Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 310
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-38574003

RESUMO

OBJECTIVES: To elucidate the mechanism of tigecycline resistance in Escherichia coli that is mediated by the tet(A) variant gene. METHODS: E. coli strain 573 carried a plasmid-borne tet(A) variant gene, tentatively designated tet(A)TIG, that conferred decreased tigecycline susceptibility (MIC 0.5 mg/L). When exposed to increasing concentrations of tigecycline (0.25-8 mg/L), mutants growing at 2, 4 and 8 mg/L were obtained and sequenced. Copies of plasmid and tet(A)TIG relative to the chromosomal DNA in the mutants were determined by WGS and quantitative PCR (qPCR). Expression of tet(A)TIG in the mutants was evaluated by RT-qPCR. The tet(A)TIG-carrying plasmids were visualized by S1-PFGE and Southern blot hybridization. PCR served for the detection of a tet(A)TIG-carrying unconventional circularizable structure (UCS). RESULTS: Tigecycline resistance with maximum MICs of 16 mg/L was seen in E. coli mutants selected in the presence of tigecycline. Compared with the parental strain, the relative copy number and transcription level of tet(A)TIG in the mutants increased significantly in the presence of 2, 4 and 8 mg/L tigecycline, respectively. With increasing tigecycline selection pressure, the tet(A)TIG-carrying plasmids in the mutants increased in size, correlating with the number of tandem amplificates of a ΔTnAs1-flanked UCS harbouring tet(A)TIG. These tandem amplificates were not stable in the absence of tigecycline. CONCLUSIONS: Tigecycline resistance is due to the tandem amplification of a ΔTnAs1-flanked tet(A)TIG-carrying plasmid-borne segment in E. coli. The gain/loss of the tandem amplificates in the presence/absence of tigecycline represents an economic way for the bacteria to survive in the presence of tigecycline.

2.
Acta Pharmacol Sin ; 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38605179

RESUMO

SCH23390 is a widely used D1 dopamine receptor (D1R) antagonist that also elicits some D1R-independent effects. We previously found that the benzazepine, SKF83959, an analog of SCH23390, produces positive allosteric modulation of the Sigma-1 receptor (Sig1R). SCH23390 does not bind to the orthodoxic site of Sig1R but enhances the binding of 3H (+)-pentazocine to Sig1R. In this study, we investigated whether SCH23390 functions as an allosteric modulator of Sig1R. We detected increased Sig1R dissociation from binding immunoglobulin protein (BiP) and translocation of Sig1R to the plasma membrane in response to SCH23390 in transfected HEK293T and SH-SY5Y cells, respectively. Activation of Sig1R by SCH23390 was further confirmed by inhibition of GSK3ß activity in a time- and dose-dependent manner; this effect was blocked by pretreatment with the Sig1R antagonist, BD1047, and by knockdown of Sig1R. SCH23390 also inhibited GSK3ß in wild-type mice but not in Sig1R knockout mice. Finally, we showed that SCH23390 allosterically modulated the effect of the Sig1R agonist SKF10047 on inhibition of GSK3ß. This positive allosteric effect of SCH23390 was further confirmed via promotion of neuronal protection afforded by SKF10047 in primary cortical neurons challenged with MPP+. These results provide the first evidence that SCH23390 elicits functional allosteric modulation of Sig1R. Our findings not only reveal novel pharmacological effects of SCH23390 but also indicate a potential mechanism for SCH23390-mediated D1R-independent effects. Therefore, attention should be paid to these Sig1R-mediated effects when explaining pharmacological responses to SCH23390.

