-
Indian Journal of Public Health Jan 2024
Topics: Pseudomonas aeruginosa; Humans; Pseudomonas Infections; Anti-Bacterial Agents; Prevalence; India; Microbial Sensitivity Tests; Drug Resistance, Bacterial
PubMed: 38847645
DOI: 10.4103/ijph.ijph_557_23 -
Frontiers in Cellular and Infection... 2024is notorious for its multidrug resistance and its involvement in hospital-acquired infections. In this study, 20 bacterial strains isolated from soil samples near the...
INTRODUCTION
is notorious for its multidrug resistance and its involvement in hospital-acquired infections. In this study, 20 bacterial strains isolated from soil samples near the Hindan River in Ghaziabad, India, were investigated for their biochemical and morphological characteristics, with a focus on identifying strains with exceptional drug resistance and pyocyanin production.
METHODS
The isolated bacterial strains were subjected to biochemical and morphological analyses to characterize their properties, with a particular emphasis on exopolysaccharide production. Strain GZB16/CEES1, exhibiting remarkable drug resistance and pyocyanin production. Biochemical and molecular analyses, including sequencing of its 16S rRNA gene (accession number LN735036.1), plasmid-curing assays, and estimation of plasmid size, were conducted to elucidate its drug resistance mechanisms and further pyocynin based target the Strain GZB16/CEES1 demonstrated 100% resistance to various antibiotics used in the investigation, with plasmid-curing assays, suggesting plasmid-based resistance gene transmission. The plasmid in GZB16/CEES1 was estimated to be approximately 24 kb in size. The study focused on 's pyocyanin production, revealing its association with anticandidal activity. The minimum inhibitory concentration (MIC) of the bacterial extract against was 50 μg/ml, with a slightly lower pyocyanin-based MIC of 38.5 μg/ml. Scanning electron microscopy illustrated direct interactions between strains and cells, leading to the destruction of the latter.
DISCUSSION
These findings underscore the potential of in understanding microbial interactions and developing strategies to combat fungal infections. The study highlights the importance of investigating bacterial-fungal interactions and the role of pyocyanin in antimicrobial activity. Further research in this area could lead to the development of novel therapeutic approaches for combating multidrug-resistant infections.
Topics: Pseudomonas aeruginosa; Pyocyanine; Drug Resistance, Multiple, Bacterial; Antifungal Agents; Microbial Sensitivity Tests; Candida albicans; RNA, Ribosomal, 16S; India; Plasmids; Soil Microbiology; Anti-Bacterial Agents; Antibiosis
PubMed: 38846355
DOI: 10.3389/fcimb.2024.1375872 -
Respiratory Research Jun 2024The effect of dual systemic antibiotic therapy against Pseudomonas aeruginosa in patients with pre-existing lung disease is unknown. To assess whether dual systemic... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
The effect of dual systemic antibiotic therapy against Pseudomonas aeruginosa in patients with pre-existing lung disease is unknown. To assess whether dual systemic antibiotics against P. aeruginosa in outpatients with COPD, non-cystic fibrosis (non-CF) bronchiectasis, or asthma can improve outcomes.
METHODS
Multicenter, randomised, open-label trial conducted at seven respiratory outpatient clinics in Denmark. Outpatients with COPD, non-CF bronchiectasis, or asthma with a current P. aeruginosa-positive lower respiratory tract culture (clinical routine samples obtained based on symptoms of exacerbation not requiring hospitalisation), regardless of prior P. aeruginosa-status, no current need for hospitalisation, and at least two moderate or one hospitalisation-requiring exacerbation within the last year were eligible. Patients were assigned 1:1 to 14 days of dual systemic anti-pseudomonal antibiotics or no antibiotic treatment. Primary outcome was time to prednisolone or antibiotic-requiring exacerbation or death from day 20 to day 365.
RESULTS
The trial was stopped prematurely based in lack of recruitment during the COVID-19 pandemic, this decision was endorsed by the Data and Safety Monitoring Board. Forty-nine outpatients were included in the study. There was a reduction in risk of the primary outcome in the antibiotic group compared to the control group (HR 0.51 (95%CI 0.27-0.96), p = 0.037). The incidence of admissions with exacerbation within one year was 1.1 (95%CI 0.6-1.7) in the dual antibiotic group vs. 2.9 (95%CI 1.3-4.5) in the control group, p = 0.037.
CONCLUSIONS
Use of dual systemic antibiotics for 14 days against P. aeruginosa in outpatients with chronic lung diseases and no judged need for hospitalisation, improved clinical outcomes markedly. The main limitation was the premature closure of the trial.
