Empyema and bloodstream infection caused by Burkholderia gladioli in a patient with cystic fibrosis after lung transplantation

Post-transplant outcomes among cystic fibrosis patients undergoing lung transplantation colonized by Burkholderia: A single center cohort study

BACKGROUND

Prior infection with Burkholderia cepacia complex (BCC) has been associated with poorer outcomes after lung transplantation, posing an important dilemma for cystic fibrosis (CF). Although current guidelines consider BCC infection to be a relative contraindication, some centers continue to offer lung transplantation to BCC-infected CF patients.

METHODS

We conducted a retrospective cohort study which included all consecutive CF-LTR between 2000 and 2019 to compare the postoperative survival of BCC-infected CF lung transplant recipients (CF-LTR) to BCC-uninfected patients. We used a Kaplan-Meier analysis to compare survival of BCC-infected to BCC-uninfected CF-LTR and fitted a multivariable Cox model, adjusted for age, sex, BMI and year of transplantation as potential confounders. As an exploratory analysis, Kaplan-Meier curves were also stratified by the presence of BCC and urgency of transplantation.

RESULTS

A total of 205 patients were included with a mean age of 30.5 years. Seventeen patients (8%) were infected with BCC prior to LT. Patients were infected with the following species: B. multivorans5, B. vietnamiensis3, combined B. multivorans and B. vietnamiensis3 and others4. None of the patients were infected with B. cenocepacia. Three patients were infected with B. gladioli. One-year survival was 91.7% (188/205) for the entire cohort, 82.4% (14/17) among BCC-infected CF-LTR, and 92.5% (173/188) among BCC uninfected CF-LTR (crude HR = 2.19; 95%CI 0.99-4.85; p = 0.05). In the multivariable model, presence of BCC was not significantly associated with worse survival (adjusted HR 1.89; 95%CI 0.85-4.24; p = 0.12). In the stratified analysis for both presence of BCC and urgency of transplantation, urgency of transplantation among BCC-infected CF-LTR appeared to be associated with poorer outcome (p = 0.003 across the 4 subgroups).

CONCLUSION

Our results suggest that non-cenocepacia BCC-infected CF-LTR have comparable survival rate to BCC-uninfected CF-LTR.

Persistent pleuritic chest pain in a patient with cystic fibrosis

A 14-year-old girl with cystic fibrosis (CF), homozygous for the Phe508del mutation, was electively admitted for optimisation of lung disease. Her CF was complicated by bronchiectasis, gastrostomy feeding, liver disease, and diabetes. Sputum cultures had identified Haemophilus parainfluenzae and Candida albicans in the previous 12 months, but she had never cultured Pseudomonas aeruginosa. She also had comorbid osteogenesis imperfecta (OI), type 3 phenotype, which was complicated by multiple long bone fractures including four rib fractures at birth. Her baseline forced expiratory volume in 1 s (FEV₁) was 44% (0.78 L), forced vital capacity (FVC) 54% (1.06 L), and FEV₁/FVC ratio 81% predicted. The combination of CF and OI had resulted in severe restrictive lung disease with nocturnal hypoventilation managed with bilevel noninvasive ventilation.

Pleural effusion is rare in cystic fibrosis. Infection leading to pleural effusion is likely to be polymicrobial, including contributory fungal infection; microbiology of pleural fluid is commonly discordant with sputum.https://bit.ly/3MJXrhk

Multiple skin abscesses associated with bacteremia caused by Burkholderia gladioli: A case report

BACKGROUND

Burkholderia gladioli (B. gladioli) is regarded as a rare opportunistic pathogen. Only a few patients with abscesses caused by B. gladioli infections have been reported, and these are usually abscesses at the incision caused by traumatic surgery.

