB, Palmer SM, Davis RD, Woods CW, Lipuma JJ. Survival after lung transplantation of cystic fibrosis patients infected with Burkholderia cepacia complex. Am J Transplant 2008; 8:1025-30. [PMID: 18318775 DOI: 10.1111/j.1600-6143.2008.02186.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Within the Burkholderia cepacia complex (Bcc), B. cenocepacia portends increased mortality compared with other species. We investigated the impact of Bcc infection on mortality and re-infection following lung transplant (LT). Species designation for isolates from Bcc-infected patients was determined using 16S rDNA and recA gene analyses. Of 75 cystic fibrosis patients undergoing LT from September 1992 to August 2002, 59 had no Bcc and 16 had Bcc (including 7 B. cenocepacia) isolated in the year before LT. Of the latter, 87.5% had Bcc recovered after transplantation, and all retained their pretransplant strains. Survival was 97%, 92%, 76% and 63% for noninfected patients; 89%, 89%, 67% and 56% for patients infected with Bcc species other than B. cenocepacia; and 71%, 29%, 29% and 29% for patients with B. cenocepacia (p = 0.014) at 1 month, 1 year, 3 years and 5 years, respectively. Patients infected with B. cenocepacia before transplant were six times more likely to die within 1 year of transplant than those infected with other Bcc species (p = 0.04) and eight times than noninfected patients (p < 0.00005). Following LT, infection with Bcc species other than B. cenocepacia does not significantly impact 5-year survival whereas infection with B. cenocepacia pretransplant is associated with decreased survival.
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Affiliation(s)
- B D Alexander
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University School of Medicine, Durham, NC, USA.
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84
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Flannagan RS, Valvano MA. Burkholderia cenocepacia requires RpoE for growth under stress conditions and delay of phagolysosomal fusion in macrophages. MICROBIOLOGY-SGM 2008; 154:643-653. [PMID: 18227267 DOI: 10.1099/mic.0.2007/013714-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Burkholderia cenocepacia is an opportunistic pathogen causing serious infections in patients with cystic fibrosis. The widespread distribution of this bacterium in the environment suggests that it must adapt to stress to be able to survive. We identified in B. cenocepacia K56-2 a gene predicted to encode RpoE, the extra-cytoplasmic stress response regulator. The rpoE gene is the first gene of a predicted operon encoding proteins homologous to RseA, RseB, MucD and a protein of unknown function. The genomic organization and the co-transcription of these genes were confirmed by PCR and RT-PCR. The mucD and rpoE genes were mutated, giving rise to B. cenocepacia RSF24 and RSF25, respectively. While mutant RSF24 did not demonstrate any growth defects under the conditions tested, RSF25 was compromised for growth under temperature (44 degrees C) and osmotic stress (426 mM NaCl). Expression of RpoE in trans could complement the osmotic growth defect but exacerbated temperature sensitivity in both RSF25 and wild-type K56-2. Inactivation of rpoE altered the bacterial cell surface, as indicated by increased binding of the fluorescent dye calcofluor white and by an altered outer-membrane protein profile. These cell surface changes were restored by complementation with a plasmid encoding rpoE. Macrophage infections in which bacterial colocalization with fluorescent dextran was examined demonstrated that the rpoE mutant could not delay the fusion of B. cenocepacia-containing vacuoles with lysosomes, in contrast to the parental strain K56-2. These data show that B. cenocepacia rpoE is required for bacterial growth under certain stress conditions and for the ability of intracellular bacteria to delay phagolysosomal fusion in macrophages.
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Affiliation(s)
- Ronald S Flannagan
- Infectious Disease Research Group, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
| | - Miguel A Valvano
- Medicine, Siebens-Drake Research Institute, University of Western Ontario, London, Ontario, Canada.,Infectious Disease Research Group, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, Canada
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Bell SC, Robinson PJ. Exacerbations in cystic fibrosis: 2 . prevention. Thorax 2007; 62:723-32. [PMID: 17687099 PMCID: PMC2117269 DOI: 10.1136/thx.2006.060897] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 01/31/2007] [Indexed: 01/12/2023]
Abstract
The life span of people with cystic fibrosis (CF) has increased dramatically over the past 50 years. Many factors have contributed to this improvement. Respiratory exacerbations of CF lung disease are associated with the need for hospitalisation and antibiotic treatment, reduction in the quality of life, fragmented sleep and mortality. A number of preventive treatment strategies have been developed to reduce the frequency and severity of respiratory exacerbations in CF including mucolytic agents, physiotherapy and exercise, antibiotics, nutritional strategies, anti-inflammatory treatments and vaccinations against common respiratory pathogens. The evidence for each of these treatments and their potential impact is discussed.
