Nosocomial acquisition of Burkholderia gladioli in patients with cystic fibrosis

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.

An Overview of Metabolic Activity, Beneficial and Pathogenic Aspects of Burkholderia Spp

Burkholderia is an important bacterial species which has different beneficial effects, such as promoting the plant growth, including rhizosphere competence for the secretion of allelochemicals, production of antibiotics, and siderophores. In addition, most of Burkholderia species have demonstrated promising biocontrol action against different phytopathogens for diverse crops. In particular, Burkholderia demonstrates significant biotechnological potential as a source of novel antibiotics and bioactive secondary metabolites. The current review is concerned with Burkholderia spp. covering the following aspects: discovering, classification, distribution, plant growth promoting effect, and antimicrobial activity of different species of Burkholderia, shedding light on the most important secondary metabolites, their pathogenic effects, and biochemical characterization of some important species of Burkholderia, such as B. cepacia, B. andropogonis, B. plantarii, B. rhizoxinica, B. glumae, B. caryophylli and B. gladioli.

Study of the Regulatory Role of N-Acyl Homoserine Lactones Mediated Quorum Sensing in the Biological Activity of Burkholderia gladioli pv. agaricicola Causing Soft Rot of Agaricus spp

Many Burkholderia spp. produce in vitro secondary metabolites with relevant biological activities and potential practical applications. Burkholderia gladioli pv. agaricicola (Bga) possess promising biological activities regulated by N-Acyl homoserine lactones (N.AHLs) based quorum sensing (QS) mechanism. In the current study, N.AHLs-deficient (ICMP11096glad-I) and N.AHLs-complemented (ICMP11096glad-IR) mutants were constructed in which the gene coding for AHL synthase was inactivated by allelic exchange in glad I mutant strain. The aims of this research were to (i) assess the antagonistic activity of the wild type (WT) and the glad-I mutant of Bga against Bacillus megaterium (G+ve) and Escherichia coli (G-ve), (ii) screen their hydrolytic enzymes and hemolytic substances, (iii) monitor the pathogenic effect against Agaricus bisporus, and finally (iv) analyze the bioactive secondary metabolites produced by WT and mutant strain using high performance liquid chromatography (HPLC). Results showed that N.AHLs-deficient mutant exhibited high reduction of antagonistic activity against the tested microorganisms and notable reduction of chitinolytic, proteolytic and glucanolytic activities and complete absence of hemolytic activity, and the glad-IR complemented mutant was able to regain the major part of these activities. Furthermore, N.AHLs-deficient mutant strain was unable to degrade flesh cubes pseudo-tissues of A. bisporus. On the other hand, the virulence effect of complemented mutant was like to the parental WT strain. HPLC analysis revealed that some of the single components produced by WT strain were absent in N.AHLs-deficient mutant and others were highly reduced. The out-findings of the current research gave a spot into the regulatory role of N.AHLs and QS phenomenon in the biological activity of Bga bacterium.

Genomes analysis and bacteria identification: The use of overlapping genes as molecular markers

The growing number of available microbial genomes offers the possibility to identify features that could be used for identification. In this work, the possibility to exploit overlapping genes to develop a simple PCR based method of identification, was explored. Using the Burkholderia cepacia complex as a model, genomic analyses were performed to check the phylogenetic distribution of an overlap between marC and hisH genes and then, a PCR specific for Burkholderia was designed, set up and tested on a panel of strains and on DNA extracted from the sputum of cystic fibrosis patients. Results obtained revealed the usefulness of this approach, which could then be used to develop PCR for the identification of specific bacteria species or genera.

Infections in patients with cystic fibrosis: diagnostic microbiology update

Survival has improved in patients with cystic fibrosis (CF), in part because of aggressive antimicrobial management. Two multidrug-resistant environmental bacteria, the Burkholderia cepacia group and nontuberculous mycobacteria, have emerged. Improving genomic and proteomic technologies are allowing better identification of bacteria and fungi found in the CF lung and detection of viral agents that may be associated with pulmonary exacerbations. Anaerobic bacteria and Streptococcus angionsus group organisms may play a role in chronic CF lung infections. The diversity of organisms declines perhaps as a result of aggressive antimicrobial therapy, and an apex predator, Pseudomonas aeruginosa, may emerge in many patients with CF.

Clinical significance of microbial infection and adaptation in cystic fibrosis

A select group of microorganisms inhabit the airways of individuals with cystic fibrosis. Once established within the pulmonary environment in these patients, many of these microbes adapt by altering aspects of their structure and physiology. Some of these microbes and adaptations are associated with more rapid deterioration in lung function and overall clinical status, whereas others appear to have little effect. Here we review current evidence supporting or refuting a role for the different microbes and their adaptations in contributing to poor clinical outcomes in cystic fibrosis.

