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Biomolecules Aug 2021BceF is a bacterial tyrosine kinase (BY-kinase) from , a Gram-negative bacterium accountable for respiratory infections in immunocompromised and cystic fibrosis...
BceF is a bacterial tyrosine kinase (BY-kinase) from , a Gram-negative bacterium accountable for respiratory infections in immunocompromised and cystic fibrosis patients. BceF is involved in the production of exopolysaccharides secreted to the biofilm matrix and promotes resistant and aggressive infections. BY-kinases share no homology with mammalian kinases, and thereby offer a means to develop novel and specific antivirulence drugs. Here, we report the crystal structure of the BceF kinase domain at 1.85 Å resolution. The isolated BceF kinase domain is assembled as a dimer in solution and crystallized as a dimer in the asymmetric unit with endogenous adenosine-diphosphate bound at the active sites. The low enzymatic efficiency measured in solution may be explained by the partial obstruction of the active sites at the crystallographic dimer interface. This study provides insights into self-assembly and the specific activity of isolated catalytic domains. Several unique variations around the active site compared to other BY-kinases may allow for structure-based design of specific inhibitors to target virulence.
Topics: Bacterial Proteins; Biofilms; Burkholderia cepacia; Crystallography, X-Ray; Humans; Protein Structure, Secondary; Protein Structure, Tertiary; Protein-Tyrosine Kinases; Virulence
PubMed: 34439861
DOI: 10.3390/biom11081196 -
Archives of Razi Institute Apr 2022is found as part of the complex (Bcc), a collection of highly pathogenic organisms. The Bcc is present almost everywhere in nature; however, it is most prevalent in...
is found as part of the complex (Bcc), a collection of highly pathogenic organisms. The Bcc is present almost everywhere in nature; however, it is most prevalent in damp settings, plant roots, and soils. Moreover, Bcc is a major source of morbidity and death in patients due to its high intrinsic antibiotic resistance. The present study aims to isolate and identify gram-negative aerobic bacteria from clinical samples derived from a variety of pathological diseases and investigate the bacterium's virulence factors and genes. The current study included 250 specimens collected from patients suffering from diabetic foot ulcers, urine, burn, wound, sputum, and discharge from the eyes. The samples were collected from both sexes with the age range of 1-75 years. The recorded data showed that males had a higher frequency of infection (79.2%) than females (52%). The results revealed that 7.6% of infected females were between 1-15 years old, while 22% of infected males were aged between 31-45 years. In addition, 26.8% of infected patients (both males and females) were aged between 31-45 years.
Topics: Female; Male; Burkholderia cepacia; Burkholderia cepacia complex; Burkholderia Infections; Cystic Fibrosis; Probability; Soil; Virulence Factors; Humans; Adult; Middle Aged
PubMed: 36284953
DOI: 10.22092/ARI.2022.357464.2041 -
International Journal of Molecular... Jun 2022The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and...
The behavior against temperature and thermal stability of enzymes is a topic of importance for industrial biocatalysis. This study focuses on the kinetics and thermodynamics of the thermal inactivation of Lipase PS from and Palatase from . Thermal inactivation was investigated using eight inactivation models at a temperature range of 40-70 °C. Kinetic modeling showed that the first-order model and Weibull distribution were the best equations to describe the residual activity of Lipase PS and Palatase, respectively. The results obtained from the kinetic parameters, decimal reduction time (D and t), and temperature required (z and z') indicated a higher thermal stability of Lipase PS compared to Palatase. The activation energy values (Ea) also indicated that higher energy was required to denature bacterial (34.8 kJ mol) than fungal (23.3 kJ mol) lipase. The thermodynamic inactivation parameters, Gibbs free energy (ΔG), entropy (ΔS), and enthalpy (ΔH) were also determined. The results showed a ΔG for Palatase (86.0-92.1 kJ mol) lower than for Lipase PS (98.6-104.9 kJ mol), and a negative entropic and positive enthalpic contribution for both lipases. A comparative molecular dynamics simulation and structural analysis at 40 °C and 70 °C were also performed.