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Affiliation(s)
- Scott C Bell
- Adult Cystic Fibrosis Centre, The Prince Charles Hospital, Rode Road, Chermside, Brisbane 4032, Australia.
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86
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Sousa SA, Ulrich M, Bragonzi A, Burke M, Worlitzsch D, Leitão JH, Meisner C, Eberl L, Sá-Correia I, Döring G. Virulence of Burkholderia cepacia complex strains in gp91phox-/- mice. Cell Microbiol 2007; 9:2817-25. [PMID: 17627623 DOI: 10.1111/j.1462-5822.2007.00998.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In cystic fibrosis (CF), infection with Burkholderia cepacia complex (Bcc) strains may cause long-term asymptomatic airway colonization, or severe lung infection leading to rapid pulmonary decline. To assess the virulence of Bcc strains, we established a lung infection model in mice with a null allele of the gene involved in X-linked chronic granulomatous disease (CGD). CGD mice, challenged intratracheally with 10(3) cells of the epidemic Burkholderia cenocepacia strain J2315, died within 3 days from sepsis after bacteria had multiplied to 3.3 x 10(8) cells. Infected mice developed neutrophil-dominated lung abscesses. Other B. cenocepacia strains and a B. cepacia strain were less virulent and one B. multivorans and one B. vietnamensis CF isolate were both avirulent. Bcc mutants, defective in exopolysaccharide synthesis or quorum sensing revealed diminished or no abscess formation and mortality. Immunofluorescence staining of Bcc-infected murine and CF lung tissues revealed colocalization of Bcc and neutrophils, suggesting Bcc persistence within neutrophils in CGD and CF. In vitro, Bcc cells were rapidly killed during aerobic neutrophil phagocytosis; however, the pathogens survived in neutrophils with blocked nicotinamide adenine dinucleotide phosphate oxidase activity and under anaerobic conditions. We conclude that the Bcc infection model in CGD mice is well suited for the assessment of Bcc virulence.
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Affiliation(s)
- Silvia A Sousa
- Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Wilhelmstrasse 31, 72074 Tübingen, Germany
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87
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Abstract
In this article, the authors outline some of the major historical events that signaled the need to better understand mechanisms of infection in cystic fibrosis (CF). The authors discuss general principles of infection control, focusing on issues of particular importance to patients who have CF. The authors also describe the major pathogens associated with the CF airway, provide a review of findings from inpatient and outpatient studies of infection control, and provide an outline of future directions for investigation.
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Affiliation(s)
- Jonathan B Zuckerman
- Department of Medicine, The University of Vermont College of Medicine, E-126 Given Building, 89 Beaumont Avenue, Burlington, VT 05405-0068, USA.
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88
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Courtney JM, Bradley J, Mccaughan J, O'Connor TM, Shortt C, Bredin CP, Bradbury I, Elborn JS. Predictors of mortality in adults with cystic fibrosis. Pediatr Pulmonol 2007; 42:525-32. [PMID: 17469153 DOI: 10.1002/ppul.20619] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Assessment of prognostic indicators in patients with cystic fibrosis (CF) is important. The study's aim was to assess the relative contribution of gender, genetics and microbiology on survival in adults with CF. Adult patients were studied from 1995 to 2005 and data collected included FEV(1) (%predicted), body mass index (BMI), genetics, and microbiology. Data was available on 183 patients in 1995. Forty-five patients died in the subsequent 10 years. Patients who died during the study had lower mean (SD) FEV(1) %predicted in 1995 when compared to those remaining alive, 41.5 (15.2)% versus 69.8 (23.2)% predicted, respectively, P<0.001 and they had lower mean (SD) BMI in 1995, 19.2 (3.3) kg/m(2) in comparison to those remaining alive, 20.7 (3.4) kg/m(2), P=0.008. The proportion of patients infected with Pseudomonas aeruginosa and Burkholderia cepacia complex was higher in the group who died during the study compared to those remaining alive, odds ratio 20.9 P<0.0001 and 7.1 P<0.0001, respectively. The presence of the Delta F508 homozygous mutation did not alter survival, P=0.3. Patients infected with either P.aeruginosa or B.cepacia complex had reduced survival compared to those without infection, P=0.01 and P<0.0001, respectively. FEV(1)% (P<0.0001), infection with P.aeruginosa (P=0.005) or B.cepacia complex (P=0.03) were the only significant predictors of mortality. This study demonstrates adults who died were more likely to have worse lung function and be infected with either P.aeruginosa or B.cepacia complex. FEV(1)% and infection with P.aeruginosa or B.cepacia complex were the most significant predictors of survival in adults with CF.