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: five year experience in a cystic fibrosis and lung transplantation center

BACKGROUND

The impact of infection with Burkholderia gladioli in cystic fibrosis, other chronic airway diseases and immunosuppressed patients is unknown.

METHODS

A six-year retrospective review of all patients with B. gladioli infection was performed in a tertiary referral center with cystic fibrosis and lung transplantation programs. In addition, a targeted survey of all 251 lung transplant recipients was performed. Available B. gladioli isolates were analyzed via pulsed field gel electrophoresis.

RESULTS

Thirty-five patients were culture positive for B. gladioli, including 33 CF patients. No bacteremia was identified. Isolates were available in 18 patients and all were genetically distinct. Two-thirds of these isolates were susceptible to usual anti-pseudomonal antibiotics. After acquisition, only 40% of CF patients were chronically infected (> or =2 positive cultures separated by at least 6 months). Chronic infection was associated with resistance to > or =2 antibiotic groups on initial culture and failure of eradication after antibiotic therapy. The impact of acquisition of B. gladioli infection in chronic infection was variable. Three CF patients with chronic infection underwent lung transplantation. One post-transplant patient developed a B. gladioli mediastinal abscess, which was treated successfully.

CONCLUSIONS

The majority of patients' culture positive for B. gladioli at our center have CF. B. gladioli infection is often transient and is compatible with satisfactory post-lung transplantation outcomes.

Phenotypic methods for determining genomovar status of the Burkholderia cepacia complex

Recent taxonomic advances have demonstrated that Burkholderia cepacia is a cluster of at least seven closely related genomic species (or genomovars) collectively referred to as the B. cepacia complex, all of which may cause infections among cystic fibrosis patients and other vulnerable individuals. Thus, it is important for clinical microbiologists to be able to differentiate genomovars. Prior to this study, 361 B. cepacia complex isolates and 51 isolates easily confused with B. cepacia complex previously had been identified using a polyphasic approach, and in this study, a comparison of phenotypic and biochemical tests was carried out. It was determined that Burkholderia multivorans and Burkholderia stabilis could reliably be separated from other members of the B. cepacia complex by phenotypic methods. A combination of phenotypic and molecular tests such as recA PCR and 16S rRNA RFLP are recommended for differentiation among the genomovars of the B. cepacia complex. A biochemical reaction scheme for the identification of B. gladioli, Pandoraea species, and Ralstonia pickettii and the differentiation of these species from the B. cepacia complex is also presented.

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.

Clinical outcome after acquisition of Burkholderia cepacia in patients with cystic fibrosis

BACKGROUND

Respiratory disease is the major cause of morbidity and mortality in cystic fibrosis (CF). The significance of Burkholderia cepacia (B. cepacia) in the pathogenesis of lung disease in CF is debated, but its exact role remains unclear.

AIM

To assess the impact of respiratory tract colonisation with B. cepacia in patients with CF by measuring changes in pulmonary function and body mass index (BMI).

METHODS

Three groups of patients were defined based on sputum culture isolates: Group 1 were B. cepacia and Pseudomonas aeruginosa (P. aeruginosa) positive patients; Group 2 were P. aeruginosa positive; and Group 3 were colonised with neither organism. Forced expiratory volume (FEV) and BMI were measured annually from 1987 to 1995 and the year of acquisition of P. aeruginosa or B. cepacia was recorded.

RESULTS

The mean annual decrease in FEV1 was significantly different in all three groups: Group 1, -5.4 (5.1)%; Group 2, -3.9 (6.5)%; and Group 3, -1.6 (1.0)%, (p<0.05). The mean percentage decrease in FEV1 of a sub-group of Group 1 patients where the B. cepacia acquisition date was known was 6.1% per year versus 1.55% in Group 2 patients (p<0.05).

CONCLUSIONS

Acquisition of B. cepacia may be a cause of, rather than a marker for, a decrease in pulmonary function.

Simple and inexpensive but highly discriminating method for computer-assisted DNA fingerprinting of Pseudomonas aeruginosa

We describe here a method for computer-assisted fingerprinting of Pseudomonas aeruginosa. In this method, DNA is digested with SalI, and bands with molecular sizes of >/=9.7 kb are visually scored after electrophoresis on agarose gels. Pattern scores are entered into a Microsoft Excel database. In scoring, the number of bands within each of a set of molecular size ranges is scored, rather than the absolute molecular size of each band, substantially enhancing the speed and reproducibility of the method, while eliminating the need for using expensive gel scanning equipment and software. Pattern scores are used to generate matrices of genetic distance values, which can be visualized in neighbor-joining trees. The method reliably distinguishes two epidemiologically unrelated isolates in 99.3% of all comparisons. The genetic relationships between isolates observed with the method were consistent with those obtained by analysis of two P. aeruginosa genes, indicating that it provides valid estimates of genetic divergence between isolates. Using the method, respiratory tract isolates from cystic fibrosis patients in Green Lane Hospital in Auckland, New Zealand, were shown to be genetically less diverse than epidemiologically unrelated isolates from other patients. This finding was not due to the existence of clusters of related strains specialized toward colonization of the respiratory tract and thus was indicative of transmission between patients. Analysis of multiple isolates from individual cystic fibrosis patients suggested that up to five separate clusters of genetically related strains may simultaneously be present in a patient. The method described should significantly enhance our ability to investigate the epidemiology of P. aeruginosa.

