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Frontiers in Microbiology 2024Cotrimoxazole, the combined formulation of sulfamethoxazole and trimethoprim, is one of the treatments of choice for several infectious diseases, particularly urinary...
Cotrimoxazole, the combined formulation of sulfamethoxazole and trimethoprim, is one of the treatments of choice for several infectious diseases, particularly urinary tract infections. Both components of cotrimoxazole are synthetic antimicrobial drugs, and their combination was introduced into medical therapeutics about half a century ago. In Gram-negative bacteria, resistance to cotrimoxazole is widespread, being based on the acquisition of genes from the auxiliary genome that confer resistance to each of its antibacterial components. Starting from previous knowledge on the genotype of resistance to sulfamethoxazole in a collection of cotrimoxazole resistant uropathogenic strains, this work focused on the identification of the genetic bases of the trimethoprim resistance of these same strains. Molecular techniques employed included PCR and Sanger sequencing of specific amplicons, conjugation experiments and NGS sequencing of the transferred plasmids. Mobile genetic elements conferring the trimethoprim resistance phenotype were identified and included integrons, transposons and single gene cassettes. Therefore, strains exhibited several ways to jointly resist both antibiotics, implying different levels of genetic linkage between genes conferring resistance to sulfamethoxazole () and trimethoprim (). Two structures were particularly interesting because they represented a highly cohesive arrangements ensuring cotrimoxazole resistance. They both carried a single gene cassette, or , integrated in two different points of a conserved cluster , carried on transferable plasmids. The results suggest that the pressure exerted by cotrimoxazole on bacteria of our environment is still promoting the evolution toward increasingly compact gene arrangements, carried by mobile genetic elements that move them in the genome and also transfer them horizontally among bacteria.
PubMed: 38946902
DOI: 10.3389/fmicb.2024.1395953 -
Frontiers in Microbiology 2024The dissemination of carbapenem-resistant Enterobacteriales (CRE) in nosocomial settings is primarily associated with the horizontal transfer of plasmids. However,...
INTRODUCTION
The dissemination of carbapenem-resistant Enterobacteriales (CRE) in nosocomial settings is primarily associated with the horizontal transfer of plasmids. However, limited research has focused on the in-host transferability of carbapenem resistance. In this study, ten isolates were collected from gut specimens of five individuals, each hosting two different species, including , , , , or .
METHODS
Species identification and antimicrobial susceptibility were determined by MALDI-TOF MS and broth microdilution method. Carbapenemase genes were detected and localized using PCR, S1-PFGE and southern blot. The transferability of carbapenemase genes between species was investigated through filter mating experiments, and the genetic contexts of the plasmids were analyzed using whole genome sequencing.
RESULTS AND DISCUSSION
Our results revealed that each of the ten isolates harbored a carbapenemase gene, including , , or , on a plasmid. Five different plasmids were successfully transferred to recipient cells of or by transconjugation. The genetic contexts of the carbapenemase gene were remarkably similar between the two CRE isolates from each individual. This study highlights the potential for interspecies plasmid transmission in human gut, emphasizing the colonization of CRE as a significant risk factor for the dissemination of carbapenemase genes within the host. These findings underscore the need for appropriate intestinal CRE screening and colonization prevention.
PubMed: 38946899
DOI: 10.3389/fmicb.2024.1416454 -
World Journal of Clinical Oncology Jun 2024Tankyrase 2 (TNKS2) is a potential candidate molecular target for the prognosis and treatment of non-small cell lung cancer (NSCLC), but its biological functions are...
BACKGROUND
Tankyrase 2 (TNKS2) is a potential candidate molecular target for the prognosis and treatment of non-small cell lung cancer (NSCLC), but its biological functions are unclear.
AIM
To investigate the biological functions of TNKS2 in NSCLC.
METHODS
Using a lentiviral vector, we generated H647 model cells with TNKS2 knockdown by RNA interference and A549 model cells with TNKS2 overexpression by transfection with a TNKS2 overexpressing plasmid. Increased and decreased expression levels of TNKS2 in the two cell lines were verified using real-time reverse transcriptase-polymerase chain reaction and Western blot analyses. Cell apoptosis, proliferation, and migration were determined using flow cytometry, carboxyfluorescein succinimidyl ester staining, and scratch assay, respectively. Immunofluorescence staining was conducted to examine TNKS2 and β-catenin expression levels in the two transfected cell lines and the non-transfected cells.