3.
Sci Rep ; 14(1): 8005, 2024 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-38580695

RESUMO

The association between high blood pressure and fracture showed obvious discrepancies and were mostly between hypertension with future fracture, but rarely between fracture and incident hypertension. The present study aims to investigate the associations of hypertension with future fracture, and fracture with incident hypertension. We included adult participants from the China Health and Nutrition Survey (CHNS) prospective cohort in 1997-2015 (N = 10,227), 2000-2015 (N = 10,547), 2004-2015 (N = 10,909), and 2006-2015 (N = 11,121) (baseline in 1997, 2000, 2004, 2006 respectively and outcome in 2015). Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs. In the analysis of the association between hypertension and future fracture, the adjusted HRs (95% CIs) were 1.34 (0.95-1.90) in 1997-2015, 1.40 (1.04-1.88) in 2000-2015, 1.32 (0.98-1.78) in 2004-2015, and 1.38 (1.01-1.88) in 2006-2015. In the analysis of the association between fracture and incident hypertension, the adjusted HRs (95% CIs) were 1.28 (0.96-1.72) in 1997-2015, 1.18 (0.94-1.49) in 2000-2015, 1.12 (0.89-1.40) in 2004-2015, and 1.09 (0.85-1.38) in 2006-2015. The present study showed that hypertension history was associated with increased risk of future fracture, but not vice versa.


Assuntos
Fraturas Ósseas , Hipertensão , Adulto , Humanos , Estudos Prospectivos , Fatores de Risco , Inquéritos Epidemiológicos , Pressão Sanguínea , Modelos de Riscos Proporcionais
4.
Artigo em Inglês | MEDLINE | ID: mdl-38403735

RESUMO

There is inconsistent evidence for an association of obesity with white matter microstructural alterations. Such inconsistent findings may be related to the cumulative effects of obesity and alcohol dependence. This study aimed to investigate the possible interactions between alcohol dependence and overweight/obesity on white matter microstructure in the human brain. A total of 60 inpatients with alcohol dependence during early abstinence (44 normal weight and 16 overweight/obese) and 65 controls (42 normal weight and 23 overweight/obese) were included. The diffusion tensor imaging (DTI) measures [fractional anisotropy (FA) and radial diffusivity (RD)] of the white matter microstructure were compared between groups. We observed significant interactive effects between alcohol dependence and overweight/obesity on DTI measures in several tracts. The DTI measures were not significantly different between the overweight/obese and normal-weight groups (although widespread trends of increased FA and decreased RD were observed) among controls. However, among the alcohol-dependent patients, the overweight/obese group had widespread reductions in FA and widespread increases in RD, most of which significantly differed from the normal-weight group; among those with overweight/obesity, the alcohol-dependent group had widespread reductions in FA and widespread increases in RD, most of which were significantly different from the control group. This study found significant interactive effects between overweight/obesity and alcohol dependence on white matter microstructure, indicating that these two controllable factors may synergistically impact white matter microstructure and disrupt structural connectivity in the human brain.

5.
Nano Lett ; 24(4): 1238-1245, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38180780

RESUMO

The metasurface analogue of electromagnetically induced transparency (EIT) provides a chip-scale platform for achieving light delay and storage, high Q factors, and greatly enhanced optical fields. However, the literature relies on the coupling between localized and localized or localized and collective resonances, limiting the Q factor and related performance. Here, we report a novel approach for realizing collective EIT-like bands with a measured Q factor reaching 2750 in silicon metasurfaces in the near-infrared regime, exceeding the state of the art by more than 5 times. It employs the coupling between two collective resonances, the Mie electric dipole surface lattice resonance (SLR) and the out-of-plane/in-plane electric quadrupole SLR (EQ-SLR). Remarkably, the collective EIT-like resonance can have diverging Q factor and group delay due to the bound state in the continuum characteristics of the in-plane EQ-SLR. With these findings, our study opens a new route for tailoring light flow in metasurfaces.

6.
Clin Immunol ; 258: 109857, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38043757

RESUMO

Systemic lupus erythematosus (SLE) is a typical systemic autoimmune disease that manifests as skin rash, arthritis, lymphadenopathy, and multiple organ lesions. Epigenetics, including DNA methylation, histone modification, and non-coding RNA regulation, mainly affect the function and characteristics of cells through the regulation of gene transcription or translation. Increasing evidence indicates that there are a variety of complex epigenetic effects in patients with SLE, which interfere with the differentiation and function of T, and B lymphocytes, monocytes, and neutrophils, and enhance the expression of SLE-associated pathogenic genes. This paper summarizes our currently knowledge regarding pathogenesis of SLE, and introduces current advances in the epigenetic regulation of SLE from three aspects: immune function, inflammatory response, and lupus complications. We propose that epigenetic changes could be used as potential biomarkers and therapeutic targets of SLE.


