scholarly journals Immunobiological Properties of Biofilms of Bacteria of the Genus Bordetella

2021 ◽  
Vol 20 (5) ◽  
pp. 123-128
Author(s):  
E. M. Zaitsev ◽  
I. G. Bazhanova ◽  
M. V. Britsina ◽  
M. N. Ozeretskovskaya
Keyword(s):  
Biofilm Formation ◽  
Whooping Cough ◽  
Public Health Problem ◽  
Extracellular Dna ◽  
Cellular Mechanisms ◽  
Antimicrobial Drugs ◽  
Pertussis Infection ◽  
Signaling Systems ◽  
Vaccination Rates ◽  
The Matrix

Relevance. Whooping cough remains a pressing public health problem worldwide, including in countries with high vaccination rates. One of the probable causes of the ongoing epidemic process of pertussis infection is B. pertussis biofilms, which differ from plankton cultures by an altered gene expression spectrum and are highly resistant to environmental conditions, antibiotics, and immune factors.Aims. Analysis of literature data on the genetic and molecular - cellular mechanisms of biofilm formation by bacteria of the genus Bordetella, as well as approaches to the search for means aimed at suppressing the growth of biofilms and the destruction of formed biofilms in the macroorganism.Conclusions. Biofilm formation by microbes of the genus Bordetella is a complex multistage process regulated by genetic signaling systems: the Bvg AS system and the 2-nucleotide (p) ppGrp system, as well as other regulatory proteins and the polysaccharide complex. The matrix of B. pertussis biofilms consists of extracellular DNA, proteins, and a polysaccharide polymer that play an important role in the formation of biofilms in the respiratory tract and on abiotic surfaces. The genetic and molecular-cellular processes of biofilm formation and maintenance, as well as the various components of the biofilm matrix, can serve as targets for new antimicrobial drugs and more effective pertussis vaccines that will better control the entire pertussis infection cycle, including colonization, persistence, and transmission of the causative agent. One of the approaches to the development of new-generation cell-free pertussis vaccines is the identification of new biofilm-associated antigens that can induce effective cellular and humoral responses. The search for drugs that can destroy biofilms, including substances that affect the matrix and facilitate the access of antibacterial drugs to microbial cells, is promising.

scholarly journals Infant Rhesus Macaques as a Nonhuman Primate Model of Bordetella Pertussis

2020 ◽  
Author(s):  
Li Shi ◽  
Wenwen Jiang ◽  
Chen Wei ◽  
Dachao Mou ◽  
Weilun Zuo ◽  
...  
Keyword(s):  
Animal Model ◽  
Bordetella Pertussis ◽  
Whooping Cough ◽  
Rhesus Macaques ◽  
Public Health Problem ◽  
Primate Model ◽  
Pertussis Infection ◽  
Cellular Immune ◽  
Infant Rhesus ◽  
Human Primate

Abstract Background: The prevalent resurgence of pertussis recently creates a vital public health problem worldwide. To understand the pertussis pathogenesis and host response to both pathogen and vaccine, a suitable pertussis animal model, particularly a non-human primate model, is necessary. Recently, a successful non-human primate pertussis model of baboons have been established. However, though the rhesus macaques have been proven to be ideal animal models for several infectious diseases, the infectious model of pertussis has not been established on it. The previous studies on rhesus macaque models of pertussis were performed in 1920s-1930s with limited experimental details. Recent monkey pertussis models failed to be established because the typical clinic syndrome and transmission were not investigated.Methods: In the present study, infant rhesus macaques were challenged with Bordetella pertussis (B.p) using the aerosol method to evaluate the feasibility of using it as an animal model of pertussis infection.Results: Upon aerosol infection, monkeys infected with the recent clinically isolated B.p strain 2016-CY-41 developed typical whooping cough, leukocytosis, bacteria-positive nasopharyngeal wash (NPW), and inter-animal transmission. Both humoral and cellular immune responses were induced by B.pertussis.Conclusion: These results demonstrate that a model of pertussis infection was successfully established in infant rhesus macaques, which provides a valuable platform to study pertussis pathogenesis and evaluate vaccine candidates.