TRIAL REGISTRATION
ClinicalTrials.gov, NCT03262142, registration date 2017-08-25.
Topics: Humans; Male; Female; Pseudomonas Infections; Anti-Bacterial Agents; Aged; Middle Aged; Pseudomonas aeruginosa; Denmark; Outpatients; Disease Progression; Treatment Outcome; Hospitalization; Pulmonary Disease, Chronic Obstructive
PubMed: 38844921
DOI: 10.1186/s12931-024-02860-9 -
PloS One 2024Cellular metabolic activity can be detected by tetrazolium-based colorimetric assays, which rely on dehydrogenase enzymes from living cells to reduce tetrazolium...
Cellular metabolic activity can be detected by tetrazolium-based colorimetric assays, which rely on dehydrogenase enzymes from living cells to reduce tetrazolium compounds into colored formazan products. Although these methods have been used in different fields of microbiology, their application to the detection of bacteria with plastic-degrading activity has not been well documented. Here, we report a microplate-adapted method for the detection of bacteria metabolically active on the commercial polyester polyurethane (PU) Impranil®DLN using the tetrazolium salt 2,3-bis [2-methyloxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide (XTT). Bacterial cells that are active on PU reduce XTT to a water-soluble orange dye, which can be quantitatively measured using a microplate reader. We used the Pseudomonas putida KT2440 strain as a study model. Its metabolic activity on Impranil detected by our novel method was further verified by Fourier-transform infrared spectroscopy (FTIR) analyses. Measurements of the absorbance of reduced XTT at 470 nm in microplate wells were not affected by the colloidal properties of Impranil or cell density. In summary, we provide here an easy and high-throughput method for screening bacteria active on PU that can be adapted to other plastic substrates.
Topics: Polyurethanes; Pseudomonas putida; Tetrazolium Salts; Spectroscopy, Fourier Transform Infrared; Water; Colorimetry
PubMed: 38843174
DOI: 10.1371/journal.pone.0303210 -
Microbiome Jun 2024Plant microbiota contributes to plant growth and health, including enhancing plant resistance to various diseases. Despite remarkable progress in understanding diseases...
BACKGROUND
Plant microbiota contributes to plant growth and health, including enhancing plant resistance to various diseases. Despite remarkable progress in understanding diseases resistance in plants, the precise role of rhizosphere microbiota in enhancing watermelon resistance against soil-borne diseases remains unclear. Here, we constructed a synthetic community (SynCom) of 16 core bacterial strains obtained from the rhizosphere of grafted watermelon plants. We further simplified SynCom and investigated the role of bacteria with synergistic interactions in promoting plant growth through a simple synthetic community.
RESULTS
Our results demonstrated that the SynCom significantly enhanced the growth and disease resistance of ungrafted watermelon grown in non-sterile soil. Furthermore, analysis of the amplicon and metagenome data revealed the pivotal role of Pseudomonas in enhancing plant health, as evidenced by a significant increase in the relative abundance and biofilm-forming pathways of Pseudomonas post-SynCom inoculation. Based on in vitro co-culture experiments and bacterial metabolomic analysis, we selected Pseudomonas along with seven other members of the SynCom that exhibited synergistic effects with Pseudomonas. It enabled us to further refine the initially constructed SynCom into a simplified SynCom comprising the eight selected bacterial species. Notably, the plant-promoting effects of simplified SynCom were similar to those of the initial SynCom. Furthermore, the simplified SynCom protected plants through synergistic effects of bacteria.
CONCLUSIONS
Our findings suggest that the SynCom proliferate in the rhizosphere and mitigate soil-borne diseases through microbial synergistic interactions, highlighting the potential of synergistic effects between microorganisms in enhancing plant health. This study provides a novel insight into using the functional SynCom as a promising solution for sustainable agriculture. Video Abstract.
Topics: Citrullus; Rhizosphere; Fusarium; Soil Microbiology; Plant Diseases; Pseudomonas; Microbiota; Disease Resistance; Bacteria; Plant Roots
PubMed: 38840214
DOI: 10.1186/s40168-024-01814-z -
Microbial Genomics Jun 2024is a leading cause of infections in immunocompromised individuals and in healthcare settings. This study aims to understand the relationships between phenotypic...
is a leading cause of infections in immunocompromised individuals and in healthcare settings. This study aims to understand the relationships between phenotypic diversity and the functional metabolic landscape of clinical isolates. To better understand the metabolic repertoire of in infection, we deeply profiled a representative set from a library of 971 clinical isolates with corresponding patient metadata and bacterial phenotypes. The genotypic clustering based on whole-genome sequencing of the isolates, multilocus sequence types, and the phenotypic clustering generated from a multi-parametric analysis were compared to each other to assess the genotype-phenotype correlation. Genome-scale metabolic network reconstructions were developed for each isolate through amendments to an existing PA14 network reconstruction. These network reconstructions show diverse metabolic functionalities and enhance the collective pangenome metabolic repertoire. Characterizing this rich set of clinical isolates allows for a deeper understanding of the genotypic and metabolic diversity of the pathogen in a clinical setting and lays a foundation for further investigation of the metabolic landscape of this pathogen and host-associated metabolic differences during infection.