CASE SUMMARY

A 74-year-old male patient with abscesses and pain throughout his body for 1 mo was admitted to our hospital. Some of the abscesses had ruptured with purulent secretions on admission. Color Doppler ultrasound examination of the body surface masses showed mixed masses 75 mm × 19 mm, 58 mm × 17 mm, 17 mm × 7 mm, and 33 mm × 17 mm in size in the muscle tissues of both the right and left forearms, the posterior area of the right knee and the left leg, respectively. Abscess secretions and blood cultures grew B. gladioli. The following 3 methods were used to jointly identify the bacterium: an automatic microbial identification system, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and full-length 16S rDNA sequencing. After 27 d of treatment with meropenem, etimicin, trimethoprim-sulfamethoxazole and other antibiotics, most of his skin abscesses were flat and he was discharged without any symptoms.

CONCLUSION

This is the first reported case of multiple skin abscesses associated with bacteremia caused by B. gladioli. Our study provides important reference values for the clinical diagnosis and treatment of B. gladioli infections.

The Impact of Resistant Bacterial Pathogens including Pseudomonas aeruginosa and Burkholderia on Lung Transplant Outcomes

Pseudomonas and Burkholderia are gram-negative organisms that achieve colonization within the lungs of patients with cystic fibrosis, and are associated with accelerated pulmonary function decline. Multidrug resistance is a hallmark of these organisms, which makes eradication efforts difficult. Furthermore, the literature has outlined increased morbidity and mortality for lung transplant (LTx) recipients infected with these bacterial genera. Indeed, many treatment centers have considered Burkholderia cepacia infection an absolute contraindication to LTx. Ongoing research has delineated different species within the B. cepacia complex (BCC), with significantly varied morbidity and survival profiles. This review considers the current evidence for LTx outcomes between the different subspecies encompassed within these genera as well as prophylactic and management options. The availability of meta-genomic tools will make differentiation between species within these groups easier in the future, and will allow more evidence-based decisions to be made regarding suitability of candidates colonized with these resistant bacteria for LTx. This review suggests that based on the current evidence, not all species of BCC should be considered contraindications to LTx, going forward.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

A rapid screening method for the detection of specialised metabolites from bacteria: Induction and suppression of metabolites from Burkholderia species

Screening microbial cultures for specialised metabolites is essential for the discovery of new biologically active compounds. A novel, cost-effective and rapid screening method is described for extracting specialised metabolites from bacteria grown on agar plates, coupled with HPLC for basic identification of known and potentially novel metabolites. The method allows the screening of culture collections to identify optimal production strains and metabolite induction conditions. The protocol was optimised on two Burkholderia species known to produce the antibiotics, enacyloxin IIa (B. ambifaria) and gladiolin (B. gladioli), respectively; it was then applied to strains of each species to identify high antibiotic producers. B. ambifaria AMMD and B. gladioli BCC0238 produced the highest concentrations of the respective antibiotic under the conditions tested. To induce expression of silent biosynthetic gene clusters, the addition of low concentrations of antibiotics to growth media was evaluated as known elicitors of Burkholderia specialised metabolites. Subinhibitory concentrations of trimethoprim and other clinically therapeutic antibiotics were evaluated and screened against a panel of B. gladioli and B. ambifaria. To enhance rapid strain screening with more antibiotic elicitors, antimicrobial susceptibility testing discs were included within the induction medium. Low concentrations of trimethoprim suppressed the production of specialised metabolites in B. gladioli, including the toxins, toxoflavin and bongkrekic acid. However, the addition of trimethoprim significantly improved enacylocin IIa concentrations in B. ambifaria AMMD. Rifampicin and ceftazidime significantly improved the yield of gladiolin and caryoynencin by B. gladioli BCC0238, respectively, and cepacin increased 2-fold with tobramycin in B. ambifaria BCC0191. Potentially novel metabolites were also induced by subinhibitory concentrations of tobramycin and chloramphenicol in B. ambifaria. In contrast to previous findings that low concentrations of antibiotic elicit Burkholderia metabolite production, we found they acted as both inducers or suppressors dependent on the metabolite and the strains producing them. In conclusion, the screening protocol enabled rapid characterization of Burkholderia metabolites, the identification of suitable producer strains, potentially novel natural products and an understanding of metabolite regulation in the presence of inducing or suppressing conditions.

