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Frontiers in Cellular and Infection... 2017is a genus within the β that contains at least 90 validly named species which can be found in a diverse range of environments. A number of pathogenic species occur... (Review)
Review
is a genus within the β that contains at least 90 validly named species which can be found in a diverse range of environments. A number of pathogenic species occur within the genus. These include and , opportunistic pathogens that can infect the lungs of patients with cystic fibrosis, and are members of the complex (Bcc). is also an opportunistic pathogen, but in contrast to Bcc species it causes the tropical human disease melioidosis, while its close relative is the causative agent of glanders in horses. For these pathogens to survive within a host and cause disease they must be able to acquire iron. This chemical element is essential for nearly all living organisms due to its important role in many enzymes and metabolic processes. In the mammalian host, the amount of accessible free iron is negligible due to the low solubility of the metal ion in its higher oxidation state and the tight binding of this element by host proteins such as ferritin and lactoferrin. As with other pathogenic bacteria, species have evolved an array of iron acquisition mechanisms with which to capture iron from the host environment. These mechanisms include the production and utilization of siderophores and the possession of a haem uptake system. Here, we summarize the known mechanisms of iron acquisition in pathogenic species and discuss the evidence for their importance in the context of virulence and the establishment of infection in the host. We have also carried out an extensive bioinformatic analysis to identify which siderophores are produced by each species that is pathogenic to humans.
Topics: Animals; Burkholderia; Burkholderia Infections; Burkholderia gladioli; Burkholderia mallei; Burkholderia pseudomallei; Computational Biology; Cystic Fibrosis; Ferritins; Glanders; Heme; Horses; Humans; Iron; Lactoferrin; Lung; Melioidosis; Siderophores; Virulence
PubMed: 29164069
DOI: 10.3389/fcimb.2017.00460 -
Microbiology Spectrum Feb 2022Chromids (secondary chromosomes) in bacterial genomes that are present in addition to the main chromosome appear to be evolutionarily conserved in some specific...
Chromids (secondary chromosomes) in bacterial genomes that are present in addition to the main chromosome appear to be evolutionarily conserved in some specific bacterial groups. In rare cases among these groups, a small number of strains from and were shown to possess a naturally fused single chromosome that was reported to have been generated through intragenomic homologous recombination between repeated sequences on the chromosome and chromid. Similar examples have never been reported in the family , a well-documented group that conserves chromids. Here, an in-depth genomic characterization was performed on a bacterium that was isolated from a soil bacterial consortium maintained on diesel fuel and mutagenic benzo[]pyrene. This organism, Cupriavidus necator strain KK10, was revealed to carry a single chromosome with unexpectedly large size (>6.6 Mb), and results of comparative genomics with the genome of C. necator N-1 indicated that the single chromosome of KK10 was generated through fusion of the prototypical chromosome and chromid at the rRNA operons. This fusion hypothetically occurred through homologous recombination with a crossover between repeated rRNA operons on the chromosome and chromid. Some metabolic functions that were likely expressed from genes on the prototypical chromid region were indicated to be retained. If this phenomenon-the bacterial chromosome-chromid fusion across the rRNA operons through homologous recombination-occurs universally in prokaryotes, the multiple rRNA operons in bacterial genomes may not only contribute to the robustness of ribosome function, but also provide more opportunities for genomic rearrangements through frequent recombination. A bacterial chromosome that was naturally fused with the secondary chromosome, or "chromid," and presented as an unexpectedly large single replicon was discovered in the genome of Cupriavidus necator strain KK10, a biotechnologically useful member of the family . Although is a well-documented group that conserves chromids in their genomes, this chromosomal fusion event has not been previously reported for this family. This fusion has hypothetically occurred through intragenomic homologous recombination between repeated rRNA operons and, if so, provides novel insight into the potential of multiple rRNA operons in bacterial genomes to lead to chromosome-chromid fusion. The harsh conditions under which strain KK10 was maintained-a genotoxic hydrocarbon-enriched milieu-may have provided this genotype with a niche in which to survive.
