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Human Vaccines & Immunotherapeutics Mar 2016A great number of cystic fibrosis (CF) pathogens such as Pseudomonas aeruginosa, the Burkholderia cepacia and the Mycobacterium abscessus complex raised difficult...
A great number of cystic fibrosis (CF) pathogens such as Pseudomonas aeruginosa, the Burkholderia cepacia and the Mycobacterium abscessus complex raised difficult therapeutic problems due to their intrinsic multi-resistance to numerous antibiotics. Vaccine strategies represent one of the key weapons against these multi-resistant bacteria in a number of clinical settings like CF. Different strategies are considered in order to develop such vaccines, linked either to priming the host response, or by exploiting genomic data derived from the bacterium. Interestingly, virulence factors synthesized by various pathogens might serve as targets for vaccine development and have been, for example, evaluated in the context of CF.
Topics: Bacterial Vaccines; Burkholderia cepacia; Cystic Fibrosis; Drug Discovery; Humans; Mycobacterium; Pneumonia, Bacterial; Pseudomonas aeruginosa
PubMed: 26618824
DOI: 10.1080/21645515.2015.1102810 -
Journal of the Royal Society of Medicine 2003
Review
Topics: Burkholderia Infections; Burkholderia cepacia; Cystic Fibrosis; Drug Design; Genome, Bacterial; Humans; Oligonucleotide Array Sequence Analysis; Pseudomonas Infections; Pseudomonas aeruginosa; Research; Respiratory Tract Infections; Sequence Analysis, DNA
PubMed: 12906327
DOI: No ID Found -
Microbiology (Reading, England) Jul 1999Members of the taxonomically diverse Burkholderia cepacia complex have become a major health risk for patients with cystic fibrosis (CF). Although patient-to-patient...
Members of the taxonomically diverse Burkholderia cepacia complex have become a major health risk for patients with cystic fibrosis (CF). Although patient-to-patient transmission of B. cepacia strains has been well-documented, very little is known about possible vehicles of transmission and reservoirs for these micro-organisms. In this work, it is shown that strains of the B. cepacia complex can survive within different isolates of the genus Acanthamoeba. Trophozoites containing bacteria developed profuse cytoplasmic vacuolization. Vacuolization was not detected in trophozoites infected with live Escherichia coli or heat-killed B. cepacia, or by incubation of trophozoites with filter-sterilized culture supernatants, indicating that metabolically active intracellular bacteria are required for the formation of vacuoles. Experiments with two different B. cepacia strains and two different Acanthamoeba isolates revealed that bacteria display a low level of intracellular replication approximately 72-96 h following infection. In contrast, extracellular bacteria multiplied efficiently on by-products released by amoebae. The findings suggest that amoebae may be a reservoir for B. cepacia and possibly a vehicle for transmission of this opportunistic pathogen among CF patients.
Topics: Acanthamoeba; Animals; Burkholderia Infections; Burkholderia cepacia; Cystic Fibrosis; Humans; Microscopy, Electron; Opportunistic Infections; Temperature; Vacuoles
PubMed: 10439391
DOI: 10.1099/13500872-145-7-1509 -
Biotechnology Journal Jul 2016Lipases resistant to inhibition and denaturation by methanol are valuable tools for biotechnological applications, in particular for biofuel production. Microbial...
Lipases resistant to inhibition and denaturation by methanol are valuable tools for biotechnological applications, in particular for biofuel production. Microbial lipases have attracted a great deal of interest because of their stability at high concentrations of organic solvents. Burkholderia cepacia lipase (BCL) is tested here for robustness towards methanol in terms of conformational stability and catalytic activity in transesterification assays. This lipase turns out to be even more tolerant than the homologous and better characterized enzyme from Burkholderia glumae. BCL unfolding transition, as monitored by far-UV circular dichroism (CD) and intrinsic fluorescence, displays a Tm above 60°C in the presence of 50% methanol. The protein unfolds at low pH, and the organic solvent affects the nature of the denatured state under acidic conditions. The protein performs well in transesterification assays upon prolonged incubations at high methanol concentrations. BCL is highly tolerant to methanol and displays particularly high conformational stability under conditions employed for transesterification reactions. These features depict BCL as a promising enzyme for biofuel industry.