Discrimination of Burkholderia gladioli pv.alliicola and B. cepacia complex using the gyrB gene of B. gladioli pv. alliicola

The aim of the present study was to investigate the efficiency of the gyrB gene derived from Burkholderia gladioli pv.Alliicola (Bga) on the identification of Bga from the B. cepacia complex (Bcc) based on the COnsensus-DEgenerate Hybrid Oligonucleotide Primer (CODEHOP) strategy. A set of primers used for the specific amplification of the gyrB gene in Bga were designed according to the CODEHOP principle. A total of 1,644 bp of the gyrB gene sequence of Bga were acquired by CODEHOP amplification. The sequence was blasted in GenBank and it revealed an average of 86% similarity with the gyrB gene of nine genomovars of Bcc. A phylogenetic tree was constructed using the gyrB gene sequences. The microarray method was adopted to discriminate Bga from Bcc based on the specific probes designed upon the gyrB gene, and five genomovars of Bcc demonstrated a good discrimination from Bga on the microarray chip. CODEHOP strategy succeeded in amplification of the gyrB gene of Bga, which made it possible for the identification of Bga from five genomovars of Bcc.

Empyema in a woman with cystic fibrosis: a cautionary tale

Cystic fibrosis (CF) is a disease which predisposes individuals to recurrent infective exacerbations of suppurative lung disease; however, empyema is a rare complication in these patients. Empyemas secondary to Staphylococcus aureus and Burkholderia cepacia have been described in patients with CF. We report the case of pleural empyema with mixed S. aureus and Pseudomonas aeruginosa infection in a 34-year-old woman with CF, which was managed with ultrasound-guided pigtail catheter insertion, fibrinolysis, and antibiotic therapy. Physicians should be aware of this unusual complication in CF patients, especially those receiving an immunosuppressive therapy.

Empyema due to a highly transmissible Pseudomonas aeruginosa strain in an adult cystic fibrosis patient

Chronic pulmonary infection with Pseudomonas aeruginosa occurs in up to 85 % of individuals with cystic fibrosis (CF) by the time they reach adulthood, and is the major cause of morbidity and mortality: nearly all patients die from progressive respiratory failure due to repeated pulmonary exacerbations. However, despite the predilection of this organism for the lungs of CF people, infection of the pleura is much less common and is not well described in the CF population. We describe what is believed to be the first case of pleural empyema due to a particularly pathogenic transmissible strain of P. aeruginosa (the Liverpool epidemic strain) in an adult CF patient.

Mediastinal abscess after lung transplantation secondary to Burkholderia gladioli infection

Burkholderia gladioli is an unusual organism that has become increasingly responsible for infections in patients who are immunosuppressed, including patients who have undergone solid organ transplantation. This article presents a patient in whom a mediastinal mass due to Burkholderia gladioli developed after lung transplantation. A review of the literature is also presented.

Microbiological and epidemiological features of clinical respiratory isolates of Burkholderia gladioli

Burkholderia gladioli, primarily known as a plant pathogen, is involved in human infections, especially in patients with cystic fibrosis (CF). In the present study, the first respiratory isolates recovered from 14 French patients with CF and 4 French patients without CF, identified by 16S rRNA gene analysis, were tested for growth on B. cepacia selective media, for identification by commercial systems, and for their antimicrobial susceptibilities, and were compared by pulsed-field gel electrophoresis (PFGE). Patients' data were collected. All 18 isolates grew on oxidation-fermentation-polymyxin B-bacitracin-lactose medium and Pseudomonas cepacia agar, but only 13 grew on Burkholderia cepacia selective agar. API 20NE strips did not differentiate B. gladioli from B. cepacia, whereas Vitek 2 GN cards correctly identified 15 isolates. All isolates were susceptible to piperacillin, imipenem, aminoglycosides, and ciprofloxacin and were far less resistant to ticarcillin than B. cepacia complex organisms. Fifteen PFGE types were observed among the 18 isolates, but shared types were not identified among epidemiologically related patients. The microbiological follow-up of CF patients showed that colonization was persistent in 3 of 13 documented cases; B. gladioli was isolated from posttransplantation cultures of blood from 1 patient. Among the patients without CF, B. gladioli was associated with intubation (three cases) or bronchiectasis (one case). In summary, the inclusion of B. gladioli in the databases of commercial identification systems should improve the diagnostic capabilities of those systems. In CF patients, this organism is more frequently involved in transient infections than in chronic infections, but it may be responsible for complications posttransplantation; patient-to-patient transmission has not been demonstrated to date. Lastly, B. gladioli appears to be naturally susceptible to aminoglycosides and ciprofloxacin, although resistant isolates may emerge in the course of chronic infections.

