Antibiotics as deep modulators of gut microbiota: between good and evil

Amoxicillin Modulates ApoA-I Transcription and Secretion, Predominantly via PPARα Transactivation Inhibition

In a recent human study, we observed that amoxicillin treatment decreased HDL-C concentration. We hypothesize that antibiotics lower the transcription and secretion of ApoA-I, the responsible protein for HDL production. HepG2 and Caco-2 cells were exposed to increasing dose of amoxicillin, penicillin, and streptomycin. Secreted ApoA-I protein and mRNA transcripts were analyzed using ELISA and qPCR, respectively. To unravel underlying mechanisms, KEAP1, CPT1, and CHOP mRNA expressions were determined as well as PPARα transactivation. In HepG2 and Caco-2, amoxicillin decreased ApoA-I transcription and secretion. Effects on ApoA-I expression were clearly there for amoxicillin while no effects were observed for penicillin or streptomycin. KEAP1, CPT1, and CHOP mRNA expressions were reduced by amoxicillin treatments. Moreover, a significant correlation between ApoA-I and CPT1 mRNA expressions was found. Furthermore, amoxicillin lowered PPARα transactivation. All together, these data suggest that inhibited PPARα transactivation is involved in the effects of amoxicillin on ApoA-I. In conclusion, the direct effect of amoxicillin in treated HepG2 and Caco-2 cells was a lower ApoA-I secretion and transcription. Based on evaluating alterations in KEAP1, CPT1, and CHOP mRNA expressions plus PPARα transactivation, we suggest that a reduced PPARα activation is a potential mechanism behind the observed amoxicillin effects on ApoA-I expression.

Minor Effect of Antibiotic Pre-treatment on the Engraftment of Donor Microbiota in Fecal Transplantation in Mice

Fecal microbiota transplantation (FMT) is an effective therapy for recurrent Clostridioides difficile infection (rCDI) and is also considered a potential treatment for a wide range of intestinal and systemic diseases. FMT corrects the microbial dysbiosis associated with rCDI, and the engraftment of donor microbiota is likely to play a key role in treatment efficacy. For disease indications other than rCDI, FMT treatment efficacy has been moderate. This may be partly due to stronger resilience of resident host microbiota in patients who do not suffer from rCDI. In rCDI, patients typically have undergone several antibiotic treatments prior to FMT, depleting the microbiota. In this study, we addressed the effect of broad-spectrum antibiotics (Ab) as a pre-treatment to FMT on the engraftment of donor microbiota in recipients. We conducted a pre-clinical study of FMT between two healthy mouse strains, Balb/c as donors and C57BL/6 as recipients, to perform FMT within the same species and to mimic interindividual FMT between human donors and patients. Microbiota composition was assessed with high-throughput 16S rDNA amplicon sequencing. The microbiota of Balb/c and C57BL/6 mice differed significantly, which allowed for the assessment of microbiota transplantation from the donor strain to the recipient. Our results showed that Ab-treatment depleted microbiota in C57BL/6 recipient mice prior to FMT. The diversity of microbiota did not recover spontaneously to baseline levels during 8 weeks after Ab-treatment, but was restored already at 2 weeks in mice receiving FMT. Interestingly, pre-treatment with antibiotics prior to FMT did not increase the overall similarity of the recipient’s microbiota to that of the donor’s, as compared with mice receiving FMT without Ab-treatment. Pre-treatment with Ab improved the establishment of only a few donor-derived taxa, such as Bifidobacterium, in the recipients, thus having a minor effect on the engraftment of donor microbiota in FMT. In conclusion, pre-treatment with broad-spectrum antibiotics did not improve the overall engraftment of donor microbiota, but did improve the engraftment of specific taxa. These results may inform future therapeutic studies of FMT.

The effect of antibiotics on the clinical outcomes of patients with solid cancers undergoing immune checkpoint inhibitor treatment: a retrospective study

BACKGROUND

This study aimed to assess the effect of antibiotics on the clinical outcomes of patients with solid cancers undergoing treatment with immune checkpoint inhibitors (ICIs).

METHODS

The medical records of 234 patients treated with ICIs for any type of solid cancer between February 2012 and May 2018 at the Seoul St. Mary's Hospital were retrospectively reviewed. The data of patients who received antibiotics within 60 days before the initiation of ICI treatment were analyzed. The patients' responses to ICI treatment and their survival were evaluated.

RESULTS

Non-small-cell lung carcinoma was the most common type of cancer. About half of the patients were treated with nivolumab (51.9%), and cephalosporin (35.2%) was the most commonly used class of antibiotics. The total objective response rate was 21%. Antibiotics use was associated with a decreased objective response (odds ratio 0.466, 95% confidence interval [CI] 0.225-0.968, p = 0.040). The antibiotics group exhibited shorter progression-free survival (PFS) and overall survival (OS) than the no antibiotics group (median PFS: 2 months vs. 4 months, p < 0.001; median OS: 5 months vs. 17 months, p < 0.001). In the multivariate analysis, antibiotics use was a significant predictor of patient survival (PFS: hazard ratio [HR] 1.715, 95% CI 1.264-2.326, p = 0.001; OS: HR 1.785, 95% CI 1.265-2.519, p = 0.001).

CONCLUSIONS

The use of antibiotics may affect the clinical outcomes of patients with solid cancers treated with ICIs. Careful prescription of antibiotics is warranted in candidates who are scheduled for ICI treatment.

TRIAL REGISTRATION

Not applicable (retrospective study).

Antibiotic effects on gut microbiota, metabolism, and beyond

Current advances on gut microbiota have broadened our view on host-microbiota interactions. As a microbiota-targeted approach, the use of antibiotics has been widely adopted to explore the role of gut microbiota in vivo. Antibiotics can change the microbial composition, resulting in varied effects, depending on the antibiotic class, dosage, and duration. Antibiotic intervention in early life leads to life-long phenotype alterations, including obesity. Antibiotic-induced changes in gut microbiota affect the epithelial utilization of both macronutrients (e.g., amino acids) and micronutrients (e.g., copper, vitamin E) and the redox homeostasis. Of particular interest is the regulation of gut anaerobiosis and aerobiosis by oxygen availability, which is closely related to epithelial metabolism. Additionally, antibiotic interventions enable to identify novel roles of gut microbiota in gut-liver axis and gut-brain axis. Indigenous antimicrobial molecules are produced by certain microbes, and they have the potential to affect function through eliciting changes in the gut microbiota. This review discusses at length these findings to gain a better and novel insight into microbiota-host interactions and the mechanisms involved.