RESULTS
TNKS2 mRNA and protein expression was significantly higher in the highly malignant NCI-H647 cells, while it remained at a low level in the less malignant A549 cells. Lentivirus-mediated overexpression of TNKS2 in A549 cells resulted in a 3-fold increase in gene expression and a 1.7-fold increase in protein expression ( < 0.01). Conversely, shRNA interference targeting Led to an 8-fold decrease in gene expression and a 3-fold decrease in protein expression ( < 0.01) in NCI-H647 cells. Furthermore, the cell apoptosis rate was significantly reduced (50%) and cell migration rate was increased (35%) in the TNKS2 overexpression group than in the control group ( < 0.05). In contrast, sh promoted apoptosis by more than one fold and reduced migration by 60% ( < 0.05). Immunofluorescence analysis revealed enhanced nuclear localization of β-catenin fluorescence signal associated with high TNKS2 expression levels. Western blot analysis investigating TNKS2/β-catenin-related proteins indicated consistent changes between TNKS2 and β-catenin expression in lung cancer cells, whereas Axin displayed an opposite trend ( < 0.05).
CONCLUSION
The obtained results revealed that TNKS2 may serve as an adverse prognostic factor and a potential therapeutic target in NSCLC.
PubMed: 38946832
DOI: 10.5306/wjco.v15.i6.755 -
Developmental Dynamics : An Official... Jun 2024The Tol2 transposable element is the most widely used transgenesis tool in zebrafish. However, its high activity almost always leads to multiple unlinked integrations of...
BACKGROUND
The Tol2 transposable element is the most widely used transgenesis tool in zebrafish. However, its high activity almost always leads to multiple unlinked integrations of the transgenic cassette in F fish. Each of these transgenes is susceptible to positional effects from the surrounding regulatory landscape, which can lead to altered expression and, consequently, activity. Scientists therefore must strike a balance between the need to maximize reproducibility by establishing single-insertion transgenic lines and the need to complete experiments within a reasonable timeframe.
RESULTS
In this article, we introduce a simple competitive dilution strategy for rapid generation of single-insertion transgenics. By using cry:BFP reporter plasmid as a competitor, we achieved a nearly fourfold reduction in the number of the transgene of interest integrations while simultaneously increasing the proportion of single-insertion F generation transgenics to over 50%. We also observed variations in transgene of interest expression among independent single-insertion transgenics, highlighting that the commonly used ubiquitous ubb promoter is susceptible to position effects.
CONCLUSIONS
Wide application of our competitive dilution strategy will save time, reduce animal usage, and improve reproducibility of zebrafish research.
PubMed: 38946125
DOI: 10.1002/dvdy.719 -
Food Research International (Ottawa,... Aug 2024Kinema, a traditional fermented soybean food from the Himalayas, is well-liked for its sticky texture and flavourful umami taste. Among 175 bacterial strains from...
Kinema, a traditional fermented soybean food from the Himalayas, is well-liked for its sticky texture and flavourful umami taste. Among 175 bacterial strains from spontaneously fermented kinema samples, Bacillus subtilis Tamang strain stood out for its high stickiness and viscosity. The strain's Poly-γ-glutamic acid (γ-PGA) contains various groups of glutamic acid and has a molecular weight of 660 kDa. It demonstrates the ability to solubilize iron, preserve ferritin in Caco-2 cells, and exhibit antibacterial properties. The genome of B. subtilis Tamang is devoid of plasmid elements but does feature nine insert elements. Noteworthy is the presence of unique secondary metabolites with potential antimicrobial effects, such as amyloliquecidin GF610, bogorol A, and thermoactinoamide A. A total of 132 carbohydrate-active enzymes (CAZy) were identified, hinting at possible prebiotic characteristics. The genome analysis revealed genes responsible for γ-PGA production via the capBCA complex. Furthermore, genes associated with fibrinolytic activity, taste enhancement, biopeptides, immunomodulators, and vitamins like B12 and K2 were found, along with probiotics and various health benefits. The genetic material for L-asparaginase production, known for its anti-cancer properties, was also detected, as well as CRISPR-Cas systems. The absence of virulence factors and antimicrobial resistance genes confirms the safety of consuming B. subtilis Tamang as a food-grade bacterium.
