scholarly journals Burkholderia cepaciaComplex: Emerging Multihost Pathogens Equipped with a Wide Range of Virulence Factors and Determinants

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Sílvia A. Sousa ◽  
Christian G. Ramos ◽  
Jorge H. Leitão
Keyword(s):  
Virulence Factors ◽  
Burkholderia Cepacia ◽  
Multidrug Resistant ◽  
Human Pathogens ◽  
Closely Related Species ◽  
Oncological Patients ◽  
Wide Range ◽  
Life Threatening ◽  
Novel Therapeutic Strategies

TheBurkholderia cepaciacomplex (Bcc) comprises at least 17 closely-related species of theβ-proteobacteria subdivision, widely distributed in natural and man-made inhabitats. Bcc bacteria are endowed with an extraordinary metabolic diversity and emerged in the 1980s as life-threatening and difficult-to-treat pathogens among patients suffering from cystic fibrosis. More recently, these bacteria became recognized as a threat to hospitalized patients suffering from other diseases, in particular oncological patients. In the present paper, we review these and other traits of Bcc bacteria, as well as some of the strategies used to identify and validate the virulence factors and determinants used by these bacteria. The identification and characterization of these virulence factors is expected to lead to the design of novel therapeutic strategies to fight the infections caused by these emergent multidrug resistant human pathogens.

scholarly journals Isolation, Identification and Molecular Characterization of Nocardiopsaceae Producing Novel Antibiotics From Soil Samples in Bingol, Turkey

2020 ◽  
Vol 11 (2) ◽  
pp. 94
Author(s):  
Samer Abuzerr ◽  
Kate Zinszer ◽  
Syamand Ahmed Qadir ◽  
Ekrem Atalan ◽  
Halgord Ali M. Farag ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Gene Sequence ◽  
Multidrug Resistant ◽  
Physicochemical Analysis ◽  
Soil Samples ◽  
Morphological Properties ◽  
16S Rdna Gene ◽  
Life Threatening ◽  
Immense Potential

There is growing interest in the antimicrobial discovery of life-threatening multidrug-resistant pathogens. The study was undertaken to isolate, identify, and characterize antibiotic-producing actinomycetaceae, particularly nocadisosaceae, from soil samples of Bingol, Turkey. Soil samples were collected from three different regions of Bingol, Turkey. The physicochemical analysis of the soil samples was immediately measured using standard methods. This was followed by isolation of Nocardiopsaceae, nutritional tests, chemotaxonomic analysis, and molecular characterization. The isolated organisms showed morphological properties consistent with the Nocardiopsaceae soil bacteria.  The 16s rDNA gene sequence indicated a similarity between the strains with 99.86% which was Nocardiopsaceae synnemata-formans. The BLAST hits had a significant e-value of 0.005. The results of the present study revealed that soil Nocardiopsaceae of Bingol appears to have immense potential as a source of antibacterial compounds.

scholarly journals Comparative characterization of microbiota between the sibling species of tea geometrid moth Ectropis obliqua Prout and E. grisescens Warren

2020 ◽  
Vol 110 (6) ◽  
pp. 684-693
Author(s):  
Zhibo Wang ◽  
Hong Li ◽  
Xiaogui Zhou ◽  
Meijun Tang ◽  
Liang Sun ◽  
...  
Keyword(s):  
Reproductive Biology ◽  
Sibling Species ◽  
Molecular Mechanisms ◽  
Closely Related Species ◽  
Endosymbiotic Bacteria ◽  
Wide Range ◽  
Geometrid Moth ◽  
Geographical Populations ◽  
Developmental Programme

AbstractFor a wide range of insect species, the microbiota has potential roles in determining host developmental programme, immunity and reproductive biology. The tea geometrid moths Ectropis obliqua and E. grisescens are two closely related species that mainly feed on tea leaves. Although they can mate, infertile hybrids are produced. Therefore, these species provide a pair of model species for studying the molecular mechanisms of microbiotal involvement in host reproductive biology. In this study, we first identified and compared the compositions of microbiota between these sibling species, revealing higher microbiotal diversity for E. grisescens. The microbiota of E. obliqua mainly comprised the phyla Firmicutes, Proteobacteria and Cyanobacteria, whereas that of E. grisescens was dominated by Proteobacteria, Actinobacteria and Firmicutes. At the genus level, the dominant microbiota of E. grisescens included Wolbachia, Enterobacter and Pseudomonas and that of E. obliqua included Melissococcus, Staphylococcus and Enterobacter. Furthermore, we verified the rate of Wolbachia to infect 80 samples from eight different geographical populations, and the results supported that only E. grisescens harboured Wolbachia. Taken together, our findings indicate significantly different microbiotal compositions for E. obliqua and E. grisescens, with Wolbachia possibly being a curial factor influencing the reproductive isolation of these species. This study provides new insight into the mechanisms by which endosymbiotic bacteria, particularly Wolbachia, interact with sibling species.