Antibiotic Exposure Disturbs the Gut Microbiota and Its Metabolic Phenotype Differently in Rats with Advanced-Stage Type 1 Diabetes and Age-Matched Controls

Antibiotic-induced microbial perturbations alter host metabolism and affect host physiology. In this study, we aimed to investigate the effects of vancomycin (Vanc) and ciprofloxacin/metronidazole (CiMe) exposures on the gut microbiome and metabolome in the colonic content and tissue samples from advanced-stage type 1 diabetic (AST1D) rats and age-matched controls (AMCs) using 16S ribosomal RNA gene sequencing and nuclear magnetic resonance-based metabolomics. The results show that antibiotic effects on the gut microbiota were stronger in AMC rats relative to AST1D rats. These microbial alterations were accompanied by a series of metabolic changes, including energy metabolism, short-chain fatty acid metabolism, and amino acid metabolism. We found that AMC rats had a more notable metabolic response to antibiotic exposure than AST1D rats. Additionally, Vanc had a stronger impact on the gut microbiota and host metabolic phenotype versus CiMe. Therefore, our results reveal that antibiotic-induced shifts in the gut microbiome and metabolome are different between AST1D and AMC rats. If confirmed in human studies, these findings suggest that diabetic patients may need a specific strategy for antibiotic use in clinical practice.

Is there an association between Helicobacter pylori infection and irritable bowel syndrome? A meta-analysis

BACKGROUND

Irritable bowel syndrome (IBS) is a prevalent and debilitating gastrointestinal condition. Research has reported persistent, low-grade mucosal inflammation and significant overlaps between patients with IBS and those with dyspepsia, suggesting a possible pathogenic role of Helicobacter pylori (H. pylori) in IBS. This study therefore aimed to provide the first systematic review and meta-analysis on the association between H. pylori infection and IBS.

AIM

To investigate the association between H. pylori infection and IBS.

METHODS

Using the keywords "H. pylori OR Helicobacter OR Helicobacter pylori OR infection" AND "irritable bowel syndrome OR IBS", a preliminary search of PubMed, Medline, Embase, Cochrane Database of Systematic Reviews, Web of Science, Google Scholar and WanFang databases yielded 2924 papers published in English between 1 January 1960 and 1 June 2018. Attempts were also made to search grey literature.

RESULTS

A total of 13 clinical studies were systematically reviewed and nine studies were included in the final meta-analysis. Random-effects meta-analysis found a slight increased likelihood of H. pylori infection in patients with IBS, albeit this was not statistically significant (pooled odds ratio 1.47, 95% confidence interval: 0.90-2.40, P = 0.123). It must also be acknowledged that all of the available studies reported only crude odd ratios. H. pylori eradication therapy also does not appear to improve IBS symptoms. Although publication bias was not observed in the funnel plot, there was a high degree of heterogeneity amongst the studies included in the meta-analysis (I 2 = 87.38%).

CONCLUSION

Overall, current evidence does not support an association between IBS and H. pylori infection. Further rigorous and detailed studies with larger sample sizes and after H. pylori eradication therapy are warranted.

Hydrogen-Rich Saline Regulates Intestinal Barrier Dysfunction, Dysbiosis, and Bacterial Translocation in a Murine Model of Sepsis

Bacterial translocation is a major cause of multiple organ dysfunction syndrome in critical illness, and its management is an important therapeutic strategy. In this study, we focused on the key factors responsible for bacterial translocation including the intestinal microbiome and investigated the impact of molecular hydrogen therapy as a countermeasure against bacterial translocation in a murine model of sepsis. The experimental protocols were divided into the sham, saline treatment (control), and hydrogen treatment (H2) groups. In the H2 group, 15 mL/kg of hydrogen-rich saline (7 ppm) was gavaged daily for 7 days following cecal ligation and puncture (CLP). In the control group, normal saline was gavaged in the same way. In the results, the 7-day survival rate was significantly improved in the H2 group versus the control group (69% vs. 31%, P < 0.05). The incidence of bacterial translocation at 24 h after CLP as assessed by cultivation of mesenteric lymph nodes and blood was significantly decreased in the H2 group versus the control group. Administration of hydrogen-rich saline also prevented the expansion of facultative anaerobic Enterobacteriaceae and ameliorated intestinal hyperpermeability at 24 h after CLP. Intestinal tissue levels of inflammatory mediators such as inducible nitric oxide synthases, tumor necrosis factor α, interleukin (IL)-1β, IL-6, and oxidative stress marker malondialdehyde at 6 h after CLP were down-regulated in the H2 group. These results suggest luminal administration of hydrogen-rich saline, which prevents intestinal dysbiosis, hyperpermeability, and bacterial translocation, could potentially be a new therapeutic strategy in critical illness.

Measuring antibiotic levels and their relationship with the microbiome in chronic rhinosinusitis

Background

The evidence supporting the efficacy of antibiotic therapy in the treatment of chronic rhinosinusitis is not compelling. A limited number of studies show that the changes in the nasal microbiome in patients following drug therapy are unpredictable and variable. The evidence for the impact of oral antibiotics on the gut microbiota is stronger, possibly as a result of differences in drug distribution to various sites around the body. There are few studies on sinus mucosal and mucus levels of oral antibiotics used in the treatment of chronic rhinosinusitis. The distribution dependent effects of antibiotics on the sinonasal microbiome is unclear.

Conclusion

This review highlights that relative drug concentrations and their efficacy on microbiota at different sites is an important subject for future studies investigating chronic rhinosinusitis.

Monocyte mobilisation, microbiota & mental illness

The gastrointestinal microbiome has emerged as a key player in regulating brain and behaviour. This has led to the strategy of targeting the gut microbiota to ameliorate disorders of the central nervous system. Understanding the underlying signalling pathways in which the microbiota impacts these disorders is crucial for the development of future therapeutics for improving CNS functionality. One of the major pathways through which the microbiota influences the brain is the immune system, where there is an increasing appreciation for the role of monocyte trafficking in regulating brain homeostasis. In this review, we will shed light on the role of monocyte trafficking as a relay of microbiota signals in conditions where the central nervous system is in disorder, such as stress, peripheral inflammation, ageing, traumatic brain injury, stroke, multiple sclerosis, Alzheimer's disease and Parkinson's disease. We also cover how the gastrointestinal microbiota is implicated in these mental illnesses. In addition, we aim to discuss how the monocyte system can be modulated by the gut microbiota to mitigate disorders of the central nervous system, which will lead to novel microbiota-targeted strategies.

Gut Microbiota and Microbiota-Related Metabolites as Possible Biomarkers of Cognitive Aging

Gut microbiota composition and functionality can influence the pathophysiology of age-related cognitive impairment and dementia, according to a large number of animal studies. The translation of this concept to humans is still uncertain, due to the relatively low number of clinical studies focused on fecal microbiota and large number of environmental factors that influence the microbiota composition. However, the fecal microbiota composition of older patients with dementia is deeply different from that of healthy active controls, conditioning a different metabolic profile. The possible use of fecal microbiota-related parameters and microbiota-derived metabolites as biomarkers of cognitive performance and dementia is critically reviewed in this paper, focusing on the most promising areas of research for the future.

