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Microbiome Dec 2022The gut microbiome promotes specific immune responses, and in turn, the immune system has a hand in shaping the microbiome. Cancer and autoimmune diseases are two major... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The gut microbiome promotes specific immune responses, and in turn, the immune system has a hand in shaping the microbiome. Cancer and autoimmune diseases are two major disease families that result from the contrasting manifestations of immune dysfunction. We hypothesized that the opposing immunological profiles between cancer and autoimmunity yield analogously inverted gut microbiome signatures. To test this, we conducted a systematic review and meta-analysis on gut microbiome signatures and their directionality in cancers and autoimmune conditions.
METHODOLOGY
We searched PubMed, Web of Science, and Embase to identify relevant articles to be included in this study. The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements and PRISMA 2009 checklist. Study estimates were pooled by a generic inverse variance random-effects meta-analysis model. The relative abundance of microbiome features was converted to log fold change, and the standard error was calculated from the p-values, sample size, and fold change.
RESULTS
We screened 3874 potentially relevant publications. A total of 82 eligible studies comprising 37 autoimmune and 45 cancer studies with 4208 healthy human controls and 5957 disease cases from 27 countries were included in this study. We identified a set of microbiome features that show consistent, opposite directionality between cancers and autoimmune diseases in multiple studies. Fusobacterium and Peptostreptococcus were the most consistently increased genera among the cancer cases which were found to be associated in a remarkable 13 (+0.5 log fold change in 5 studies) and 11 studies (+3.6 log fold change in 5 studies), respectively. Conversely, Bacteroides was the most prominent genus, which was found to be increased in 12 autoimmune studies (+0.2 log fold change in 6 studies) and decreased in six cancer studies (-0.3 log fold change in 4 studies). Sulfur-metabolism pathways were found to be the most frequent pathways among the member of cancer-increased genus and species.
CONCLUSIONS
The surprising reproducibility of these associations across studies and geographies suggests a shared underlying mechanism shaping the microbiome across cancers and autoimmune diseases. Video Abstract.
Topics: Humans; Reproducibility of Results; Autoimmune Diseases; Neoplasms
PubMed: 36482486
DOI: 10.1186/s40168-022-01373-1 -
Cureus Oct 2022Deaths from colorectal cancer (CRC) are still rising, and various links to etiology have been proposed. However, a direct link between microbial dysbiosis and colorectal... (Review)
Review
Deaths from colorectal cancer (CRC) are still rising, and various links to etiology have been proposed. However, a direct link between microbial dysbiosis and colorectal cancer has not been postulated. This study aimed to identify the role of microbes in the pathogenesis of colorectal cancer. This systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was done considering papers published over the past 12 years, using PubMed, PubMed Central, Cochrane, Google Scholar, and ScienceDirect databases. Studies were selected based on the following predefined eligibility criteria: English-language systematic reviews, meta-analysis, randomized controlled trials (RCTs), and clinical trials, which included papers on microbes playing roles in colorectal cancer with the derived data transferred to a template. Following this, quality assessment was done using each study's relevant assessment tool. The initial search generated 128 studies. From the study, we found the ratio of , when compared between healthy and colorectal cancer patients' guts, was the highest, although it was not the most predominant gut organism. Enterotoxigenic (ETBF), and , and showed links with colorectal cancer and described pathways that could explain its implication in colorectal cancer. However, overt conclusions cannot be drawn because further research needs to be conducted.
PubMed: 36465770
DOI: 10.7759/cureus.30893 -
Cancers Jul 2022The intestinal microbiome is associated with colorectal cancer. Although the mucosal microbiota better represents an individual's local microbiome, studies on the... (Review)
Review
The intestinal microbiome is associated with colorectal cancer. Although the mucosal microbiota better represents an individual's local microbiome, studies on the colorectal cancer microbiota mainly reflect knowledge obtained from fecal samples. This systematic review aimed to summarize the current evidence on the relationship between the mucosal-associated bacterial microbiota and colorectal cancer. Searches were conducted in PubMed and Web of Science databases for publications comparing the mucosal microbiome of colorectal cancer patients with that of healthy controls, or with that of non-cancerous mucosal tissues. The primary outcomes were differences in microbial diversity and taxonomy. The Newcastle-Ottawa Scale was used to assess the quality of the included studies. Of the 5080 studies identified, 39 were eligible and included in the systematic review. No consistent results were identified for the α- and β-diversity, due to high heterogeneity in reporting and to differences in metrics and statistical approaches, limiting study comparability. Qualitative synthesis of microbial taxonomy identified 12 taxa with strong positive and 18 taxa with strong negative associations with colorectal cancer. , , , , , and were defined as enriched in colorectal cancer. Despite the methodological limitations of the studies, consistent evidence on bacterial taxa associated with colorectal cancer was identified. Prospective studies in large and well-characterized patient populations will be crucial to validate these findings.
