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Molecular Psychiatry Dec 2023A body of pre-clinical evidence shows how the gut microbiota influence brain functioning, including brain connectivity. Linking measures of brain connectivity to the gut...
A body of pre-clinical evidence shows how the gut microbiota influence brain functioning, including brain connectivity. Linking measures of brain connectivity to the gut microbiota can provide important mechanistic insights into the bi-directional gut-brain communication. In this systematic review, we therefore synthesized the available literature assessing this association, evaluating the degree of consistency in microbiota-connectivity associations. Following the PRISMA guidelines, a PubMed search was conducted, including studies published up to September 1, 2022. We identified 16 studies that met the inclusion criteria. Several bacterial genera, including Prevotella, Bacteroides, Ruminococcus, Blautia, and Collinsella were most frequently reported in association with brain connectivity. Additionally, connectivity of the salience (specifically the insula and anterior cingulate cortex), default mode, and frontoparietal networks were most frequently associated with the gut microbiota, both in terms of microbial diversity and composition. There was no discernible pattern in the association between microbiota and brain connectivity. Altogether, based on our synthesis, there is evidence for an association between the gut microbiota and brain connectivity. However, many findings were poorly replicated across studies, and the specificity of the association is yet unclear. The current studies show substantial inter-study heterogeneity in methodology and reporting, limiting the robustness and reproducibility of the findings and emphasizing the need to harmonize methodological approaches. To enhance comparability and replicability, future research should focus on further standardizing processing pipelines and employing data-driven multivariate analysis strategies.
Topics: Humans; Gastrointestinal Microbiome; Brain; Brain-Gut Axis; Connectome; Nerve Net
PubMed: 37479779
DOI: 10.1038/s41380-023-02146-4 -
International Journal of Food... Oct 2023Salmonella enterica serovar Infantis is an emergent foodborne and zoonotic Salmonella serovar with critical implications for global health. In recent years, the... (Review)
Review
Salmonella enterica serovar Infantis is an emergent foodborne and zoonotic Salmonella serovar with critical implications for global health. In recent years, the prevalence of S. Infantis infections has increased in the United States, Europe, and Latin America, due to contaminated chicken and other foods. An essential trait of S. Infantis is its resistance to multiple antibiotics, including the critically important third-generation cephalosporins and quinolones, undermining effective medical treatment, particularly in low-resource settings. We describe the emergence of multidrug-resistant (MDR) S. Infantis, focusing on humans, animals, the environment, and food. We conducted a systematic review (1979-2021), selected 183 studies, and analyzed the origin, source, antimicrobial resistance, and presence of a conjugative plasmid of emerging S. Infantis (pESI) in reported isolates. S. Infantis has been detected worldwide, with a substantial increase since 2011. We found the highest number of isolations in the Americas (42.9 %), Europe (29.8 %), Western Pacific (17.2 %), Eastern Mediterranean (6.6 %), Africa (3.4 %), and South-East Asia (0.1 %). S. Infantis showed MDR patterns and numerous resistant genes in all sources. The primary source of MDR S. Infantis is broiler and their meat; however, this emerging pathogen is also present in other reservoirs such as food, wildlife, and the environment. Clinical cases of MDR S. Infantis have been reported in children and adults. The global emergence of S. Infantis is related to a plasmid (pESI) with antibiotic and arsenic- and mercury-resistance genes. Additionally, a new megaplasmid (pESI-like), carrying bla and antibiotic-resistant genes reported in an ancestral version, was detected in the broiler, human, and chicken meat isolates. Strains harboring pESI-like were primarily observed in the Americas and Europe. MDR S. Infantis has spread globally, potentially becoming a major public health threat, particularly in low- and middle-income countries.