Assuntos
Artrite , Lúpus Eritematoso Sistêmico , Humanos , Epigênese Genética , Metilação de DNA , Artrite/genética , Diferenciação Celular
7.
Exp Biol Med (Maywood) ; 248(23): 2393-2407, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38159074

RESUMO

Palmitoylation, which is mediated by protein acyltransferase (PAT) and performs important biological functions, is the only reversible lipid modification in organism. To study the effect of protein palmitoylation on hypopharyngeal squamous cell carcinoma (HPSCC), the expression levels of 23 PATs in tumor tissues of 8 HPSCC patients were determined, and high mRNA and protein levels of DHHC9 and DHHC15 were found. Subsequently, we investigated the effect of 2-bromopalmitate (2BP), a small-molecular inhibitor of protein palmitoylation, on the behavior of Fadu cells in vitro (50 µM) and in nude mouse xenograft models (50 µmol/kg), and found that 2BP suppressed the proliferation, invasion, and migration of Fadu cells without increasing cell apoptosis. Mechanistically, the effect of 2BP on the transduction of BMP, Wnt, Shh, and FGF signaling pathways was tested with qRT-PCR, and its drug target was explored with western blotting and acyl-biotinyl exchange assay. Our results showed that 2BP inhibited the transduction of the FGF/ERK signaling pathway. The palmitoylation level of Ras protein decreased after 2BP treatment, and its distribution in the cell membrane structure was reduced significantly. The findings of this work reveal that protein palmitoylation mediated by DHHC9 and DHHC15 may play important roles in the occurrence and development of HPSCC. 2BP is able to inhibit the malignant biological behaviors of HPSCC cells, possibly via hindering the palmitoylation and membrane location of Ras protein, which might, in turn, offer a low-toxicity anti-cancer drug for targeting the treatment of HPSCC.


Assuntos
Neoplasias de Cabeça e Pescoço , Proteínas ras , Camundongos , Animais , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço , Palmitatos/farmacologia
8.
Radiat Oncol ; 18(1): 194, 2023 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-38031125

RESUMO

PURPOSE: To report the planning benchmark case results of the POTENTIAL trial-a multicenter, randomized, phase 3 trial-to evaluate the value of internal mammary nodal (IMN) irradiation for patients with high-risk breast cancer. METHODS: All participating institutions were provided the outlines of one benchmark case, and they generated radiation therapy plans per protocol. The plans were evaluated by a quality assurance team, after which the institutions resubmitted their revised plans. The information on beams arrangement, skin flash, inhomogeneity corrections, and protocol compliance was assessed in the first and final submission. RESULTS: The plans from 26 institutions were analyzed. Some major deviations were found in the first submission. The protocol compliance rates of dose coverage for the planning target volume of chest wall, supraclavicular fossa plus axilla, and IMN region (PTVim) were all significantly improved in the final submission, which were 96.2% vs. 69.2%, 100% vs. 76.9%, and 88.4% vs. 53.8%, respectively. For OARs, the compliance rates of heart Dmean, left anterior descending coronary artery V40Gy, ipsilateral lung V5Gy, and stomach V5Gy were significantly improved. In the first and final submission, the mean values of PTVim V100% were 79.9% vs. 92.7%; the mean values of heart Dmean were 11.5 Gy vs. 9.7 Gy for hypofractionated radiation therapy and 11.5 Gy vs. 11.0 Gy for conventional fractionated radiation therapy, respectively. CONCLUSION: The major deviations were corrected and protocol compliance was significantly improved after revision, which highlighted the importance of planning benchmark case to guarantee the planning quality for multicenter trials.


