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Revista Chilena de Infectologia :... Jun 2022
Topics: Enterobacteriaceae; Enterobacteriaceae Infections; Humans
PubMed: 36156693
DOI: 10.4067/s0716-10182022000200319 -
EcoSal Plus Jun 2019Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the... (Review)
Review
Plasmids are ubiquitous in the microbial world and have been identified in almost all species of bacteria that have been examined. Their localization inside the bacterial cell has been examined for about two decades; typically, they are not randomly distributed, and their positioning depends on copy number and their mode of segregation. Low-copy-number plasmids promote their own stable inheritance in their bacterial hosts by encoding active partition systems, which ensure that copies are positioned in both halves of a dividing cell. High-copy plasmids rely on passive diffusion of some copies, but many remain clustered together in the nucleoid-free regions of the cell. Here we review plasmid localization and partition (Par) systems, with particular emphasis on plasmids from and on recent results describing the localization properties and molecular mechanisms of each system. Partition systems also cause plasmid incompatibility such that distinct plasmids (with different replicons) with the same Par system cannot be stably maintained in the same cells. We discuss how partition-mediated incompatibility is a consequence of the partition mechanism.
Topics: Bacterial Proteins; Enterobacteriaceae; Plasmids; Replicon
PubMed: 31187729
DOI: 10.1128/ecosalplus.ESP-0003-2019 -
BMC Microbiology Dec 2022Acute Oak Decline (AOD) is a decline disease first reported on native oaks in the UK, but in recent years reports from further afield such as Europe and the Middle East,...
Description of a novel species of Leclercia, Leclercia tamurae sp. nov. and proposal of a novel genus Silvania gen. nov. containing two novel species Silvania hatchlandensis sp. nov. and Silvania confinis sp. nov. isolated from the rhizosphere of oak.
BACKGROUND
Acute Oak Decline (AOD) is a decline disease first reported on native oaks in the UK, but in recent years reports from further afield such as Europe and the Middle East, indicate that the distribution and host range is increasing at an alarming rate. The stem weeping symptoms of the disease partially develop due to polymicrobial-host interaction, caused by several members of the order Enterobacterales. While investigating the rhizosphere soil of AOD-unaffected trees, termed 'healthy' trees, and diseased oaks suffering from Acute Oak Decline (AOD), an enrichment method designed for enhanced recovery of Enterobacterales led to the recovery of several isolates that could not be classified as any existing species. These isolates showed a close relationship to the genus Leclercia, of which both species are of clinical importance, but the type species Leclercia adecarboxylata also displays plant growth-promoting properties in the rhizosphere.
RESULTS
Partial sequencing of four housekeeping genes revealed similarity to the genus Leclercia with varying degrees of relatedness. As such a complete polyphasic approach was used to determine the true taxonomic position of these isolates. This involved whole genome sequencing, phylogenomic analysis, phylogenetic analysis of both the 16S rRNA and four housekeeping gene sequences, combined with phenotypic testing and fatty acid analysis. Both the phylogenomic and phylogenetic analyses separated the isolates into four clusters, two of which were contained in the Leclercia clade. The remaining two clusters formed a separate lineage far removed from any currently defined species. Further investigation into the role of the isolates as plant growth-promoting bacteria as well as plant pathogens was investigated computationally, revealing a number of plant growth-promoting traits as well as virulence genes related to motility, adhesion and immune modulation.
CONCLUSION
Based on the genotypic and phenotypic data presented here, these isolates could be differentiated from each other and their closest neighbours. As such we propose the description of Leclercia tamurae sp. nov. (type strain H6S3 = LMG 32609 = CCUG 76176), Silvania gen. nov., Silvania hatchlandensis sp. nov. (type strain H19S6 = LMG 32608 = CCUG 76185) and Silvania confinis sp. nov. (type strain H4N4 = LMG 32607 = CCUG 76175). Due to their interesting protein annotations and alignments, these species warrant further investigation for their role in relation to plant health.