Topics: Bacterial Proteins; Biocatalysis; Biofuels; Burkholderia cepacia; Circular Dichroism; Enzyme Activation; Enzyme Stability; Esterification; Hydrogen-Ion Concentration; Lipase; Methanol; Protein Conformation; Protein Unfolding
PubMed: 27067648
DOI: 10.1002/biot.201500305 -
Emerging Infectious Diseases 1998In the past 2 decades, Burkholderia cepacia has emerged as a human pathogen causing numerous outbreaks, particularly among cystic fibrosis (CF) patients. One highly... (Review)
Review
In the past 2 decades, Burkholderia cepacia has emerged as a human pathogen causing numerous outbreaks, particularly among cystic fibrosis (CF) patients. One highly transmissible strain has spread across North America and Britain, and another between hospitalized CF and non-CF patients. Meanwhile, the organism has been developed as a biopesticide for protecting crops against fungal diseases and has potential as a bioremediation agent for breaking down recalcitrant herbicides and pesticides. However, B. cepacia is inherently resistant to multiple antibiotics; selection of strains "safe" for environmental application is not at present possible phenotypically or genotypically; molecular epidemiology and phylogenetic studies demonstrate that highly transmissible strains emerge randomly; and the organism has a capacity for rapid mutation and adaptation (facilitated by numerous insertion sequences), and a large, complex genome divided into separate chromosomes. Therefore, the widespread agricultural use of B. cepacia should be approached with caution.
Topics: Agriculture; Burkholderia Infections; Burkholderia cepacia; Cystic Fibrosis; Environmental Microbiology; Humans; Infection Control; Mutation; Pest Control, Biological
PubMed: 9621192
DOI: 10.3201/eid0402.980209 -
BMC Microbiology Mar 2014Bacterial species coexist commonly in mixed communities, for instance those occurring in microbial infections of humans. Interspecies effects contribute to alterations...
BACKGROUND
Bacterial species coexist commonly in mixed communities, for instance those occurring in microbial infections of humans. Interspecies effects contribute to alterations in composition of communities with respect to species and thus, to the course and severity of infection. Therefore, knowledge concerning growth and viability of single species in medically-relevant mixed communities is of high interest to resolve complexity of interspecies dynamics and to support development of treatment strategies. In this study, a flow cytometric method was established to assess the species-specific viability in defined three-species mixed cultures. The method enables the characterization of viability of Pseudomonas aeruginosa, Burkholderia cepacia and Staphylococcus aureus, which are relevant to lung infections of Cystic Fibrosis (CF) patients. The method combines fluorescence detection by antibody and lectin labeling with viability fluorescence staining using SYBRGreen I and propidium iodide. In addition, species-specific cell enumeration analysis using quantitative terminal restriction fragment length polymorphisms (qT-RFLP) was used to monitor the growth dynamics. Finally, to investigate the impact of substrate availability on growth and viability, concentrations of main substrates and metabolites released were determined.
RESULTS
For each species, the time course of growth and viability during mixed culture cultivations was obtained by using qT-RFLP analysis in combination with flow cytometry. Comparison between mixed and pure cultures revealed for every species differences in growth properties, e.g. enhanced growth of P. aeruginosa in mixed culture. Differences were also observed for B. cepacia and S. aureus in the time course of viability, e.g. an early and drastic reduction of viability of S. aureus in mixed culture. Overall, P. aeruginosa clearly dominated the mixed culture with regard to obtained cell concentrations.
CONCLUSIONS
In combination with qT-RFLP analysis, the methods enabled monitoring of species-specific cell concentrations and viability during co-cultivation of theses strains. Experimental findings suggest that the predominance of P. aeruginosa over B. cepacia and S. aureus in mixed culture under the chosen cultivation conditions is promoted by more efficient substrate consumption of P. aeruginosa, and antagonistic interspecies effects induced by P. aeruginosa.
