Epidemiology of Burkholderia cepacia complex species recovered from cystic fibrosis patients: issues related to patient segregation

Species distribution and antimicrobial susceptibility of Burkholderia cepacia complex isolates in clinical infections: Experience from a tertiary care hospital, Southern India

PURPOSE

Burkholderia cepacia complex (Bcc) is a diverse group of environmental bacteria associated with opportunistic infections. The identification of Bcc using conventional methods poses challenges. Bcc infections are difficult to treat due to intrinsic antibiotic resistance. The study aimed to investigate the species distribution and antimicrobial susceptibility of clinical Bcc isolates.

METHODS

A total of 153 Bcc isolates obtained from clinical samples were analysed. Species identification was carried out using automated methods, including MALDI-TOF MS and VITEK2. Antimicrobial susceptibility testing was performed using the disc diffusion method.

RESULTS

Burkholderia cenocepacia (70.5%) emerged as the most prevalent species, followed by Burkholderia contaminans (9.8%) and Burkholderia cepacia (7.2%). Ventilator-associated pneumonia (38.6%) was the most common infection, followed by sepsis (28.1%). Co-existence of Bcc with other pathogens in many cases suggested potential co-infection scenarios. Antimicrobial susceptibility revealed that ceftazidime, co-trimoxazole and meropenem were the most effective drugs, while levofloxacin proved to be the least effective. Moderate susceptibility was noted to minocycline, with 4.6% of isolates exhibiting multi-drug resistance.

CONCLUSION

This study provides valuable insights into the prevalence, clinical associations, and antibiotic susceptibility of Bcc in India. It highlights the importance of Bcc as a nosocomial pathogen, especially in vulnerable patient populations. The findings contribute to understanding Bcc infections, their distribution, and emphasize the necessity for accurate identification methods in clinical settings.

Impact of cystic fibrosis multidisciplinary virtual clinics on patient experience, time commitments and costs

BACKGROUND AND AIMS

The experience of outpatient care may differ for select patient groups. This prospective study evaluates the adult patient experience of multidisciplinary outpatient cystic fibrosis (CF) care with videoconferencing through telehealth compared with face-to-face care the year prior.

METHODS

People with CF without a lung transplant were recruited. Patient-reported outcomes were obtained at commencement and 12 months into the study, reflecting both their face-to-face and telehealth through videoconferencing experience, respectively. Three patient cohorts were analysed: (i) participants with a regional residence, (ii) participants with a nonregional including metropolitan residence and (iii) participants with colonised multiresistant microbiota.

RESULTS

Seventy-four patients were enrolled in the study (mean age, 37 ± 11 years; 50% male; mean forced expiratory volume in the first second of expiration, 60% [standard deviation, 23]) between February 2020 and May 2021. No differences between models were observed in the participants' rating of the health care team, general and mental health rating, and their confidence in handling treatment plans at home. No between-group differences in the Cystic Fibrosis Questionnaire - Revised (CFQ-R) were observed. Travel duration and the cost of attending a clinic was significantly reduced, particularly for the regional group (4 h, AU$108 per clinic; P < 0.05). A total of 93% respondents preferred to continue with a hybrid approach.

CONCLUSION

In this pilot study, participants' experience of care and quality of life were no different with face-to-face and virtual care between the groups. Time and cost-savings, particularly for patients living in regional areas, were observed. Most participants preferred to continue with a hybrid model for outpatient care.

Differences in Cystic Fibrosis-Associated Burkholderia spp. Bacteria Metabolomes after Exposure to the Antibiotic Trimethoprim

The Burkholderia cepacia complex is a group of closely related bacterial species with large genomes that infect immunocompromised individuals and those living with cystic fibrosis. Some of these species are found more frequently and cause more severe disease than others, yet metabolomic differences between these have not been described. Furthermore, our understanding of how these species respond to antibiotics is limited. We investigated the metabolomics differences between three most prevalent Burkholderia spp. associated with cystic fibrosis: B. cenocepacia, B. multivorans, and B. dolosa in the presence and absence of the antibiotic trimethoprim. Using a combination of supervised and unsupervised metabolomics data visualization and analysis tools, we describe the overall differences between strains of the same species and between species. Specifically, we report, for the first time, the role of the pyomelanin pathway in the metabolism of trimethoprim. We also report differences in the detection of known secondary metabolites such as fragin, ornibactin, and N-acylhomoserine lactones and their analogs in closely related strains. Furthermore, we highlight the potential for the discovery of new secondary metabolites in clinical strains of Burkholderia spp. The metabolomics differences described in this study highlight the personalized nature of closely related Burkholderia strains.

Genomic analyses of Burkholderia cenocepacia reveal multiple species with differential host-adaptation to plants and humans

Background

Burkholderia cenocepacia is a human opportunistic pathogen causing devastating symptoms in patients suffering from immunodeficiency and cystic fibrosis. Out of the 303 B. cenocepacia strains with available genomes, the large majority were isolated from a clinical context. However, several isolates originate from other environmental sources ranging from aerosols to plant endosphere. Plants can represent reservoirs for human infections as some pathogens can survive and sometimes proliferate in the rhizosphere. We therefore investigated if B. cenocepacia had the same potential.

Results

We selected genome sequences from 31 different strains, representative of the diversity of ecological niches of B. cenocepacia, and conducted comparative genomic analyses in the aim of finding specific niche or host-related genetic determinants. Phylogenetic analyses and whole genome average nucleotide identity suggest that strains, registered as B. cenocepacia, belong to at least two different species. Core-genome analyses show that the clade enriched in environmental isolates lacks multiple key virulence factors, which are conserved in the sister clade where most clinical isolates fall, including the highly virulent ET12 lineage. Similarly, several plant associated genes display an opposite distribution between the two clades. Finally, we suggest that B. cenocepacia underwent a host jump from plants/environment to animals, as supported by the phylogenetic analysis. We eventually propose a name for the new species that lacks several genetic traits involved in human virulence.