Topics: Quercus; Rhizosphere; Phylogeny; RNA, Ribosomal, 16S; Enterobacteriaceae; Gammaproteobacteria
PubMed: 36460957
DOI: 10.1186/s12866-022-02711-x -
Nature Reviews. Microbiology Mar 2020Gram-negative bacteria and their complex cell envelope, which comprises an outer membrane and an inner membrane, are an important and attractive system for studying the... (Review)
Review
Gram-negative bacteria and their complex cell envelope, which comprises an outer membrane and an inner membrane, are an important and attractive system for studying the translocation of small molecules across biological membranes. In the outer membrane of Enterobacteriaceae, trimeric porins control the cellular uptake of small molecules, including nutrients and antibacterial agents. The relatively slow porin-mediated passive uptake across the outer membrane and active efflux via efflux pumps in the inner membrane creates a permeability barrier. The synergistic action of outer membrane permeability, efflux pump activities and enzymatic degradation efficiently reduces the intracellular concentrations of small molecules and contributes to the emergence of antibiotic resistance. In this Review, we discuss recent advances in our understanding of the molecular and functional roles of general porins in small-molecule translocation in Enterobacteriaceae and consider the crucial contribution of porins in antibiotic resistance.
Topics: Anti-Bacterial Agents; Bacterial Outer Membrane Proteins; Biological Transport; Cell Membrane; Drug Resistance, Bacterial; Enterobacteriaceae; Porins
PubMed: 31792365
DOI: 10.1038/s41579-019-0294-2 -
Journal of Bacteriology Jan 2013Many Proteobacteria are capable of quorum sensing using N-acyl-homoserine lactone (acyl-HSL) signaling molecules that are synthesized by LuxI or LuxM homologs and... (Review)
Review
Many Proteobacteria are capable of quorum sensing using N-acyl-homoserine lactone (acyl-HSL) signaling molecules that are synthesized by LuxI or LuxM homologs and detected by transcription factors of the LuxR family. Most quorum-sensing species have at least one LuxR and one LuxI homolog. However, members of the Escherichia, Salmonella, Klebsiella, and Enterobacter genera possess only a single LuxR homolog, SdiA, and no acyl-HSL synthase. The most obvious hypothesis is that these organisms are eavesdropping on acyl-HSL production within the complex microbial communities of the mammalian intestinal tract. However, there is currently no evidence of acyl-HSLs being produced within normal intestinal communities. A few intestinal pathogens, including Yersinia enterocolitica, do produce acyl-HSLs, and Salmonella can detect them during infection. Therefore, a more refined hypothesis is that SdiA orthologs are used for eavesdropping on other quorum-sensing pathogens in the host. However, the lack of acyl-HSL signaling among the normal intestinal residents is a surprising finding given the complexity of intestinal communities. In this review, we examine the evidence for and against the possibility of acyl-HSL signaling molecules in the mammalian intestine and discuss the possibility that related signaling molecules might be present and awaiting discovery.
Topics: Acyl-Butyrolactones; Animals; Enterobacteriaceae; Humans; Intestines; Signal Transduction
PubMed: 23144246
DOI: 10.1128/JB.01341-12 -
Clinical Infectious Diseases : An... May 2015Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae present an ever-growing burden in the hospital and community settings, across all ages and... (Review)
Review
Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae present an ever-growing burden in the hospital and community settings, across all ages and demographics. Infections due to ESBL-containing pathogens continue to be associated with significant morbidity and mortality worldwide. With widespread empiric broad-spectrum β-lactam use creating selective pressure, and the resultant emergence of stable, rapidly proliferating ESBL-producing clones with continued horizontal gene transfer across genera, addressing this issue remains imperative. Although well characterized in adults, the epidemiology, risk factors, outcomes, therapies, and control measures for ESBL-producing bacteria are less appreciated in children. This analysis provides a brief summary of ESBL-producing Enterobacteriaceae in children, with a focus on recent clinical and molecular data regarding colonization and infection in nonoutbreak settings.