Loss of microbial diversity and pathogen domination of the gut microbiota in critically ill patients

Among long-stay critically ill patients in the adult intensive care unit (ICU), there are often marked changes in the complexity of the gut microbiota. However, it remains unclear whether such patients might benefit from enhanced surveillance or from interventions targeting the gut microbiota or the pathogens therein. We therefore undertook a prospective observational study of 24 ICU patients, in which serial faecal samples were subjected to shotgun metagenomic sequencing, phylogenetic profiling and microbial genome analyses. Two-thirds of the patients experienced a marked drop in gut microbial diversity (to an inverse Simpson’s index of <4) at some stage during their stay in the ICU, often accompanied by the absence or loss of potentially beneficial bacteria. Intravenous administration of the broad-spectrum antimicrobial agent meropenem was significantly associated with loss of gut microbial diversity, but the administration of other antibiotics, including piperacillin/tazobactam, failed to trigger statistically detectable changes in microbial diversity. In three-quarters of ICU patients, we documented episodes of gut domination by pathogenic strains, with evidence of cryptic nosocomial transmission of Enterococcus faecium. In some patients, we also saw an increase in the relative abundance of apparent commensal organisms in the gut microbiome, including the archaeal species Methanobrevibacter smithii. In conclusion, we have documented a dramatic absence of microbial diversity and pathogen domination of the gut microbiota in a high proportion of critically ill patients using shotgun metagenomics.

Effects of anti-H. pylori triple therapy and a probiotic complex on intestinal microbiota in duodenal ulcer

This study aimed to investigate the intestinal microbiota in duodenal ulcer (DU) patients, effects of proton pump inhibitors,clarithromycin and amoxicillin, PCA) for Helicobacter pylori (H. pylori) and Bacillus subtilis and Enterococcus faecium (BSEF) on intestinal microbiota. DU patients were randomly assigned to receive either PCA (group TT) or PCA plus BSEF(group TP). The fecal microbiome was conducted using high throughput 16S rDNA gene and internal transcribed spacer sequencings. The diversity and abundance of intestinal bacteria in the DU were significantly lower than health check control (HC) group. In the TT group, the abundance and diversity of both intestinal bacteria and fungi decreased after PCA treatment, compared with those before treatment, whereas in the TP group no obvious changes were observed. In the TT group at all the time points, both the intestinal bacteria and fungi were different from those in the HC group. However, in the TP group, at 10w the bacterial flora abundance was close to that in the HC group. The results indicate that anti- H. pylori treatment induced significant decrease in the diversity of intestinal microbiota, while the combined therapy supplemented with BSEF could protect and restore the intestinal microbiota.

Antibiotic-induced microbiome depletion protects against MPTP-induced dopaminergic neurotoxicity in the brain

Although the brain-gut axis appears to play a role in the pathogenesis of Parkinson's disease, the precise mechanisms underlying the actions of gut microbiota in this disease are unknown. This study was undertaken to investigate whether antibiotic-induced microbiome depletion affects dopaminergic neurotoxicity in the mouse brain after administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP significantly decreased dopamine transporter (DAT) immunoreactivity in the striatum and tyrosine hydroxylase (TH) immunoreactivity in the substantia nigra of water-treated mice. However, MPTP did not decrease DAT or TH immunoreactivity in the brains of mice treated with an antibiotic cocktail. Furthermore, antibiotic treatment significantly decreased the diversity and altered the composition of the host gut microbiota at the genus and species levels. Interestingly, MPTP also altered microbiome composition in antibiotic-treated mice. These findings suggest that antibiotic-induced microbiome depletion might protect against MPTP-induced dopaminergic neurotoxicity in the brain via the brain-gut axis.

The Potential Role of Gut Mycobiome in Irritable Bowel Syndrome

The human gut is inhabited by diverse microorganisms that play crucial roles in health and disease. Gut microbiota dysbiosis is increasingly considered as a vital factor in the etiopathogenesis of irritable bowel syndrome (IBS), which is a common functional gastrointestinal disorder with a high incidence all over the world. However, investigations to date are primarily directed to the bacterial community, and the gut mycobiome, another fundamental part of gut ecosystem, has been underestimated. Intestinal fungi have important effects on maintaining gut homeostasis just as bacterial species. In the present article, we reviewed the potential roles of gut mycobiome in the pathogenesis of IBS and the connections between the fungi and existing mechanisms such as chronic low-grade inflammation, visceral hypersensitivity, and brain-gut interactions. Moreover, possible strategies targeted at the gut mycobiome for managing IBS were also described. This review provides a basis for considering the role of the mycobiome in IBS and offers novel treatment strategies for IBS patients; moreover, it adds new dimensions to researches on microorganism.

Pancreas–Microbiota Cross Talk in Health and Disease

The pancreas controls metabolism through endocrine and exocrine functions. Pancreatic diseases comprise a spectrum of mild to life-threatening conditions, including acute and chronic pancreatitis, diabetes, and pancreatic cancer, which affect endocrine and exocrine pancreatic function and impose a substantial disease burden on individuals. Increasing experimental evidence demonstrates that the intestinal microbiota has an important impact on pancreatic function and diseases. This influence may be conferred by bacterial metabolites, such as short-chain fatty acids, or the modulation of immune responses. In turn, pancreatic factors, such as the excretion of antimicrobials, might have a substantial impact on the composition and functional properties of the gut microbiota. Here, we summarize experimental and clinical approaches used to untie the intricate pancreas–microbiota cross talk. Future advances will allow clinicians to manipulate the intestinal microbiota and guide patient management in pancreatic diseases.

Antibiotic use and the risk of rheumatoid arthritis: a population-based case-control study

BACKGROUND

Antibiotic-induced disturbances of the human microbiota have been implicated in the development of chronic autoimmune conditions. This study aimed to assess whether antibiotic use is associated with the onset of rheumatoid arthritis (RA).

METHODS

A nested case-control study was conducted utilising data from the primary care Clinical Practice Research Datalink (CPRD). Patients with an incident diagnosis of RA were identified (1995-2017). Each case was matched on age, gender, and general practice to ≥ 5 controls without RA. Conditional logistic regression was used to examine previous antibiotic prescriptions and RA onset after controlling for confounding factors.