Topics: Burkholderiaceae; Chromosomes, Bacterial; Genome, Bacterial; Genomics; RNA, Bacterial; Recombination, Genetic; Replicon; rRNA Operon
PubMed: 34985328
DOI: 10.1128/spectrum.02225-21 -
Expert Opinion on Drug Discovery Jul 2021: The increasing threat of antibiotic-resistant pathogens makes it imperative that new antibiotics to combat them are discovered. is a genus of Gram-negative,... (Review)
Review
: The increasing threat of antibiotic-resistant pathogens makes it imperative that new antibiotics to combat them are discovered. is a genus of Gram-negative, non-sporulating bacteria. While ubiquitous and capable of growing within plants and groundwater, they are primarily soil-dwelling organisms. These include the more virulent forms of such as , and the complex (Bcc).: This review provides a synopsis of current research on the natural products isolated from the genus . The authors also cover the research on the drug discovery efforts that have been performed on the natural products derived from .: Though has a small number of pathogenic species, the majority of the genus is avirulent and almost all members of the genus are capable of producing useful antimicrobial products that could potentially lead to the development of novel therapeutics against infectious diseases. The need for discovery of new antibiotics is urgent due to the ever-increasing prevalence of antibiotic-resistant pathogens, coupled with the decline in the discovery of new antibiotics.
Topics: Biological Products; Burkholderia; Burkholderia Infections; Burkholderia pseudomallei; Drug Discovery; Humans
PubMed: 33467922
DOI: 10.1080/17460441.2021.1877655 -
Applied and Environmental Microbiology May 2022Microbial symbionts are critical for the development and survival of many eukaryotes. Recent research suggests that the genes enabling these relationships can be...
Microbial symbionts are critical for the development and survival of many eukaryotes. Recent research suggests that the genes enabling these relationships can be localized in horizontally transferred regions of microbial genomes termed "symbiotic islands." Recently, a putative symbiotic island was found that may facilitate symbioses between true bugs and numerous species, based on analysis of five symbionts. We expanded on this work by exploring the putative island's prevalence, origin, and association with colonization across the bacterial family . We performed a broad comparative analysis of 229 genomes, including 8 new genomes of insect- or soil-associated sequenced for this study. We detected the region in 23% of the genomes; these were located solely within two clades. Our analyses suggested that the contiguous region arose at the common ancestor of plant- and insect-associated clades, but the genes themselves are ancestral. Although the region was initially discovered on plasmids and we did detect two likely instances of horizontal transfer within , we found that the region is almost always localized to a chromosome and does not possess any of the mobility elements that typify genomic islands. Finally, to attempt to deduce the region's function, we combined our data with information on several strains' abilities to colonize the insect's symbiotic organ. Although the region was associated with improved colonization of the host, this relationship was confounded with, and likely driven by, clade membership. These findings advance our understanding of the genomic underpinnings of a widespread insect-microbe symbiosis. Many plants and animals form intricate associations with bacteria. These pairings can be mediated by genomic islands, contiguous regions containing numerous genes with cohesive functionality. Pathogen-associated islands are well described, but recent evidence suggests that mutualistic islands, which benefit both host and symbiont, may also be common. Recently, a putative symbiosis island was found in symbionts of insects. We determined that this genomic region is located in only two clades of (the plant- and insect-associated species) and that although it has undergone horizontal transfer, it is most likely a symbiosis-associated region rather than a true island. This region is associated with improved host colonization, although this is may be due to specific clades' abilities to colonize rather than presence of the region. By studying the genomic basis of the insect- symbiosis, we can better understand how mutualisms evolve in animals.
Topics: Animals; Burkholderia; Burkholderiaceae; Genomics; Heteroptera; Insecta; Prevalence; Symbiosis
PubMed: 35435710
DOI: 10.1128/aem.02502-21 -
Applied Microbiology and Biotechnology Dec 2021Bacteria belonging to the Burkholderia genus are extremely versatile and diverse. They can be environmental isolates, opportunistic pathogens in cystic fibrosis,... (Review)
Review
Bacteria belonging to the Burkholderia genus are extremely versatile and diverse. They can be environmental isolates, opportunistic pathogens in cystic fibrosis, immunocompromised or chronic granulomatous disease patients, or cause disease in healthy people (e.g., Burkholderia pseudomallei) or animals (as in the case of Burkholderia mallei). Since the genus was separated from the Pseudomonas one in the 1990s, the methodological tools to study and characterize these bacteria are evolving fast. Here we reviewed the techniques used in the last few years to update the taxonomy of the genus, to study gene functions and regulations, to deepen the knowledge on the drug resistance which characterizes these bacteria, and to elucidate their mechanisms to establish infections. The availability of these tools significantly impacts the quality of research on Burkholderia and the choice of the most appropriated is fundamental for a precise characterization of the species of interest.Key points• Updated techniques to study the genus Burkholderia were reviewed.• Taxonomy, genomics, assays, and animal models were described.• A comprehensive overview on recent advances in Burkholderia studies was made.