Topics: Bacillus subtilis; Polyglutamic Acid; Fermentation; Whole Genome Sequencing; Genome, Bacterial; Caco-2 Cells; Humans; Food Microbiology; Fermented Foods; Soy Foods; Anti-Bacterial Agents
PubMed: 38945588
DOI: 10.1016/j.foodres.2024.114655 -
European Journal of Pharmaceutics and... Jun 2024In the current "era of lipid carriers," numerous strategies have been developed to manufacture lipid nanoparticles (LNPs). Nevertheless, the potential impact of various...
In the current "era of lipid carriers," numerous strategies have been developed to manufacture lipid nanoparticles (LNPs). Nevertheless, the potential impact of various preparation methods on the characteristics, use, and/or stability of these LNPs remains unclear. In this work, we attempted to compare the effects of three different preparation methods: microfluidics (MF), reverse phase evaporation (RV), and ouzo (OZ) on lipid-peptide NPs (LPNPs) as plasmid DNA delivery carriers. These LPNPs had the same components, namely DOTMA cationic lipid, DSPC, cholesterol, and protamine. Subsequently, we compared the LPNPs in terms of their physicochemical features, functionality as gene delivery vehicles in two distinct cell lines (NT2 and D1-MSCs), and finally, their storage stability over a six-month period. It was clear that all three LPNP formulations worked to deliver EGFP-pDNA while keeping cells alive, and their physicochemical stability was high for 6 months. However, the preparation technique had a significant impact on their physicochemical characteristics. The MF produced LPNPs with a lesser size, polydispersity index, and zeta potential than the other synthesis methods. Additionally, their DNA entrapment efficiency, cell viability, and functional stability profiles were generally superior. These findings provide new insights for comparing different manufacturing methods to create LPNPs with the desired characteristics for effective and safe gene delivery.
PubMed: 38945408
DOI: 10.1016/j.ejpb.2024.114385 -
Nature Communications Jun 2024Real-time genomics through nanopore sequencing holds the promise of fast antibiotic resistance prediction directly in the clinical setting. However, concerns about the...
Real-time genomics through nanopore sequencing holds the promise of fast antibiotic resistance prediction directly in the clinical setting. However, concerns about the accuracy of genomics-based resistance predictions persist, particularly when compared to traditional, clinically established diagnostic methods. Here, we leverage the case of a multi-drug resistant Klebsiella pneumoniae infection to demonstrate how real-time genomics can enhance the accuracy of antibiotic resistance profiling in complex infection scenarios. Our results show that unlike established diagnostics, nanopore sequencing data analysis can accurately detect low-abundance plasmid-mediated resistance, which often remains undetected by conventional methods. This capability has direct implications for clinical practice, where such "hidden" resistance profiles can critically influence treatment decisions. Consequently, the rapid, in situ application of real-time genomics holds significant promise for improving clinical decision-making and patient outcomes.
Topics: Klebsiella pneumoniae; Genomics; Humans; Anti-Bacterial Agents; Klebsiella Infections; Drug Resistance, Multiple, Bacterial; Plasmids; Nanopore Sequencing; Genome, Bacterial; Microbial Sensitivity Tests
PubMed: 38944650
DOI: 10.1038/s41467-024-49851-4 -
Nature Communications Jun 2024IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, bla, are rapidly spreading globally in both humans and animals. Given that carbapenems are...
IncX3 plasmids carrying the New Delhi metallo-β-lactamase-encoding gene, bla, are rapidly spreading globally in both humans and animals. Given that carbapenems are listed on the WHO AWaRe watch group and are prohibited for use in animals, the drivers for the successful dissemination of Carbapenem-Resistant Enterobacterales (CRE) carrying bla-IncX3 plasmids still remain unknown. We observe that E. coli carrying bla-IncX3 can persist in chicken intestines either under the administration of amoxicillin, one of the largest veterinary β-lactams used in livestock, or without any antibiotic pressure. We therefore characterise the bla-IncX3 plasmid and identify a transcription regulator, VirBR, that binds to the promoter of the regulator gene actX enhancing the transcription of Type IV secretion systems (T4SS); thereby, promoting conjugation of IncX3 plasmids, increasing pili adhesion capacity and enhancing the colonisation of bla-IncX3 transconjugants in animal digestive tracts. Our mechanistic and in-vivo studies identify VirBR as a major factor in the successful spread of bla-IncX3 across one-health AMR sectors. Furthermore, VirBR enhances the plasmid conjugation and T4SS expression by the presence of copper and zinc ions, thereby having profound ramifications on the use of universal animal feeds.