PubMed: 35884445
DOI: 10.3390/cancers14143385 -
Journal of Clinical and Experimental... Oct 2022Patients with odontogenic infections are commonly prescribed antimicrobials on an experiential base without knowing the precise microorganisms implicated. The aim of... (Review)
Review
BACKGROUND
Patients with odontogenic infections are commonly prescribed antimicrobials on an experiential base without knowing the precise microorganisms implicated. The aim of this systematic scoping review is to evaluate the prevalence and proportions of antimicrobial-resistant species in patients with odontogenic infections.
MATERIAL AND METHODS
A systematic scoping review of scientific evidence was accomplished involving different databases.
RESULTS
Eight randomized clinical trials and 13 prospective observational studies were included. These investigations analyzed 1506 patients. The species that showed higher levels of resistance included aerobic and facultative anaerobe such as , and . In obligate anaerobes sampled were Peptostreptococcos spp., Bacteroides spp., and Prevotella spp. Staphylococcus showed resistance to ampicillin, piperacillin, clindamycin, amoxicillin, metronidazole, and penicillin. Streptococcus had resistance to metronidazole, clindamycin, doxycycline, penicillin, and amoxicillin. Peptostreptococcus spp. presented resistance to penicillin, amoxicillin, erythromycin, and cefalexin. Gram-negative microorganisms had resistance to tetracycline, ciprofloxacin, azithromycin, amoxicillin, erythromycin, and penicillin. Bacteroides spp. exhibited resistance to penicillin, erythromycin, and gentamicin. Prevotella spp. showed resistance to penicillin, amoxicillin, erythromycin, clindamycin, levofloxacin, and imipenem. Finally, Klebsiella spp. displayed resistance to ampicillin, amoxicillin, moxifloxacin, and cefalexin. Interestingly, one clinical trial showed that after therapy there was a reduction in sensitivity of 18% for azithromycin and 26% for spiramycin.
CONCLUSIONS
Most of the microorganisms had resistance to diverse groups of antimicrobials. Suitable antimicrobials must be prescribed founded on the microbial samples, culture susceptibility, and clinical progression of the odontogenic infection. Furthermore, it was observed high levels of resistance to antimicrobials that have been used in local and systemic therapy of oral cavity infections. A preponderance of anaerobic microorganisms over aerobic ones was observed. Antibiotic resistance, odontogenic infections, efficacy, microorganisms, scoping review.
PubMed: 36320675
DOI: 10.4317/jced.59830 -
Journal of the Turkish German... Sep 2020Accumulating evidence indicates the potential correlation between the vaginal microbioma and the acquisition and persistence of human papillomavirus (HPV) infection....
Accumulating evidence indicates the potential correlation between the vaginal microbioma and the acquisition and persistence of human papillomavirus (HPV) infection. This study aims to demonstrate the potential relationship through a systematic review of the current literature. A search was conducted on the following medical databases: PubMed and Scopus. Nineteen studies met the inclusion criteria and were incorporated in the present review. A total of 12.204 patients and their demographic characteristics were studied. Commercially available DNA tests and polymerase chain reaction (PCR) were used for the detection of different HPV subtypes, while the identification of the microbiomes was performed through specific diagnostic methods and PCR assay. The most frequently encountered species were classified based on their protective or detrimental impact on the progression of HPV infection. The beneficial role of some types of is generally supported. On the other hand, high microbial diversity and specific microorganisms such as and were found to be implicated with higher frequency and severity of disease, potentially resulting in pre-cancerous and cancerous cervical lesions.The role of vaginal microbiota appears to play an as yet not fully understood role in the susceptibility to HPV infection and its natural history.
PubMed: 31564082
DOI: 10.4274/jtgga.galenos.2019.2019.0051 -
Frontiers in Oncology 2022Emerging evidence has demonstrated a close association between perturbations in vaginal microbiota composition in women and human papillomavirus (HPV) infection,...