Topics: Burkholderia cepacia; Enzyme Stability; Kinetics; Lipase; Molecular Dynamics Simulation; Rhizomucor; Temperature; Thermodynamics
PubMed: 35743268
DOI: 10.3390/ijms23126828 -
PloS One 2011Burkholderia cepacia is a Gram-negative pathogen that causes serious respiratory infections in immunocompromised patients and individuals with cystic fibrosis. This...
BACKGROUND
Burkholderia cepacia is a Gram-negative pathogen that causes serious respiratory infections in immunocompromised patients and individuals with cystic fibrosis. This bacterium is known to release extracellular proteins that may be involved in virulence.
METHODOLOGY/PRINCIPAL FINDINGS
In the present study, B. cepacia grown to mid-logarithmic and early-stationary phases were investigated on their ability to invade and survive intracellularly in A549 lung epithelial cells in order to discern the fate of these bacteria in the pathogenesis of B. cepacia lung infections in in vitro condition. The early-stationary phase B. cepacia was demonstrated to be more invasive than mid-logarithmic phase. In addition, culture supernatants of B. cepacia obtained from these phases of growth were also demonstrated to cause different cytotoxic potency on the A549 human lung epithelial cells. Profiling of the supernatants using the gel-based proteomics approach identified 43 proteins that were commonly released in both the growth phases and 40 proteins newly-released at the early-stationary phase. The latter proteins may account for the higher cytotoxic activity of the early-stationary culture supernatant compared to that obtained at the mid-logarithmic phase. Among the newly-released proteins in the early-stationary phase supernatant were flagellar hook-associated domain protein (FliD), flagellar hook-associated protein (FlgK), TonB-dependent siderophore (Fiu), Elongation factor G (FusA), phosphoglycerate kinase (Pgk) and sulfatase (AslA) which are known for their virulence.
CONCLUSION/SIGNIFICANCE
Differences in the ability of B. cepacia to invade and survive intracellularly inside the epithelial cells at different phases of growth may improve our understanding of the varied disease progressions associated with B. cepacia infections. In addition, the identified culture supernatant proteins may be used as targets for the development of new strategies to control B. cepacia infection using agents that can block their release.
Topics: Bacterial Proteins; Bacterial Secretion Systems; Burkholderia cepacia; Cell Line; Epithelial Cells; Humans; Proteomics; Respiratory Tract Infections; Virulence
PubMed: 22046299
DOI: 10.1371/journal.pone.0026518 -
Polimery W Medycynie 2022Burkholderia cepacia adhesion and biofilm formation onto abiotic surfaces is an important feature of clinically relevant isolates. The in vitro biofilm formation of B....
BACKGROUND
Burkholderia cepacia adhesion and biofilm formation onto abiotic surfaces is an important feature of clinically relevant isolates. The in vitro biofilm formation of B. cepacia onto coated indwelling urinary catheters (IDCs) with moxifloxacin has not been previously investigated.
OBJECTIVES
To examine the ability of B. cepacia to form biofilms on IDCs and the effect of coating IDCs with moxifloxacin on biofilm formation by B. cepacia in vitro.
MATERIAL AND METHODS
The adhesion of B. cepacia to coated and uncoated IDCs with moxifloxacin was evaluated. Pieces of IDCs were coated with moxifloxacin (adsorption method). The spectrophotometric method was used to check moxifloxacin leaching into tubes. Coated and uncoated tubes were incubated with 107 colony forming units (cfu)/mL of B. cepacia. The viable bacterial count was used to count the number of bacteria adhered to coated and uncoated IDC pieces.
RESULTS
A significant adhesion of B. cepacia to uncoated IDC pieces started 15 min after the incubation in a bacterial suspension (107 cfu/mL). A maximum adhesion was observed at 48 h. The pretreatment of IDCs with 100 μg/mL of moxifloxacin produced the best adsorption of antibiotic onto the IDCs. Coating IDC pieces with moxifloxacin significantly reduced the adhesion and biofilm formation of B. cepacia (p < 0.05) at various time intervals (1 h, 4 h and 24 h).