Topics: Animals; Burkholderia; Burkholderia Infections; Burkholderia mallei; Burkholderia pseudomallei; Cystic Fibrosis; Humans
PubMed: 34755214
DOI: 10.1007/s00253-021-11667-3 -
International Journal of Molecular... Dec 2018The members of the genus are characterized by high versatility and adaptability to various ecological niches. With the availability of the genome sequences of numerous... (Review)
Review
The members of the genus are characterized by high versatility and adaptability to various ecological niches. With the availability of the genome sequences of numerous species of , many studies have been conducted to elucidate the unique features of this exceptional group of bacteria. Genomic and metabolic plasticity are common among species, as evidenced by their relatively large multi-replicon genomes that are rich in insertion sequences and genomic islands and contain a high proportion of coding regions. Such unique features could explain their adaptability to various habitats and their versatile lifestyles, which are reflected in a multiplicity of species including free-living rhizospheric bacteria, plant endosymbionts, legume nodulators, and plant pathogens. The phytopathogenic group encompasses several pathogens representing threats to important agriculture crops such as rice. Contrarily, plant-beneficial have also been reported, which have symbiotic and growth-promoting roles. In this review, the taxonomy of is discussed emphasizing the recent updates and the contributions of genomic studies to precise taxonomic positioning. Moreover, genomic and functional studies on are reviewed and insights are provided into the mechanisms underlying the virulence and benevolence of phytopathogenic and plant-beneficial , respectively, on the basis of cutting-edge knowledge.
Topics: Burkholderia; Crops, Agricultural; Genome, Bacterial; Host-Pathogen Interactions; Phylogeny; Symbiosis
PubMed: 30598000
DOI: 10.3390/ijms20010121 -
Emerging Infectious Diseases Nov 2023Pandoraea spp. are gram-negative, nonfermenting rods mainly known to infect patients with cystic fibrosis (CF). Outbreaks have been reported from several CF centers. We... (Review)
Review
Pandoraea spp. are gram-negative, nonfermenting rods mainly known to infect patients with cystic fibrosis (CF). Outbreaks have been reported from several CF centers. We report a Pandoraea spp. outbreak comprising 24 non-CF patients at a large university hospital and a neighboring heart center in Germany during July 2019-December 2021. Common features in the patients were critical illness, invasive ventilation, antimicrobial pretreatment, and preceding surgery. Complicated and relapsing clinical courses were observed in cases with intraabdominal infections but not those with lower respiratory tract infections. Genomic analysis of 15 isolates identified Pandoraea commovens as the genetically most similar species and confirmed the clonality of the outbreak strain, designated P. commovens strain LB-19-202-79. The strain exhibited resistance to most antimicrobial drugs except ampicillin/sulbactam, imipenem, and trimethoprim/sulfamethoxazole. Our findings suggest Pandoraea spp. can spread among non-CF patients and underscore that clinicians and microbiologists should be vigilant in detecting and assessing unusual pathogens.
Topics: Humans; Cystic Fibrosis; Gram-Negative Bacteria; Anti-Infective Agents; Trimethoprim, Sulfamethoxazole Drug Combination; Burkholderiaceae; Germany
PubMed: 37877517
DOI: 10.3201/eid2911.230493 -
Microbiology Spectrum Feb 2022Bacteria have developed unique mechanisms to adapt to environmental stresses and challenges of the immune system. Here, we report that Burkholderia pseudomallei, the...
