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Frontiers in Cellular and Infection... 2021The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex... (Meta-Analysis)
Meta-Analysis
The development of periodontitis is associated with an imbalanced subgingival microbial community enriched with species such as the traditionally classified red-complex bacteria (, , and ). Saliva has been suggested as an alternative to subgingival plaque for the microbial analysis due to its easy and non-invasive collection. This systematic review aims to determine whether the levels of red-complex bacteria assessed using saliva reflect those in subgingival plaque from periodontitis patients. The MEDLINE, EMBASE, and Cochrane Library databases were searched up to April 30, 2021. Studies were considered eligible if microbial data of at least one of the red-complex species were reported in both saliva and subgingival plaque from periodontitis patients, based on DNA-based methods. Of the 17 included studies, 4 studies used 16S rRNA gene sequencing techniques, and the rest used PCR-based approaches. The detection frequency of each red-complex species in periodontitis patients was reported to be > 60% in most studies, irrespective of samples types. Meta-analyses revealed that both detection frequencies and relative abundances of red-complex bacteria in saliva were significantly lower than those in subgingival plaque. Moreover, the relative abundances of all 3 bacterial species in saliva showed significantly positive correlation with those in subgingival plaque. In conclusion, current evidence suggests that one-time saliva sampling cannot replace subgingival plaque for microbial analysis of the red-complex bacteria in periodontitis patients. Given the positive microbial associations between saliva and subgingival plaque, a thorough review of longitudinal clinical studies is needed to further assess the role of saliva.
Topics: Aggregatibacter actinomycetemcomitans; Humans; Periodontitis; Porphyromonas gingivalis; RNA, Ribosomal, 16S; Saliva; Treponema denticola
PubMed: 34692561
DOI: 10.3389/fcimb.2021.727732 -
Microbial Genomics Aug 2021Ethnicity is consistently reported as a strong determinant of human gut microbiota. However, the bulk of these studies are from Western countries, where microbiota... (Meta-Analysis)
Meta-Analysis
Ethnicity is consistently reported as a strong determinant of human gut microbiota. However, the bulk of these studies are from Western countries, where microbiota variations are mainly driven by relatively recent migration events. Malaysia is a multicultural society, but differences in gut microbiota persist across ethnicities. We hypothesized that migrant ethnic groups continue to share fundamental gut traits with the population in the country of origin due to shared cultural practices despite subsequent geographical separation. To test this hypothesis, the 16S rRNA gene amplicons from 16 studies comprising three major ethnic groups in Malaysia were analysed, covering 636 Chinese, 248 Indian and 123 Malay individuals from four countries (China, India, Indonesia and Malaysia). A confounder-adjusted permutational multivariate analysis of variance (PERMANOVA) detected a significant association between ethnicity and the gut microbiota (PERMANOVA =0.005, pseudo-=2.643, =0.001). A sparse partial least squares - discriminant analysis model trained using the gut microbiota of individuals from China, India and Indonesia (representation of Chinese, Indian and Malay ethnic group, respectively) showed a better-than-random performance in classifying Malaysian of Chinese descent, although the performance for Indian and Malay were modest (true prediction rate, Chinese=0.60, Indian=0.49, Malay=0.44). Separately, differential abundance analysis singled out as being elevated in Indians. We postulate that despite the strong influence of geographical factors on the gut microbiota, cultural similarity due to a shared ethnic origin drives the presence of a shared gut microbiota composition. The interplay of these factors will likely depend on the circumstances of particular groups of migrants.
Topics: China; Ethnicity; Gastrointestinal Microbiome; High-Throughput Nucleotide Sequencing; Humans; India; Indonesia; Malaysia; RNA, Ribosomal, 16S
PubMed: 34463609
DOI: 10.1099/mgen.0.000619 -
Medicine Aug 2021Plenty of studies have showed matrix metalloproteinase 14 (MMP14) expression might be associated with the prognosis of gastric cancer (GC). However, no definite... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Plenty of studies have showed matrix metalloproteinase 14 (MMP14) expression might be associated with the prognosis of gastric cancer (GC). However, no definite conclusion has been obtained for the contradictory results.