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Affiliation(s)
- J M Courtney
- Adult Cystic Fibrosis Unit, Belfast City Hospital, Belfast, Northern Ireland, Ireland.
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89
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Hadjiliadis D. Special considerations for patients with cystic fibrosis undergoing lung transplantation. Chest 2007; 131:1224-31. [PMID: 17426231 DOI: 10.1378/chest.06-1163] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
This article reviews lung transplantation in patients with cystic fibrosis (CF). Lung transplantation is commonly utilized for patients with end-stage CF. There are several characteristics of CF that present unique challenges before and after lung transplantation. There is new information available that can be utilized to predict outcomes in patients with end-stage CF, and therefore can help in decisions of referral and listing for lung transplantation. The new lung allocation score, which allocates organs to patients who are on the lung transplant waiting list in the United States, presents new challenges and opportunities for patients with end-stage CF. In addition, the effect of the presence of microbiological flora prior to lung transplantation has been better linked to outcomes after lung transplantation. It is now known that, other than those patients harboring Burkholderia cepacia in their lungs before transplantation, most CF patients can undergo transplantation successfully. Nutrition remains an important issue among CF patients, and diabetes is a common problem after lung transplantation. In contrast, liver disease does not usually present major problems but, if it is severe, can necessitate liver and lung transplantation. Mechanical ventilation prior to transplantation might not be an absolute contraindication for CF patients. CF lung transplant recipients have good outcomes after lung transplantation compared with those of other lung transplant recipients. Quality of life is dramatically improved. However, they are still prone to common complications that all lung transplant recipients are prone to, including primary graft dysfunction, acute and chronic rejection, a variety of infections and malignancies, and renal failure.
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Affiliation(s)
- Denis Hadjiliadis
- Allergy, Pulmonary and Critical Care, University of Pennsylvania, Associate Medical Director, Lung Transplantation Program, 835W Gates Building, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA.
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90
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Downey DG, Martin SL, Dempster M, Moore JE, Keogan MT, Starcher B, Edgar J, Bilton D, Elborn JS. The relationship of clinical and inflammatory markers to outcome in stable patients with cystic fibrosis. Pediatr Pulmonol 2007; 42:216-20. [PMID: 17238189 DOI: 10.1002/ppul.20553] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Decreased survival in patients with cystic fibrosis has been related to FEV1, BMI, and infection with Burkholderia cepacia complex (BCC). We have assessed the relationship of blood, sputum, and urine inflammatory markers to lung function, BMI, colonization with B cenocepacia (Bc), and patient survival. Thirty-nine stable cystic fibrosis (CF) patients (10 with Bc) were enrolled in a study to determine the effect of alpha-1-antitrypsin on airways inflammation. Pre-treatment measurements were used in this study. Demographics, sputum microbiology, heart rate, oxygen saturation, lung function were recorded. Blood samples were obtained for white blood count (WBC), C-Reactive Protein (CRP), and plasma neutrophil elastase/AAT complexes (pNEC). Neutrophil elastase (NE), neutrophil elastase/AAT complexes (sNEC), interleukin-8 (IL-8), TNF-receptor 1 (sTNFr), and myeloperoxidase (MPO) were measured in sputum and urinary desmosine concentration determined. Patients with Bc had significantly higher levels of pNEC, 332 +/- 91.4 ng/ml (mean +/- SEM) versus 106 +/- 18.2 ng/ml (P = 0.0005) and sNEC, 369 +/- 76.6 ng/ml versus 197 +/- 36.0 ng/ml compared to those who were not. Five deaths were reported at the end of 1 year, (four with Bc) (P = 0.011). Patients who subsequently died had significantly lower lung function FEV1, 1.2 +/- 0.2 L versus 2.0 +/- 0.1 L (P = 0.03) and FVC, 2 +/- 0.3 L versus 3.1 +/- 0.2 L (P = 0.01), compared to those that survived. There was significantly higher NE activity, 3.6 +/- 1.6 U/ml versus 1.5 +/- 0.6 U/ml (P = 0.03), pNEC, 274 +/- 99 ng/ml versus 142 +/- 30 ng/ml (P = 0.05), MPO, 163 +/- 62 mcg/ml versus 54 +/- 6.9 mcg/ml (P = 0.03), and urinary desmosines 108 +/- 19.9 pM/mg creatinine versus 51.1 +/- 3.3 pM/mg creatinine (P = 0.001), in those patients who subsequently died compared to those that survived. These data suggest there is increased neutrophil degranulation in patients infected with Bc and these patients have a poor outcome.