Assuntos
Neoplasias da Mama , Radioterapia de Intensidade Modulada , Humanos , Feminino , Neoplasias da Mama/radioterapia , Neoplasias da Mama/cirurgia , Benchmarking , Mastectomia , Planejamento da Radioterapia Assistida por Computador/métodos , Dosagem Radioterapêutica , Radioterapia de Intensidade Modulada/métodos , Órgãos em Risco/efeitos da radiação
9.
Hum Brain Mapp ; 44(17): 6245-6257, 2023 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-37837649

RESUMO

Rumination is closely linked to the onset and maintenance of major depressive disorder (MDD). Prior neuroimaging studies have identified the association between self-reported rumination trait and the functional coupling among a network of brain regions using resting-state functional magnetic resonance imaging (MRI). However, little is known about the underlying neural circuitry mechanism during active rumination in MDD. Degree centrality (DC) is a simple metric to denote network integration, which is critical for higher-order psychological processes such as rumination. During an MRI scan, individuals with MDD (N = 45) and healthy controls (HC, N = 46) completed a rumination state task. We examined the interaction effect between the group (MDD vs. HC) and condition (rumination vs. distraction) on vertex-wise DC. We further characterized the identified brain region's functional involvement with Neurosynth and BrainMap. Network-wise seed-based functional connectivity (FC) analysis was also conducted for the identified region of interest. Finally, exploratory correlation analysis was conducted between the identified region of interest's network FCs and self-reported in-scanner affect levels. We found that a left superior frontal gyrus (SFG) region, generally overlapped with the frontal eye field, showed a significant interaction effect. Further analysis revealed its involvement with executive functions. FCs between this region, the frontoparietal, and the dorsal attention network (DAN) also showed significant interaction effects. Furthermore, its FC to DAN during distraction showed a marginally significant negative association with in-scanner affect level at the baseline. Our results implicated an essential role of the left SFG in the rumination's underlying neural circuitry mechanism in MDD and provided novel evidence for the conceptualization of rumination in terms of impaired executive control.


Assuntos
Transtorno Depressivo Maior , Humanos , Encéfalo/diagnóstico por imagem , Córtex Pré-Frontal , Função Executiva , Lobo Frontal , Imageamento por Ressonância Magnética , Mapeamento Encefálico
11.
Asian J Psychiatr ; 89: 103767, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37717506

RESUMO

Identifying biomarkers to predict lapse of alcohol-dependence (AD) is essential for treatment and prevention strategies, but remains remarkably challenging. With an aim to identify neuroimaging features for predicting AD lapse, 66 male AD patients during early-abstinence (baseline) after hospitalized detoxification underwent resting-state functional magnetic resonance imaging and were then followed-up for 6 months. The relevance-vector-machine (RVM) analysis on baseline large-scale brain networks yielded an elegant model for differentiating relapsing patients (n = 38) from abstainers, with the area under the curve of 0.912 and the accuracy by leave-one-out cross-validation of 0.833. This model captured key information about neuro-connectome biomarkers for predicting AD lapse.


Assuntos
Alcoolismo , Humanos , Masculino , Alcoolismo/terapia , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Neuroimagem , Biomarcadores
12.
Environ Pollut ; 338: 122581, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37748638

RESUMO

A multicopper oxidase Lac-W from Weizmannia coagulans 36D1 was identified and characterized as a laccase (Lac-W) with a robust enzymatic activity, which was used in various mycotoxins degradation. We demonstrated that Lac-W could directly degrade six major mycotoxins in the absence of redox mediators in pH 9.0, 24h static incubation at room temperature, including aflatoxin B1 (AFB1, 88%), zearalenone (60%), deoxynivalenol (34%), T-2 toxin (19%), fumonisin B1 (18%), and ochratoxin A (12%). The optimal condition for Lac-W to degrade AFB1 was 30 °C, pH 9.0, enzyme-substrate ratio 3U/µg in 24h static condition. Furthermore, we characterized aflatoxin Q1 as a Lac-W-mediated degradation product of AFB1 using UHPLC-MS/MS. Interestingly, degradation products of AFB1 failed to generate cell death and apoptosis of intestinal porcine epithelial cells. Finally, our molecular docking simulation results revealed that the substrate-binding pocket of Lac-W was large enough to allow the entry of six mycotoxins with different structures, and their degradation rates were positively correlated to their interacting affinity with Lac-W. In summary, the unique properties of the Lac-W make it a great candidate for detoxifying multiple mycotoxins contaminated food and feed cost-effectively and eco-friendly. Our study provides new insights into development of versatile enzymes which could simultaneously degrade multiple mycotoxins.