scholarly journals An Electrostatic Net Model for the Role of Extracellular DNA in Biofilm Formation by Staphylococcus aureus

2015 ◽  
Vol 197 (24) ◽  
pp. 3779-3787 ◽  
Author(s):  
Vanina Dengler ◽  
Lucy Foulston ◽  
Alicia S. DeFrancesco ◽  
Richard Losick
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Extracellular Dna ◽  
Matrix Proteins ◽  
Exogenous Dna ◽  
Content Type ◽  
Cytoplasmic Proteins ◽  
The Matrix ◽  
Biofilm Matrix

ABSTRACTStaphylococcus aureusis an important human pathogen that can form biofilms on various surfaces. These cell communities are protected from the environment by a self-produced extracellular matrix composed of proteins, DNA, and polysaccharide. The exact compositions and roles of the different components are not fully understood. In this study, we investigated the role of extracellular DNA (eDNA) and its interaction with the recently identified cytoplasmic proteins that have a moonlighting role in the biofilm matrix. These matrix proteins associate with the cell surface upon the drop in pH that naturally occurs during biofilm formation, and we found here that this association is independent of eDNA. Conversely, the association of eDNA with the matrix was dependent on matrix proteins. Both proteinase and DNase treatments severely reduced clumping of resuspended biofilms; highlighting the importance of both proteins and eDNA in connecting cells together. By adding an excess of exogenous DNA to DNase-treated biofilm, clumping was partially restored, confirming the crucial role of eDNA in the interconnection of cells. On the basis of our results, we propose that eDNA acts as an electrostatic net, interconnecting cells surrounded by positively charged matrix proteins at a low pH.IMPORTANCEExtracellular DNA (eDNA) is an important component of the biofilm matrix of diverse bacteria, but its role in biofilm formation is not well understood. Here we report that inStaphylococcus aureus, eDNA associates with cells in a manner that depends on matrix proteins and that eDNA is required to link cells together in the biofilm. These results confirm previous studies that showed that eDNA is an important component of theS. aureusbiofilm matrix and also suggest that eDNA acts as an electrostatic net that tethers cells together via the proteinaceous layer of the biofilm matrix.

scholarly journals Biofilm Formation by Staphylococcus aureus is Triggered by a Drop in the Levels of the Second Messenger cyclic-di-AMP

2020 ◽  
Author(s):  
Adnan K. Syed ◽  
Christopher R. Vickery ◽  
Taliesin Lenhart ◽  
Eliza Llewellyn ◽  
Suzanne Walker ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Bacterial Pathogen ◽  
Second Messenger ◽  
Positive Control ◽  
Extracellular Dna ◽  
Dependent Manner ◽  
Accessory Gene ◽  
Accessory Gene Regulator ◽  
The Matrix

AbstractThe bacterial pathogen Staphylococcus aureus forms multicellular communities known as biofilms in which cells are held together by an extracellular matrix. The matrix consists of repurposed cytoplasmic proteins and extracellular DNA. These communities assemble during growth on medium containing glucose, but the intracellular signal for biofilm formation was unknown. Here we present evidence that biofilm formation is triggered by a drop in the levels of the second messenger cyclic-di-AMP. Previous work identified genes needed for the release of extracellular DNA, including genes for the cyclic-di-AMP phosphodiesterase GdpP, the transcriptional regulator XdrA, and the purine salvage enzyme Apt. Using a cyclic-di-AMP riboswitch biosensor and mass spectrometry, we show that the levels of the second messenger drop during biofilm formation in a glucose-dependent manner and that the drop is prevented in mutants of all three genes. Importantly, we also show that expression of the “accessory gene regulator” operon agr is under the positive control of cyclic-di-AMP and that an agr mutation, which is known to promote biofilm formation, bypasses the block in biofilm formation and eDNA release caused by a gdpP mutation. We conclude that the effect of the glucose-dependent drop in c-di-AMP levels is principally mediated by a reduction in agr expression, which in turn promotes biofilm formation.

scholarly journals Genome-wide screen for genes involved in eDNA release during biofilm formation byStaphylococcus aureus