RESULTS

We identified 22,677 cases of RA, matched to 90,013 controls, with a median follow-up of 10 years before RA diagnosis. The odds of developing RA were 60% higher in those exposed to antibiotics than in those not exposed (OR 1.60; 95% CI 1.51-1.68). A dose- or frequency-dependent association was observed between the number of previous antibiotic prescriptions and RA. All classes of antibiotics were associated with higher odds of RA, with bactericidal antibiotics carrying higher risk than bacteriostatic (45% vs. 31%). Those with antibiotic-treated upper respiratory tract (URT) infections were more likely to be RA cases. However, this was not observed for URT infections not treated with antibiotics. Antifungal (OR = 1.27; 95% CI 1.20-1.35) and antiviral (OR = 1.19; 95% CI 1.14-1.24) prescriptions were also associated with increased odds of RA.

CONCLUSION

Antibiotic prescriptions are associated with a higher risk of RA. This may be due to microbiota disturbances or underlying infections driving risk. Further research is needed to explore these mechanisms.

A Novel Use of Model for End-Stage Liver Disease (MELD) Score in Guiding Therapeutic Antibiotics Choice for Critically Ill Cirrhotic Patients

BACKGROUND Inappropriate use of antibiotics results in antimicrobial resistance and dysbacteriosis. Among critically ill cirrhotic patients, consensus regarding the most optimal prescription strategy for antibiotics use has not been achieved. For these patients, the score for end-stage liver disease (MELD) demonstrated its value in predicting prognosis of cirrhosis. This study investigated use of the MELD score to guide antibiotics choice. MATERIAL AND METHODS We enrolled 1250 patients with cirrhosis. We collected patient information, including antibiotics administration. Linear regression analyses were performed to determine independent predictors of antibiotic administration. Survival curves were constructed based on Cox regression models. Cox proportional hazard models were used to calculate the hazard ratio, shown by forest plots. RESULTS The population was equally stratified into 4 groups based on the MELD score (Q1: MELD <10; Q2: 10≤ MELD <17; Q3: 17≤ MELD <26; Q4: 26≤ MELD). In Q1, all the HR (hazard ratio) related to the duration of antibiotics use demonstrated no statistical significance. In Q2, the HR related to the duration of antibiotics use revealed a successive decrease. In Q3, the HR showed statistical significance only with a duration of antibiotics use of 7 days or more. In Q4, all the HR were statistically significant. As for categories of antibiotics use, whatever the MELD score was, the HR continued to increase with ascending categories. CONCLUSIONS For low MELD score patients (MELD <17), changing the duration of antibiotics use was not associated with a better prognosis. For high MELD score patients (MELD ≥17), longer duration of antibiotics use was associated with a reduction in mortality. Whatever the MELD score was, an increase of number of antibiotic categories was positively associat ed with poor prognosis.

The standardized herbal combination BNO 2103 contained in Canephron® N alleviates inflammatory pain in experimental cystitis and prostatitis

BACKGROUND

Urinary tract infections are among the most common types of infections and give rise to inflammation with pain as one of the main symptoms. The herbal medicinal product Canephron^® N contains BNO 2103, a defined mixture of pulverized rosemary leaves, centaury herb, and lovage root, and has been used in the treatment of urinary tract infections for more than 25 years.

PURPOSE

To test the hypothesis that BNO 2103 reduces pain in cystitis and prostatitis by virtue of anti-inflammatory properties, and to reveal potential mechanisms underlying the anti-inflammatory features.

STUDY DESIGN

BNO 2103 was studied for anti-inflammatory and analgesic properties in three animal models in vivo, and the mode of action underlying the anti-inflammatory features was investigated in human leukocytes and cell-free assays in vitro.

METHODS

To assess the anti-inflammatory and analgesic efficacy of BNO 2103 we employed cyclophosphamide-induced cystitis and carrageenan-induced prostatitis in rats, and zymosan-induced peritonitis in mice. Human neutrophils and monocytes as well as isolated human 5-lipoxygenase and microsomal prostaglandin E₂ synthase-1-containing microsomes were utilized to assess inhibition of leukotriene and/or prostaglandin E₂ production by HPLC and/or ELISA.

RESULTS

When given orally, BNO 2103 reduced inflammation and hyperalgesia in experimental cystitis in rats, while individual components of BNO 2103 also reduced hyperalgesia. Furthermore, BNO 2103 reduced hyperalgesia in rats with carrageenan-induced prostatitis. Cell-based and cell-free studies implicate inhibition of prostaglandin E₂ and leukotriene B₄ biosynthesis as potential mechanisms underlying the analgesic and anti-inflammatory effects.

CONCLUSION

Our data support the hypothesis that BNO 2103 reduces pain by virtue of its anti-inflammatory properties, possibly related to suppression of prostaglandin E₂ and leukotriene B₄ formation, and suggest that this combination has the potential to treat clinical symptoms such as inflammatory pain. Thus BNO 2103 may represent an alternative to reduce the use of antibiotics in urinary tract infections.

Antibiotic Pollution in the Environment: From Microbial Ecology to Public Policy

The ability to fight bacterial infections with antibiotics has been a longstanding cornerstone of modern medicine. However, wide-spread overuse and misuse of antibiotics has led to unintended consequences, which in turn require large-scale changes of policy for mitigation. In this review, we address two broad classes of corollaries of antibiotics overuse and misuse. Firstly, we discuss the spread of antibiotic resistance from hotspots of resistance evolution to the environment, with special concerns given to potential vectors of resistance transmission. Secondly, we outline the effects of antibiotic pollution independent of resistance evolution on natural microbial populations, as well as invertebrates and vertebrates. We close with an overview of current regional policies tasked with curbing the effects of antibiotics pollution and outline areas in which such policies are still under development.

Antibiotic Exposure Has Sex-Dependent Effects on the Gut Microbiota and Metabolism of Short-Chain Fatty Acids and Amino Acids in Mice

Accumulating evidence shows that the gut microbiota regulates host metabolism by producing a series of metabolites, such as amino acids, bile acids, fatty acids, and others. These metabolites have a positive or negative effect on host health. Antibiotic exposure can disrupt the gut microbiota and thereby affect host metabolism and physiology. However, there are a limited number of studies addressing whether antibiotic effects on the gut microbiota and host metabolism are sex dependent. In this study, we uncovered a sex-dependent difference in antibiotic effects on the gut microbiota and metabolome in colonic contents and tissues in mice. These findings reveal that sex-dependent effects need to be considered for antibiotic use in scientific research or clinical practice. Moreover, this study will also give an important direction for future use of antibiotics to modify the gut microbiome and host metabolism in a sex-specific manner.