CONCLUSIONS
The present study has demonstrated for the first time that coated IDCs with moxifloxacin reduce B. cepacia adhesion and biofilm formation. This finding has opened the door to the production of the new generation IDCs that prevent bacteria from attaching and forming biofilms.
Topics: Biofilms; Burkholderia cepacia; Catheters, Indwelling; Moxifloxacin; Urinary Catheterization; Urinary Catheters
PubMed: 35754328
DOI: 10.17219/pim/149986 -
Production of both l- and d- N-acyl-homoserine lactones by Burkholderia cepacia and Vibrio fischeri.MicrobiologyOpen Nov 2021Quorum sensing (QS) is a complex process in which molecules, such as l-N-acyl-homoserine lactones (l-AHLs), are produced as essential signaling molecules allowing...
Quorum sensing (QS) is a complex process in which molecules, such as l-N-acyl-homoserine lactones (l-AHLs), are produced as essential signaling molecules allowing bacteria to detect and respond to cell population density by gene regulation. Few studies have considered the natural production and role of the opposite enantiomers, d-AHLs. In this work, production of d,l-AHLs by Burkholderia cepacia and Vibrio fischeri was monitored over time, with significant amounts of d-AHLs detected. Bioluminescence of V. fischeri was observed with maximum bioluminescence correlating with the maximum concentrations of both l- and d- octanoyl-homoserine lactones (l- and d-OHL). l-Methionine, a precursor to l-AHLs, was examined via supplementation studies conducted by growing three parallel cultures of B. cepacia in M9 minimal media with added l-, d-, or d,l-methionine and observing their effect on the production of d,l-AHL by B. cepacia. The results show that addition of any methionine (l-, d-, or d,l-) does not affect the overall ratio of l- to d-AHLs, that is d-AHL production was not selectively enhanced by d-methionine addition. However, the overall AHL (l- and d-) concentration does increase with the addition of any methionine supplement. These findings indicate the possibility of a distinct biosynthetic pathway for d-AHL production, possibly exposing a new dimension within bacterial communication.
Topics: 4-Butyrolactone; Acyl-Butyrolactones; Aliivibrio fischeri; Biosynthetic Pathways; Burkholderia cepacia; Culture Media; Methionine; Quorum Sensing; Stereoisomerism
PubMed: 34964286
DOI: 10.1002/mbo3.1242 -
Journal of Clinical Microbiology Oct 2001
Review
Topics: Bacterial Typing Techniques; Burkholderia Infections; Burkholderia cepacia; Genotype; Humans; Phenotype
PubMed: 11574551
DOI: 10.1128/JCM.39.10.3427-3436.2001 -
Journal of Medical Microbiology Aug 2020complex (Bcc) bacteria, currently consisting of 23 closely related species, and , can cause serious and difficult-to-treat infections in people with cystic fibrosis.... (Comparative Study)
Comparative Study
complex (Bcc) bacteria, currently consisting of 23 closely related species, and , can cause serious and difficult-to-treat infections in people with cystic fibrosis. Identifying 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. 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 compared to gene sequencing, which is considered the current gold standard for Bcc. 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 , were assessed for bacterial identifications using the two MALDI-TOF systems. At the genus level, 100 and 97.0 % of isolates were confidently identified as 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. Currently available MALDI-TOF systems frequently do not accurately identify Bcc bacteria to the species level.
Topics: Animals; Bacterial Typing Techniques; Burkholderia cepacia; Burkholderia gladioli; Cluster Analysis; DNA, Bacterial; Fourier Analysis; Humans; Multilocus Sequence Typing; Phylogeny; Rec A Recombinases; Sequence Alignment; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 32597748
DOI: 10.1099/jmm.0.001223 -
Journal of Applied Microbiology 2004To investigate the dynamics of binary culture biofilm formation through use of both the Sorbarod model of biofilm growth and the constant depth film fermenter (CDFF).
AIMS
To investigate the dynamics of binary culture biofilm formation through use of both the Sorbarod model of biofilm growth and the constant depth film fermenter (CDFF).