Topics: Animals; Plasmids; beta-Lactamases; Chickens; Humans; Escherichia coli; Anti-Bacterial Agents; Conjugation, Genetic; Escherichia coli Proteins; Type IV Secretion Systems; Transcription Factors; Amoxicillin; Promoter Regions, Genetic; Escherichia coli Infections; Gene Expression Regulation, Bacterial; Intestines
PubMed: 38944647
DOI: 10.1038/s41467-024-49800-1 -
Cancer Genomics & Proteomics 2024We have reviewed the literature for circular RNAs (circRNAs) with efficacy in preclinical pancreatic-cancer related in vivo models. The identified circRNAs target... (Review)
Review
We have reviewed the literature for circular RNAs (circRNAs) with efficacy in preclinical pancreatic-cancer related in vivo models. The identified circRNAs target chemoresistance mechanisms (n=5), secreted proteins and transmembrane receptors (n=15), transcription factors (n=9), components of the signaling- (n=11), ubiquitination- (n=2), autophagy-system (n=2), and others (n=9). In addition to identifying targets for therapeutic intervention, circRNAs are potential new entities for treatment of pancreatic cancer. Up-regulated circRNAs can be inhibited by antisense oligonucleotides (ASO), small interfering RNAs (siRNAs), short hairpin RNAs (shRNAs) or clustered regularly interspaced short-palindromic repeats-CRISPR associated protein (CRISPR-CAS)-based intervention. The function of down-regulated circRNAs can be reconstituted by replacement therapy using plasmids or virus-based vector systems. Target validation experiments and the development of improved delivery systems for corresponding agents were examined.
Topics: Humans; RNA, Circular; Pancreatic Neoplasms; Animals; Molecular Targeted Therapy
PubMed: 38944427
DOI: 10.21873/cgp.20451 -
Chemosphere Jun 2024Colistin is a polymyxin antimicrobic mainly used to treat infection caused by multi-drug resistant Gram-negative bacteria. Mechanisms of colistin resistance are linked...
Colistin is a polymyxin antimicrobic mainly used to treat infection caused by multi-drug resistant Gram-negative bacteria. Mechanisms of colistin resistance are linked to the mobile colistin resistance (mcr) genes, which are transferable within mobile plasmids. Currently, there is limited research on the environmental dissemination of these genes. The behavioural and morphological characteristics of Apis mellifera L. make honey bees effective environmental bioindicators for assessing the prevalence of antimicrobial-resistant bacteria. This study aims to evaluate the colistin phenotypic and genotypic resistance in environmental Gram-negative bacteria isolated from foraging honey bees, across a network of 33 colonies distributed across the Emilia-Romagna region in Italy. Phenotypic resistances were determined through a microdilution assay using the minimum inhibitory concentration (MIC) with dilutions ranging from 0.5 μg/ml to 256 μg/ml. Strains with MIC values gather than 2 μg/ml were classified as resistant. Also, the identification of the nine mcr genes was carried out using two separate multiplex PCR assays. The study found that 68.5% of isolates were resistant and the genus with the higher resistance rates observed in Enterobacter spp. (84.5%). At least one mcr gene was found in 137 strains (53.3%). The most detected gene was mcr5 (35.3%), which was the most frequently detected gene in the seven provinces, while the least observed was mcr4 (4.8%), detected only in two provinces. These results suggested the feasibility of detecting specific colistin resistance genes in environmentally spread bacteria and understanding their distribution at the environmental level, despite their restricted clinical use. In a One-Health approach, this capability enables valuable environmental monitoring, considering the significant role of colistin in the context of public health.
PubMed: 38944352
DOI: 10.1016/j.chemosphere.2024.142717