Topics: Child; Animals; Humans; Salmonella enterica; Serogroup; Chickens; Drug Resistance, Multiple, Bacterial; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37406596
DOI: 10.1016/j.ijfoodmicro.2023.110297 -
The Science of the Total Environment Oct 2023Antimicrobial resistance has been a serious and complex issue for over a decade. Although research on antimicrobial resistance (AMR) has mainly focused on clinical and... (Review)
Review
Antimicrobial resistance has been a serious and complex issue for over a decade. Although research on antimicrobial resistance (AMR) has mainly focused on clinical and animal samples as essential for treatment, the AMR situation in aquatic environments may vary and have complicated patterns according to geographical area. Therefore, this study aimed to examine recent literature on the current situation and identify gaps in the AMR research on freshwater, seawater, and wastewater in Southeast Asia. The PubMed, Scopus, and ScienceDirect databases were searched for relevant publications published from January 2013 to June 2023 that focused on antimicrobial resistance bacteria (ARB) and antimicrobial resistance genes (ARGs) among water sources. Based on the inclusion criteria, the final screening included 41 studies, with acceptable agreement assessed using Cohen's inter-examiner kappa equal to 0.866. This review found that 23 out of 41 included studies investigated ARGs and ARB reservoirs in freshwater rather than in seawater and wastewater, and it frequently found that Escherichia coli was a predominant indicator in AMR detection conducted by both phenotypic and genotypic methods. Different ARGs, such as bla, sul1, and tetA genes, were found to be at a high prevalence in wastewater, freshwater, and seawater. Existing evidence highlights the importance of wastewater management and constant water monitoring in preventing AMR dissemination and strengthening effective mitigation strategies. This review may be beneficial for updating current evidence and providing a framework for spreading ARB and ARGs, particularly region-specific water sources. Future AMR research should include samples from various water systems, such as drinking water or seawater, to generate contextually appropriate results. Robust evidence regarding standard detection methods is required for prospective-era work to raise practical policies and alerts for developing microbial source tracking and identifying sources of contamination-specific indicators in aquatic environment markers.
Topics: Animals; Bacteria; Drug Resistance, Bacterial; Escherichia coli; Genes, Bacterial; Prospective Studies; Wastewater; Water; Seawater; Fresh Water; Water Microbiology; Asia, Southeastern
PubMed: 37394072
DOI: 10.1016/j.scitotenv.2023.165229 -
PLoS Medicine Jun 2023Inappropriate antimicrobial usage is a key driver of antimicrobial resistance (AMR). Low- and middle-income countries (LMICs) are disproportionately burdened by AMR and...
BACKGROUND
Inappropriate antimicrobial usage is a key driver of antimicrobial resistance (AMR). Low- and middle-income countries (LMICs) are disproportionately burdened by AMR and young children are especially vulnerable to infections with AMR-bearing pathogens. The impact of antibiotics on the microbiome, selection, persistence, and horizontal spread of AMR genes is insufficiently characterized and understood in children in LMICs. This systematic review aims to collate and evaluate the available literature describing the impact of antibiotics on the infant gut microbiome and resistome in LMICs.
METHODS AND FINDINGS
In this systematic review, we searched the online databases MEDLINE (1946 to 28 January 2023), EMBASE (1947 to 28 January 2023), SCOPUS (1945 to 29 January 2023), WHO Global Index Medicus (searched up to 29 January 2023), and SciELO (searched up to 29 January 2023). A total of 4,369 articles were retrieved across the databases. Duplicates were removed resulting in 2,748 unique articles. Screening by title and abstract excluded 2,666 articles, 92 articles were assessed based on the full text, and 10 studies met the eligibility criteria that included human studies conducted in LMICs among children below the age of 2 that reported gut microbiome composition and/or resistome composition (AMR genes) following antibiotic usage. The included studies were all randomized control trials (RCTs) and were assessed for risk of bias using the Cochrane risk-of-bias for randomized studies tool. Overall, antibiotics reduced gut microbiome diversity and increased antibiotic-specific resistance gene abundance in antibiotic treatment groups as compared to the placebo. The most widely tested antibiotic was azithromycin that decreased the diversity of the gut microbiome and significantly increased macrolide resistance as early as 5 days posttreatment. A major limitation of this study was paucity of available studies that cover this subject area. Specifically, the range of antibiotics assessed did not include the most commonly used antibiotics in LMIC populations.
CONCLUSION
In this study, we observed that antibiotics significantly reduce the diversity and alter the composition of the infant gut microbiome in LMICs, while concomitantly selecting for resistance genes whose persistence can last for months following treatment. Considerable heterogeneity in study methodology, timing and duration of sampling, and sequencing methodology in currently available research limit insights into antibiotic impacts on the microbiome and resistome in children in LMICs. More research is urgently needed to fill this gap in order to better understand whether antibiotic-driven reductions in microbiome diversity and selection of AMR genes place LMIC children at risk for adverse health outcomes, including infections with AMR-bearing pathogens.