The gut microbiota has the capability to regulate homeostasis of the host metabolism. Since antibiotic exposure can adversely affect the microbiome, we hypothesized that antibiotic effects on the gut microbiota and host metabolism are sex dependent. In this study, we examined the effects of antibiotic treatments, including vancomycin (Vanc) and ciprofloxacin-metronidazole (CiMe), on the gut microbiome and metabolome in colonic contents and tissues in both male and female mice. We found that the relative abundances and structural composition of Firmicutes were significantly reduced in female mice after both Vanc and CiMe treatments but in male mice only after treatment with Vanc. However, Vanc exposure considerably altered the relative abundances and structural composition of representatives of the Proteobacteria especially in male mice. The levels of short-chain fatty acids (SCFAs; acetate, butyrate, and propionate) in colonic contents and tissues were significantly decreased in female mice after both antibiotic treatments, while these reductions were detected in male mice only after Vanc treatment. However, another SCFA, formate, exhibited the opposite tendency in colonic tissues. Both antibiotic exposures significantly decreased the levels of alanine, branched-chain amino acids (BCAAs; leucine, isoleucine, and valine) and aromatic amino acids (AAAs; phenylalanine and tyrosine) in colonic contents of female mice but not in male mice. Additionally, female mice had much greater correlations between microbe and metabolite than male mice. These findings suggest that sex-dependent effects should be considered for antibiotic-induced modifications of the gut microbiota and host metabolism.

IMPORTANCE Accumulating evidence shows that the gut microbiota regulates host metabolism by producing a series of metabolites, such as amino acids, bile acids, fatty acids, and others. These metabolites have a positive or negative effect on host health. Antibiotic exposure can disrupt the gut microbiota and thereby affect host metabolism and physiology. However, there are a limited number of studies addressing whether antibiotic effects on the gut microbiota and host metabolism are sex dependent. In this study, we uncovered a sex-dependent difference in antibiotic effects on the gut microbiota and metabolome in colonic contents and tissues in mice. These findings reveal that sex-dependent effects need to be considered for antibiotic use in scientific research or clinical practice. Moreover, this study will also give an important direction for future use of antibiotics to modify the gut microbiome and host metabolism in a sex-specific manner.

In Vitro and In Vivo Activities of Zinc Linolenate, a Selective Antibacterial Agent against Helicobacter pylori

Helicobacter pylori is a major global pathogen, and its infection represents a key factor in the etiology of various gastric diseases, including gastritis, peptic ulcers, and gastric carcinoma. The efficacy of current standard treatment for H. pylori infection including two broad-spectrum antibiotics is compromised by toxicity toward the gut microbiota and the development of drug resistance, which will likely only be resolved through novel and selective antibacterial strategies. Here, we synthesized a small molecule, zinc linolenate (ZnLla), and investigated its therapeutic potential for the treatment of H. pylori infection. ZnLla showed effective antibacterial activity against standard strains and drug-resistant clinical isolates of H. pyloriin vitro with no development of resistance during continuous serial passaging. The mechanisms of ZnLla action against H. pylori involved the disruption of bacterial cell membranes and generation of reactive oxygen species. In mouse models of multidrug-resistant H. pylori infection, ZnLla showed in vivo killing efficacy comparable and superior to the triple therapy approach when use as a monotherapy and a combined therapy with omeprazole, respectively. Moreover, ZnLla treatment induces negligible toxicity against normal tissues and causes minimal effects on both the diversity and composition of the murine gut microbiota. Thus, the high degree of selectivity of ZnLla for H. pylori provides an attractive candidate for novel targeted anti-H. pylori treatment.

Are Probiotics Effective in Targeting Alcoholic Liver Diseases?

Alcoholic liver disease (ALD) encompasses a broad spectrum of disorders including steatosis, steatohepatitis, fibrosis, and cirrhosis. Despite intensive research in the last two decades, there is currently no Food and Drug Administration-approved therapy for treating ALD. Several studies have demonstrated the importance of the gut-liver axis and gut microbiome on the pathogenesis of ALD. Alcohol may induce intestinal dysbiosis and increased intestinal permeability, which in turn result in increased levels of pathogen-associated molecular patterns such as lipopolysaccharide (LPS) and translocation of microbial products from the gut to the liver (bacterial translocation). LPS is an inflammatory signal that activates toll-like receptor 4 on Kupffer cells, contributing to the inflammation observed in ALD. Recently, probiotics have been shown to be effective in reducing or preventing the progression of ALD. A potential mechanism is that the probiotics transforms the composition of intestinal microbiota, which leads to reductions in alcohol-induced dysbiosis, intestinal permeability, bacterial translocation, endotoxemia, and consequently, the development of ALD. While transformation of intestinal microbiota by probiotics appears to be a promising therapeutic strategy for the treatment of intestinal barrier dysfunction, there is a scarcity of research that studies probiotics in the context of ALD. In this review, we discuss the potential therapeutic applications of probiotics in the treatment of ALD.

Antibiotics, gut microbiota, and Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease whose various pathophysiological aspects are still being investigated. Recently, it has been hypothesized that AD may be associated with a dysbiosis of microbes in the intestine. In fact, the intestinal flora is able to influence the activity of the brain and cause its dysfunctions.Given the growing interest in this topic, the purpose of this review is to analyze the role of antibiotics in relation to the gut microbiota and AD. In the first part of the review, we briefly review the role of gut microbiota in the brain and the various theories supporting the hypothesis that dysbiosis can be associated with AD pathophysiology. In the second part, we analyze the possible role of antibiotics in these events. Antibiotics are normally used to remove or prevent bacterial colonization in the human body, without targeting specific types of bacteria. As a result, broad-spectrum antibiotics can greatly affect the composition of the gut microbiota, reduce its biodiversity, and delay colonization for a long period after administration. Thus, the action of antibiotics in AD could be wide and even opposite, depending on the type of antibiotic and on the specific role of the microbiome in AD pathogenesis.Alteration of the gut microbiota can induce changes in brain activity, which raise the possibility of therapeutic manipulation of the microbiome in AD and other neurological disorders. This field of research is currently undergoing great development, but therapeutic applications are still far away. Whether a therapeutic manipulation of gut microbiota in AD could be achieved using antibiotics is still not known. The future of antibiotics in AD depends on the research progresses in the role of gut bacteria. We must first understand how and when gut bacteria act to promote AD. Once the role of gut microbiota in AD is well established, one can think to induce modifications of the gut microbiota with the use of pre-, pro-, or antibiotics to produce therapeutic effects.

Fungal-Bacterial Interactions in Health and Disease

Fungi and bacteria encounter each other in various niches of the human body. There, they interact directly with one another or indirectly via the host response. In both cases, interactions can affect host health and disease. In the present review, we summarized current knowledge on fungal-bacterial interactions during their commensal and pathogenic lifestyle. We focus on distinct mucosal niches: the oral cavity, lung, gut, and vagina. In addition, we describe interactions during bloodstream and wound infections and the possible consequences for the human host.