scholarly journals Lysogeny and bacteriophage host range within the Burkholderia cepacia complex

2003 ◽  
Vol 52 (6) ◽  
pp. 483-490 ◽  
Author(s):  
Ross Langley ◽  
Dervla T. Kenna ◽  
Peter Vandamme ◽  
Rebecca Ure ◽  
John R. W. Govan
Keyword(s):  
Host Range ◽  
Burkholderia Cepacia ◽  
Potential Role ◽  
River Sediments ◽  
Burkholderia Cepacia Complex ◽  
Potential Contribution ◽  
Closely Related Species ◽  
Burkholderia Gladioli ◽  
Life Threatening ◽  
Species Specific

The Burkholderia cepacia complex comprises a group of nine closely related species that have emerged as life-threatening pulmonary pathogens in immunocompromised patients, particularly individuals with cystic fibrosis or chronic granulomatous disease. Attempts to explain the genomic plasticity, adaptability and virulence of the complex have paid little attention to bacteriophages, particularly the potential contribution of lysogenic conversion and transduction. In this study, lysogeny was observed in 10 of 20 representative strains of the B. cepacia complex. Three temperate phages and five lytic phages isolated from soils, river sediments or the plant rhizosphere were chosen for further study. Six phages exhibited T-even morphology and two were lambda-like. The host range of individual phages, when tested against 66 strains of the B. cepacia complex and a representative panel of other pseudomonads, was not species-specific within the B. cepacia complex and, in some phages, included Burkholderia gladioli and Pseudomonas aeruginosa. These new data indicate a potential role for phages of the B. cepacia complex in the evolution of these soil bacteria as pathogens of plants, humans and animals, and as novel therapeutic agents.

scholarly journals Multiplex CRISPRi System Enables the Study of Stage-Specific Biofilm Genetic Requirements in Enterococcus faecalis

mBio ◽  
2020 ◽  
Vol 11 (5) ◽  
Author(s):  
Irina Afonina ◽  
June Ong ◽  
Jerome Chua ◽  
Timothy Lu ◽  
Kimberly A. Kline
Keyword(s):  
Enterococcus Faecalis ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Expression System ◽  
Multidrug Resistant ◽  
Essential Genes ◽  
Host Bacterium ◽  
Content Type ◽  
Wide Range ◽  
Life Threatening

ABSTRACT Enterococcus faecalis is an opportunistic pathogen, which can cause multidrug-resistant life-threatening infections. Gaining a complete understanding of enterococcal pathogenesis is a crucial step in identifying a strategy to effectively treat enterococcal infections. However, bacterial pathogenesis is a complex process often involving a combination of genes and multilevel regulation. Compared to established knockout methodologies, CRISPR interference (CRISPRi) approaches enable the rapid and efficient silencing of genes to interrogate gene products and pathways involved in pathogenesis. As opposed to traditional gene inactivation approaches, CRISPRi can also be quickly repurposed for multiplexing or used to study essential genes. Here, we have developed a novel dual-vector nisin-inducible CRISPRi system in E. faecalis that can efficiently silence via both nontemplate and template strand targeting. Since the nisin-controlled gene expression system is functional in various Gram-positive bacteria, the developed CRISPRi tool can be extended to other genera. This system can be applied to study essential genes, genes involved in antimicrobial resistance, and genes involved in biofilm formation and persistence. The system is robust and can be scaled up for high-throughput screens or combinatorial targeting. This tool substantially enhances our ability to study enterococcal biology and pathogenesis, host-bacterium interactions, and interspecies communication. IMPORTANCE Enterococcus faecalis causes multidrug-resistant life-threatening infections and is often coisolated with other pathogenic bacteria from polymicrobial biofilm-associated infections. Genetic tools to dissect complex interactions in mixed microbial communities are largely limited to transposon mutagenesis and traditional time- and labor-intensive allelic-exchange methods. Built upon streptococcal dCas9, we developed an easily modifiable, inducible CRISPRi system for E. faecalis that can efficiently silence single and multiple genes. This system can silence genes involved in biofilm formation and antibiotic resistance and can be used to interrogate gene essentiality. Uniquely, this tool is optimized to study genes important for biofilm initiation, maturation, and maintenance and can be used to perturb preformed biofilms. This system will be valuable to rapidly and efficiently investigate a wide range of aspects of complex enterococcal biology.