2017 ◽  
Vol 114 (29) ◽  
pp. E5969-E5978 ◽  
Author(s):  
Alicia S. DeFrancesco ◽  
Nadezda Masloboeva ◽  
Adnan K. Syed ◽  
Aaron DeLoughery ◽  
Niels Bradshaw ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Extracellular Dna ◽  
Sequencing Analysis ◽  
Reduced Representation ◽  
Genome Wide ◽  
A Genome ◽  
The Matrix ◽  
Genes Encoding ◽  
Mutant Phenotypes

Staphylococcus aureusis a leading cause of both nosocomial and community-acquired infection. Biofilm formation at the site of infection reduces antimicrobial susceptibility and can lead to chronic infection. During biofilm formation, a subset of cells liberate cytoplasmic proteins and DNA, which are repurposed to form the extracellular matrix that binds the remaining cells together in large clusters. Using a strain that forms robust biofilms in vitro during growth under glucose supplementation, we carried out a genome-wide screen for genes involved in the release of extracellular DNA (eDNA). A high-density transposon insertion library was grown under biofilm-inducing conditions, and the relative frequency of insertions was compared between genomic DNA (gDNA) collected from cells in the biofilm and eDNA from the matrix. Transposon insertions into genes encoding functions necessary for eDNA release were identified by reduced representation in the eDNA. On direct testing, mutants of some of these genes exhibited markedly reduced levels of eDNA and a concomitant reduction in cell clustering. Among the genes with robust mutant phenotypes weregdpP, which encodes a phosphodiesterase that degrades the second messenger cyclic-di-AMP, andxdrA, the gene for a transcription factor that, as revealed by RNA-sequencing analysis, influences the expression of multiple genes, including many involved in cell wall homeostasis. Finally, we report that growth in biofilm-inducing medium lowers cyclic-di-AMP levels and does so in a manner that depends on thegdpPphosphodiesterase gene.

scholarly journals Infant rhesus macaques as a non-human primate model of Bordetella pertussis infection

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wenwen Jiang ◽  
Chen Wei ◽  
Dachao Mou ◽  
Weilun Zuo ◽  
Jiangli Liang ◽  
...  
Keyword(s):  
Animal Model ◽  
Bordetella Pertussis ◽  
Clinical Symptoms ◽  
Whooping Cough ◽  
Rhesus Macaques ◽  
Public Health Problem ◽  
Primate Model ◽  
Pertussis Infection ◽  
Infant Rhesus ◽  
Human Primate

Abstract Background The prevalent resurgence of pertussis has recently become a critical public health problem worldwide. To understand pertussis pathogenesis and the host response to both the pathogen and vaccines, a suitable pertussis animal model, particularly a non-human primate model, is necessary. Recently, a non-human primate pertussis model was successfully established with baboons. Rhesus macaques have been shown to be ideal animal models for several infectious diseases, but a model of infectious pertussis has not been established in these organisms. Studies on rhesus macaque models of pertussis were performed in the 1920s–1930s, but limited experimental details are available. Recent monkey pertussis models have not been successful because the typical clinical symptoms and transmission have not been achieved. Methods In the present study, infant rhesus macaques were challenged with Bordetella pertussis (B.p) using an aerosol method to evaluate the feasibility of this system as an animal model of pertussis. Results Upon aerosol infection, monkeys infected with the recently clinically isolated B.p strain 2016-CY-41 developed the typical whooping cough, leukocytosis, bacteria-positive nasopharyngeal wash (NPW), and interanimal transmission of pertussis. Both systemic and mucosal humoral responses were induced by B.p. Conclusion These results demonstrate that a model of pertussis was successfully established in infant rhesus macaques. This model provides a valuable platform for research on pertussis pathogenesis and evaluation of vaccine candidates.

scholarly journals The first recorded incidence of Deinococcus radiodurans R1 biofilm formation and its implications in heavy metals bioremediation

2017 ◽  
Author(s):  
Sudhir K. Shukla ◽  
T. Subba Rao
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Biofilm Formation ◽  
Deinococcus Radiodurans ◽  
Extracellular Dna ◽  
Metal Biosorption ◽  
Removal Of Heavy Metals ◽  
The Matrix ◽  
Heavy Metal Biosorption ◽  
Biofilm Matrix