The effects of short-chain fatty acids on the transcription and secretion of apolipoprotein A-I in human hepatocytes in vitro

BACKGROUND

Apolipoprotein-I (ApoA-I), the major component of high-density lipoprotein (HDL) particles, mediates cholesterol efflux by which it facilitates the removal of excess cholesterol from peripheral tissues. Therefore, elevating ApoA-I production leading to the production of new pre-β-HDL particles is thought to be beneficial in the prevention of cardiovascular diseases. Recently, we observed that amoxicillin treatment led to decreased HDL concentrations in healthy human volunteers. We questioned whether this antibiotic effect was directly or indirectly, via changed short-chain fatty acids (SCFA) concentrations through an altered gut microflora. Therefore, we here evaluated the effects of amoxicillin and various SCFA on hepatic ApoA-I expression, secretion, and the putative underlying pathways.

METHODS AND RESULTS

Human hepatocytes (HepG2) were exposed to increasing dose of amoxicillin or SCFA for 48  hours. ApoA-I messenger RNA (mRNA) transcription and secreted protein were analyzed using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. To study underlying mechanisms, changes in mRNA expression of KEAP1, CPT1, and PPARα, as well as a PPARα transactivation assay, were analyzed. Amoxicillin dose-dependently decreased ApoA-I mRNA transcription as well as ApoA-I protein secretion. SCFA treatment resulted in a dose-dependent stimulation of ApoA-I mRNA transcription, however, the ApoA-I protein secretion was decreased. Furthermore, SCFA treatment increased PPARα transactivation, PPARα and CPT1 mRNA transcription, whereas KEAP1 mRNA transcription was decreased.

CONCLUSION

Direct treatment of HepG2 cells with amoxicillin has either direct effects on lowering ApoA-I transcription and secretion or indirect effects via modified SCFA concentrations because SCFA were found to stimulate hepatic ApoA-I expression. Furthermore, BET inhibition and PPARα activation were identified as possible mechanisms behind the observed effects on ApoA-I transcription.

Overuse of antianaerobic drug is associated with poor postchemotherapy prognosis of patients with hepatocellular carcinoma

Overuse of antibiotic drugs alters the composition of gut microbiota and has detrimental effects on the host. In our study, we investigated association of gut flora and antibiotics in the prognosis of patients with liver cancer who have undergone chemotherapy by analyzing two independent clinical studies. We retrospectively subanalyzed a previously reported randomized controlled trial (RCT) on hepatic arterial infusion chemotherapy in patients with hepatocellular carcinoma (HCC) to investigate the association between use of antibiotics and prognosis. In the other study, we prospectively determined the abundance of specific bacterial genus in patients with HCC by sequencing 16S ribosomal RNA and assessed its association with survival. Subanalysis of the RCT data showed that, of 26 types of antibiotics used, administration of carbapenem before or during chemotherapy was associated with poor progression‐free survival (PFS) and overall survival (OS) of patients with HCC (carbapenem + vs. −; median PFS, 78 days vs. 154 days, p = 0.0053; median OS, 177 days vs. 475 days, p = 0.0003). Multivariate analysis revealed that antianaerobic drug use is an independent predictor of poor prognosis. In the prospective study, the abundance of Blautia in fecal microbiota correlated positively with both PFS and OS of patients with HCC who underwent chemotherapy. Use of antibiotics targeting anaerobes is associated with a poor prognosis in patients with HCC who have undergone chemotherapy, whereas the intestinal anaerobic bacteria, Blautia is associated with a good prognosis. These findings might indicate the need for caution regarding overuse of broad‐spectrum antibiotics targeting anaerobes in patients with HCC.

What's new?

Overuse of antibiotic drugs alters the composition of gut microbiota and can have detrimental effects on the host. However, it remains unclear whether antibiotics impair the anti‐cancer effects of cytotoxic drugs in cancer patients. Using data from two independent clinical studies, here the authors reveal that use of antibiotics targeting anaerobes is associated with a poor prognosis in patients with hepatocellular carcinoma (HCC) who have undergone chemotherapy, whereas the intestinal anaerobic bacteria, Blautia is associated with a good prognosis. These findings might indicate the need for caution regarding overuse of broad‐spectrum antibiotics targeting anaerobes in patients with HCC.

The impact of early-life sub-therapeutic antibiotic treatment (STAT) on excessive weight is robust despite transfer of intestinal microbes

The high-fat, high-calorie diets of westernized cultures contribute to the global obesity epidemic, and early life exposure to antibiotics may potentiate those dietary effects. Previous experiments with mice had shown that sub-therapeutic antibiotic treatment (STAT)-even restricted to early life-affected the gut microbiota, altered host metabolism, and increased adiposity throughout the lifetime of the animals. Here we carried out a large-scale cohousing experiment to investigate whether cohousing STAT and untreated (Control) mice would transfer the STAT-perturbed microbiota and transmit its impact on weight. We exposed pregnant dams and their young offspring to either low-dose penicillin (STAT) or water (Control) until weaning, and then followed the offspring as they grew and endured a switch from normal to high-fat diet at week 17 of life. Cohousing, which started at week 4, rapidly approximated the microbiota within cages, lowering the weight of STAT mice relative to non-cohoused mice. The effect, however, varied between cages, and was restricted to the first 16 weeks when diet consisted of normal chow. Once mice switched to high-fat diet, the microbiota α- and β-diversity expanded and the effect of cohousing faded: STAT mice, again, were heavier than control mice independently of cohousing. Metabolomics revealed serum metabolites associated with STAT exposure, but no significant differences were detected in glucose or insulin tolerance. Our results show that cohousing can partly ameliorate the impact of STAT on the gut microbiota but not prevent increased weight with high-fat diet. These observations have implications for microbiota therapies aimed to resolve the collateral damage of antibiotics and their load on human obesity.

