Burkholderia gladioli - a predictor of poor outcome in cystic fibrosis patients who receive lung transplants? A case of locally invasive rhinosinusitis and persistent bacteremia in a 36-year-old lung transplant recipient with cystic fibrosis

Prophylactic phage biocontrol prevents Burkholderia gladioli infection in a quantitative ex planta model of bacterial virulence

Agricultural crop yield losses and food destruction due to infections by phytopathogenic bacteria such as Burkholderia gladioli, which causes devastating diseases in onion, mushroom, corn, and rice crops, pose major threats to worldwide food security and cause enormous damage to the global economy. Biocontrol using bacteriophages has emerged as a promising strategy against a number of phytopathogenic species but has never been attempted against B. gladioli due to a lack of quantitative infection models and a scarcity of phages targeting this specific pathogen. In this study, we present a novel, procedurally straightforward, and highly generalizable fully quantitative ex planta maceration model and an accompanying quantitative metric, the ex planta maceration index (xPMI). In utilizing this model to test the ex planta virulence of a panel of 12 strains of B. gladioli in Allium cepa and Agaricus bisporus, we uncover substantial temperature-, host-, and strain-dependent diversity in the virulence of this fascinating pathogenic species. Crucially, we demonstrate that Burkholderia phages KS12 and AH2, respectively, prevent and reduce infection-associated onion tissue destruction, measured through significant (P < 0.0001) reductions in xPMI, by phytopathogenic strains of B. gladioli, thereby demonstrating the potential of agricultural phage biocontrol targeting this problematic microorganism.IMPORTANCEAgricultural crop destruction is increasing due to infections caused by bacteria such as Burkholderia gladioli, which causes plant tissue diseases in onion, mushroom, corn, and rice crops. These bacteria pose a major threat to worldwide food production, which, in turn, damages the global economy. One potential solution being investigated to prevent bacterial infections of plants is "biocontrol" using bacteriophages (or phages), which are bacterial viruses that readily infect and destroy bacterial cells. In this article, we demonstrate that Burkholderia phages KS12 and AH2 prevent or reduce infection-associated plant tissue destruction caused by strains of B. gladioli, thereby demonstrating the inherent potential of agricultural phage biocontrol.

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.

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.

Epidemiology of Burkholderia Infections in People with Cystic Fibrosis in Canada between 2000 and 2017

Rationale: Infections by Burkholderia species bacteria in cystic fibrosis (CF) may be transmissible, necessitating infection control measures, and remain a serious cause of morbidity and mortality. The last major study of Burkholderia epidemiology in Canada included cases up until July 2000 and was marked by the dominance of a limited number of epidemic clones of Burkholderia cenocepacia.Objectives: Describe the nationwide epidemiology of Burkholderia species infections in people with cystic fibrosis in Canada over the 17-year period since 2000.Methods: Isolates were collected from across Canada between August 2000 and July 2017 and identified to the species and, for isolates between 2015 and 2017, strain level.Results: We analyzed 1,362 Burkholderia isolates from at least 396 people with CF. Forty-nine percent (n = 666) of all isolates and 47% (n = 179) of new incident infections were identified as B. multivorans. The incidence of Burkholderia infection in the Canadian CF population did not change between 2000 and 2017 at 6 cases per 1,000 annually. Multilocus sequence typing analysis suggested minimal sharing of clones in Canada.Conclusions: The epidemiology of Burkholderia in CF in Canada has shifted from limited numbers of epidemic strains of B. cenocepacia to largely nonclonal isolates of B. multivorans, B. cenocepacia, and other species. Despite widespread infection control, however, Burkholderia species bacteria continue to be acquired by people with CF at an unchanged rate, posing a continued hazard.

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.

Pan-Genome Analysis Reveals Host-Specific Functional Divergences in Burkholderia gladioli

Burkholderia gladioli has high versatility and adaptability to various ecological niches. Here, we constructed a pan-genome using 14 genome sequences of B. gladioli, which originate from different niches, including gladiolus, rice, humans, and nature. Functional roles of core and niche-associated genomes were investigated by pathway enrichment analyses. Consequently, we inferred the uniquely important role of niche-associated genomes in (1) selenium availability during competition with gladiolus host; (2) aromatic compound degradation in seed-borne and crude oil-accumulated environments, and (3) stress-induced DNA repair system/recombination in the cystic fibrosis-niche. We also identified the conservation of the rhizomide biosynthetic gene cluster in all the B. gladioli strains and the concentrated distribution of this cluster in human isolates. It was confirmed the absence of complete CRISPR/Cas system in both plant and human pathogenic B. gladioli and the presence of the system in B. gladioli living in nature, possibly reflecting the inverse relationship between CRISPR/Cas system and virulence.

Kill and cure: genomic phylogeny and bioactivity of Burkholderia gladioli bacteria capable of pathogenic and beneficial lifestyles

Burkholderia gladioli is a bacterium with a broad ecology spanning disease in humans, animals and plants, but also encompassing multiple beneficial interactions. It is a plant pathogen, a toxin-producing food-poisoning agent, and causes lung infections in people with cystic fibrosis (CF). Contrasting beneficial traits include antifungal production exploited by insects to protect their eggs, plant protective abilities and antibiotic biosynthesis. We explored the genomic diversity and specialized metabolic potential of 206 B. gladioli strains, phylogenomically defining 5 clades. Historical disease pathovars (pv.) B. gladioli pv. allicola and B. gladioli pv. cocovenenans were distinct, while B. gladioli pv. gladioli and B. gladioli pv. agaricicola were indistinguishable; soft-rot disease and CF infection were conserved across all pathovars. Biosynthetic gene clusters (BGCs) for toxoflavin, caryoynencin and enacyloxin were dispersed across B. gladioli, but bongkrekic acid and gladiolin production were clade-specific. Strikingly, 13 % of CF infection strains characterized were bongkrekic acid-positive, uniquely linking this food-poisoning toxin to this aspect of B. gladioli disease. Mapping the population biology and metabolite production of B. gladioli has shed light on its diverse ecology, and by demonstrating that the antibiotic trimethoprim suppresses bongkrekic acid production, a potential therapeutic strategy to minimize poisoning risk in CF has been identified.