Topics: Bacterial Load; Burkholderia cepacia; Coinfection; Cystic Fibrosis; Flow Cytometry; Fluorescence; Humans; Microbial Viability; Pneumonia, Bacterial; Polymorphism, Restriction Fragment Length; Pseudomonas aeruginosa; Staining and Labeling; Staphylococcus aureus
PubMed: 24606608
DOI: 10.1186/1471-2180-14-56 -
The Turkish Journal of Pediatrics 2021Burkholderia cepacia complex (Bcc) comprises multi-drug resistant, Gram-negative, motile, and aerobic bacteria. Bcc causes severe nosocomial infections particularly in...
BACKGROUND
Burkholderia cepacia complex (Bcc) comprises multi-drug resistant, Gram-negative, motile, and aerobic bacteria. Bcc causes severe nosocomial infections particularly in patients with intravascular catheters and in those with cystic fibrosis. We studied a Bcc outbreak in non-cystic fibrosis patients.
METHODS
We analyzed data from six patients hospitalized at our center. Blood cultures identified as infectious were incubated onto 5% blood sheep agar, chocolate agar, and eosin methylene blue (EMB) agar. We examined possible sites that could be sources of infection at the clinic. We confirmed isolations with pulsed-field gel electrophoresis (PFGE) tests.
RESULTS
The first patient was hospitalized due to left renal agenesis, urinary tract infection, and renal failure. Bcc was isolated in blood cultures obtained due to high fever on the third day of hospitalization. We stopped new patient hospitalizations after detecting Bcc in blood cultures of other five patients. We did not detect further positive specimens obtained from other clinic and the patient rooms. PFGE patterns were similar in all clinical isolates of Bcc indicating that the outbreak had originated from the source.
CONCLUSIONS
Bcc infection should be considered in cases of nosocomial outbreaks of multi-drug resistant organisms that require hospitalization at intensive care units. Control measures should be taken for prevention of nosocomial infections and required investigations should be done to detect the source of infection.
Topics: Animals; Bacteremia; Burkholderia Infections; Burkholderia cepacia; Burkholderia cepacia complex; Cross Infection; Cystic Fibrosis; Disease Outbreaks; Hospitals, University; Humans; Sheep
PubMed: 33929111
DOI: 10.24953/turkjped.2021.02.005 -
Applied and Environmental Microbiology Apr 2015Regulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of the development of resistance in organisms...
Regulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of the development of resistance in organisms targeted by microbicidal products. There is no standard protocol to assess the risk of the development of resistance to microbicidal formulations. This study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. Three industrial isolates (Pseudomonas aeruginosa, Burkholderia cepacia, and Klebsiella pneumoniae) and two Salmonella enterica serovar Typhimurium strains (SL1344 and 14028S) were exposed to a shampoo, a mouthwash, eye makeup remover, and the microbicides contained within these formulations (chlorhexidine digluconate [CHG] and benzalkonium chloride [BZC]) under realistic, in-use conditions. Baseline and postexposure data were compared. No significant increases in the MIC or the minimum bactericidal concentration (MBC) were observed for any strain after exposure to the three formulations. Increases as high as 100-fold in the MICs and MBCs of CHG and BZC for SL1344 and 14028S were observed but were unstable. Changes in antibiotic susceptibility were not clinically significant. The use of MICs and MBCs combined with antibiotic susceptibility profiling and stability testing generated reproducible data that allowed for an initial prediction of the development of resistance to microbicides. These approaches measure characteristics that are directly relevant to the concern over resistance and cross-resistance development following the use of microbicides. These are low-cost, high-throughput techniques, allowing manufacturers to provide to regulatory bodies, promptly and efficiently, data supporting an early assessment of the risk of resistance development.
Topics: Anti-Bacterial Agents; Bacteria; Benzalkonium Compounds; Burkholderia cepacia; Chlorhexidine; Cosmetics; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Microbial Sensitivity Tests; Pseudomonas aeruginosa
PubMed: 25636848
DOI: 10.1128/AEM.03843-14 -
Annals of Clinical Microbiology and... Jan 2010Acinetobacter baumannii and species within the Burkholderia cepacia complex (BCC) are significant opportunistic bacterial pathogens of humans. These species exhibit a...