Topics: Adult; Anti-Bacterial Agents; Child; Child, Preschool; Drug Resistance, Multiple, Bacterial; Enterobacteriaceae; Enterobacteriaceae Infections; Humans; Infection Control; Microbial Sensitivity Tests; Risk Factors; beta-Lactamases
PubMed: 25595742
DOI: 10.1093/cid/civ020 -
Journal of Bacteriology Jan 2018Attaching and effacing (AE) pathogens colonize the gut mucosa using a type three secretion system (T3SS) and a suite of effector proteins. The locus of enterocyte... (Review)
Review
Attaching and effacing (AE) pathogens colonize the gut mucosa using a type three secretion system (T3SS) and a suite of effector proteins. The locus of enterocyte effacement (LEE) is the defining genetic feature of the AE pathogens, encoding the T3SS and the core effector proteins necessary for pathogenesis. Extensive research has revealed a complex regulatory network that senses and responds to a myriad of host- and microbiota-derived signals in the infected gut to control transcription of the LEE. These signals include microbiota-liberated sugars and metabolites in the gut lumen, molecular oxygen at the gut epithelium, and host hormones. Recent research has revealed that AE pathogens also recognize physical signals, such as attachment to the epithelium, and that the act of effector translocation remodels gene expression in infecting bacteria. In this review, we summarize our knowledge to date and present an integrated view of how chemical, geographical, and physical cues regulate the virulence program of AE pathogens during infection.
Topics: Attachment Sites, Microbiological; Enterobacteriaceae; Escherichia coli; Escherichia coli Proteins; Gene Expression Regulation, Bacterial; Genes, Bacterial; Host-Pathogen Interactions; Phosphoproteins; Quorum Sensing; Type III Secretion Systems; Virulence
PubMed: 28760850
DOI: 10.1128/JB.00336-17 -
EcoSal Plus Feb 2019CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against invasion by bacteriophages and other mobile genetic elements. Short fragments of invader... (Review)
Review
CRISPR-Cas systems provide bacteria and archaea with adaptive immunity against invasion by bacteriophages and other mobile genetic elements. Short fragments of invader DNA are stored as immunological memories within CRISPR (clustered regularly interspaced short palindromic repeat) arrays in the host chromosome. These arrays provide a template for RNA molecules that can guide CRISPR-associated (Cas) proteins to specifically neutralize viruses upon subsequent infection. Over the past 10 years, our understanding of CRISPR-Cas systems has benefited greatly from a number of model organisms. In particular, the study of several members of the Gram-negative family, especially and , have provided significant insights into the mechanisms of CRISPR-Cas immunity. In this review, we provide an overview of CRISPR-Cas systems present in members of the . We also detail the current mechanistic understanding of the type I-E and type I-F CRISPR-Cas systems that are commonly found in enterobacteria. Finally, we discuss how phages can escape or inactivate CRISPR-Cas systems and the measures bacteria can enact to counter these types of events.
Topics: Archaea; Bacteriophages; CRISPR-Cas Systems; Enterobacteriaceae; Escherichia coli; Host Microbial Interactions; Pectobacterium
PubMed: 30724156
DOI: 10.1128/ecosalplus.ESP-0008-2018 -
The American Journal of Case Reports Mar 2021BACKGROUND Leclercia adecarboxylata is a gram-negative rod, which is normally found in water and food. It is an emerging pathogen that affects immunocompromised...
BACKGROUND Leclercia adecarboxylata is a gram-negative rod, which is normally found in water and food. It is an emerging pathogen that affects immunocompromised patients, including patients with hematological malignancies or those receiving chemotherapy. Generally, L. adecarboxylata is considered a low-virulence pathogen with an excellent susceptibility profile, but some strains may be resistant to multiple antibiotics, such as b-lactams. Moreover, L. adecarboxylata is usually isolated as a part of polymicrobial cultures in immunocompetent individuals, but there have been cases where it was the only isolate. CASE REPORT A 74-year-old woman who was non-immunosuppressed and had multiple comorbidities was admitted with acute decompensated heart failure due to pneumonia. She was treated with multiple courses of antibiotics including amoxicillin-clavulanate and ciprofloxacin for pneumonia, but her infection worsened, and she had cardiopulmonary arrest. After resuscitation, she was stable for several days but suddenly became confused and hypotensive. The septic screen showed L. adecarboxylata bacteremia without a clear source, which was treated successfully with meropenem for 14 days. After the meropenem course, the patient developed diarrhea and was found to have severe Clostridium difficile infection. She did not respond to oral vancomycin and intravenous metronidazole and died. CONCLUSIONS This case illustrated an infection in a non-immunosuppressed individual by an organism that is considered an opportunistic pathogen, mainly affecting immunocompromised patients. The patient's blood culture grew L. adecarboxylata, which was sensitive to all antibiotics but resolved with meropenem treatment. Owing to increasing L. adecarboxylata infections, we recommend further studies to understand the organism's pathogenesis, risk factors, and resistance pattern.