Two cases of keratitis and corneal ulcers caused by Burkholderia gladioli

We report two cases of protracted keratitis complicated by corneal ulcer. Burkholderia gladioli, primarily known as a plant pathogen, was cultured from corneal swabs. The epithelial defects healed after extended adequate antibiotic therapy. Despite identical patterns of both strains in restriction fragment length polymorphism analysis, a common infection source was not detectable.

Burkholderia gladioli osteomyelitis in association with chronic granulomatous disease: case report and review

We describe a case of insidious small bone osteomyelitis and soft tissue abscess with Burkholderia gladioli in a 6-year-old Caucasian boy with chronic granulomatous disease. DNA sequencing of the 16S ribosomal RNA gene confirmed the bacterial identification. Clinical cure was achieved with a combination of antimicrobial therapy and surgical debridement. A review of infections caused by Burkholderia spp., other than Burkholderia cepacia complex, in pediatric patients with chronic granulomatous disease is provided.

Naturally occurring anti-IFN-gamma autoantibody and severe infections with Mycobacterium cheloneae and Burkholderia cocovenenans

Recently various genetic defects in immunity mediated by interferon gamma (IFN-gamma) have been described, including mutations in the IFN-gamma receptor 1 (IFN-gammaR1) and receptor 2 (IFN-gammaR2), signal transducer and activator of transcription 1 (STAT 1), and interleukin 12 receptor beta 1 (IL-12Rbeta1), and IL-12 p40 genes. These mutations are associated with the occurrence of severe infections with intracellular pathogens especially nontuberculous mycobacteria and vaccine-associated bacilli Calmette-Guérin (BCG). Here we report data on a previously healthy adult patient primarily presenting with severe infections with Burkholderia cocovenenans and subsequently Mycobacterium cheloneae. We found a strong inhibitory anti-IFN-gamma activity in the patient's plasma and identified a high-affinity neutralizing anti-IFN-gamma autoantibody. Unfortunately, the patient died due to severe sepsis before we knew the nature of the inhibitory activity. The application of alternative therapeutic approaches such as intravenous immunoglobulin or immunoadsorption may have been beneficial in this case. Screening for neutralizing anti-IFN-gamma autoantibodies should supplement testing for IFN-gamma and IL-12 pathway defects in patients with recurrent infections with intracellular pathogens, especially with nontuberculous mycobacteria.

Burkholderia gladioli keratitis associated with consecutive recurrent endophthalmitis

PURPOSE

To report a case of Burkholderia gladioli keratitis with consecutive endophthalmitis.

METHODS

Case report and literature review.

RESULTS

A 76-year-old man with a history of diabetes mellitus developed bacterial keratitis and consecutive endophthalmitis in the corneal graft of the left eye. Corneal, aqueous, and vitreous cultures yielded Burkholderia gladioli. Emergent keratoplasty, pars plana vitrectomy, and injection of intravitreal antibiotics led to resolution of the infection and improved vision. Four months later, the patient developed recurrent Burkholderia keratitis and endophthalmitis, necessitating a total keratoplasty and repeat injection of intravitreal antibiotics.

CONCLUSION

This is the first report, to our knowledge, of ocular Burkholderia gladioli infection, an uncommon aerobic, gram-negative rod, recently subclassified from the genus Pseudomonas based on DNA-rRNA homology studies.

Burkholderia gladioli: recurrent abscesses in a patient with cystic fibrosis

We describe a case of an adult patient with cystic fibrosis who developed chronic pulmonary infection and multiple episodes of soft tissue abscesses with Burkholderia gladioli; this organism should be added to the list of potential pathogens for individuals with cystic fibrosis.