Conclusion

Regardless of the method used, our studies resulted in a disunited perspective of the B. cenocepacia species. Strains currently affiliated to this taxon belong to at least two distinct species, one having lost several determining animal virulence factors.

Refractory Burkholderia cepacia bacteraemia from a consolidation pneumonia lasting more than 7 weeks, successfully treated with systemic antibiotics and nebulised meropenem

We present a case of a 55-year-old Filipino man who was transferred from another institution where he was recently diagnosed with Crohn's disease but not started on any immunosuppressants. He underwent laparoscopic cholecystectomy with T-tube placement a few weeks prior to admission. On workup, abdominal CT scan was unremarkable, but blood cultures on the third hospital day grew Burkholderia cepacia Antibiotic regimen was shifted to ceftazidime and levofloxacin. The bacteraemia and febrile episodes persisted despite removal of the central line and T tube. White blood cell scan and chest CT scan showed left-sided consolidation pneumonia. Blood cultures continued to grow B. cepacia despite shifting to meropenem and trimethoprim-sulfamethoxazole. Meropenem nebulisation at 250 mg every 12 hours was added to the regimen on the third week then oral minocycline was added on the fourth week due to persistence of bacteraemia. He subsequently developed a small vegetation on the aortic valve, so amikacin was added. Fever lysed on the sixth week, but the B. cepacia bacteraemia persisted, clearing only on the 51st hospital day. The patient was discharged with a plan to continue antibiotics, including meropenem nebulisation, for 6 more weeks. On follow-up, the patient had no recurrence of fever. There was also resolution of consolidation on chest CT scan and disappearance of vegetation on echocardiography.

The Essential Genome of Burkholderia cenocepacia H111

The study of the minimum set of genes required to sustain life is a fundamental question in biological research. Recent studies on bacterial essential genes suggested that between 350 and 700 genes are essential to support autonomous bacterial cell growth. Essential genes are of interest as potential new antimicrobial drug targets; hence, our aim was to identify the essential genome of the cystic fibrosis (CF) isolate Burkholderia cenocepacia H111. Using a transposon sequencing (Tn-Seq) approach, we identified essential genes required for growth in rich medium under aerobic and microoxic conditions as well as in a defined minimal medium with citrate as a sole carbon source. Our analysis suggests that 398 genes are required for autonomous growth in rich medium, a number that represents only around 5% of the predicted genes of this bacterium. Five hundred twenty-six genes were required to support growth in minimal medium, and 434 genes were essential under microoxic conditions (0.5% O₂). A comparison of these data sets identified 339 genes that represent the minimal set of essential genes required for growth under all conditions tested and can be considered the core essential genome of B. cenocepacia H111. The majority of essential genes were found to be located on chromosome 1, and few such genes were located on chromosome 2, where most of them were clustered in one region. This gene cluster is fully conserved in all Burkholderia species but is present on chromosome 1 in members of the closely related genus Ralstonia, suggesting that the transfer of these essential genes to chromosome 2 in a common ancestor contributed toward the separation of the two genera.IMPORTANCE Transposon sequencing (Tn-Seq) is a powerful method used to identify genes that are essential for autonomous growth under various conditions. In this study, we have identified a set of "core essential genes" that are required for growth under multiple conditions, and these genes represent potential antimicrobial targets. We also identified genes specifically required for growth under low-oxygen and nutrient-limited environments. We generated conditional mutants to verify the results of our Tn-Seq analysis and demonstrate that one of the identified genes was not essential per se but was an artifact of the construction of the mutant library. We also present verified examples of genes that were not truly essential but, when inactivated, showed a growth defect. These examples have identified so-far-underestimated shortcomings of this powerful method.

Novel glycopolymer sensitizes Burkholderia cepacia complex isolates from cystic fibrosis patients to tobramycin and meropenem

Burkholderia cepacia complex (Bcc) infection, associated with cystic fibrosis (CF) is intrinsically multidrug resistant to antibiotic treatment making eradication from the CF lung virtually impossible. Infection with Bcc leads to a rapid decline in lung function and is often a contraindication for lung transplant, significantly influencing morbidity and mortality associated with CF disease. Standard treatment frequently involves antibiotic combination therapy. However, no formal strategy has been adopted in clinical practice to guide successful eradication. A new class of direct-acting, large molecule polycationic glycopolymers, derivatives of a natural polysaccharide poly-N-acetyl-glucosamine (PAAG), are in development as an alternative to traditional antibiotic strategies. During treatment, PAAG rapidly targets the anionic structural composition of bacterial outer membranes. PAAG was observed to permeabilize bacterial membranes upon contact to facilitate potentiation of antibiotic activity. Three-dimensional checkerboard synergy analyses were used to test the susceptibility of eight Bcc strains (seven CF clinical isolates) to antibiotic combinations with PAAG or ceftazidime. Potentiation of tobramycin and meropenem activity was observed in combination with 8-128 μg/mL PAAG. Treatment with PAAG reduced the minimum inhibitory concentration (MIC) of tobramycin and meropenem below their clinical sensitivity breakpoints (≤4 μg/mL), demonstrating the ability of PAAG to sensitize antibiotic resistant Bcc clinical isolates. Fractional inhibitory concentration (FIC) calculations showed PAAG was able to significantly potentiate antibacterial synergy with these antibiotics toward all Bcc species tested. These preliminary studies suggest PAAG facilitates a broad synergistic activity that may result in more positive therapeutic outcomes and supports further development of safe, polycationic glycopolymers for inhaled combination antibiotic therapy, particularly for CF-associated Bcc infections.