Unusual respiratory bacterial flora in cystic fibrosis: microbiologic and clinical features

Pulmonary infections continue to be a significant source of morbidity and mortality among patients with cystic fibrosis. Although our understanding of the pathogenesis and clinical consequences of pulmonary infections with Pseudomonas aeruginosa has increased greatly in recent years, very little is known about potentially emerging pathogens such as Burkholderia cepacia complex, Stenotrophomonas maltophilia, Alcaligenes xylosoxidans, and methicillin-resistant Staphylococcus aureus. In this review, the authors discuss methods for appropriate identification of these "unusual" organisms and their epidemiologic and clinical features. Multicenter surveillance studies are needed to more clearly establish the pathogenicity of these organisms.

Misidentification of Burkholderia cepacia in US cystic fibrosis treatment centers: an analysis of 1,051 recent sputum isolates

BACKGROUND

Burkholderia cepacia remains a significant pathogen in persons with cystic fibrosis (CF). The medical and psychosocial consequences of pulmonary colonization with this bacterium are enormous. However, B cepacia may be frequently misidentified from CF sputum culture.

STUDY OBJECTIVES

To determine the rate of misidentification of B cepacia recently recovered from CF sputum culture of persons receiving care in US treatment centers.

DESIGN

Bacterial isolates cultured from CF sputum and putatively identified as B cepacia or other related nonlactose-fermenting Gram-negative species were referred from participating treatment centers. Isolates underwent polyphasic analyses employing phenotypic (selective media and biochemical testing) and genotypic (polymerase chain reaction) assays to determine species identification. Taxonomic evaluations were performed by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins and amplified-fragment length polymorphism analysis.

MEASUREMENTS AND RESULTS

A total of 1,051 isolates recovered from 608 patients were received from 115 treatment centers in 91 US cities. Among the isolates identified as B cepacia by referring laboratories, 11% could not be confirmed as B cepacia by polyphasic analyses. In addition, 36% of isolates not specifically identified by the referring laboratory or identified as a species other than B cepacia were, in fact, found to be members of the B cepacia complex.

CONCLUSIONS

Rates of misidentification of B cepacia remain unacceptably high among US treatment centers. These data suggest the need for increased awareness of this problem among CF centers and their affiliated laboratories, better adherence to recommended protocols for evaluation of CF sputum, and greater use of reference laboratories equipped to provide advanced analyses.

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.

Activity of abundant antimicrobials of the human airway

Human airways produce several antimicrobial factors; the most abundant are lysozyme and lactoferrin. Despite their likely importance in preventing infection, and their possible key role in the pathogenesis of cystic fibrosis (CF), we know little about their antibacterial activity in the context of the CF airway. We found that abundant airway antimicrobial factors kill common CF pathogens, although Burkholderia was relatively resistant. To study the antibacterial activity, we developed a rapid, sensitive, and quantitative in vitro luminescence assay. Because NaCl concentrations may be elevated in CF airway surface liquid, we tested the effect of salt on antibacterial activity. Activity of individual factors and of airway lavage fluid was inhibited by high ionic strength, and it was particularly sensitive to divalent cations. However, it was not inhibited by nonionic osmolytes and thus did not require hypotonic liquid. The inhibition by ionic strength could be partially compensated by increased concentrations of antibacterial factors, thus there was no one unique salt concentration for inhibition. CF airway secretions also contain abundant mucin and elastase; however, these had no effect on antibacterial activity of lysozyme, lactoferrin, or airway lavage fluids. When studied at low NaCl concentrations, CF and non-CF airway lavage fluids contained similar levels of antibacterial activity. These results suggest approaches toward developing treatments aimed at preventing or reducing airway infections in individuals with CF.

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.

Burkholderia cepacia. Management issues and new insights

Although Burkholderia cepacia colonizes a relatively small proportion of individuals with cystic fibrosis (CF), it is associated with significant morbidity and mortality, and has had a profound impact on infection control practices. This article reviews the current understanding of the epidemiology of B. cepacia infection, describes important recent developments in the microbiology and taxonomy of this species, and presents issues that remain obstacles to defining the optimal management of B. cepacia infection in CF.