Distinguishing species of the Burkholderia cepacia complex and Burkholderia gladioli by automated ribotyping

Several species belonging to the genus Burkholderia are clinically relevant, opportunistic pathogens that inhabit major environmental reservoirs. Consequently, the availability of means for adequate identification and epidemiological characterization of individual environmental or clinical isolates is mandatory. In the present communication we describe the use of the Riboprinter microbial characterization system (Qualicon, Warwick, United Kingdom) for automated ribotyping of 104 strains of Burkholderia species from diverse sources, including several publicly accessible collections. The main outcome of this analysis was that all strains were typeable and that strains of Burkholderia gladioli and of each species of the B. cepacia complex, including B. multivorans, B. stabilis, and B. vietnamiensis, were effectively discriminated. Furthermore, different ribotypes were discerned within each species. Ribotyping results were in general agreement with strain classification based on restriction fragment analysis of 16S ribosomal amplicons, but the resolution of ribotyping was much higher. This enabled automated molecular typing below the species level. Cluster analysis of the patterns obtained by ribotyping (riboprints) showed that within B. gladioli, B. multivorans, and B. cepacia genomovar VI, the different riboprints identified always clustered together. Riboprints of B. cepacia genomovars I and III, B. stabilis, and B. vietnamiensis did not show distinct clustering but rather exhibited the formation of loose assemblages within which several smaller, genomovar-specific clusters were delineated. Therefore, ribotyping proved useful for genomovar identification. Analysis of serial isolates from individual patients demonstrated that infection with a single ribotype had occurred, despite minor genetic differences that were detected by pulsed-field gel electrophoresis of DNA macrorestriction fragments. The automated approach allows very rapid and reliable identification and epidemiological characterization of strains and generates an easily manageable database suited for expansion with information on additional bacterial isolates.

Species-specific PCR as a tool for the identification of Burkholderia gladioli

Burkholderia gladioli colonizes the respiratory tracts of patients with cystic fibrosis and chronic granulomatous disease. However, due to the high degree of phenotypic similarity between this species and closely related species in the Burkholderia cepacia complex, accurate identification is difficult. Incorrect identification of these species may have serious repercussions for the management of patients with cystic fibrosis. To develop an accurate procedure for the identification of B. gladioli, a molecular method to discriminate between this species and other species commonly isolated from the sputa of patients with cystic fibrosis was investigated. The 23S ribosomal DNA was cloned from several clinical isolates of B. gladioli, and the nucleotide sequence was determined. Computer-assisted sequence comparisons indicated four regions of the 23S rRNA specific for this species; these regions were used to design three primer pairs for species-specific PCR. Two of the primer pairs showed 100% sensitivity and specificity for B. gladioli when tested against a panel of 47 isolates comprising 19 B. gladioli isolates and 28 isolates of 16 other bacterial species. One of the primer pairs was further assessed for species specificity by using a panel of 102 isolates obtained from the Burkholderia cepacia Research Laboratory and Repository. The species-specific PCR was positive for 70 of 74 isolates of B. gladioli and was negative for all other bacterial species examined. Overall, this primer pair displayed a sensitivity and specificity of 96% (89 of 93) and 100%, respectively. These data demonstrate the potential of species-specific PCR for the identification of B. gladioli.