Prevalence of Burkholderia species, including members of Burkholderia cepacia complex, among UK cystic and non-cystic fibrosis patients

PURPOSE

We aimed to establish the prevalence of different Burkholderia species among UK cystic fibrosis (CF) and non-CF patients over a 2 year period.

METHODOLOGY

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry was used to identify isolates to genus level, followed by recA/gyrB sequence clustering or species-specific PCR. In all, 1047 Burkholderia isolates were submitted for identification from 361 CF patients and 112 non-CF patients, 25 from the hospital environment and three from a commercial company. Potential cross-infection was assessed by pulsed-field gel electrophoresis (PFGE) and multi- locus-sequence typing (MLST). MICs were determined for 161 Burkholderia cepacia complex (Bcc) isolates. CF Trust registry data were sought to examine clinical parameters relating to Bcc infection.

RESULTS

Burkholderia multivorans was the most prevalent species among CF patients affecting 56 % (192) patients, followed by Burkholderia cenocepacia IIIA (15 %; 52 patients). Five novel recA clusters were found. Among non-CF patients, Burkholderia cepacia was the most prevalent species (37/112; 34 %), with 18 of 40 isolates part of a UK-wide B. cepacia 'cluster'. This and three other clusters were investigated by PFGE and MLST. Cable-pili positive isolates included two novel sequence types and representatives of ET12. Antibiotic susceptibility varied between and within species and CF/non- CF isolates. CF Trust registry data suggested no significant difference in lung function between patients harbouring B. cenocepacia, B. multivorans and other Bcc species (P=0.81).

CONCLUSION

The dominance of B. multivorans in CF, the presence of a B. cepacia cluster among non-CF patients and the existence of putative novel species all highlighted the continuing role of Burkholderia species as opportunistic pathogens.

Identification and analysis of genomic islands in Burkholderia cenocepacia AU 1054 with emphasis on pathogenicity islands

BACKGROUND

Genomic islands (GIs) are genomic regions that reveal evidence of horizontal DNA transfer. They can code for many functions and may augment a bacterium's adaptation to its host or environment. GIs have been identified in strain J2315 of Burkholderia cenocepacia, whereas in strain AU 1054 there has been no published works on such regions according to our text mining and keyword search in Medline.

RESULTS

In this study, we identified 21 GIs in AU 1054 by combining two computational tools. Feature analyses suggested that the predictions are highly reliable and hence illustrated the advantage of joint predictions by two independent methods. Based on putative virulence factors, four GIs were further identified as pathogenicity islands (PAIs). Through experiments of gene deletion mutants in live bacteria, two putative PAIs were confirmed, and the virulence factors involved were identified as lipA and copR. The importance of the genes lipA (from PAI 1) and copR (from PAI 2) for bacterial invasion and replication indicates that they are required for the invasive properties of B. cenocepacia and may function as virulence determinants for bacterial pathogenesis and host infection.

CONCLUSIONS

This approach of in silico prediction of GIs and subsequent identification of potential virulence factors in the putative island regions with final validation using wet experiments could be used as an effective strategy to rapidly discover novel virulence factors in other bacterial species and strains.

Phenotypic diversity and genotypic flexibility of Burkholderia cenocepacia during long-term chronic infection of cystic fibrosis lungs

Chronic bacterial infections of the lung are the leading cause of morbidity and mortality in cystic fibrosis patients. Tracking bacterial evolution during chronic infections can provide insights into how host selection pressures—including immune responses and therapeutic interventions—shape bacterial genomes. We carried out genomic and phenotypic analyses of 215 serially collected Burkholderia cenocepacia isolates from 16 cystic fibrosis patients, spanning a period of 2–20 yr and a broad range of epidemic lineages. Systematic phenotypic tests identified longitudinal bacterial series that manifested progressive changes in liquid media growth, motility, biofilm formation, and acute insect virulence, but not in mucoidy. The results suggest that distinct lineages follow distinct evolutionary trajectories during lung infection. Pan-genome analysis identified 10,110 homologous gene clusters present only in a subset of strains, including genes restricted to different molecular types. Our phylogenetic analysis based on 2148 orthologous gene clusters from all isolates is consistent with patient-specific clades. This suggests that initial colonization of patients was likely by individual strains, followed by subsequent diversification. Evidence of clonal lineages shared by some patients was observed, suggesting inter-patient transmission. We observed recurrent gene losses in multiple independent longitudinal series, including complete loss of Chromosome III and deletions on other chromosomes. Recurrently observed loss-of-function mutations were associated with decreases in motility and biofilm formation. Together, our study provides the first comprehensive genome-phenome analyses of B. cenocepacia infection in cystic fibrosis lungs and serves as a valuable resource for understanding the genomic and phenotypic underpinnings of bacterial evolution.

Respiratory infection rates differ between geographically distant paediatric cystic fibrosis cohorts

Respiratory infections are a major cause of pulmonary decline in children with cystic fibrosis (CF). We compared the prevalence of infection in early life at geographically distant CF treatment centres participating in the same surveillance programme in Australia.

Lower airway microbiology, inflammation and structural lung disease at annual review were evaluated for 260 children 0–8 years old with CF at 1032 visits to CF treatment centres in Melbourne or Perth.

Melbourne patients were more likely to be culture-positive for common respiratory pathogens at all age groups (odds ratio (OR) 1.85, 95% CI 1.33–2.58). Subjects <2 years old in Melbourne were also more likely to have neutrophil elastase present (OR 3.11, 95% CI 1.62–5.95). Bronchiectasis (OR 2.02, 95% CI 1.21–3.38) and air trapping (OR 2.53, 95% CI 1.42–4.51) in subjects 2–5 years old was more common in Melbourne subjects. The severity of structural lung disease was also worse in Melbourne patients >5 years old. Patients at both centres had a similar rate of hospitalisations and prescribed antibiotics.