Screening a mushroom extract library for activity against Acinetobacter baumannii and Burkholderia cepacia and the identification of a compound with anti-Burkholderia activity.
BACKGROUND
Acinetobacter baumannii and species within the Burkholderia cepacia complex (BCC) are significant opportunistic bacterial pathogens of humans. These species exhibit a high degree of antibiotic resistance, and some clinical isolates are resistant to all currently available antimicrobial drugs used for treatment. Thus, new drugs are needed to treat infections by these species. Mushrooms could be a potential source for new drugs to treat A. baumannii and BCC infections.
METHODS
The aim of this study was to screen a library of crude extracts from 330 wild mushrooms by disk diffusion assays for antibacterial activity against A. baumannii and Burkholderia cepacia in the hope of identifying a novel natural drug that could be used to treat infections caused by these species. Once positive hits were identified, the extracts were subjected to bioassay-guided separations to isolate and identify the active drug molecules. MICs were performed to gauge the in vitro activity of the purified compounds.
RESULTS
Only three crude extracts (0.9%) had activity against A. baumannii and B. cepacia. Compounds from two of these extracts had MICs greater than 128 microg/ml, and further analyses were not performed. From the third extract, prepared from Leucopaxillus albissimus, 2-aminoquinoline (2-AQ) was isolated. This compound exhibited a modest MIC in vitro against strains from nine different BCC species, including multi-drug resistant clinical isolates (MIC = 8-64 microg/ml), and a weak MIC (128 microg/ml) against A baumannii. The IC50 against a murine monocyte line was 1.5 mg/ml.
CONCLUSION
The small number of positive hits in this study suggests that finding a new drug from mushrooms to treat Gram-negative bacterial infections may be difficult. Although 2-AQ was identified in one mushroom, and it was shown to inhibit the growth of multi-drug resistant BCC isolates, the relatively high MICs (8-128 microg/ml) for both A. baumannii and BCC strains suggests that 2-AQ is not suitable for further drug development in its current form.
Topics: Acinetobacter baumannii; Agaricales; Aminoquinolines; Animals; Anti-Bacterial Agents; Burkholderia cepacia; Complex Mixtures; Drug Evaluation, Preclinical; Mice; Microbial Sensitivity Tests; Monocytes
PubMed: 20092635
DOI: 10.1186/1476-0711-9-4 -
Journal of Clinical Microbiology May 1999We present a PCR procedure for identification of Burkholderia cepacia, Burkholderia multivorans, and Burkholderia vietnamiensis. 16S and 23S ribosomal DNAs (rDNAs) of B....
We present a PCR procedure for identification of Burkholderia cepacia, Burkholderia multivorans, and Burkholderia vietnamiensis. 16S and 23S ribosomal DNAs (rDNAs) of B. multivorans and B. vietnamiensis were sequenced and aligned with published sequences for definition of species-specific 18-mer oligonucleotide primers. Specific antisense 16S rDNA primers (for B. cepacia, 5'-AGC ACT CCC RCC TCT CAG-3'; for B. multivorans, 5'-AGC ACT CCC GAA TCT CTT-3') and 23S rDNA primers (for B. vietnamiensis, 5'-TCC TAC CAT GCG TGC AA-3') were paired with a general sense primer of 16S rDNAs (5'-AGR GTT YGA TYM TGG CTC AG-3') or with a sense primer of 23S rDNA (5'-CCT TTG GGT CAT CCT GGA-3'). PCR with these primers under optimized conditions is appropriate to specifically and rapidly identify B. multivorans, B. vietnamiensis, and B. cepacia (genomovars I, III, and IV are not discriminated). In comparison with the polyphasic taxonomic analyses presently necessary for species and genomovar identification within the B. cepacia complex, our procedure is more rapid and easier to perform and may contribute to clarifying the clinical significance of individual members of the complex in cystic fibrosis.
Topics: Burkholderia; Burkholderia cepacia; Cystic Fibrosis; DNA, Ribosomal; Humans; Polymerase Chain Reaction; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Sensitivity and Specificity
PubMed: 10203482
DOI: 10.1128/JCM.37.5.1335-1339.1999