BACKGROUND
Emerging evidence has demonstrated a close association between perturbations in vaginal microbiota composition in women and human papillomavirus (HPV) infection, cervical lesions, and cervical cancer (Ca); however, these findings are highly heterogeneous and inconclusive.
AIM
To perform a comprehensive systematic review of the global disturbance in the vaginal microbiota, specifically in women with HPV-associated cervical diseases, and to further conduct within- and across-disease comparisons.
METHOD
Twenty-two records were identified in a systematic literature search of PubMed, Web of Science, and Embase up to February 28, 2022. We extracted microbial changes at the community (alpha and beta diversity) and taxonomic (relative abundance) levels. Within- and across-disease findings on the relative abundance of taxonomic assignments were qualitatively synthesized.
RESULTS
Generally, significantly higher alpha diversity was observed for HPV infection, cervical lesions, and/or cancer patients than in controls, and significant differences within beta diversity were observed for the overall microbial composition across samples. In within-disease comparisons, the genera , , , , and showed the greatest abundances with HPV infection; and showed inconsistent abundance with HPV infection, and was observed in Ca. Across diseases, we find increased levels of and varying levels of were shared across HPV infections, high-grade squamous intraepithelial lesions, and Ca, whereas varied depending on the HPV-related disease subtype.
CONCLUSIONS
This systematic review reports that vaginal microbiome disturbances are correlated to the depletion of , enrichment of anaerobes, and increased abundance of aerobic bacteria in HPV infection and related cervical diseases. Moreover, may exert either protective or pathogenic effects on different HPV-related diseases.
PubMed: 35903684
DOI: 10.3389/fonc.2022.941741 -
British Journal of Cancer May 2022Substantial evidence indicates that dysbiosis of the gut microbial community is associated with colorectal neoplasia. This review aims to systematically summarise the...
BACKGROUND
Substantial evidence indicates that dysbiosis of the gut microbial community is associated with colorectal neoplasia. This review aims to systematically summarise the microbial markers associated with colorectal neoplasia and to assess their predictive performance.
METHODS
A comprehensive literature search of MEDLINE and EMBASE databases was performed to identify eligible studies. Observational studies exploring the associations between microbial biomarkers and colorectal neoplasia were included. We also included prediction studies that constructed models using microbial markers to predict CRC and adenomas. Risk of bias for included observational and prediction studies was assessed.
RESULTS
Forty-five studies were included to assess the associations between microbial markers and colorectal neoplasia. Nine faecal microbiotas (i.e., Fusobacterium, Enterococcus, Porphyromonas, Salmonella, Pseudomonas, Peptostreptococcus, Actinomyces, Bifidobacterium and Roseburia), two oral pathogens (i.e., Treponema denticola and Prevotella intermedia) and serum antibody levels response to Streptococcus gallolyticus subspecies gallolyticus were found to be consistently associated with colorectal neoplasia. Thirty studies reported prediction models using microbial markers, and 83.3% of these models had acceptable-to-good discrimination (AUROC > 0.75). The results of predictive performance were promising, but most of the studies were limited to small number of cases (range: 9-485 cases) and lack of independent external validation (76.7%).
CONCLUSIONS
This review provides insight into the evidence supporting the association between different types of microbial species and their predictive value for colorectal neoplasia. Prediction models developed from case-control studies require further external validation in high-quality prospective studies. Further studies should assess the feasibility and impact of incorporating microbial biomarkers in CRC screening programme.
Topics: Adenoma; Biomarkers; Colorectal Neoplasms; Dysbiosis; Humans; Prospective Studies
PubMed: 35292756
DOI: 10.1038/s41416-022-01740-7 -
PloS One 2021To assess the prevalence of unculturable bacteria in periapical abscess, radicular cyst, and periapical granuloma. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To assess the prevalence of unculturable bacteria in periapical abscess, radicular cyst, and periapical granuloma.
METHODS
PubMed, Scopus, Science Direct, and Ovid databases were systematically searched from January 1990 to May 2020. All the included studies were cross-sectional design. The risk of bias was assessed using Joanna Briggs Institute check-list. Heterogeneity was described using meta-regression and mixed-effects model for lesion, country, and sequence technique moderators. Funnel plot and unweighted Egger's regression test were used to estimate the publication bias. Microbiome data on diversity, abundance, and frequency of unculturable bacteria in the periapical lesions were reviewed, analysed, and the principal component analysis (PCA) was performed.