Topics: Infant; Child; Humans; Child, Preschool; Anti-Bacterial Agents; Developing Countries; Gastrointestinal Microbiome; Azithromycin; Drug Resistance, Microbial
PubMed: 37368871
DOI: 10.1371/journal.pmed.1004235 -
Journal of Clinical Microbiology Sep 2023rRNA gene Sanger sequencing is being used for the identification of cultured pathogens. A new diagnostic approach is sequencing of uncultured samples by using the... (Meta-Analysis)
Meta-Analysis
Direct 16S/18S rRNA Gene PCR Followed by Sanger Sequencing as a Clinical Diagnostic Tool for Detection of Bacterial and Fungal Infections: a Systematic Review and Meta-Analysis.
rRNA gene Sanger sequencing is being used for the identification of cultured pathogens. A new diagnostic approach is sequencing of uncultured samples by using the commercial DNA extraction and sequencing platform SepsiTest (ST). The goal was to analyze the clinical performance of ST with a focus on nongrowing pathogens and the impact on antibiotic therapy. A literature search used PubMed/Medline, Cochrane, Science Direct, and Google Scholar. Eligibility followed PRISMA-P criteria. Quality and risk of bias were assessed drawing on QUADAS-2 (quality assessment of diagnostic accuracy studies, revised) criteria. Meta-analyses were performed regarding accuracy metrics compared to standard references and the added value of ST in terms of extra found pathogens. We identified 25 studies on sepsis, infectious endocarditis, bacterial meningitis, joint infections, pyomyositis, and various diseases from routine diagnosis. Patients with suspected infections of purportedly sterile body sites originated from various hospital wards. The overall sensitivity (79%; 95% confidence interval [CI], 73 to 84%) and specificity (83%; 95% CI, 72 to 90%) were accompanied by large effect sizes. ST-related positivity was 32% (95% CI, 30 to 34%), which was significantly higher than the culture positivity (20%; 95% CI, 18 to 22%). The overall added value of ST was 14% (95% CI, 10 to 20%) for all samples. With 130 relevant taxa, ST uncovered high microbial richness. Four studies demonstrated changes of antibiotic treatment at 12% (95% CI, 9 to 15%) of all patients upon availability of ST results. ST appears to be an approach for the diagnosis of nongrowing pathogens. The potential clinical role of this agnostic molecular diagnostic tool is discussed regarding changes of antibiotic treatment in cases where culture stays negative.
Topics: Humans; Anti-Bacterial Agents; Bacteria; Genes, rRNA; Meta-Analysis as Topic; Mycoses; Polymerase Chain Reaction; RNA, Ribosomal, 16S; RNA, Ribosomal, 18S; Sensitivity and Specificity; Systematic Reviews as Topic
PubMed: 37367430
DOI: 10.1128/jcm.00338-23 -
Behavioural Brain Research Aug 2023Alzheimer's disease (AD), a prevalent progressive neurodegenerative disease, is mainly characterized by dementia, memory loss, and cognitive disorder. Rising research... (Review)
Review
BACKGROUND AND AIM
Alzheimer's disease (AD), a prevalent progressive neurodegenerative disease, is mainly characterized by dementia, memory loss, and cognitive disorder. Rising research was performed to develop pharmacological or non-pharmacological approaches to treat or improve AD complications. Mesenchymal stem cells (MSCs) are stromal cells that can self-renew and exhibit multilineage differentiation. Recent evidence suggested that some of the therapeutic effects of MSCs are mediated by the secreted paracrine factors. These paracrine factors, called MSC- conditioned medium (MSC-CM), may stimulate endogenous repair, promote angio- and artery genesis, and reduce apoptosis through paracrine mechanisms. The current study aims to systematically review the advantages of MSC-CM to the development of research and therapeutic concepts for AD management.
MATERIAL AND METHODS
The present systematic review was performed using PubMed, Web of Science, and Scopus from April 2020 to May 2022 following the "Preferred Reporting Items for Systematic Reviews" (PRISMA) guidelines. The keywords, including "Conditioned medium OR Conditioned media OR Stem cell therapy" AND "Alzheimer's," was searched, and finally, 13 papers were extracted.