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Affiliation(s)
- Damian G Downey
- Adult Cystic Fibrosis Centre, Belfast City Hospital and Queens University, Belfast, Northern Ireland
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91
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Keith KE, Valvano MA. Characterization of SodC, a periplasmic superoxide dismutase from Burkholderia cenocepacia. Infect Immun 2007; 75:2451-60. [PMID: 17325048 PMCID: PMC1865777 DOI: 10.1128/iai.01556-06] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cenocepacia is a gram-negative, non-spore-forming bacillus and a member of the Burkholderia cepacia complex. B. cenocepacia can survive intracellularly in phagocytic cells and can produce at least one superoxide dismutase (SOD). The inability of O2- to cross the cytoplasmic membrane, coupled with the periplasmic location of Cu,ZnSODs, suggests that periplasmic SODs protect bacteria from superoxide that has an exogenous origin (for example, when cells are faced with reactive oxygen intermediates generated by host cells in response to infection). In this study, we identified the sodC gene encoding a Cu,ZnSOD in B. cenocepacia and demonstrated that a sodC null mutant was not sensitive to a H2O2, 3-morpholinosydnonimine, or paraquat challenge but was killed by exogenous superoxide generated by the xanthine/xanthine oxidase method. The sodC mutant also exhibited a growth defect in liquid medium compared to the parental strain, which could be complemented in trans. The mutant was killed more rapidly than the parental strain was killed in murine macrophage-like cell line RAW 264.7, but killing was eliminated when macrophages were treated with an NADPH oxidase inhibitor. We also confirmed that SodC is periplasmic and identified the metal cofactor. B. cenocepacia SodC was resistant to inhibition by H2O2 and was unusually resistant to KCN for a Cu,ZnSOD. Together, these observations establish that B. cenocepacia produces a periplasmic Cu,ZnSOD that protects this bacterium from exogenously generated O2- and contributes to intracellular survival of this bacterium in macrophages.
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Affiliation(s)
- Karen E Keith
- Infectious Diseases Research Group, Siebens-Drake Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
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92
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Waters V, Ratjen F. Multidrug-resistant organisms in cystic fibrosis: management and infection-control issues. Expert Rev Anti Infect Ther 2007; 4:807-19. [PMID: 17140357 DOI: 10.1586/14787210.4.5.807] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Chronic infection and inflammation are the hallmarks of cystic fibrosis lung disease. As cystic fibrosis patients are living longer owing to more intense treatment, multidrug-resistant organisms are being isolated increasingly from patients' respiratory tracts. While the adverse effects of Pseudomonas aeruginosa and Burkholderia cepacia complex are well described, less is known about the clinical significance of other emerging multidrug-resistant organisms, such as methicillin-resistant Staphylococcus aureus and Stenotrophomonas maltophilia. Owing to multiple mechanisms of antimicrobial resistance, these organisms are difficult to treat and often require combination antibiotic therapy. Until more is known about their pathogenicity and effect on clinical outcomes, physicians should be aware of the potential transmissibility of these organisms and implement adequate infection control strategies.
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Affiliation(s)
- Valerie Waters
- Division of Infectious Diseases, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, M5G 1X8 Canada
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93
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Maloney KE, Valvano MA. The mgtC gene of Burkholderia cenocepacia is required for growth under magnesium limitation conditions and intracellular survival in macrophages. Infect Immun 2006; 74:5477-86. [PMID: 16988222 PMCID: PMC1594880 DOI: 10.1128/iai.00798-06] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Burkholderia cenocepacia, a bacterium commonly found in the environment, is an important opportunistic pathogen in patients with cystic fibrosis (CF). Very little is known about the mechanisms by which B. cenocepacia causes disease, but chronic infection of the airways in CF patients may be associated, at least in part, with the ability of this bacterium to survive within epithelial cells and macrophages. Survival in macrophages occurs in a membrane-bound compartment that is distinct from the lysosome, suggesting that B. cenocepacia prevents phagolysosomal fusion. In a previous study, we employed signature-tagged mutagenesis and an agar bead model of chronic pulmonary infection in rats to identify B. cenocepacia genes that are required for bacterial survival in vivo. One of the most significantly attenuated mutants had an insertion in the mgtC gene. Here, we show that mgtC is also needed for growth of B. cenocepacia in magnesium-depleted medium and for bacterial survival within murine macrophages. Using fluorescence microscopy, we demonstrated that B. cenocepacia mgtC mutants, unlike the parental isolate, colocalize with the fluorescent acidotropic probe LysoTracker Red. At 4 h postinfection, mgtC mutants expressing monomeric red fluorescent protein cannot retain this protein within the bacterial cytoplasm. Together, these results demonstrate that, unlike the parental strain, an mgtC mutant does not induce a delay in phagolysosomal fusion and the bacterium-containing vacuoles are rapidly targeted to the lysosome, where bacteria are destroyed.