RESULTS
A total of 13 studies out of 14,780, were selected for the final analysis. These studies focused on the prevalence of unculturable bacteria in periapical abscesses and related lesions. Approximately 13% (95% CI: 7-23%) of the cumulative number of bacteria derived from periapical abscesses was unculturable. Country moderator significantly (P = 0.05) affects the diversity summary proportion. While the pooled frequency of unculturable bacteria was 8%; 95% CI: 5, 14%, the estimate of the pooled abundance of unculturable bacteria was 5%; 95% CI: 2, 12% with a significant (P = 0.05) country moderator that affects the abundance summary proportion. Of the 62 unculturable bacteria, 35 were subjected to PCA and Peptostreptococcus sp. oral clone CK035 was the most abundant species in periapical abscesses. Hybridization techniques were found to be the most reliable molecular methods in detecting the abundance and frequency of unculturable bacteria.
CONCLUSION
The significant prevalence of unculturable bacteria in the periapical abscess, suggests that they are likely to play, a yet unknown, critical role in the pathogenesis and progression of the disease. Further research remains to be done to confirm their specific contributions in the virulence and disease progression.
Topics: Bacteria; Bacterial Infections; Humans; Periapical Abscess; Prevalence
PubMed: 34351963
DOI: 10.1371/journal.pone.0255485 -
Cancer Epidemiology, Biomarkers &... Oct 2020The microbiome has been hypothesized to play a role in cancer development. Because of the diversity of published data, an overview of available epidemiologic evidence...
The microbiome has been hypothesized to play a role in cancer development. Because of the diversity of published data, an overview of available epidemiologic evidence linking the microbiome with cancer is now needed. We conducted a systematic review using a tailored search strategy in Medline and EMBASE databases to identify and summarize the current epidemiologic literature on the relationship between the microbiome and different cancer outcomes published until December 2019. We identified 124 eligible articles. The large diversity of parameters used to describe microbial composition made it impossible to harmonize the different studies in a way that would allow meta-analysis, therefore only a qualitative description of results could be performed. Fifty studies reported differences in the gut microbiome between patients with colorectal cancer and various control groups. The most consistent findings were for , and being significantly enriched in fecal and mucosal samples from patients with colorectal cancer. For the oral microbiome, significantly increased and decreased abundance was reported for and , respectively, in patients with oral cancer compared with controls. Overall, although there was a large amount of evidence for some of these alterations, most require validation in high-quality, preferably prospective, epidemiologic studies.
Topics: Gastrointestinal Microbiome; Humans; Neoplasms; Risk
PubMed: 32727720
DOI: 10.1158/1055-9965.EPI-20-0288 -
Nutrients Apr 2021Growing attention has been given to the role of nutrition and alterations of microbial diversity of the gut microbiota in colorectal cancer (CRC) pathogenesis. It has...
BACKGROUND
Growing attention has been given to the role of nutrition and alterations of microbial diversity of the gut microbiota in colorectal cancer (CRC) pathogenesis. It has been suggested that probiotics and synbiotics modulate enteric microbiota and therefore may be used as an intervention to reduce the risk of CRC. The aim of this study was to evaluate the influence of probiotics/synbiotics administration on gut microbiota in patients with CRC.
METHODS
PubMed, Scopus, and Web of Science were searched between December 2020 and January 2021. Randomized controlled trials (RCTs) recruiting adults with CRC, who have taken probiotics/synbiotics for at least 6 days were included. Changes in gut microbiota and selected biochemical and inflammatory parameters (i.e., hsCRP, IL-2, hemoglobin) were retrieved.
RESULTS
The search resulted in 198 original research articles and a final 6 were selected as being eligible, including 457 subjects. The median age of patients was 65.4 years old and they were characterized by the median BMI value: 23.8 kg/m. The literature search revealed that probiotic/synbiotic administration improved enteric microbiota by increasing the abundance of beneficial bacteria such as and , and decreased the abundance of potentially harmful bacteria such as and . Additionally, probiotic/synbiotic intervention improved release of antimicrobials, intestinal permeability, tight junction function in CRC patients.
CONCLUSIONS
The use of probiotics/synbiotics positively modulates enteric microbiota, improves postoperative outcomes, gut barrier function and reduces inflammatory parameters in patients suffering from CRC.
Topics: Bacteria; Colorectal Neoplasms; Gastrointestinal Microbiome; Humans; Probiotics
PubMed: 33915854
DOI: 10.3390/nu13041160