METHODS
We searched PubMed, Web of science, Embase, and Cochrane library for eligible studies. The association between MMP14 expression and prognostic outcomes of GC was evaluated. Hazard ratio (HR) and 95% confidence interval (CI) were integrated to show the effect of MMP14 expression on the overall survival (OS) or recurrence-free survival (RFS). Data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) was used to validate the association of MMP14 expression with OS or RFS in GC. A brief bioinformatics analysis was also performed to determine the prognostic role of MMP14 expression in GC.
RESULTS
High MMP14 expression was associated with shorter OS compared to low MMP14 expression in GC (HR = 1.95, P < .01). Patients with high MMP14 expression tended to have worse differentiation (P = .03), deeper tumor invasion (P < .01), earlier lymph node metastasis (P < .01), earlier distant metastasis (P < .01) and more advanced clinical stage (P < .01) compared to those with low MMP14 expression. The data from TCGA and GEO showed MMP14 was overexpressed in tumor tissues compared to normal tissues (P < .05), and high MMP14 expression was significantly related to shorter OS (HR = 1.70, 95% CI = 1.32-2.20, P < .01) and RFS (HR = 1.45, 95% CI = 1.15-1.83, P < .01) compared to low MMP14 expression in GC. Expression of MMP14 was linked to functional networks involving the biological process, metabolic process, response to stimulus, cell communication and so on. Functional network analysis suggested that MMP14 regulated the protein digestion and absorption, extracellular matrix receptor interaction, focal adhesion, ribosome, spliceosome, and so on.
CONCLUSION
High MMP14 expression was associated with worse prognosis of GC compared to low MMP14 expression. MMP14 expression could serve as a prognostic factor and potential therapeutic target of GC.
Topics: Biomarkers, Tumor; DNA, Neoplasm; Disease Progression; Gene Expression Regulation, Neoplastic; Humans; Matrix Metalloproteinase 14; Prognosis; Stomach Neoplasms
PubMed: 34397871
DOI: 10.1097/MD.0000000000026545 -
Genes & Nutrition Jul 2021Peripheral blood mononuclear cells (PBMCs) have shown promise as a tissue sensitive to subtle and possibly systemic transcriptomic changes, and as such may be useful in... (Review)
Review
BACKGROUND AND OBJECTIVES
Peripheral blood mononuclear cells (PBMCs) have shown promise as a tissue sensitive to subtle and possibly systemic transcriptomic changes, and as such may be useful in identifying responses to weight loss interventions. The primary aim was to comprehensively evaluate the transcriptomic changes that may occur during weight loss and to determine if there is a consistent response across intervention types in human populations of all ages.
METHODS
Included studies were randomised control trials or cohort studies that administered an intervention primarily designed to decrease weight in any overweight or obese human population. A systematic search of the literature was conducted to obtain studies and gene expression databases were interrogated to locate corresponding transcriptomic datasets. Datasets were normalised using the ArrayAnalysis online tool and differential gene expression was determined using the limma package in R. Over-represented pathways were explored using the PathVisio software. Heatmaps and hierarchical clustering were utilised to visualise gene expression.
RESULTS
Seven papers met the inclusion criteria, five of which had raw gene expression data available. Of these, three could be grouped into high responders (HR, ≥ 5% body weight loss) and low responders (LR). No genes were consistently differentially expressed between high and low responders across studies. Adolescents had the largest transcriptomic response to weight loss followed by adults who underwent bariatric surgery. Seven pathways were altered in two out of four studies following the intervention and the pathway 'cytoplasmic ribosomal proteins' (WikiPathways: WP477) was altered between HR and LR at baseline in the two datasets with both groups. Pathways related to 'toll-like receptor signalling' were altered in HR response to the weight loss intervention in two out of three datasets.
CONCLUSIONS
Transcriptomic changes in PBMCs do occur in response to weight change. Transparent and standardised data reporting is needed to realise the potential of transcriptomics for investigating phenotypic features.