Bacterial and Protozoan Lipoxygenases Could be Involved in Cell-to-Cell Signaling and Immune Response Suppression

Lipoxygenases are found in animals, plants, and fungi, where they are involved in a wide range of cell-to-cell signaling processes. The presence of lipoxygenases in a number of bacteria and protozoa has been also established, but their biological significance remains poorly understood. Several hypothetical functions of lipoxygenases in bacteria and protozoa have been suggested without experimental validation. The objective of our study was evaluating the functions of bacterial and protozoan lipoxygenases by evolutionary and taxonomic analysis using bioinformatics tools. Lipoxygenase sequences were identified and examined using BLAST, followed by analysis of constructed phylogenetic trees and networks. Our results support the theory on the involvement of lipoxygenases in the formation of multicellular structures by microorganisms and their possible evolutionary significance in the emergence of multicellularity. Furthermore, we observed association of lipoxygenases with the suppression of host immune response by parasitic and symbiotic bacteria including dangerous opportunistic pathogens.

Matrix-assisted laser desorption/ionization time-of-flight MS for the accurate identification of Burkholderia cepacia complex and Burkholderia gladioli in the clinical microbiology laboratory

Introduction. Burkholderia cepacia complex (Bcc) bacteria, currently consisting of 23 closely related species, and Burkholderia gladioli, can cause serious and difficult-to-treat infections in people with cystic fibrosis. Identifying Burkholderia bacteria to the species level is considered important for understanding epidemiology and infection control, and predicting clinical outcomes. Matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF) is a rapid method recently introduced in clinical laboratories for bacterial species-level identification. However, reports on the ability of MALDI-TOF to accurately identify Bcc to the species level are mixed.Aim. The aim of this project was to evaluate the accuracy of MALDI-TOF using the Biotyper and VITEK MS systems in identifying isolates from 22 different Bcc species and B. gladioli compared to recA gene sequencing, which is considered the current gold standard for Bcc.Methodology. To capture maximum intra-species variation, phylogenetic trees were constructed from concatenated multi-locus sequence typing alleles and clustered with a novel k-medoids approach. One hundred isolates representing 22 Bcc species, plus B. gladioli, were assessed for bacterial identifications using the two MALDI-TOF systems.Results. At the genus level, 100 and 97.0 % of isolates were confidently identified as Burkholderia by the Biotyper and VITEK MS systems, respectively; moreover, 26.0 and 67.0 % of the isolates were correctly identified to the species level, respectively. In many, but not all, cases of species misidentification or failed identification, a representative library for that species was lacking.Conclusion. Currently available MALDI-TOF systems frequently do not accurately identify Bcc bacteria to the species level.

Head Tilt in Immunodeficient Mice Due to Contamination of Drinking Water by Burkholderia gladioli

Immunodeficient mice in multiple holding rooms presented with head tilt, circling, spinning when picked up by the tail, dehydration, and lethargy. Burkholderia gladioli, a plant pathogen, was identified as the causative agent. Environmental testing revealed the presence of B. gladioli within the automatic watering system, water bottles, and sipper tubes. Here we describe steps taken to reduce the presence of this organism within the automatic watering system and water bottles. Facilities housing immunodeficient mice should take measures to minimize the accumulation of biofilm within their water-supply systems.

Recipient selection process and listing for lung transplantation

Lung transplantation remains the ultimate treatment option for selected patients with end-stage (cardio) pulmonary disease. Given the current organ shortage, it is without any doubt that careful selection of potential transplant candidates is essential as this may greatly influence survival after the procedure. In this paper, we will review the current guidelines for referral and listing of lung transplant candidates in general, and in more depth for the specific underlying diseases. Needless to state that these are not absolute guidelines, and that decisions depend upon center's activity, waiting list, etc. Therefore, every patient should be discussed with the transplant center before any definite decision is made to accept or decline a patient for lung transplantation.

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.

The impact of chronic rhinosinusitis on long-term survival in lung transplantation recipients

CONCLUSIONS

Chronic rhinosinusitis diagnosed according to the European Position Paper on Rhinosinusitis and Nasal Polyps 2012, not by computed tomography alone, is one of the prognostic factors affecting long-term survival in patients with lung transplantation. Endoscopic sinus surgery might play a beneficial role in the management of lung transplantation recipients with chronic rhinosinusitis.

OBJECTIVE

To show the effect of paranasal sinus infection on post-lung transplantation survival.

METHOD

Lung transplantation recipients were included in this study. Computed tomography was performed before and after lung transplantation. The severity of chronic rhinosinusitis was evaluated by Lund-Mackay scoring system. The survival rate was calculated by the Kaplan-Meier method.

RESULTS

One hundred and forty-eight patients received lung transplantation for various indications. Chronic rhinosinusitis was found in 18.9% (28/148) of the lung transplantation recipients. Of 28 patients with chronic rhinosinusitis, seven patients underwent endoscopic sinus surgery due to persistent post-nasal drip. The recipients with chronic rhinosinusitis who did not receive endoscopic sinus surgery (n = 21) showed a significantly lower survival rate as compared to the patients without chronic rhinosinusitis. There was no statistically significant difference in the survival rate between the recipients with (n = 50) and without (n = 98) paranasal sinus abnormality on computed tomography.