RESULTS
The obtained data revealed that MSC-CMs might positively affect neurodegenerative diseases prognosis, especially AD, through various mechanisms, including a decrease in neuro-inflammation, reduction of oxidative stress and Aβ formation, modulation of Microglia function and count, reduction of apoptosis, induction of synaptogenesis and neurogenesis. Also, the results showed that MSC-CM administration could significantly improve cognitive and memory function, increase the expression of neurotrophic factors, decrease the production of pro-inflammatory cytokines, improve mitochondrial function, reduce cytotoxicity, and increase neurotransmitter levels.
CONCLUSION
While inhibiting the induction of neuroinflammation could be considered the first therapeutic effect of CMs, the prevention of apoptosis could be regarded as the most crucial effect of CMs on AD improvement.
Topics: Humans; Alzheimer Disease; Culture Media, Conditioned; Neurodegenerative Diseases; Stem Cells; Mesenchymal Stem Cells
PubMed: 37311523
DOI: 10.1016/j.bbr.2023.114543 -
Frontiers in Cellular and Infection... 2023For a long time, the uterus had been considered a sterile organ, meaning that under physiological conditions the uterus would not be colonized by bacteria. Based on... (Review)
Review
For a long time, the uterus had been considered a sterile organ, meaning that under physiological conditions the uterus would not be colonized by bacteria. Based on available data, it may be concluded that the gut and uterine microbiome are related, and that the role of this microbiome is greater than expected. Despite being the most common pelvic neoplasms in women of reproductive age, uterine fibroids (UFs) are still poorly understood tumors whose etiology has not been fully determined. This systematic review presents the relationship between intestinal and uterine dysbiosis and uterine fibroids. A systematic review of three medical databases was carried out: the MEDLINE/PubMed, Scopus and Cochrane. In this study, 195 titles and abstracts were reviewed, including only original articles and clinical trials of uterine microbiome criteria. Finally, 16 studies were included to the analysis. In recent years, researchers dealing with reproduction in a broad sense have focused on the microbiome in various locations to study its role in the pathogenesis and, consequently, the prevention and treatment of diseases of the genital organ. Conventional microbial detection methods are not suitable for identifying bacteria, which are difficult to culture. Next-generation sequencing (NGS) provides an easier and faster and more informative analysis of bacterial populations. It seems that gut microbiota dysbiosis has the potential to be a risk factor for uterine fibroids or affect the disease process. Some changes were shown in many types of bacteria, such as and detected in fecal samples in patients with uterine fibroids. In view of the few results on the link between the microbiome and uterine fibroids, further intensive studies in humans and animal models are necessary, including the possible use of different microbiome modulations in the prevention or treatment of uterine fibroids.
Topics: Animals; Humans; Female; Dysbiosis; Microbiota; Leiomyoma; Gastrointestinal Microbiome; Actinobacteria
PubMed: 37305407
DOI: 10.3389/fcimb.2023.1177366 -
Head & Neck Aug 2023The relationship between head and neck squamous cell carcinoma (HNSCC) and the oral microbiome has been drawn in various studies. Microbial diversities, microbiome... (Review)
Review
OBJECTIVES
The relationship between head and neck squamous cell carcinoma (HNSCC) and the oral microbiome has been drawn in various studies. Microbial diversities, microbiome profiles, metagenomic analysis, and host-pathogen interactions were collected from these studies to highlight similarities and account for inconsistencies. We also evaluate the possible clinical applications of the microbiome regarding screening and diagnosis of HNSCC.
METHODS
Systematic analysis of studies regarding HNSCC and the microbiome was done according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. Articles were retrieved from four databases (PubMed, ScienceDirect, CUHK Full-Text Journals, and Cochrane database) and were screened using predefined criteria.
RESULTS
Twenty studies were chosen after screening for full-text review. α-diversity comparison was inconsistent whereas β-diversity between HNSCC and normal samples showed distinct clustering. Microbial dysbiosis characterized by change in the relative abundances of several bacterial species were also seen in HNSCC patients. At a phylum level, inconsistencies were seen between studies using HNSCC tumor tissue samples and saliva samples. At a genus level, Fusobacterium, Peptostreptococcus, Alloprevotella, Capnocytophaga, Catonella, and Prevotella were differentially enriched in HNSCC while Streptococcus, Actinomyces Veillonella, and Rothia were differentially depleted. Co-occurrence network analysis revealed a positive correlation of HNSCC with periodontal pathogens and a negative correlation with commensal bacteria. Metagenomic analysis of microbiota revealed a differential enrichment of pro-inflammatory genomic pathways which was consistent across various studies. Microbial dysbiosis was applied in clinical use as a tool for HNSCC screening. Random-forest analysis was adopted to differentiate between tumor and normal tissue, at 95.7% and 70.0% accuracies respectively in two studies. Microbial dysbiosis index was also used to predict prognosis.