REGISTRATION NUMBER
PROSPERO: CRD42019106582.
PubMed: 34281497
DOI: 10.1186/s12263-021-00692-6 -
Acta Dermato-venereologica Jul 2021Advances in technology have led to an increased number of studies investigating the microbiome in patients with psoriasis. This systematic review examined data regarding...
Advances in technology have led to an increased number of studies investigating the microbiome in patients with psoriasis. This systematic review examined data regarding the oral and gut microbiota in patients with psoriasis and/or psoriatic arthritis and the effect of probiotics on the microbiota and severity of psoriasis. Of 1,643 studies, 23 were included (22 observational, 1 interventional). Studies examined the microbiota using culture or 16S rRNA gene sequencing analysis. All culture-based studies identified an increased presence of oral Candida in patients with psoriasis, whereas small variations in the oral microbiota were found in a 16S rRNA gene-based study. All 16S rRNA gene sequencing based studies agreed that the gut microbiota of patients with psoriatic disease differed from that of healthy controls, but the results were heterogeneous. Probiotics were associated with a significant improvement in the severity of psoriasis, but did not change microbiota. Overall, studies lacked relevant inclusion criteria and baseline information. In conclusion, the role of the microbiota in patients with psoriasis requires further investigation using more robust methods.
Topics: Arthritis, Psoriatic; Gastrointestinal Microbiome; Humans; Microbiota; Psoriasis; RNA, Ribosomal, 16S
PubMed: 34263334
DOI: 10.2340/00015555-3882 -
Archives of Oral Biology Sep 2021To review published oral microbiome studies and create a comprehensive list of bacterial species found in saliva and dental plaque among healthy children and adults... (Review)
Review
OBJECTIVE
To review published oral microbiome studies and create a comprehensive list of bacterial species found in saliva and dental plaque among healthy children and adults associated with presence of carious lesions and caries-free state (oral health).
DESIGN
This review followed PRISMA-ScR guidelines. We searched published studies querying PUBMED and EMBASE using the following keywords: (plaque OR saliva) AND caries AND (next generation sequencing OR checkerboard OR 16s rRNA or qPCR). Studies were limited to human studies published in English between January 1, 2010 and June 24, 2020 that included > 10 caries-active and > 10 caries-free participants, and assessed the entire bacterial community.
RESULTS
Our search strategy identified 298 articles. After exclusion criteria, 22 articles remained; we considered 2 studies that examined saliva and plaque as separate studies, for a total of 24 studies. Species associated with caries or oral health varied widely among studies reviewed, with notable differences by age and biologic sample type. No bacterial species was associated with caries in all studies. Streptococcus mutans was found more frequently among those with caries (14/24 (58.3 %)) and Fusobacterium periodonticum was found more frequently among those that were caries-free (5/24 (20.8 %)).
CONCLUSION
No bacterial species was associated with caries or oral health across all studies supporting multiple pathways to cariogenesis. However, the variation may be due to sampling at different time points during caries development, varying methods of specimen sampling, storage, sequencing or analysis or differences in host factors such as age.
Topics: Adult; Child; Dental Caries; Fusobacterium; Humans; Mouth; Oral Health; RNA, Ribosomal, 16S; Saliva; Streptococcus mutans
PubMed: 34246103
DOI: 10.1016/j.archoralbio.2021.105204 -
Clinical Microbiology and Infection :... Sep 2021Bacteria colonizing the upper respiratory tract (URT) of young children play a key role in the pathogenesis of lower respiratory tract infection (LRTI). (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Bacteria colonizing the upper respiratory tract (URT) of young children play a key role in the pathogenesis of lower respiratory tract infection (LRTI).
OBJECTIVES
To systematically review the literature on the association between bacteria colonizing the URT and LRTI among young children.
DATA SOURCES
MEDLINE, Academic Search Premier, Africa-Wide Information and CINAHL, Scopus and Web of Science.
STUDY ELIGIBILITY CRITERIA
Studies published between 1923 and 2020, investigating URT bacteria from LRTI cases and controls.