Topics: Aged; Anti-Bacterial Agents; Bacteremia; Enterobacteriaceae; Enterobacteriaceae Infections; Female; Humans; Immunocompromised Host
PubMed: 33782375
DOI: 10.12659/AJCR.929537 -
BMC Microbiology Apr 2019The utilization of plant growth-promoting microbes is an environment friendly strategy to counteract stressful condition and encourage plants tolerance. In this regards,...
Indole-3-acetic-acid and ACC deaminase producing Leclercia adecarboxylata MO1 improves Solanum lycopersicum L. growth and salinity stress tolerance by endogenous secondary metabolites regulation.
BACKGROUND
The utilization of plant growth-promoting microbes is an environment friendly strategy to counteract stressful condition and encourage plants tolerance. In this regards, the current study was designed to isolate ACC deaminase and indole-3-acetic acid (IAA) producing halotolerant bacteria to promote tomato (Solanum lycopersicum L.) growth and tolerance against salinity stress.
RESULTS
The selected bacterial isolate MO1 was identified as Leclercia adecarboxylata and IAA quantification results revealed that MO1 produced significant amount of IAA (9.815 ± 0.6293 μg mL). The MO1 showed the presence of ACC (1-Aminocyclopropane-1-Carboxylate) deaminase responsible acdS gene and tolerance against salinity stress. A plant microbe interaction experiment using tomato (Solanum lycopersicum L.) with glycine betaine (GB) as a positive control was carried out to investigate the positive role MO1 in improving plant growth and stress tolerance. The results indicated that MO1 inoculation and GB application significantly increased growth attributes under normal as well as saline condition (120 mM NaCl). The MO1 inoculation and GB treatment approach conferred good protection against salinity stress by significantly improving glucose by 17.57 and 18.76%, sucrose by 34.2 and 12.49%, fructose by 19.9 and 10.9%, citric acid by 47.48 and 34.57%, malic acid by 52.19 and 28.38%, serine by 43.78 and 69.42%, glycine by 14.48 and 22.76%, methionine by 100 and 124.99%, threonine by 70 and 63.08%, and proline by 36.92 and 48.38%, respectively, while under normal conditions MO1 inoculation and GB treatment also enhanced glucose by 19.83 and 13.19%, sucrose by 23.43 and 15.75%, fructose by 15.79 and 8.18%, citric acid by 43.26 and 33.14%, malic acid by 36.18 and 14.48%, serine by 46.5 and 48.55%, glycine by 19.85 and 29.77%, methionine by 22.22 and 38.89%, threonine by 21.95 and 17.07%, and proline by 29.61 and 34.68% compared to levels in non-treated plants, respectively. In addition, the endogenous abscisic acid (ABA) level was noticeably lower in MO1-inoculated (30.28 and 30.04%) and GB-treated plants (45 and 35.35%) compared to their corresponding control plants under normal condition as well as salinity stress, respectively.
CONCLUSION
The current findings suggest that the IAA- and ACC-deaminase-producing abilities MO1 can improve plants tolerance to salinity stress.
Topics: Betaine; Carbon-Carbon Lyases; Enterobacteriaceae; Indoleacetic Acids; Solanum lycopersicum; Plant Roots; Salt Tolerance; Secondary Metabolism; Seedlings; Sodium Chloride
PubMed: 31023221
DOI: 10.1186/s12866-019-1450-6