CONCLUSIONS
Oral microbial dysbiosis could be a promising tool for HNSCC screening and diagnosis. However, more research should be conducted pertaining to clinical applications to improve diagnostic accuracy and explore other clinical uses.
Topics: Humans; Bacteria; Dysbiosis; Head and Neck Neoplasms; Microbiota; Squamous Cell Carcinoma of Head and Neck
PubMed: 37249085
DOI: 10.1002/hed.27422 -
Journal of Chemotherapy (Florence,... Nov 2023Pyrazinamide (PZA) is an essential first-line tuberculosis drug for its unique mechanism of action active against multidrug-resistant-TB (MDR-TB). Thus, the aim of... (Meta-Analysis)
Meta-Analysis Review
Pyrazinamide (PZA) is an essential first-line tuberculosis drug for its unique mechanism of action active against multidrug-resistant-TB (MDR-TB). Thus, the aim of updated meta-analysis was to estimate the PZA weighted pooled resistance (WPR) rate in M. tuberculosis isolates based on publication date and WHO regions. We systematically searched the related reports in PubMed, Scopus, and Embase (from January 2015 to July 2022). Statistical analyses were performed using STATA software. The 115 final reports in the analysis investigated phenotypic PZA resistance data. The WPR of PZA was 57% (95% CI 48-65%) in MDR-TB cases. According to the WHO regions, the higher WPRs of PZA were reported in the Western Pacific (32%; 95% CI 18-46%), South East Asian region (37%; 95% CI 31-43%), and the Eastern Mediterranean (78%; 95% CI 54-95%) among any-TB patients, high risk of MDR-TB patients, and MDR-TB patients, respectively. A negligible increase in the rate of PZA resistance were showed in MDR-TB cases (55% to 58%). The rate of PZA resistance has been rising in recent years among MDR-TB cases, underlines the essential for both standard and novel drug regimens development.
Topics: Humans; Pyrazinamide; Mycobacterium tuberculosis; Antitubercular Agents; Tuberculosis, Multidrug-Resistant; Drug Resistance, Multiple, Bacterial; Amidohydrolases; Mutation; Microbial Sensitivity Tests; Tuberculosis
PubMed: 37211822
DOI: 10.1080/1120009X.2023.2214473 -
Journal of Global Antimicrobial... Mar 2024Cystic fibrosis (CF) is a hereditary recessive disease that affects the mucous clearance of the lungs and allows bacteria such as Staphylococcus aureus to settle in the... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Cystic fibrosis (CF) is a hereditary recessive disease that affects the mucous clearance of the lungs and allows bacteria such as Staphylococcus aureus to settle in the lung and cause infection. This study examined the prevalence of antibiotic resistance of S. aureus in cystic fibrosis infection using a systematic review and meta-analysis.
METHODS
A comprehensive and systematic search of related articles was conducted through the PubMed, Scopus, and Web of Science databases until March 2022. The weighted pooled resistance rate of antibiotics was analysed with Freeman-Tukey double arcsine transformation in the Stata software version 17.1 using the Metaprop command.
RESULTS
In this meta-analysis, 25 studies were used based on criteria to evaluate the pattern of S. aureus resistance in CF. Vancomycin and teicoplanin were the most effective options for treatment of CF patients; the highest level of antibiotic resistance observed was to erythromycin and clindamycin.
CONCLUSION
High levels of resistance to most of the antibiotics studied was observed. The high levels of antibiotic resistance observed are worrisome and indicate the need to monitor antibiotic use.
Topics: Humans; Staphylococcus aureus; Cystic Fibrosis; Prevalence; Staphylococcal Infections; Anti-Bacterial Agents; Drug Resistance, Microbial
PubMed: 37211214
DOI: 10.1016/j.jgar.2023.05.006