No procedural differences were identified that could explain the disparity between pathogen prevalence. Geographical differences in early acquisition of infection may contribute to variability in outcomes between CF centres.

Infection rates different between two Australian paediatric cystic fibrosis patient cohortshttp://ow.ly/PAmG302IYL4

Linocin and OmpW Are Involved in Attachment of the Cystic Fibrosis-Associated Pathogen Burkholderia cepacia Complex to Lung Epithelial Cells and Protect Mice against Infection

Members of the Burkholderia cepacia complex (Bcc) cause chronic opportunistic lung infections in people with cystic fibrosis (CF), resulting in a gradual lung function decline and, ultimately, patient death. The Bcc is a complex of 20 species and is rarely eradicated once a patient is colonized; therefore, vaccination may represent a better therapeutic option. We developed a new proteomics approach to identify bacterial proteins that are involved in the attachment of Bcc bacteria to lung epithelial cells. Fourteen proteins were reproducibly identified by two-dimensional gel electrophoresis from four Bcc strains representative of two Bcc species: Burkholderia cenocepacia, the most virulent, and B. multivorans, the most frequently acquired. Seven proteins were identified in both species, but only two were common to all four strains, linocin and OmpW. Both proteins were selected based on previously reported data on these proteins in other species. Escherichia coli strains expressing recombinant linocin and OmpW showed enhanced attachment (4.2- and 3.9-fold) to lung cells compared to the control, confirming that both proteins are involved in host cell attachment. Immunoproteomic analysis using serum from Bcc-colonized CF patients confirmed that both proteins elicit potent humoral responses in vivo Mice immunized with either recombinant linocin or OmpW were protected from B. cenocepacia and B. multivorans challenge. Both antigens induced potent antigen-specific antibody responses and stimulated strong cytokine responses. In conclusion, our approach identified adhesins that induced excellent protection against two Bcc species and are promising vaccine candidates for a multisubunit vaccine. Furthermore, this study highlights the potential of our proteomics approach to identify potent antigens against other difficult pathogens.

Lung transplantation for cystic fibrosis: results, indications, complications, and controversies

Survival in patients with cystic fibrosis (CF) has improved dramatically over the past 30 to 40 years, with mean survival now approximately 40 years. Nonetheless, progressive respiratory insufficiency remains the major cause of mortality in CF patients, and lung transplantation (LT) is eventually required. Timing of listing for LT is critical, because up to 25 to 41% of CF patients have died while awaiting LT. Globally, approximately 16.4% of lung transplants are performed in adults with CF. Survival rates for LT recipients with CF are superior to other indications, yet LT is associated with substantial morbidity and mortality (∼50% at 5-year survival rates). Myriad complications of LT include allograft failure (acute or chronic), opportunistic infections, and complications of chronic immunosuppressive medications (including malignancy). Determining which patients are candidates for LT is difficult, and survival benefit remains uncertain. In this review, we discuss when LT should be considered, criteria for identifying candidates, contraindications to LT, results post-LT, and specific complications that may be associated with LT. Infectious complications that may complicate CF (particularly Burkholderia cepacia spp., opportunistic fungi, and nontuberculous mycobacteria) are discussed.

Clinical and in vitro evidence for the antimicrobial therapy in Burkholderia cepacia complex infections

Treatment of infections caused by Burkholderia cepacia complex (Bcc) in cystic fibrosis (CF) patients poses a complex problem. Bcc is multidrug-resistant due to innate and acquired mechanisms of resistance. As CF patients receive multiple courses of antibiotics, susceptibility patterns of strains from CF patients may differ from those noted in strains from non-CF patients. Thus, there was a need for assessing in vitro and clinical data to guide antimicrobial therapy in these patients. A systematic search of literature, followed by extraction and analysis of available information from human and in vitro studies was done. The results of the analysis are used to address various aspects like use of antimicrobials for pulmonary and non-pulmonary infections, use of combination versus monotherapy, early eradication, duration of therapy, route of administration, management of biofilms, development of resistance during therapy, pharmacokinetics-pharmacodynamics correlations, therapy in post-transplant patients and newer drugs in Bcc-infected CF patients.

Identification of the flagellin glycosylation system in Burkholderia cenocepacia and the contribution of glycosylated flagellin to evasion of human innate immune responses

Burkholderia cenocepacia is an opportunistic pathogen threatening patients with cystic fibrosis. Flagella are required for biofilm formation, as well as adhesion to and invasion of epithelial cells. Recognition of flagellin via the Toll-like receptor 5 (TLR5) contributes to exacerbate B. cenocepacia-induced lung epithelial inflammatory responses. In this study, we report that B. cenocepacia flagellin is glycosylated on at least 10 different sites with a single sugar, 4,6-dideoxy-4-(3-hydroxybutanoylamino)-D-glucose. We have identified key genes that are required for flagellin glycosylation, including a predicted glycosyltransferase gene that is linked to the flagellin biosynthesis cluster and a putative acetyltransferase gene located within the O-antigen lipopolysaccharide cluster. Another O-antigen cluster gene, rmlB, which is required for flagellin glycan and O-antigen biosynthesis, was essential for bacterial viability, uncovering a novel target against Burkholderia infections. Using glycosylated and nonglycosylated purified flagellin and a cell reporter system to assess TLR5-mediated responses, we also show that the presence of glycan in flagellin significantly impairs the inflammatory response of epithelial cells. We therefore suggest that flagellin glycosylation reduces recognition of flagellin by host TLR5, providing an evasive strategy to infecting bacteria.