PARTICIPANTS
Children under 5 years with and without acute LRTI.
METHODS
Three reviewers independently screened titles, abstracts and full texts. Meta-analysis was done using Mantel-Haenszel fixed- or random-effects models.
RESULTS
Most eligible studies (41/50) tested nasopharyngeal specimens when investigating URT bacteria. Most studies were of cross-sectional design (44/50). Twenty-four studies were performed in children in lower- or lower-middle-income countries (LMICs). There was higher prevalence of Haemophilus influenzae (pooled OR 1.60; 95% CI 1.23-2.07) and Klebsiella spp. (pooled OR 2.04; 95% CI 1.17-3.55) from URT specimens of cases versus controls. We observed a positive association between the detection of Streptococcus pneumoniae from URT specimens and LRTI after excluding studies where there was more antibiotic treatment prior to sampling in cases vs. controls (pooled OR 1.41; 95% CI 1.04-1.90). High density colonization with S. pneumoniae (>6.9 log copies/mL) was associated with an increased risk for LRTI. The associations between both Streptococcus and Haemophilus URT detection and LRTI were supported, at genus level, by 16S rRNA sequencing. Evidence for the role of Moraxella catarrhalis and Staphylococcus aureus was inconclusive.
CONCLUSIONS
Detection of H. influenzae or Klebsiella spp. in the URT was associated with LRTI, while evidence for association with S. pneumoniae was less conclusive. Longitudinal studies assessing URT microbial communities, together with environmental and host factors are needed to better understand pathogenesis of childhood LRTI.
Topics: Bacteria; Child; Child, Preschool; Cross-Sectional Studies; Humans; RNA, Ribosomal, 16S; Respiratory Tract Infections
PubMed: 34111578
DOI: 10.1016/j.cmi.2021.05.034 -
BioMed Research International 2021To determine the accuracy of 16S rRNA polymerase chain reaction (PCR) for the diagnosis of neonatal sepsis through a systematic review and meta-analysis. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To determine the accuracy of 16S rRNA polymerase chain reaction (PCR) for the diagnosis of neonatal sepsis through a systematic review and meta-analysis.
METHODS
Studies involving 16S rRNA PCR tests for the diagnosis of neonatal sepsis were searched in the PubMed, Medline, Embase, and Cochrane Library databases. The methodological quality of the identified studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2), and the sensitivity, the specificity, the positive likelihood ratio (PLR), the negative likelihood ratio (NLR), the diagnostic odds ratio (DOR), and the area under the curve (AUC) of operator characteristic (SROC) curves were determined. Heterogeneity between studies was analyzed by metaregression. Stata 14.0 and Meta-disc 1.4 software were used for the analyses.
RESULTS
This meta-analysis included 19 related studies. The analysis found a sensitivity of 0.98 (95% CI: 0.85-1), specificity of 0.94 (95% CI: 0.87-0.97), PLR of 16.0 (95% CI: 7.6-33.9), NLR of 0.02 (95% CI: 0.00-0.18), DOR of 674 (95% CI: 89-5100), and AUC of 0.99 (95% CI: 0.97-0.99). Metaregression analysis identified Asian countries, arterial blood in blood samples, and sample size > 200 as the main sources of heterogeneity. This meta-analysis did not uncover publication bias. Sensitivity analysis showed that the study was robust. Fagan's nomogram results showed clinical usability.
CONCLUSIONS
The results from this meta-analysis indicate that 16S rRNA PCR testing is effective for the rapid diagnosis of neonatal sepsis.
Topics: Area Under Curve; Bacteria; Biomarkers; Data Accuracy; Humans; Infant, Newborn; Neonatal Sepsis; Odds Ratio; Polymerase Chain Reaction; RNA, Ribosomal, 16S; ROC Curve; Sensitivity and Specificity; Sepsis
PubMed: 34095300
DOI: 10.1155/2021/5550387 -
International Journal of Molecular... May 2021Bicistronic reporter assays have been instrumental for transgene expression, understanding of internal ribosomal entry site (IRES) translation, and identification of...