Efficacy and Long-Term Safety of H. pylori Eradication for Gastric Cancer Prevention

Helicobacter pylori (H. pylori) has been shown to be a causal factor of gastric cancer in cohort studies and animal models. Meta-analysis of case-control studies nested within prospective cohorts showed that H. pylori infection was associated with a 5.9-fold increased risk of non-cardia gastric cancer. Prospective cohort studies showed that gastric cancer developed in 1–4% of H. pylori-infected subjects. Gastric cancer was successfully induced in Mongolian gerbils and insulin-gastrin (INS-GAS) transgenic mice after inoculation of H. pylori. Meta-analysis of randomized control trials also showed that eradication of H. pylori may reduce the risk of gastric cancer. However, there are several concerns regarding the widespread use of antibiotics to prevent gastric cancer, including the emergence of antibiotic resistance and the perturbation of gut microbiota after H. pylori eradication. Recent studies showed that eradication of H. pylori resulted in an increase in the bacterial diversity and restoration of the relative abundance of other bacteria to levels similar to H. pylori non-infected subjects in the gastric microbiota. The administration of antibiotics may also alter the composition of intestinal microbiota. The α-diversity and β-diversity of fecal microbiota are significantly altered immediately after H. pylori eradication but are gradually restored to levels similar to those before therapy. Yet, the rate of recovery varies with regimens. The diversity was restored at week 8 after triple therapy but was not yet fully recovered at 1 year after concomitant and quadruple therapies. Some studies showed that supplementation of probiotics may reduce the dysbiosis during H. pylori eradication therapy. Although some earlier studies showed high levels of macrolide resistance after triple therapy, recent studies showed that the increased antibiotic resistance rate may be restored 2–12 months after eradication therapy. These results collectively provide evidence of the long-term safety of H. pylori eradication. Yet, more prospective cohort studies and randomized trials are warranted to assess the efficacy and long-term safety of H. pylori eradication for gastric cancer prevention.

Efficacy and safety of probiotics in eradicating Helicobacter pylori: A network meta-analysis

BACKGROUND

Due to decreasing eradication rate and increasing side effects, probiotics have gradually become an important supplement to standard eradication regimens for Helicobacter pylori.

OBJECTIVE

To evaluate the effectiveness and safety of probiotics in facilitating the eradication of H pylori and to explore the best timing and duration of probiotic supplementation, use of eradication regimens, strains, locations, and common side effects.

METHODS

Eligible studies were retrieved from the PubMed, EMBASE, Cochrane Library, Web of Science, and CNKI databases, and we applied the Stata 12.0 software for the standard meta-analysis and network meta-analysis.

RESULTS

Forty eligible studies with 8924 patients were included in the analysis. We used a random-effects model (I = 52.1% and I = 81.4%) to analyze the eradication rate and the incidence of total side effects by intention to treat (ITT). Compared with the control group, a higher eradication rate (relative risk [RR] 1.140, 95% confidence interval (CI) 1.101-1.180, P < .001) and lower incidence of total side effects (RR 0.470, 95% CI 0.391-0.565, P < .001) were observed in the probiotic group. In the subgroup analysis, we evaluated the surface under the cumulative ranking curve scores for the before + same (75.2%), >2 weeks (92.6%), probiotic + quadruple regimen (99.9%), Lactobacillus (73.6%), multiple strains (72.1%), China (98.5%) groups. The rankings of common side effects are shown in Table 6. SUCRA scores for diarrhea (39.7%), abdominal pain (43.9%), nausea (78.8%), taste disturbance (99.6%), vomiting (7.1%), and constipation (30.9%) were reported. The consistency of all comparison groups was good.

CONCLUSIONS

Probiotics improved the eradication rate and reduced side effects when added to the treatments designed to eradicate H pylori. The use of probiotics before the eradication treatment and throughout the eradication treatment, and also the use of probiotics for more than 2 weeks, exerted better eradication effects. Probiotics combined with the bismuth quadruple regimen was the best combination. Lactobacillus and multiple strains were better choices of probiotic strains. The eradication effect observed in China was better than the effect observed in other countries.

Molecular mechanisms of Vibrio parahaemolyticus pathogenesis

Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is mainly distributed in the seafood such as fish, shrimps and shellfish throughout the world. V. parahaemolyticus can cause diseases in marine aquaculture, leading to huge economic losses to the aquaculture industry. More importantly, it is also the leading cause of seafood-borne diarrheal disease in humans worldwide. With the development of animal model, next-generation sequencing as well as biochemical and cell biological technologies, deeper understanding of the virulence factors and pathogenic mechanisms of V. parahaemolyticus has been gained. As a globally transmitted pathogen, the pathogenicity of V. parahaemolyticus is closely related to a variety of virulence factors. This article comprehensively reviewed the molecular mechanisms of eight types of virulence factors: hemolysin, type III secretion system, type VI secretion system, adhesion factor, iron uptake system, lipopolysaccharide, protease and outer membrane proteins. This review comprehensively summarized our current understanding of the virulence factors in V. parahaemolyticus, which are potentially new targets for the development of therapeutic and preventive strategies.

Loading ceftriaxone, vancomycin, and Bifidobacteria bifidum TMC3115 to neonatal mice could differently and consequently affect intestinal microbiota and immunity in adulthood

Recent studies have demonstrated that antibiotics/or probiotics administration in early life play key roles on modulating intestinal microbiota and the alterations might cause long-lasting consequences both physiologically and immunologically. We investigated the effects of early life ceftriaxone, vancomycin and Bifidobacterium bifidum TMC3115 (TMC3115) treatment on intestinal microbiota and immunity both in neonates and adults even after termination of antibiotics exposure. We found that ceftriaxone and vancomycin, but not TMC3115, significantly altered the intestinal microbiota, serum total IgE level, and the morphology and function of the intestinal epithelium in the neonatal mice. In the adult stages, the diversity and composition of the intestinal microbiota were significantly different in the antibiotic-treated mice, and ceftriaxone-treated mice exhibited significantly higher serum total IgE and OVA-specific IgE levels. TMC3115 significantly mitigated the alteration of intestinal microbiota caused by ceftriaxone not vancomycin. Antibiotics and TMC3115 can differently modulate intestinal microbiota and SCFAs metabolism, affecting the development and function of the immunity and intestinal epithelium to different degrees in neonatal mice. Neonatal ceftriaxone-induced abnormal intestinal microbiota, immunity and epithelium could last to adulthood partly, which might be associated with the enhancement of host susceptibility to IgE-mediated allergies and related immune responses, TMC3115 may protect against the side effects of antibiotic treatment, at least partly.

Gut microbiome patterns correlate with higher postoperative complication rates after pancreatic surgery

Background

Postoperative complications are of great relevance in daily clinical practice, and the gut microbiome might play an important role by preventing pathogens from crossing the intestinal barrier. The two aims of this prospective clinical pilot study were: (1) to examine changes in the gut microbiome following pancreatic surgery, and (2) to correlate these changes with the postoperative course of the patient.

Results

In total, 116 stool samples of 32 patients undergoing pancreatic surgery were analysed by 16S-rRNA gene next-generation sequencing. One sample per patient was collected preoperatively in order to determine the baseline gut microbiome without exposure to surgical stress and/or antibiotic use. At least two further samples were obtained within the first 10 days following the surgical procedure to observe longitudinal changes in the gut microbiome. Whenever complications occurred, further samples were examined.