Bacteria have developed unique mechanisms to adapt to environmental stresses and challenges of the immune system. Here, we report that Burkholderia pseudomallei, the causative agent of melioidosis, and its laboratory surrogate, Burkholderia thailandensis, utilize distinct mechanisms for surviving starvation at different incubation temperatures. At 21°C, are present as short rods which can rapidly reactivate and form colonies on solid media. At 4°C, convert into coccoid forms that cannot be cultured on solid agar but can be resuscitated in liquid media supplemented with supernatant obtained from logarithmic phase cultures of B. thailandensis, or catalase and Tween 80, thus displaying characteristics of differentially culturable bacteria (DCB). These DCB have low intensity fluorescence when stained with SYTO 9, have an intact cell membrane (propidium iodide negative), and contain 16S rRNA at levels comparable with growing cells. We also present evidence that lytic transglycosylases, a family of peptidoglycan-remodeling enzymes, are involved in the generation of coccoid forms and their resuscitation to actively growing cells. A B. pseudomallei Δ mutant with four genes deleted did not produce coccoid forms at 4°C and could not be resuscitated in the liquid media evaluated. Our findings provide insights into the adaptation of to nutrient limitation and the generation of differentially culturable bacteria. Bacterial pathogens exhibit physiologically distinct forms that enable their survival in an infected host, the environment and following exposure to antimicrobial agents. B. pseudomallei causes the disease melioidosis, which has a high mortality rate and is difficult to treat with antibiotics. The bacterium is endemic to several countries and detected in high abundance in the environment. Here, we report that during starvation at low temperature, B. pseudomallei produces coccoid forms that cannot grow in standard media and which, therefore, can be challenging to detect using common tools. We provide evidence that the formation of these cocci is mediated by cell wall-specialized enzymes and lytic transglycosylases, and that resuscitation of these forms occurs following the addition of catalase and Tween 80. Our findings have important implications for the disease control and detection of B. pseudomallei, an agent of both public health and defense interest.
Topics: Burkholderia; Burkholderia pseudomallei; Cell Culture Techniques; Humans; Melioidosis; Peptidoglycan; RNA, Ribosomal, 16S; Temperature
PubMed: 34985335
DOI: 10.1128/spectrum.02110-21 -
Infection and Immunity Jun 2020The regulation and timely expression of bacterial genes during infection is critical for a pathogen to cause an infection. Bacteria have multiple mechanisms to regulate... (Review)
Review
The regulation and timely expression of bacterial genes during infection is critical for a pathogen to cause an infection. Bacteria have multiple mechanisms to regulate gene expression in response to their environment, one of which is two-component systems (TCS). TCS have two components. One component is a sensory histidine kinase (HK) that autophosphorylates when activated by a signal. The activated sensory histidine kinase then transfers the phosphoryl group to the second component, the response regulator, which activates transcription of target genes. The genus contains members that cause human disease and are often extensively resistant to many antibiotics. The complex (BCC) can cause severe lung infections in patients with cystic fibrosis (CF) or chronic granulomatous disease (CGD). BCC members have also recently been associated with several outbreaks of bacteremia from contaminated pharmaceutical products. Separate from the BCC is , which is the causative agent of melioidosis, a serious disease that occurs in the tropics, and a potential bioterrorism weapon. Bioinformatic analysis of sequenced isolates predicts that most strains have at least 40 TCS. The vast majority of these TCS are uncharacterized both in terms of the signals that activate them and the genes that are regulated by them. This review will highlight TCS that have been described to play a role in virulence in either the BCC or Since many of these TCS are involved in virulence, TCS are potential novel therapeutic targets, and elucidating their function is critical for understanding pathogenesis.
Topics: Bacterial Physiological Phenomena; Burkholderia; Burkholderia Infections; Burkholderia cepacia complex; Gene Expression Regulation, Bacterial; Host-Pathogen Interactions; Humans; Signal Transduction; Virulence; Virulence Factors
PubMed: 32284365
DOI: 10.1128/IAI.00927-19 -
Journal of Natural Products Jul 2019bacteria are multifaceted organisms that are ecologically and metabolically diverse. The genus has gained prominence because it includes human pathogens; however, many...
bacteria are multifaceted organisms that are ecologically and metabolically diverse. The genus has gained prominence because it includes human pathogens; however, many strains are nonpathogenic and have desirable characteristics such as beneficial plant associations and degradation of pollutants. The diversity of the genus is reflected within the large genomes that feature multiple replicons. genomes encode a plethora of natural products with potential therapeutic relevance and biotechnological applications. This review highlights as an emerging source of natural products. An overview of the taxonomy of the genus, which is currently being revised, is provided. We then present a curated compilation of natural products isolated from sensu lato and analyze their characteristics in terms of biosynthetic class, discovery method, and bioactivity. Finally, we describe and discuss genome characteristics and highlight the biosynthesis of a select number of natural products that are encoded in unusual biosynthetic gene clusters. The availability of >1000 genomes in public databases provides an opportunity to realize the genetic potential of this underexplored taxon for natural product discovery.
Topics: Biological Products; Burkholderia; Genes, Bacterial
PubMed: 31294966
DOI: 10.1021/acs.jnatprod.8b01068