Topics: Pseudomonas aeruginosa; Humans; Phenotype; Pseudomonas Infections; Genotype; Metabolic Networks and Pathways; Whole Genome Sequencing; Multilocus Sequence Typing; Genome, Bacterial; Genetic Variation
PubMed: 38836744
DOI: 10.1099/mgen.0.001259 -
Frontiers in Immunology 2024Although many studies have underscored the importance of T cells, phenotypically and functionally, fewer have studied the functions of myeloid cells in COVID disease. In...
INTRODUCTION
Although many studies have underscored the importance of T cells, phenotypically and functionally, fewer have studied the functions of myeloid cells in COVID disease. In particular, the potential role of myeloid cells such as monocytes and low-density neutrophils (LDNs) in innate responses and particular in the defense against secondary bacterial infections has been much less documented.
METHODS
Here, we compared, in a longitudinal study, healthy subjects, idiopathic fibrosis patients, COVID patients who were either hospitalized/moderate (M-) or admitted to ICU (COV-ICU) and patients in ICU hospitalized for other reasons (non-COV-ICU).
RESULTS
We show that COVID patients have an increased proportion of low-density neutrophils (LDNs), which produce high levels of proteases (particularly, NE, MMP-8 and MMP-9) (unlike non-COV-ICU patients), which are partly responsible for causing type II alveolar cell damage in co-culture experiments. In addition, we showed that M- and ICU-COVID monocytes had reduced responsiveness towards further live (PAO1 strain) infection, an important pathogen colonizing COVID patients in ICU, as assessed by an impaired secretion of myeloid cytokines (IL-1, TNF, IL-8,…). By contrast, lymphoid cytokines (in particular type 2/type 3) levels remained high, both basally and post PAO1 infection, as reflected by the unimpaired capacity of T cells to proliferate, when stimulated with anti-CD3/CD28 beads.
DISCUSSION
Overall, our results demonstrate that COVID circulatory T cells have a biased type 2/3 phenotype, unconducive to proper anti-viral responses and that myeloid cells have a dual deleterious phenotype, through their LDN-mediated damaging effect on alveolar cells and their impaired responsiveness (monocyte-mediated) towards bacterial pathogens such as .
Topics: Humans; COVID-19; Pseudomonas aeruginosa; Monocytes; Male; Female; Middle Aged; SARS-CoV-2; Pseudomonas Infections; Neutrophils; Aged; Cytokines; Adult; Longitudinal Studies; Leukocytes, Mononuclear; Lung
PubMed: 38835759
DOI: 10.3389/fimmu.2024.1398369 -
PLoS Pathogens Jun 2024Microbial pathogenicity often depends on the route of infection. For instance, P. aeruginosa or S. marcescens cause acute systemic infections when low numbers of...
Microbial pathogenicity often depends on the route of infection. For instance, P. aeruginosa or S. marcescens cause acute systemic infections when low numbers of bacteria are injected into D. melanogaster flies whereas flies succumb much slower to the continuous ingestion of these pathogens, even though both manage to escape from the gut compartment and reach the hemocoel. Here, we have developed a latent P. aeruginosa infection model by feeding flies on the bacteria for a short period. The bacteria stably colonize internal tissues yet hardly cause any damage since latently-infected flies live almost as long as noninfected control flies. The apparently dormant bacteria display particular characteristics in terms of bacterial colony morphology, composition of the outer cell wall, and motility. The virulence of these bacteria can however be reactivated upon wounding the host. We show that melanization but not the cellular or the systemic humoral response is the predominant host defense that establishes latency and may coerce the bacteria to a dormant state. In addition, the lasting activation of the melanization responses in latently-infected flies provides a degree of protection to the host against a secondary fungal infection. Latent infection by an ingested pathogen protects against a variety of homologous or heterologous systemic secondary infectious challenges, a situation previously described for the endosymbiotic Wolbachia bacteria, a guard against viral infections.