AbstractRadiation tolerant Deinococcus radiodurans R1 is reported to be a potential bacterium for the treatment of low level active wastes. So far there are no reports on the biofilm producing capability of D. radiodurans and heavy metal biosorption. In this study, it was observed that a recombinant D. radiodurans strain with a plasmid harbouring gfp and kanR has formed significant biofilm (~10 μm thick). Analysis of biofilm matrix components produced by D. radiodurans showed that the matrix consisted primarily of proteins and carbohydrates with a little amount of extracellular DNA (eDNA). Further, studies showed that D. radiodurans biofilm formation was enhanced at higher concentrations (up to 25 mM) of Ca2+. Further studies on D. radiodurans biofilm showed that Ca2+ enhanced significant biosorption of the heavy metals (Co, Ni). In the presence of 25 mM Ca2+, the D. radiodurans (Kanr) biofilm showed 35% and 25% removal of Co2+ and Ni2+ respectively. While in the absence of Ca2+, D. radiodurans biofilm showed relatively low biosorption of Co (7%) and Ni (3%). Ca2+ also significantly enhanced exopolysaccharide (EPS) production in the biofilm matrix. This infers that EPS could have mediated the heavy metal biosorption. This study signifies the potential use of D. radiodurans biofilm in the remediation of radioactive waste components.Significance and Impact of this StudyThis is the first ever recorded study on the Deinococcus radiodurans R1 biofilm. This organism, being the most radioresistant micro-organism ever known, has always been speculated as a potential bacterium to develop a bioremediation process for radioactive heavy metal contaminants. However, the lack of biofilm forming capability proved to be a bottleneck in developing such technology. This study records the first incidence of biofilm formation in a recombinant D. radiodurans, serendipitously, and also discusses its implications in removal of heavy-metals, such as Co and Ni.

CLINICAL AND LABORATORY PECULIARITIES OF WHOOPING COUGH IN CHILDREN OF DIFFERENT AGE GROUPS

2020 ◽  
Vol 99 (6) ◽  
pp. 98-104
Author(s):  
I.V. Babachenko ◽  
◽  
Y.V. Nesterova ◽  
N.V. Skripchenko ◽  
◽  
...  
Keyword(s):  
Whooping Cough ◽  
Severe Disease ◽  
Respiratory Rhythm ◽  
Age Groups ◽  
Low Frequency ◽  
Pertussis Infection ◽  
Group 2 ◽  
Sick Children ◽  
Hematological Changes ◽  
Group 1

Objective of the research: to present the clinical and laboratory peculiarities of modern whooping cough in hospitalized children of different ages. Materials and methods: сlinical and laboratory characteristics of whooping cough were analyzed in 88 hospitalized sick children aged 1 month to 18 years in groups of children: group 1 – children under 1 year old; group 2 – children 1–6 years old; group 3 – children 7–17 years old. DNA of causative agents of pertussis infection was isolated by PCR in nasopharyngeal swabs using a commercial kit AmpliSens®Bordetella multi-FL (Moscow). Results: children of group 1 in 90% (n=43) of cases were not vaccinated against whooping cough, severe forms were recorded in 17% (n=8) of children of the 1st year of life, and in 15% (n=7) – due to respiratory rhythm disturbances. The diagnosis was confirmed by PCR in 94% (n=45) of children, leukocytosis with lymphocytosis was detected in 81,5% (n=101). Along with hematological changes typical for whooping cough, 79% (n=38) of patients in the first year of life had thrombocytosis (>400×109/l), which was most pronounced in severe disease course 511,5 [425; 568,5]×109/l vs 421 [347; 505,5]×109/l; p<0,05, which has no tendency to decrease throughout the entire observation period and correlates with the level of leukocytes (rs=0,69; p<0,001). Patients over 7 years old in 88% (n=21) of cases were vaccinated against whooping cough, but 79% (n=27) hemograms had no characteristic changes, which, along with a low frequency of confirmation of the diagnosis by PCR 22% (n=4), made it difficult to diagnose whooping cough. Conclusion: children over 7 years of age may not have characteristic hematological changes and PCR diagnostics are insufficiently effective, which contributes to the spread of whooping cough in family foci.