METHODS AND RESULTS
Pseudo steady-state biofilm cultures of laboratory and clinical strains of Pseudomonas aeruginosa, selected on the basis of their ability to produce a Burkholderia cepacia growth-inhibitory substance, were established on Sorbarod filters and challenged with corresponding planktonic grown cultures of B. cepacia. Reverse challenges were also conducted. Both B. cepacia and P. aeruginosa were able to form steady-state monoculture biofilms after 48 h growth. When steady-state biofilms of B. cepacia NTCT 10661 were challenged with planktonically grown P. aeruginosa PAO1 known to produce a B. cepacia growth-inhibitory substance, the immigrant population was rapidly and almost completely bound to the biofilm, displacing B. cepacia. By contrast, established biofilms of P. aeruginosa PAO1 resisted immigration of B. cepacia 10661. Similar experiments conducted with a nongrowth inhibitory substance producing clinical pairing of P. aeruginosa 313113 and B. cepacia 313113 led to the formation of stable, mixed biofilm populations in both instances. Moreover, co-inoculation with these clinical isolates resulted in a stable, mixed steady-state biofilm. Similar observations were made for biofilms generated in CDFFs. In such instances following pan-swapping between two monoculture CDFFs, B. cepacia 313113 was able to integrate into an established P. aeruginosa 313113 biofilm to form a stable binary biofilm.
CONCLUSIONS
Establishment of a mixed species community follows a specific sequence of inoculation that may either be due to some degree of match between co-colonizers or that P. aeruginosa predisposes uncolonized sections of the surface to permit B. cepacia colonization.
SIGNIFICANCE AND IMPACT OF THE STUDY
Colonization of a surface with one bacterial species confers colonization resistance towards other species. Disinfection of a surface might well increase the probability of pathogen harbourage.
Topics: Bacteriological Techniques; Biofilms; Burkholderia cepacia; Drug Resistance, Bacterial; Movement; Pseudomonas aeruginosa
PubMed: 14962125
DOI: 10.1111/j.1365-2672.2004.02201.x -
Infection and Immunity Jan 2000Burkholderia cepacia has emerged as an important pulmonary pathogen in immunocompromised patients and in patients with cystic fibrosis (CF). Little is known about the...
Burkholderia cepacia has emerged as an important pulmonary pathogen in immunocompromised patients and in patients with cystic fibrosis (CF). Little is known about the virulence factors and pathogenesis of B. cepacia, although the persistent and sometimes invasive infections caused by B. cepacia suggest that the organism possesses mechanisms for both cellular invasion and evasion of the host immune response. In this study, cultured human cells were used to analyze the invasion and intracellular survival of B. cepacia J2315, a highly transmissible clinical isolate responsible for morbidity and mortality in CF patients. Quantitative invasion and intracellular growth assays demonstrated that B. cepacia J2315 was able to enter, survive, and replicate intracellularly in U937-derived macrophages and A549 pulmonary epithelial cells. Transmission electron microscopy of infected macrophages confirmed the presence of intracellular B. cepacia and showed that intracellular bacteria were contained within membrane-bound vacuoles. An environmental isolate of B. cepacia, strain J2540, was also examined for its ability to invade and survive intracellularly in cultured human cells. J2540 entered cultured macrophages with an invasion frequency similar to that of the clinical strain, but it was less invasive than the clinical strain in epithelial cells. In marked contrast to the clinical strain, the environmental isolate was unable to survive or replicate intracellularly in either cultured macrophages or epithelial cells. Invasion and intracellular survival may play important roles in the ability of virulent strains of B. cepacia to evade the host immune response and cause persistent infections in CF patients.
Topics: Burkholderia Infections; Burkholderia cepacia; Cell Division; Cell Line; Cystic Fibrosis; Environmental Microbiology; Epithelial Cells; Humans; Lung; Macrophages; Microscopy, Electron; Opportunistic Infections; Respiratory Tract Infections; U937 Cells; Virulence
PubMed: 10603364
DOI: 10.1128/IAI.68.1.24-29.2000