Immunoproteomic analysis of proteins expressed by two related pathogens, Burkholderia multivorans and Burkholderia cenocepacia, during human infection

Burkholderia cepacia complex (Bcc) is an opportunistic bacterial pathogen that causes chronic infections in people with cystic fibrosis (CF). It is a highly antibiotic resistant organism and Bcc infections are rarely cleared from patients, once they are colonized. The two most clinically relevant species within Bcc are Burkholderia cenocepacia and Burkholderia multivorans. The virulence of these pathogens has not been fully elucidated and the virulence proteins expressed during human infection have not been identified to date. Furthermore, given its antibiotic resistance, prevention of infection with a prophylactic vaccine may represent a better alternative than eradication of an existing infection. We have compared the immunoproteome of two strains each from these two species of Bcc, with the aim of identifying immunogenic proteins which are common to both species. Fourteen immunoreactive proteins were exclusive to both B. cenocepacia strains, while 15 were exclusive to B. multivorans. A total of 15 proteins were immunogenic across both species. DNA-directed RNA polymerase, GroEL, 38kDa porin and elongation factor-Tu were immunoreactive proteins expressed by all four strains examined. Many proteins which were immunoreactive in both species, warrant further investigations in order to aid in the elucidation of the mechanisms of pathogenesis of this difficult organism. In addition, identification of some of these could also allow the development of protective vaccines which may prevent colonisation.

Genotypic diversity of Pseudomonas aeruginosa in cystic fibrosis siblings in Qatar using AFLP fingerprinting

Pseudomonas aeruginosa is one of the primary pathogens in patients with cystic fibrosis (CF) and a major cause of morbidity and mortality. Reports of the spread of epidemic or transmissible strains of P. aeruginosa within and across CF centers raised the possibility of clonal spread among siblings with CF. This work reports the genotypic relatedness of P. aeruginosa in CF patients with the CFTR I1234V mutation, and to determine whether the genotypes are identical among CF siblings and among different families with the same CFTR mutation. Sixty-six P. aeruginosa isolates were obtained from sputa/deep-pharyngeal swabs from 27 CF patients belonging to 17 families. Genotypic relatedness was assessed using amplified fragment-length polymorphism (AFLP) fingerprinting. Twenty-three distinct genotypes of P. aeruginosa were identified. Eleven families each had one distinct genotype. In the other 6 families more than one genotype was observed; 3 families each showed two genotypes, 2 families each had three genotypes and 1 family had four genotypes of P. aeruginosa. In several cases, siblings with CF from the same family harbored the same strain of P. aeruginosa, which were different from the genotypes in other families. On the other hand, there was an overlap in P. aeruginosa between closely related families. Some patients show persistent colonization with the same genotype of P. aeruginosa over the longitudinal period. The presence of the same genotypes in siblings of the same family and closely related families suggests cross-transmission of P. aeruginosa or acquisition from common environmental exposure.

Genetic similarity of Burkholderia cenocepacia from cystic fibrosis patients

Burkholderia cenocepacia may cause serious infections in patients with cystic fibrosis, and this microorganism can be highly transmissible. Pulsed-field gel electrophoresis is widely used to study the dynamics of strain spread in cystic fibrosis patients. The aim of this work was to perform pulsed-field gel electrophoresis-based molecular typing of B. cenocepacia isolates to evaluate the epidemiology of this species at our hospital. A total of 28 isolates from 23 cystic fibrosis patients were analyzed. Initially, we compared isolates obtained from the same patient at different periods of time. We then compared the pulsed-field gel electrophoresis profiles of 15 IIIA isolates, and in a third analysis, evaluated the genetic profile of 8 IIIB isolates from different patients. The pulsed-field gel electrophoresis profiles of isolates from the same patient indicated that they are genetically indistinguishable. Analysis of isolates from different patients revealed the presence of multiple clonal groups. These results do not indicate cross-transmission of a unique clone of B. cenocepacia among cystic fibrosis patients, although this has been observed in some patients. Our findings highlight the importance of adequate patient follow-up at cystic fibrosis centers and adherence to management and segregation measures in cystic fibrosis patients colonized with B. cenocepacia.

Diversity analysis of Burkholderia cepacia complex in the water bodies of West Lake, Hangzhou, China

A survey of Burkholderia cepacia complex (Bcc) species was conducted in water bodies of West Lake in China. A total of 670 bacterial isolates were recovered on selective media. Out of them, 39.6% (265 isolates) were assigned to the following species: Burkholderia multivorans, Burkholderia cenocepacia recA lineage IIIA, IIIB, Burkholderia stabilis, Burkholderia vietnamiensis, and Burkholderia seminalis while B. cenocepacia is documented as a dominant Bcc species in water of West Lake. In addition, all Bcc isolates tested were PCR negative for the cblA and esmR transmissibility marker genes except B. cenocepacia IIIB A8 which was positive for esmR genelater. The present study raises great concerns on the role of West Lake as a "reservoir" for potential Bcc pathogenic strains.

Unusual distribution of Burkholderia cepacia complex species in Danish cystic fibrosis clinics may stem from restricted transmission between patients

Forty-four of 48 Burkholderia cepacia complex strains cultured from Danish cystic fibrosis patients were Burkholderia multivorans, a distribution of species that has not been reported before. Although cases of cross infections were demonstrated, no major epidemic clone was found. The species distribution may represent the sporadic acquisition of bacteria from the environment.

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

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.