Assuntos
Micotoxinas , Animais , Suínos , Aflatoxina B1 , Lacase/metabolismo , Espectrometria de Massas em Tandem , Simulação de Acoplamento Molecular , Oxirredução
13.
Adv Sci (Weinh) ; 10(28): e2302539, 2023 10.
Artigo em Inglês | MEDLINE | ID: mdl-37616380

RESUMO

The treatment of bone defects remains a significant challenge to be solved clinically. Immunomodulatory properties of orthopedic biomaterials have significance in regulating osteoimmune microenvironment for osteogenesis. A lactic acid-co-glycolic acid (PLGA) scaffold incorporates black phosphorus (BP) fabricated by 3D printing technology to investigate the effect of BP on osteoimmunomodulation and osteogenesis in site. The PLGA/BP scaffold exhibits suitable biocompatibility, biodegradability, and mechanical properties as an excellent microenvironment to support new bone formation. The studies' result also demonstrate that the PLGA/BP scaffolds are able to recruit and stimulate macrophages M2 polarization, inhibit inflammation, and promote human bone marrow mesenchymal stem cells (hBMSCs) proliferation and differentiation, which in turn promotes bone regeneration in the distal femoral defect region of steroid-associated osteonecrosis (SAON) rat model. Moreover, it is screened and demonstrated that PLGA/BP scaffolds can promote osteogenic differentiation by transcriptomic analysis, and PLGA/BP scaffolds promote osteogenic differentiation and mineralization by activating PI3K-AKT signaling pathway in hBMSC cells. In this study, it is shown that the innovative PLGA/BP scaffolds are extremely effective in stimulating bone regeneration by regulating macrophage M2 polarization and a new strategy for the development of biomaterials that can be used to repair bone defects is offered.


Assuntos
Osteogênese , Tecidos Suporte , Humanos , Ratos , Animais , Fosfatidilinositol 3-Quinases/farmacologia , Regeneração Óssea , Materiais Biocompatíveis/farmacologia , Impressão Tridimensional
14.
Artigo em Inglês | MEDLINE | ID: mdl-37549732

RESUMO

OBJECTIVE: To investigate the prevalence of a tet(A) gene variant and its role in developing high-level tigecycline resistance among carbapenem-resistant Klebsiella pneumoniae (CRKP) clinical isolates. METHODS: The mechanism of high-level tigecycline resistance in CRKP mediated by a tet(A) variant was explored by induction experiments, antimicrobial susceptibility testing, whole-genome sequencing and bioinformatics analysis. The amplification and overexpression of the tet(A) variant were measured by the determination of sequencing depth, gene copy numbers, and qRT-PCR. RESULTS: A high rate (62.1%, 998/1607) of tet(A) variant carriage was observed among 1607 CRKP clinical isolates from Henan Province, China. High-level tigecycline resistance could rapidly develop by the amplification of the tet(A) variant in these isolates. The analysis of the raw sequencing data and the plasmid mapping depth revealed that the ΔtnpA homologous sequence of Tn1721 supports the amplification of the region that harbours the tet(A) variant by forming a large number of repeat arrays through translocatable units (TUs). Moreover, the epidemiological analysis of tet(A) variant-carrying structures among 1607 clinical CRKPs showed that the TU structure is widely present. CONCLUSION: The presence of a tigecycline resistance-mediating tet(A) variant in CRKP clinical isolates represents a greater health concern than initially thought and should be monitored consistently.