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

Cystic fibrosis (CF) predisposes patients to bacterial colonization and infection of the lower airways. Several species belonging to the genus Burkholderia are potential CF-related pathogens, but microbiological identification may be complicated. This situation is not in the least due to the poorly defined taxonomic status of these bacteria, and further validation of the available diagnostic assays is required. A total of 114 geographically diverse bacterial isolates, previously identified in reference laboratories as Burkholderia cepacia (n = 51), B. gladioli (n = 14), Ralstonia pickettii (n = 6), B. multivorans (n = 2), Stenotrophomonas maltophilia (n = 3), and Pseudomonas aeruginosa (n = 11), were collected from environmental, clinical, and reference sources. In addition, 27 clinical isolates putatively identified as Burkholderia spp. were recovered from the sputum of Dutch CF patients. All isolates were used to evaluate the accuracy of two selective growth media, four systems for biochemical identification (API 20NE, Vitek GNI, Vitek NFC, and MicroScan), and three different PCR-based assays. The PCR assays amplify different parts of the ribosomal DNA operon, either alone or in combination with cleavage by various restriction enzymes (PCR-restriction fragment length polymorphism [RFLP] analysis). The best system for the biochemical identification of B. cepacia appeared to be the API 20NE test. None of the biochemical assays successfully grouped the B. gladioli strains. The PCR-RFLP method appeared to be the optimal method for accurate nucleic acid-mediated identification of the different Burkholderia spp. With this method, B. gladioli was also reliably classified in a separate group. For the laboratory diagnosis of B. cepacia, we recommend parallel cultures on blood agar medium and selective agar plates. Further identification of colonies with a Burkholderia phenotype should be performed with the API 20NE test. For final confirmation of species identities, PCR amplification of the small-subunit rRNA gene followed by RFLP analysis with various enzymes is recommended.

Empyema complicating successful lung transplantation

OBJECTIVE

To assess the prevalence and etiology of empyema complicating successful lung transplantation.

DESIGN

Retrospective review.

SETTING

University medical center transplant service.

PATIENTS

All recipients (n = 392) of single-lung, double-lung, and heart-lung transplantation between May 1984 and April 1997.

RESULTS

Of the 392 transplant recipients, empyema was documented in 14 patients (3.6%) at a mean time (+/- SD) of 46 days after transplantation (range, 14 to 167 days). Of these 14 recipients with empyema, 4 recipients (28.6%) died of infectious complications related to empyema. Empyema was seen secondary to Gram-positive, Gram-negative, and saprophytic organisms; however, there was no predominance of a particular organism recovered from the empyemic fluid (chi2 = 0.53; p = 0.75). The development of empyema was not related to whether the transplant was performed secondary to a septic or nonseptic lung disorder (chi2 = 1.06; p = 0.67), nor was it related to the type of transplant procedure performed (ie, single-lung, double-lung, or heart-lung allografts; chi2 = 4.39; p = 0.30).

CONCLUSION

Empyema, a relatively uncommon complication of lung transplantation, is not related to the type of allograft received or to whether the recipient had a septic or a nonseptic lung disorder. If empyema does occur, the mortality associated with this infection is substantial.

Evaluation of three oligonucleotide primer sets in PCR for the identification of Burkholderia cepacia and their differentiation from Burkholderia gladioli

AIMS

To evaluate three oligonucleotide primer pairs--two specific for 16S and 23S rRNA sequences of Burkholderia cepacia, and the third specific for internal transcribed spacer region of 16S-23S sequences of B gladioli--for the identification and differentiation of reference and clinical strains of these and other species.

METHODS

The three primers sets were applied in polymerase chain reaction (PCR) to a collection of 177 clinical isolates submitted for identification from diagnostic laboratories as presumed B cepacia.

RESULTS

At an annealing temperature of 63 degrees C, all eight B cepacia and four B gladioli reference strains reacted with their specific primers. B vandii was the only other species that was positive with both B cepacia primers but five Burkholderia or Ralstonia species reacted with one of these primers. Seventy eight isolates were typical of B cepacia in biochemical tests and 75 of these reacted with specific primers; three, however, were positive with the B gladioli primers. Fifteen asaccharolytic isolates were confirmed as B cepacia by PCR but other non-fermenting Gram negative species were negative with each of the primers.

CONCLUSIONS

PCR using 16S rRNA sequences is recommended for identification of B cepacia that give atypical results in biochemical tests.

Discrimination of Burkholderia gladioli from other Burkholderia species detectable in cystic fibrosis patients by PCR

A procedure for molecular identification of Burkholderia gladioli is described. Specific 16S and 23S rRNA gene signature sequences were defined as primers for PCR. The method allows rapid and specific discrimination of B. gladioli from related species (B. cepacia, B. multivorans, B. vietnamiensis, B. mallei, B. pseudomallei, Ralstonia pickettii, and R. eutropha) and should contribute to the clarification of its role as a human pathogen, e.g., in cystic fibrosis.