Interactions of Burkholderia cenocepacia and other Burkholderia cepacia complex bacteria with epithelial and phagocytic cells

Burkholderia cenocepacia is a member of the B. cepacia complex (Bcc), a group of opportunistic bacteria that infect the airways of patients with cystic fibrosis (CF) and are extraordinarily resistant to almost all clinically useful antibiotics. Infections in CF patients with Bcc bacteria generally lead to a more rapid decline in lung function, and in some cases to the ‘cepacia syndrome’, a virtually deadly exacerbation of the lung infection with systemic manifestations. These characteristics of Bcc bacteria contribute to higher morbidity and mortality in infected CF patients. In the last 10 years considerable progress has been made in understanding the interactions between Bcc bacteria and mammalian host cells. Bcc isolates can survive either intracellularly within eukaryotic cells or extracellularly in host tissues. They survive within phagocytes and respiratory epithelial cells, and they have the ability to breach the respiratory epithelium layer. Survival and persistence of Bcc bacteria within host cells and tissues are believed to play a key role in pulmonary infection and to contribute to the persistent inflammation observed in patients with CF. This review summarizes recent findings concerning the interaction between Bcc bacteria and epithelial and phagocytic cells.

Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides

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.

Burkholderia cepacia complex: epithelial cell–pathogen confrontations and potential for therapeutic intervention

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.

Burkholderia cepacia complex epidemiology in persons with cystic fibrosis from Australia and New Zealand

The Burkholderia cepacia complex (Bcc) is a group of significant opportunistic respiratory pathogens which affect people with cystic fibrosis. In this study, we sought to ascertain the epidemiology and geographic species distribution of 116 Bcc isolates collected from people with CF in Australia and New Zealand. We performed a combination of recA-based PCR, amplified rDNA restriction analysis (ARDRA), pulsed-field gel electrophoresis and repetitive extragenic palindromic PCR on each isolate. Each Burkholderia cenocepacia isolate was also screened by PCR for the presence of the B. cepacia epidemic strain marker. One hundred and fourteen isolates were assigned to a species using recA-based PCR and ARDRA. B. cenocepacia, B. multivorans and B. cepacia accounted for 45.7%, 29.3% and 11.2% of the isolates, respectively. Strain analysis of B. cenocepacia revealed that 85.3% of the isolates were unrelated. One related B. cenocepacia strain was identified amongst 15 people. Whilst full details of person-to-person contact was not available, all patients attended CF centres in Queensland (Qld) and New South Wales (NSW). Although person-to-person transmission of B. cenocepacia strains has occurred in Australia, the majority of CF-related Bcc infections in Australia and New Zealand are most likely acquired from the environment.

Burkholderia cenocepacia C5424 produces a pigment with antioxidant properties using a homogentisate intermediate

Burkholderia cenocepacia is a gram-negative opportunistic pathogen that belongs to the Burkholderia cepacia complex. B. cenocepacia can survive intracellularly within phagocytic cells, and some epidemic strains produce a brown melanin-like pigment that can scavenge free radicals, resulting in the attenuation of the host cell oxidative burst. In this work, we demonstrate that the brown pigment produced by B. cenocepacia C5424 is synthesized from a homogentisate (HGA) precursor. The disruption of BCAL0207 (hppD) by insertional inactivation resulted in loss of pigmentation. Steady-state kinetic analysis of the BCAL0207 gene product demonstrated that it has 4-hydroxyphenylpyruvic acid dioxygenase (HppD) activity. Pigmentation could be restored by complementation providing hppD in trans. The hppD mutant was resistant to paraquat challenge but sensitive to H2O2 and to extracellularly generated superoxide anions. Infection experiments in RAW 264.7 murine macrophages showed that the nonpigmented bacteria colocalized in a dextran-positive vacuole, suggesting that they are being trafficked to the lysosome. In contrast, the wild-type strain did not localize with dextran. Colocalization of the nonpigmented strain with dextran was reduced in the presence of the NADPH oxidase inhibitor diphenyleneiodonium, and also the inducible nitric oxide inhibitor aminoguanidine. Together, these observations suggest that the brown pigment produced by B. cenocepacia C5424 is a pyomelanin synthesized from an HGA intermediate that is capable of protecting the organism from in vitro and in vivo sources of oxidative stress.

Differential interaction of bacterial species from the Burkholderia cepacia complex with human airway epithelial cells

To increase knowledge of the pathogenic potential of the Burkholderia cepacia complex (BCC), we investigated the effects of reference strains of the nine BCC species on human bronchial epithelial cells in vitro. B. multivorans exhibited the highest rates of adherence to and internalization by host cells. Two out of three clinical isolates recovered from cystic fibrosis patients confirmed the B. multivorans high adhesiveness. All four B. multivorans isolates exhibited an aggregated pattern of adherence but any of them expressed cable pili. When bacteria were centrifuged onto cell cultures to circumvent their poor adhesiveness, B. pyrrocinia exhibited the highest internalization rate, followed by B. multivorans. The percentages of apoptotic cells in cultures infected with B. cepacia, B. multivorans, B. cenocepacia (subgroups IIIA and IIIB), B. stabilis and B. vietnamiensis were significantly higher than in control non-infected cultures. All nine BCC species triggered a similar release of the inflammatory cytokine IL-8, that was not reduced by cell treatment with cytochalasin D. Hence, our data demonstrate, for the first time, that all BCC species exhibit a similar ability to induce the expression of host immune mediators whereas they differ on their ability to adhere to, invade and kill airway epithelial cells.

Pyrosequencing™ of a recA gene variable region for Burkholderia cepacia complex genomovar identification

We developed an assay to identify Burkholderia cepacia complex genomovars by Pyrosequencing of a variable recA gene segment. Fifteen reference strains and 30 clinical isolates of B. cepacia complex were sequenced. Full 77-base pair target sequences were obtained from 44 of the 45 isolates, and BLAST queries of the sequences correctly identified the genomovar of these 44 isolates. Three Burkholderia multivorans isolates were identified as B. multivorans/Burkholderia ambifaria, indicating that additional identification methods may be needed for some B. multivorans strains.