15.
Res Microbiol ; 174(8): 104114, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37572822

RESUMO

The mechanism of enhanced tigecycline MIC in Staphylococcus cohnii after in vitro tigecycline exposure was investigated. S. cohnii 11-B-312 was exposed to incremental concentrations of tigecycline (2-32 mg/L) and the mutants growing at 8, 16 and 32 mg/L were determined by AST and WGS. Copy number and relative transcription level of the tet(L) gene were determined by quantitative PCR. The fitness cost was evaluated by growth kinetics and competition assays. The results revealed that enhanced tigecycline MIC was identified in S. cohnii mutants. Copy number and relative transcription level of tet(L) in the mutants increased 8-, 20-, and 23-fold and 20-, 34-, and 39-fold in the presence of 8, 16, and 32 mg/L tigecycline, respectively. The read-mapping depth ratio analysis indicated that a multidrug resistance region carrying the tet(L) variant has a gradually increased copy number, correlating with the tigecycline selection pressure. S. cohnii strain 11-B-312_32 had a fitness cost, and enhanced tigecycline MIC can revert to the initial level in the absence of tigecycline. In summary, enhanced tigecycline MIC develops with extensive amplification of an IS257-flanked tet(L)-carrying segment in S. cohnii. IS257 seems to play a vital role in the gain and loss of the amplification product.


Assuntos
Antibacterianos , Staphylococcus , Tigeciclina/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana , Staphylococcus/genética , Plasmídeos
16.
Front Psychiatry ; 14: 1144989, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37496685

RESUMO

Mindfulness training among patients with major depressive disorder (MDD) reduces symptoms, prevents relapse, improves prognosis, and is more efficient for those with a high level of trait mindfulness. Upon hospital admission, 126 MDD patients completed the Beck Depression Inventory (BDI), World Health Organization Quality of Life Brief, Five-Factor Mindfulness Questionnaire (FFMQ), and the Rumination Response Scale (RRS). The 65 patients that scored less than the median of all subjects on the FFMQ were placed into the low mindfulness level (LML) group. The other 61 patients were placed in the high mindfulness level (HML) group. All facet scores were statistically different between the mental health assessment scores of the HML and LML groups except for RRS brooding and FFMQ nonjudgement. Trait mindfulness level exhibited a negative and bidirectional association with MDD severity primarily through the facets of description and aware actions. Trait mindfulness was also related positively with age primarily through the facets of nonreactivity and nonjudgement. Being married is positively associated with trait mindfulness levels primarily through the facet of observation and by an associated increase in perceived quality of life. Mindfulness training prior to MDD diagnosis also associates positively with trait mindfulness level. Hospitalized MDD patients should have their trait mindfulness levels characterized to predict treatment efficiency, help establish a prognosis, and identify mindfulness-related therapeutic targets.

17.
Adv Healthc Mater ; 12(25): e2300449, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37431870

RESUMO

Clinical treatment of multidrug resistant (MDR) pathogens-induced infection is emerging as a growing challenge in global public health due to the limited selection of clinically available antibiotics. Nanozymes as artificial enzymes that mimicked natural enzyme-like activities, are received great attention for combating MDR pathogens. However, the relatively deficient catalytic activity in the infectious microenvironment and inability to precisely targeting pathogen restrains their clinical anti-MDR applications. Here, pathogen-targeting bimetallic BiPt nanozymes for nanocatalytic therapy against MDR pathogen are reported. Benefiting from electronic coordination effect, BiPt nanozymes exhibit dual-enzymatic activities, including peroxidase-mimic and oxidase-mimic activities. Moreover, the catalytic efficiency can be efficiently increased 300-fold by ultrasound under inflammatory microenvironment. Notably, BiPt nanozyme is further cloaked with a platelet-bacteria hybrid membrane (BiPt@HMVs), thus presenting excellent homing effect to infectious sites and precise homologous targeting to pathogen. By integrating accurate targeting with highly efficient catalytic, BiPt@HMVs can eliminate carbapenem-resistant Enterobacterales and methicillin-resistant Staphylococcus aureus in osteomyelitis rats model, muscle-infected mice model, and pneumonia mice model. The work provides an alternative strategy based on nanozymes for clinically addressing MDR bacteria-induced infections.