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Affiliation(s)
- Kendra E Maloney
- Infectious Diseases Research Group, Siebens-Drake Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario, N6A 5C1, Canada
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94
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Affiliation(s)
- J S Elborn
- Respiratory Medicine Group, Queens' University of Belfast, Belfast, N. Ireland.
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95
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Vanlaere E, Coenye T, Samyn E, Van den Plas C, Govan J, De Baets F, De Boeck K, Knoop C, Vandamme P. A novel strategy for the isolation and identification of environmental Burkholderia cepacia complex bacteria. FEMS Microbiol Lett 2005; 249:303-7. [PMID: 16000240 DOI: 10.1016/j.femsle.2005.06.026] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 06/07/2005] [Accepted: 06/13/2005] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to develop a novel strategy for the isolation and identification of Burkholderia cepacia complex bacteria from the home environment of cystic fibrosis (CF) patients. Water and soil samples were enriched in a broth containing 0.1% l-arabinose, 0.1% l-threonine, and a mixture of selective agents including 1 microgml(-1) C-390, 600U ml(-1) polymyxin B sulfate, 10 microgml(-1) gentamycin, 2 microgml(-1) vancomycin and 10 microgml(-1) cycloheximide. On selective media (consisting of the same components as above plus 1.8% agar), several dilutions of the enrichment broth were inoculated and incubated for 5 days at 28 degrees C. Isolates with different randomly amplified polymorphic DNA patterns were inoculated in Stewart's medium. Putative B. cepacia complex bacteria were confirmed by means of recA PCR and further identified by HaeIII-recA restriction fragment length polymorphism analysis. Our results suggest that these organisms may be more widespread in the home environment than previously assumed and that plant associated soil and pond water may be reservoirs of B. cepacia complex infection in CF patients.
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Affiliation(s)
- Elke Vanlaere
- Laboratory of Microbiology, Ghent University, Ledeganckstraat 35, B-9000 Ghent, Belgium.
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96
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Abstract
PURPOSE OF REVIEW The Burkholderia cepacia complex is comprised of a group of related bacterial species that are capable of causing life-threatening respiratory tract infection in persons with cystic fibrosis. This article reviews advances in our understanding of Burkholderia cepacia complex infection in cystic fibrosis, focusing on the taxonomy, clinical microbiology, and epidemiology, as well as the natural history and clinical outcomes associated with Burkholderia cepacia complex infection. RECENT FINDINGS Each of the nine species of the Burkholderia cepacia complex has now received a formal species name. These names are the preferred nomenclature, replacing the former 'genomovar' designations. Studies from several countries reiterate that two species, Burkholderia cenocepacia and Burkholderia multivorans, account for most Burkholderia cepacia complex infection in cystic fibrosis. Bacterial genotyping studies indicate that specific Burkholderia cepacia complex strains infect multiple cystic fibrosis patients, implying that they may have an enhanced capacity for interpatient spread. Emerging clinical outcomes data suggest that at least some of these so-called transmissible or epidemic strains are also more virulent in the cystic fibrosis host. Ongoing research is aimed at gaining a better understanding of Burkholderia cepacia complex ecology, defining Burkholderia cepacia complex virulence factors and pathogenic mechanisms, and determining the relative virulence of distinct strains. SUMMARY Significant advances in our understanding of the Burkholderia cepacia complex serve as a critical foundation for further efforts that ultimately will enable better infection control and the development of novel therapeutics to treat Burkholderia cepacia complex infection in persons with cystic fibrosis.
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Affiliation(s)
- John J Lipuma
- Division of Infectious Diseases, Department of Pediatrics and Communicable Diseases, University of Michigan Medical School, Ann Arbor, Michigan 48109-0646, USA.
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97
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Taccetti G, Costantini D, Furnari ML. Clinical follow-up of 122 Italian cystic fibrosis patients with B. cepacia complex colonisation. J Cyst Fibros 2005; 4:145-6; author reply 147. [PMID: 15978538 DOI: 10.1016/j.jcf.2004.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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