Bicistronic reporter assays have been instrumental for transgene expression, understanding of internal ribosomal entry site (IRES) translation, and identification of novel cap-independent translational elements (CITE). We observed a large methodological variability in the use of bicistronic reporter assays and data presentation or normalization procedures. Therefore, we systematically searched the literature for bicistronic IRES reporter studies and analyzed methodological details, data visualization, and normalization procedures. Two hundred fifty-seven publications were identified using our search strategy (published 1994-2020). Experimental studies on eukaryotic adherent cell systems and the cell-free translation assay were included for further analysis. We evaluated the following methodological details for 176 full text articles: the bicistronic reporter design, the cell line or type, transfection methods, and time point of analyses post-transfection. For the cell-free translation assay, we focused on methods of in vitro transcription, type of translation lysate, and incubation times and assay temperature. Data can be presented in multiple ways: raw data from individual cistrons, a ratio of the two, or fold changes thereof. In addition, many different control experiments have been suggested when studying IRES-mediated translation. In addition, many different normalization and control experiments have been suggested when studying IRES-mediated translation. Therefore, we also categorized and summarized their use. Our unbiased analyses provide a representative overview of bicistronic IRES reporter use. We identified parameters that were reported inconsistently or incompletely, which could hamper data reproduction and interpretation. On the basis of our analyses, we encourage adhering to a number of practices that should improve transparency of bicistronic reporter data presentation and improve methodological descriptions to facilitate data replication.
Topics: Animals; Genes, Reporter; Humans; Internal Ribosome Entry Sites; Protein Biosynthesis; Regulatory Sequences, Nucleic Acid; Ribosomes
PubMed: 34068921
DOI: 10.3390/ijms22105193 -
PeerJ 2021Vaginal microbiome studies frequently report diversity metrics and communities of microbiomes associated with reproductive health outcomes. Reports of (also known as...
BACKGROUND
Vaginal microbiome studies frequently report diversity metrics and communities of microbiomes associated with reproductive health outcomes. Reports of (also known as Group B Streptococcus or GBS), the leading cause of neonatal infectious morbidity and mortality, are notably lacking from the studies of the vaginal microbiome, despite being a known contributor to preterm birth and other complications. Therefore, the purpose of this systematic review was to explore the frequency of GBS reporting in vaginal microbiome literature pertaining to pregnancy and to examine methodological bias that contributes to differences in species and genus-level microbiome reporting. Lack of identification of GBS via sequencing-based approaches due to methodologic or reporting bias may result incomplete understanding of bacterial composition during pregnancy and subsequent birth outcomes.
METHODOLOGY
A systematic review was conducted following the PRISMA guideline. Three databases (PubMed, CINAHL, and Web of Science) were used to identify papers for review based on the search terms "vaginal microbiome", "pregnancy", and "16S rRNA sequencing". Articles were evaluated for methods of DNA extraction and sequencing, 16S region, taxonomy classification database, number of participants or vaginal specimens, and pregnancy trimester.
RESULTS
Forty-five research articles reported employing a metagenomic approach or 16S approach for vaginal microbiome analysis during pregnancy that explicitly reported taxonomic composition and were included in this review. Less than 30% of articles reported the presence of GBS ( = 13). No significant differences in methodology were identified between articles that reported versus did not report GBS. However, there was large variability across research methods used for vaginal microbiome analysis and species-level bacterial community reporting.
CONCLUSION
Considerable differences in study design and data formatting methods may contribute to underrepresentation of GBS, and other known pathogens, in existing vaginal microbiome literature. Previous studies have identified considerable variation in methodology across vaginal microbiome studies. This study adds to this body of work because in addition to laboratory or statistical methods, how results and data are shared (e.g., only analyzing genus level data or 20 most abundant microbes), may hinder reproducibility and limit our understanding of the influence of less abundant microbes. Sharing detailed methods, analysis code, and raw data may improve reproducibility and ability to more accurately compare microbial communities across studies.
PubMed: 34046261
DOI: 10.7717/peerj.11437