scholarly journals The Secretion of Toxins and Other Exoproteins of Cronobacter: Role in Virulence, Adaption, and Persistence

2020 ◽  
Vol 8 (2) ◽  
pp. 229 ◽  
Author(s):  
Hyein Jang ◽  
Gopal R. Gopinath ◽  
Athmanya Eshwar ◽  
Shabarinath Srikumar ◽  
Scott Nguyen ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Human Disease ◽  
Pathogenic Bacteria ◽  
Eukaryotic Cell ◽  
Human Pathogens ◽  
Wide Range ◽  
Cell Processes ◽  
Cronobacter Species ◽  
Foodborne Pathogenic Bacteria ◽  
Species Specific

Cronobacter species are considered an opportunistic group of foodborne pathogenic bacteria capable of causing both intestinal and systemic human disease. This review describes common virulence themes shared among the seven Cronobacter species and describes multiple exoproteins secreted by Cronobacter, many of which are bacterial toxins that may play a role in human disease. The review will particularly concentrate on the virulence factors secreted by C. sakazakii, C. malonaticus, and C. turicensis, which are the primary human pathogens of interest. It has been discovered that various species-specific virulence factors adversely affect a wide range of eukaryotic cell processes including protein synthesis, cell division, and ion secretion. Many of these factors are toxins which have been shown to also modulate the host immune response. These factors are encoded on a variety of mobile genetic elements such as plasmids and transposons; this genomic plasticity implies ongoing re-assortment of virulence factor genes which has complicated our efforts to categorize Cronobacter into sharply defined genomic pathotypes.

scholarly journals A promising bioconjugate vaccine against hypervirulentKlebsiella pneumoniae

2019 ◽  
Vol 116 (37) ◽  
pp. 18655-18663 ◽  
Author(s):  
Mario F. Feldman ◽  
Anne E. Mayer Bridwell ◽  
Nichollas E. Scott ◽  
Evgeny Vinogradov ◽  
Samuel R. McKee ◽  
...  
Keyword(s):  
Capsular Polysaccharide ◽  
Multidrug Resistant ◽  
Preclinical Study ◽  
Recombinant Production ◽  
Virulent Strains ◽  
Lethal Infection ◽  
Life Threatening ◽  
Glycoconjugate Vaccines ◽  
New Generation

HypervirulentKlebsiella pneumoniae(hvKp) is globally disseminating as a community-acquired pathogen causing life-threatening infections in healthy individuals. The fact that a dose as little as 50 bacteria is lethal to mice illustrates the dramatic increase of virulence associated with hvKpstrains compared with classicalK. pneumoniae(cKp) strains, which require lethal doses greater than 107bacteria. Until recently, these virulent strains were mostly antibiotic-susceptible. However, multidrug-resistant (MDR) hvKpstrains have been emerging, spawning a new generation of hypervirulent “superbugs.” The mechanisms of hypervirulence are not fully defined, but overproduction of capsular polysaccharide significantly impedes host clearance, resulting in increased pathogenicity of hvKpstrains. While there are more than 80 serotypes ofK. pneumoniae, the K1 and K2 serotypes cause the vast majority of hypervirulent infections. Therefore, a glycoconjugate vaccine targeting these 2 serotypes could significantly reduce hvKpinfection. Conventionally, glycoconjugate vaccines are manufactured using intricate chemical methodologies to covalently attach purified polysaccharides to carrier proteins, which is widely considered to be technically challenging. Here we report on the recombinant production and analytical characterization of bioconjugate vaccines, enzymatically produced in glycoengineeredEscherichia colicells, against the 2 predominant hypervirulentK. pneumoniaeserotypes, K1 and K2. TheK. pneumoniaebioconjugates are immunogenic and efficacious, protecting mice against lethal infection from 2 hvKpstrains, NTUH K-2044 and ATCC 43816. This preclinical study constitutes a key step toward preventing further global dissemination of hypervirulent MDR hvKpstrains.

scholarly journals Metalloprotease Vsm Is the Major Determinant of Toxicity for Extracellular Products of Vibrio splendidus