Burkholderia cenocepacia, B. multivorans, B. ambifaria and B. vietnamiensis isolates from cystic fibrosis patients have different profiles of exoenzyme production

Knowledge about the virulence mechanisms of species from the Burkholderia cepacia complex (BCC) is still limited. The genomovar heterogeneity and production of different virulence factors are likely to contribute to the variation in the clinical outcome observed in BCC-infected cystic fibrosis (CF) patients. Therefore, in this study we investigated the genetic polimorphism, the presence of genetic makers associated with virulence and transmissibility in BCC, and the profile of exoenzyme production of 59 BCC isolates obtained from 59 CF patients attending the reference CF centre in Rio de Janeiro, Brazil. The DNA sequence analyses of the recA gene allowed us to identify 40 of these 59 BCC species as being B. cenocepacia, 9 as B. vietnamiensis, 6 as B. multivorans and 4 as B. ambifaria. The assessment of the bacterial genetic polymorphism by PFGE revealed that B. cenocepacia and the B. multivorans isolates belonged to four and two different PFGE profiles with prevalence of two clones, A and B, respectively. All B. vietnamiensis and B. ambifaria belonged to only one PFGE profile (J and E, respectively). None of the isolates exhibited the genetic markers cblA and BCESM, assessed by polymerase chain reaction. In contrast, the profile of enzymatic activity, assessed by phenotypic methods, differed among the BCC species: protease activity was detected only in B. cenocepacia and B. ambifaria isolates, whereas only B. vietnamiensis isolates produced hemolysin. Although the phospholipase C activity was similar among the different species, the level of lipase activity produced by B. multivorans was higher than in the other species. We speculate that the differential characteristics of exoenzyme production may account for the differences in the pathogenic potentials of each BCC species.

Infection Control Practice in Cystic Fibrosis Centers

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.

Evolving epidemiology of Pseudomonas aeruginosa and the Burkholderia cepacia complex in cystic fibrosis lung infection

The morbidity and mortality of patients with cystic fibrosis (CF) is primarily determined by chronic and debilitating lung infections caused by a surprisingly narrow spectrum of bacterial pathogens. Pseudomonas aeruginosa is by far the most prevalent life-threatening CF pathogen. In the absence of aggressive early therapy, it infects the majority of adult patients and determines long-term survival. The epidemiology of CF pulmonary infections continues to evolve. Amongst the most recent CF pathogens to have emerged are a group of closely related bacteria, known as the Burkholderia cepacia complex. These organisms are a particular challenge due to inherent antibiotic resistance, the potential for patient-to-patient spread, and the risk of ‘cepacia syndrome’, a rapid fulminating pneumonia sometimes accompanied by bacteremia. Strict cross-infection control was prompted by early epidemiological experience of the B. cepacia complex and is essential in the management of all CF pathogens.

Identification of genes regulated by the cepIR quorum-sensing system in Burkholderia cenocepacia by high-throughput screening of a random promoter library

The Burkholderia cenocepacia cepIR quorum-sensing system regulates expression of extracellular proteases, chitinase, and genes involved in ornibactin biosynthesis, biofilm formation, and motility. In a genome-wide screen we identified cepIR-regulated genes by screening a random promoter library of B. cenocepacia K56-2 constructed in a luminescence reporter detection plasmid for differential expression in response to N-octanoyl-l-homoserine lactone (OHL). Eighty-nine clones were identified; in 58 of these clones expression was positively regulated by cepIR, and in 31 expression was negatively regulated by cepIR. The expression profiles of the 89 promoter clones were compared in the cepI mutant K56-dI2 in medium supplemented with 30 pM OHL and K56-2 to confirm that the presence of OHL restored expression to wild-type levels. To validate the promoter library observations and to determine the effect of a cepR mutation on expression of selected genes, the mRNA levels of nine genes whose promoters were predicted to be regulated by cepR were quantitated by quantitative reverse transcription-PCR in the wild type and cepI and cepR mutants. The expression levels of all nine genes were similar in the cepI and cepR mutants and consistent with the promoter-lux reporter activity. The expression of four selected cepIR-regulated gene promoters was examined in a cciIR mutant, and two of these promoters were also regulated by cciIR. This study extends our understanding of genes whose expression is influenced by cepIR and indicates the global regulatory effect of the cepIR system in B. cenocepacia.

Differences in invasion and translocation of Burkholderia cepacia complex species in polarised lung epithelial cells in vitro

In order to investigate the mechanisms by which Burkholderia cepacia complex (Bcc) strains cross the epithelial barrier of the lung and cause septicaemia in a subgroup of Cystic Fibrosis (CF) patients, the invasiveness of four Bcc species have been examined in three lung epithelial cells: A549, 16HBE14o- and Calu-3. The latter two cell lines form polarised monolayers when grown on filters. Invasion of both cell lines by B. multivorans strains was reduced when the cells were grown as tight monolayers compared unpolarised cells, suggesting basolateral receptors are required for the process. In contrast, four B. cenocepacia strains showed comparable invasion of both cell lines irrespective of culture model. All four species of Bcc reduced the TER of Calu-3 monolayers. However, while B. cepacia, B. multivorans and B. stabilis strains readily translocated across the epithelial monolayer, B. cenocepacia translocation was slower. Both B. multivorans and B. cenocepacia altered expression of ZO-1 in Calu-3 cells, but not E-cadherin. Overall, the findings that Bcc strains from four species, which differ greatly in their virulence, have the potential to disrupt tight junctions and to translocate across the epithelium, demonstrates this effect is not exclusive to the most virulent species.