Biological Evaluation of Selected 1,2,3-triazole Derivatives as Antibacterial and Antibiofilm Agents

2020 ◽  
Vol 20 (24) ◽  
pp. 2186-2191
Author(s):  
Lialyz Soares Pereira André ◽  
Renata Freire Alves Pereira ◽  
Felipe Ramos Pinheiro ◽  
Aislan Cristina Rheder Fagundes Pascoal ◽  
Vitor Francisco Ferreira ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Biological Evaluation ◽  
Major Public Health Problem ◽  
Community Environments ◽  
Scanning Electron

Background: Resistance to antimicrobial agents is a major public health problem, being Staphylococcus aureus prevalent in infections in hospital and community environments and, admittedly, related to biofilm formation in biotic and abiotic surfaces. Biofilms form a complex and structured community of microorganisms surrounded by an extracellular matrix adhering to each other and to a surface that gives them even more protection from and resistance against the action of antimicrobial agents, as well as against host defenses. Methods: Aiming to control and solve these problems, our study sought to evaluate the action of 1,2,3- triazoles against a Staphylococcus aureus isolate in planktonic and in the biofilm form, evaluating the activity of this triazole through Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) tests. We have also performed cytotoxic evaluation and Scanning Electron Microscopy (SEM) of the biofilms under the treatment of the compound. The 1,2,3-triazole DAN 49 showed bacteriostatic and bactericidal activity (MIC and MBC 128 μg/mL). In addition, its presence interfered with the biofilm formation stage (1/2 MIC, p <0.000001) and demonstrated an effect on young preformed biofilm (2 MICs, p <0.05). Results: Scanning Electron Microscopy images showed a reduction in the cell population and the appearance of deformations on the surface of some bacteria in the biofilm under treatment with the compound. Conclusion: Therefore, it was possible to conclude the promising anti-biofilm potential of 1,2,3-triazole, demonstrating the importance of the synthesis of new compounds with biological activity.

scholarly journals Significance of Mast Cell Formed Extracellular Traps in Microbial Defense

2021 ◽  
Author(s):  
Daniel Elieh Ali Komi ◽  
Wolfgang M. Kuebler
Keyword(s):  
State Of The Art ◽  
Extracellular Dna ◽  
Cellular Mechanisms ◽  
Extracellular Traps ◽  
Synthetic Chemicals ◽  
Dna Strands ◽  
Associated Proteins ◽  
Microbial Defense ◽  
And Function ◽  
Insight Into

AbstractMast cells (MCs) are critically involved in microbial defense by releasing antimicrobial peptides (such as cathelicidin LL-37 and defensins) and phagocytosis of microbes. In past years, it has become evident that in addition MCs may eliminate invading pathogens by ejection of web-like structures of DNA strands embedded with proteins known together as extracellular traps (ETs). Upon stimulation of resting MCs with various microorganisms, their products (including superantigens and toxins), or synthetic chemicals, MCs become activated and enter into a multistage process that includes disintegration of the nuclear membrane, release of chromatin into the cytoplasm, adhesion of cytoplasmic granules on the emerging DNA web, and ejection of the complex into the extracellular space. This so-called ETosis is often associated with cell death of the producing MC, and the type of stimulus potentially determines the ratio of surviving vs. killed MCs. Comparison of different microorganisms with specific elimination characteristics such as S pyogenes (eliminated by MCs only through extracellular mechanisms), S aureus (removed by phagocytosis), fungi, and parasites has revealed important aspects of MC extracellular trap (MCET) biology. Molecular studies identified that the formation of MCET depends on NADPH oxidase-generated reactive oxygen species (ROS). In this review, we summarize the present state-of-the-art on the biological relevance of MCETosis, and its underlying molecular and cellular mechanisms. We also provide an overview over the techniques used to study the structure and function of MCETs, including electron microscopy and fluorescence microscopy using specific monoclonal antibodies (mAbs) to detect MCET-associated proteins such as tryptase and histones, and cell-impermeant DNA dyes for labeling of extracellular DNA. Comparing the type and biofunction of further MCET decorating proteins with ETs produced by other immune cells may help provide a better insight into MCET biology in the pathogenesis of autoimmune and inflammatory disorders as well as microbial defense.

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