2008 ◽  
Vol 74 (23) ◽  
pp. 7108-7117 ◽  
Author(s):  
Johan Binesse ◽  
Claude Delsert ◽  
Denis Saulnier ◽  
Marie-Christine Champomier-Vergès ◽  
Monique Zagorec ◽  
...  
Keyword(s):  
Virulence Factors ◽  
Avirulent Strain ◽  
Human Pathogens ◽  
Vibrio Splendidus ◽  
Major Toxicity ◽  
Extracellular Products ◽  
Toxicity Factor ◽  
Immune Inhibitor A ◽  
Direct Toxicity

ABSTRACT Genomic data combined with reverse genetic approaches have contributed to the characterization of major virulence factors of Vibrio species; however, these studies have targeted primarily human pathogens. Here, we investigate virulence factors in the oyster pathogen Vibrio splendidus LGP32 and show that toxicity is correlated to the presence of a metalloprotease and its corresponding vsm gene. Comparative genomics showed that an avirulent strain closely related to LGP32 lacked the metalloprotease. The toxicity of LGP32 metalloprotease was confirmed by exposing mollusk and mouse fibroblastic cell lines to extracellular products (ECPs) of the wild type (wt) and a vsm deletion mutant (Δvsm mutant). The ECPs of the wt induced a strong cytopathic effect whose severity was cell type dependent, while those of the Δvsm mutant were much less toxic, and exposure to purified protein demonstrated the direct toxicity of the Vsm metalloprotease. Finally, to investigate Vsm molecular targets, a proteomic analysis of the ECPs of both LGP32 and the Δvsm mutant was performed, revealing a number of differentially expressed and/or processed proteins. One of these, the VSA1062 metalloprotease, was found to have significant identity to the immune inhibitor A precursor, a virulence factor of Bacillus thuringiensis. Deletion mutants corresponding to several of the major proteins were constructed by allelic exchange, and the ECPs of these mutants proved to be toxic to both cell cultures and animals. Taken together, these data demonstrate that Vsm is the major toxicity factor in the ECPs of V. splendidus.

scholarly journals Small RNA Regulation of Virulence in Pathogenic Escherichia coli

2021 ◽  
Vol 10 ◽  
Author(s):  
Brandon M. Sy ◽  
Jai J. Tree
Keyword(s):  
Escherichia Coli ◽  
Transcriptional Regulation ◽  
Virulence Factors ◽  
Small Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Human Pathogens ◽  
Rna Regulation ◽  
Wide Range ◽  
Post Transcriptional Regulation

Enteric and extraintestinal pathotypes of Escherichia coli utilize a wide range of virulence factors to colonize niches within the human body. During infection, virulence factors such as adhesins, secretions systems, or toxins require precise regulation and coordination to ensure appropriate expression. Additionally, the bacteria navigate rapidly changing environments with fluctuations in pH, temperature, and nutrient levels. Enteric pathogens utilize sophisticated, interleaved systems of transcriptional and post-transcriptional regulation to sense and respond to these changes and modulate virulence gene expression. Regulatory small RNAs and RNA-binding proteins play critical roles in the post-transcriptional regulation of virulence. In this review we discuss how the mosaic genomes of Escherichia coli pathotypes utilize small RNA regulation to adapt to their niche and become successful human pathogens.

scholarly journals The Potential of Phage Therapy against the Emerging Opportunistic Pathogen Stenotrophomonas maltophilia

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1057
Author(s):  
Jaclyn G. McCutcheon ◽  
Jonathan J. Dennis
Keyword(s):  
Antimicrobial Resistance ◽  
Virulence Factors ◽  
Stenotrophomonas Maltophilia ◽  
Phage Therapy ◽  
Multidrug Resistant ◽  
Future Research ◽  
Isolation And Characterization ◽  
Alternative Treatment Option ◽  
Antimicrobial Resistance Genes

The isolation and characterization of bacteriophages for the treatment of infections caused by the multidrug resistant pathogen Stenotrophomonas maltophilia is imperative as nosocomial and community-acquired infections are rapidly increasing in prevalence. This increase is largely due to the numerous virulence factors and antimicrobial resistance genes encoded by this bacterium. Research on S. maltophilia phages to date has focused on the isolation and in vitro characterization of novel phages, often including genomic characterization, from the environment or by induction from bacterial strains. This review summarizes the clinical significance, virulence factors, and antimicrobial resistance mechanisms of S. maltophilia, as well as all phages isolated and characterized to date and strategies for their use. We further address the limited in vivo phage therapy studies conducted against this bacterium and discuss the future research needed to spearhead phages as an alternative treatment option against multidrug resistant S. maltophilia.

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