18.
Int J Antimicrob Agents ; 62(4): 106929, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37487950

RESUMO

OBJECTIVES: This study aimed to determine the molecular mechanisms of linezolid-resistant enterococci (LRE) in swine slaughterhouses in China and apply the "One Health" perspective to analyse the evolutionary dynamics of poxtA-positive E. faecium in clinical and non-clinical settings worldwide. METHODS: The phenotypic and genomic characteristics of multiple LRE isolates were systematically investigated using antimicrobial susceptibility testing, transfer assays, evolutionary experiments, quantitative RT-PCR assays, whole-genome sequencing, and bioinformatics analyses. RESULTS: Swine faeces served as a significant reservoir for LRE isolates, and optrA and poxtA were the primary contributors to linezolid resistance. Co-occurrence network analysis revealed a significant interconnection between optrA and several other ARGs. The poxtA copy number heterogeneity and polymorphism were initially observed in E. faecium parental and evolved isolates. The poxtA-carrying tandem repeat region exhibits high mobility and has undergone extensive duplication owing to linezolid pressure. The poxtA copy number varies from four copies on the plasmid of E. faecium IC25 to 11 copies on the plasmid and six copies on the chromosome in the evolved isolate IC25-50_poxtA. Furthermore, phylogenetic analysis of 185 poxtA-positive E. faecium strains worldwide found that one isolate from a French patient in 2018 shared only two SNPs with CC17 E. faecium isolates IC25 and IC7-2 from this study, highlighting the potential global transmission of CC17 poxtA-positive E. faecium between humans and animals. CONCLUSION: This study identified amplification of poxtA as a response of E. faecium to linezolid pressure. Phylogenetic analysis shed light on the potential global transmission of hospital-associated CC17 poxtA-positive E. faecium in clinical and non-clinical settings.


Assuntos
Enterococcus faecium , Infecções por Bactérias Gram-Positivas , Animais , Humanos , Suínos , Linezolida/farmacologia , Antibacterianos/farmacologia , Filogenia , Variações do Número de Cópias de DNA , Farmacorresistência Bacteriana/genética , Enterococcus , Genômica , Enterococcus faecalis , Infecções por Bactérias Gram-Positivas/epidemiologia , Infecções por Bactérias Gram-Positivas/veterinária , Testes de Sensibilidade Microbiana
19.
J Virol ; 97(7): e0013523, 2023 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-37338377

RESUMO

The development of effective and flexible vaccine platforms is a major public health challenge, especially in the context of influenza vaccines that have to be renewed every year. Adenoviruses (AdVs) are easy to produce and have a good safety and efficacy profile when administered orally, as demonstrated by the long-term use of oral AdV-4 and -7 vaccines in the U.S. military. These viruses therefore appear to be the ideal backbone for the development of oral replicating vector vaccines. However, research into these vaccines is limited by the ineffectiveness of human AdV replication in laboratory animals. The use of mouse AdV type 1 (MAV-1) in its natural host allows infection to be studied under replicating conditions. Here, we orally vaccinated mice with a MAV-1 vector expressing influenza hemagglutinin (HA) to assess the protection conferred against an intranasal challenge of influenza. We showed that a single oral immunization with this vaccine generates influenza-specific and -neutralizing antibodies and completely protects mice against clinical signs and viral replication, similar to traditional inactivated vaccines. IMPORTANCE Given the constant threat of pandemics and the need for annual vaccination against influenza and possibly emerging agents such as SARS-CoV-2, new types of vaccines that are easier to administer and therefore more widely accepted are a critical public health need. Here, using a relevant animal model, we have shown that replicative oral AdV vaccine vectors can help make vaccination against major respiratory diseases more available, better accepted, and therefore more effective. These results could be of major importance in the coming years in the fight against seasonal or emerging respiratory diseases such as COVID-19.


Assuntos
Infecções por Adenoviridae , Vacinas contra Adenovirus , COVID-19 , Vacinas contra Influenza , Influenza Humana , Humanos , Camundongos , Animais , Adenoviridae/genética , Influenza Humana/prevenção & controle , Anticorpos Antivirais , SARS-CoV-2 , Imunização , Vacinação/métodos , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...