Topics: Animals; Drosophila melanogaster; Pseudomonas aeruginosa; Immunity, Innate; Pseudomonas Infections; Virulence; Disease Models, Animal; Host-Pathogen Interactions
PubMed: 38833496
DOI: 10.1371/journal.ppat.1012252 -
PloS One 2024In this research, a high-throughput RNA sequencing-based transcriptome analysis technique (RNA-Seq) was used to evaluate differentially expressed genes (DEGs) in the... (Comparative Study)
Comparative Study
Comparative RNA-seq analysis of Arabidopsis thaliana response to AtPep1 and flg22, reveals the identification of PP2-B13 and ACLP1 as new members in pattern-triggered immunity.
In this research, a high-throughput RNA sequencing-based transcriptome analysis technique (RNA-Seq) was used to evaluate differentially expressed genes (DEGs) in the wild type Arabidopsis seedlings in response to AtPep1, a well-known peptide representing an endogenous damage-associated molecular pattern (DAMP), and flg22, a well-known microbe-associated molecular pattern (MAMP). We compared and dissected the global transcriptional landscape of Arabidopsis thaliana in response to AtPep1 and flg22 and could identify shared and unique DEGs in response to these elicitors. We found that while a remarkable number of flg22 up-regulated genes were also induced by AtPep1, 256 genes were exclusively up-regulated in response to flg22, and 328 were exclusively up-regulated in response to AtPep1. Furthermore, among down-regulated DEGs upon flg22 treatment, 107 genes were exclusively down-regulated by flg22 treatment, while 411 genes were exclusively down-regulated by AtPep1. We found a number of hitherto overlooked genes to be induced upon treatment with either flg22 or with AtPep1, indicating their possible involvement general pathways in innate immunity. Here, we characterized two of them, namely PP2-B13 and ACLP1. pp2-b13 and aclp1 mutants showed increased susceptibility to infection by the virulent pathogen Pseudomonas syringae DC3000 and its mutant Pst DC3000 hrcC (lacking the type III secretion system), as evidenced by increased proliferation of the two pathogens in planta. Further, we present evidence that the aclp1 mutant is deficient in ethylene production upon flg22 treatment, while the pp2-b13 mutant is deficient in the production of reactive oxygen species (ROS). The results from this research provide new information for a better understanding of the immune system in Arabidopsis.
Topics: Arabidopsis; Arabidopsis Proteins; Gene Expression Regulation, Plant; Plant Immunity; RNA-Seq; Pseudomonas syringae; Gene Expression Profiling; Innate Immunity Recognition
PubMed: 38833485
DOI: 10.1371/journal.pone.0297124 -
Nature Communications Jun 2024Respiratory infection by Pseudomonas aeruginosa, common in hospitalized immunocompromised and immunocompetent ventilated patients, can be life-threatening because of...
Respiratory infection by Pseudomonas aeruginosa, common in hospitalized immunocompromised and immunocompetent ventilated patients, can be life-threatening because of antibiotic resistance. This raises the question of whether the host's immune system can be educated to combat this bacterium. Here we show that prior exposure to a single low dose of lipopolysaccharide (LPS) protects mice from a lethal infection by P. aeruginosa. LPS exposure trained the innate immune system by promoting expansion of neutrophil and interstitial macrophage populations distinguishable from other immune cells with enrichment of gene sets for phagocytosis- and cell-killing-associated genes. The cell-killing gene set in the neutrophil population uniquely expressed Lgals3, which encodes the multifunctional antibacterial protein, galectin-3. Intravital imaging for bacterial phagocytosis, assessment of bacterial killing and neutrophil-associated galectin-3 protein levels together with use of galectin-3-deficient mice collectively highlight neutrophils and galectin-3 as central players in LPS-mediated protection. Patients with acute respiratory failure revealed significantly higher galectin-3 levels in endotracheal aspirates (ETAs) of survivors compared to non-survivors, galectin-3 levels strongly correlating with a neutrophil signature in the ETAs and a prognostically favorable hypoinflammatory plasma biomarker subphenotype. Taken together, our study provides impetus for harnessing the potential of galectin-3-expressing neutrophils to protect from lethal infections and respiratory failure.
Topics: Animals; Galectin 3; Neutrophils; Humans; Lipopolysaccharides; Mice; Pseudomonas aeruginosa; Pseudomonas Infections; Mice, Inbred C57BL; Male; Female; Respiratory Insufficiency; Mice, Knockout; Phagocytosis; Immunity, Innate; Galectins
PubMed: 38830855
DOI: 10.1038/s41467-024-48796-y