Effect of reduced pH on inorganic polyphosphate accumulation by Burkholderia cepacia complex isolates

AIMS

Burkholderia cepacia complex (Bcc) isolates causing pulmonary infection in cystic fibrosis (CF) patients grow within an acidic environment in the lung. As exposure to acid pH has been shown to increase intracellular inorganic polyphosphate (polyP) formation in some bacteria, we investigated the inter-relationship between acidic pH and polyP accumulation in Bcc isolates.

METHODS AND RESULTS

The formation of polyP by one Burkholderia cenocepacia clinical isolate was initially examined at a range of pH values by measuring total intracellular polyP accumulation and phosphate uptake. The pattern of polyP accumulation corresponded with the pattern of phosphate uptake with the maximum for both occurring at pH 5.5. Phosphate uptake and formation of polyP by this isolate was further determined over 48 h at pH 5.5, 6.5 and 7.5; formation of polyP was maximal at pH 5.5 at all time points studied. Sixteen of 17 additional clinical and environmental Bcc isolates examined also exhibited maximum phosphate uptake at pH 5.5.

CONCLUSIONS

Both clinical and environmental Bcc isolates, of five genomovars, show enhanced formation of polyP in an acidic environment. Given both the speculated role of polyP in pathogenesis, cell signalling and biofilm formation and the acidic nature of the CF lung, this may be of considerable clinical importance.

SIGNIFICANCE AND IMPACT OF THE STUDY

Growth of Bcc in an acidic environment, such as that found in the lungs of CF patients may be influenced in part by polyP accumulation.

Molecular epidemiology and antibiotic susceptibility of Burkholderia cepacia-complex isolates from an Italian cystic fibrosis centre

In order to further understanding of how different isolates of Burkholderia cepacia complex persist, spread and cause disease, B. cepacia-complex isolates from 60 patients attending the Cystic Fibrosis Centre of Verona, Italy, between 1997 and 2002 were analyzed. Strains were examined for species, presence of putative epidemic and virulence markers (i.e., cblA and the B. cepacia epidemic-strain marker [BCESM]), genetic relatedness and antibiotic susceptibility. Forty-five percent of patients were infected with B. cenocepacia recA subgroup B, 28% with B. cenocepacia recA subgroup A, 5% with B. multivorans and 5% with B. cepacia. No isolate carried cblA but 35% of B. cenocepacia and one of B. cepacia carried the BCESM transmissibility marker. Pulsed-field gel electrophoresis (PFGE) identified 40 types; 22 of these corresponded to sporadic isolates and 18 to clusters of identical or genetically related strains. Piperacillin, ceftazidime and piperacillin-tazobactam were the most active antibiotics (43.3, 31.1 and 35.5% of resistance, respectively). These results confirm the prevalence of B. cenocepacia in cystic fibrosis patients with rapid clinical deterioration and in those with stable cases of infection. The rates of multiple-source and cross infection were relatively low.

Update on the Burkholderia cepacia complex

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.

Characterization of the cciIR quorum-sensing system in Burkholderia cenocepacia

Several transmissible Burkholderia cenocepacia strains that infect multiple cystic fibrosis patients contain a genomic island designated as the cenocepacia island (cci). The cci contains a predicted N-acylhomoserine lactone (AHL) synthase gene, cciI, and a predicted response regulator gene, cciR. AHL production profiles indicated that CciI catalyzes the synthesis of N-hexanoyl-l-homoserine lactone and minor amounts of N-octanoyl-l-homoserine lactone. The cciI and cciR genes were found to be cotranscribed by reverse transcription-PCR analysis, and the expression of a cciIR::luxCDABE fusion in a cciR mutant suggested that the cciIR system negatively regulates its own expression. B. cenocepacia strains also have a cepIR quorum-sensing system. Expression of cepI::luxCDABE or cepR::luxCDABE fusions in a cciR mutant showed that CciR negatively regulates cepI but does not regulate cepR. Expression of the cciIR::luxCDABE fusion in a cepR mutant indicated that functional CepR is required for cciIR expression. Phylogenetic analysis suggested that the cciIR system was acquired by horizontal gene transfer from a distantly related organism and subsequently incorporated into the ancestral cepIR regulatory network. Mutations in cciI, cciR, cepI cciI, and cepR cciR were constructed in B. cenocepacia K56-2. The cciI mutant had greater protease activity and less swarming motility than the parent strain. The cciR mutant had less protease activity than the parent strain. The phenotypes of the cepI cciI and cepR cciR mutants were similar to cepI or cepR mutants, with less protease activity and swarming motility than the parent strain.

Widespread clone of Burkholderia cenocepacia in cystic fibrosis patients in the Czech Republic

The morbidity and mortality rates in patients with cystic fibrosis (CF) are significantly affected by infections with Burkholderia cepacia complex. In a Czech CF Centre, the prevalence of the infection reached up to 30 %, with the majority of patients found to be infected with Burkholderia cenocepacia (formerly genomovar III of the Burkholderia cepacia complex). Since B. cenocepacia is associated with patient-to-patient transmission and epidemic outbreaks among CF patients, this study sought to examine the epidemiological relatedness between the Czech isolates belonging to the genomovar-homogeneous group. Eighty-three clinical isolates recovered from 67 CF patients were analysed using a random amplified polymorphic DNA (RAPD) assay and macrorestriction typing (SpeI and XbaI) followed by PFGE. A single predominant banding pattern shared by multiple isolates was detected, although SpeI-generated PFGE results yielded a higher rate of inter-pattern variability in comparison to the more uniform RAPD and XbaI-generated PFGE results for this clone. Both typing systems also showed that only three out of 67 patients harboured strains distinct from the major strain type. The dominant clone was characterized by PCR positivity for the B. cepacia epidemic strain marker, PCR negativity for the cable pilin subunit gene and close genetic relatedness to the epidemic strain of RAPD 01 type previously identified in Canada.