Based on the structure of the gut microbiome, the samples could be allocated into three different microbial communities (A, B and C). Community B showed an increase in Akkermansia, Enterobacteriaceae and Bacteroidales as well as a decrease in Lachnospiraceae, Prevotella and Bacteroides. Patients showing a microbial composition resembling community B at least once during the observation period were found to have a significantly higher risk for developing postoperative complications (B vs. A, odds ratio = 4.96, p < 0.01**; B vs. C, odds ratio = 2.89, p = 0.019*).

Conclusions

The structure of the gut microbiome is associated with the development of postoperative complications.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1399-5) contains supplementary material, which is available to authorized users.

Beneficial Effect of Early Intervention with Garenoxacin for Bacterial Infection-Induced Acute Exacerbation of Bronchial Asthma and Chronic Obstructive Pulmonary Disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and asthma have similar clinical features and are both exacerbated by airway infection.

OBJECTIVE

To determine whether garenoxacin mesylate hydrate (GRNX) added to the standard care for bacterial infection-induced acute exacerbation of asthma or COPD in adults has clinical benefits.

METHOD

This single-arm clinical trial was conducted from January 2015 to March 2016. Adults with a history of asthma or COPD for more than 12 months were recruited within 48 h of presentation with fever and acute deterioration of asthma or COPD requiring additional intervention. Participants were administered 400 mg GRNX daily for 7 days without additional systemic corticosteroids or other antibiotics. The primary outcome was efficacy of GRNX based on clinical symptoms and blood test results after 7 days of treatment. Secondary outcomes were: (1) comparison of the blood test results, radiograph findings, and bacterial culture surveillance before and after treatment; (2) effectiveness of GRNX after 3 days of administration; (3) analyzation of patient symptoms based on patient diary; and (4) continued effectiveness of GRNX on 14th day after the treatment (visit 3).

RESULTS

The study included 44 febrile patients (34 asthma and 10 COPD). Frequently isolated bacteria included Moraxella catarrhalis (n = 6) and Klebsiella pneumoniae (n = 4). On visit 2, 40 patients responded, and no severe adverse events were observed. All secondary outcomes showed favorable results.

CONCLUSION

GRNX effectively treated asthma and COPD patients with acute bacterial infection without severe adverse events. Further research with a larger study population is needed.

The Interplay between Immunity and Microbiota at Intestinal Immunological Niche: The Case of Cancer

The gut microbiota is central to the pathogenesis of several inflammatory and autoimmune diseases. While multiple mechanisms are involved, the immune system clearly plays a special role. Indeed, the breakdown of the physiological balance in gut microbial composition leads to dysbiosis, which is then able to enhance inflammation and to influence gene expression. At the same time, there is an intense cross-talk between the microbiota and the immunological niche in the intestinal mucosa. These interactions may pave the way to the development, growth and spreading of cancer, especially in the gastro-intestinal system. Here, we review the changes in microbiota composition, how they relate to the immunological imbalance, influencing the onset of different types of cancer and the impact of these mechanisms on the efficacy of traditional and upcoming cancer treatments.

Antibiotic Perturbation of Gut Microbiota Dysregulates Osteoimmune Cross Talk in Postpubertal Skeletal Development

Commensal gut microbiota-host immune responses are experimentally delineated via gnotobiotic animal models or alternatively by antibiotic perturbation of gut microbiota. Osteoimmunology investigations in germ-free mice, revealing that gut microbiota immunomodulatory actions critically regulate physiologic skeletal development, highlight that antibiotic perturbation of gut microbiota may dysregulate normal osteoimmunological processes. We investigated the impact of antibiotic disruption of gut microbiota on osteoimmune response effects in postpubertal skeletal development. Sex-matched C57BL/6T mice were administered broad-spectrum antibiotics or vehicle-control from the age of 6 to 12 weeks. Antibiotic alterations in gut bacterial composition and skeletal morphology were sex dependent. Antibiotics did not influence osteoblastogenesis or endochondral bone formation, but notably enhanced osteoclastogenesis. Unchanged Tnf or Ccl3 expression in marrow and elevated tumor necrosis factor-α and chemokine (C-C motif) ligand 3 in serum indicated that the pro-osteoclastic effects of the antibiotics are driven by increased systemic inflammation. Antibiotic-induced broad changes in adaptive and innate immune cells in mesenteric lymph nodes and spleen demonstrated that the perturbation of gut microbiota drives a state of dysbiotic hyperimmune response at secondary lymphoid tissues draining local gut and systemic circulation. Antibiotics up-regulated the myeloid-derived suppressor cells, immature myeloid progenitor cells known for immunosuppressive properties in pathophysiologic inflammatory conditions. Myeloid-derived suppressor cell-mediated immunosuppression can be antigen specific. Therefore, antibiotic-induced broad suppression of major histocompatibility complex class II antigen presentation genes in bone marrow discerns that antibiotic perturbation of gut microbiota dysregulates critical osteoimmune cross talk.

Progress in characterizing the linkage between Fusobacterium nucleatum and gastrointestinal cancer

Microbiome research is a rapidly advancing field in human cancers. Fusobacterium nucleatum is an oral bacterium, indigenous to the human oral cavity, that plays a role in periodontal disease. Recent studies have found that F. nucleatum can promote gastrointestinal tumor progression and affect the prognosis of the disease. In addition, F. nucleatum may contribute to the chemo-resistance of gastrointestinal cancers. This review summarizes recent progress in the pathogenesis of F. nucleatum and its impact on gastrointestinal cancer.

Fecal microbiota transplantation in cancer management: Current status and perspectives

The human gut is home to a large and diverse microbial community, comprising about 1,000 bacterial species. The gut microbiota exists in a symbiotic relationship with its host, playing a decisive role in the host's nutrition, immunity and metabolism. Accumulating studies have revealed the associations between gut dysbiosis or some special bacteria and various cancers. Emerging data suggest that gut microbiota can modulate the effectiveness of cancer therapies, especially immunotherapy. Manipulating the microbial populations with therapeutic intent has become a hot topic of cancer research, and the most dramatic manipulation of gut microbiota refers to fecal microbiota transplantation (FMT) from healthy individuals to patients. FMT has demonstrated remarkable clinical efficacy against Clostridium difficile infection (CDI) and it is highly recommended for the treatment of recurrent or refractory CDI. Lately, interest is growing in the therapeutic potential of FMT for other diseases, including cancers. We briefly reviewed the current researches about gut microbiota and its link to cancer, and then summarized the recent preclinical and clinical evidence to indicate the potential of FMT in cancer management as well as cancer‐treatment associated complications. We also presented the rationale of FMT for cancer management such as reconstruction of intestinal microbiota, amelioration of bile acid metabolism, and modulation of immunotherapy efficacy. This article would help to better understand this new therapeutic approach for cancer patients by targeting gut microbiota.

The impact of intestinal microbiota on bio-medical research: definitions, techniques and physiology of a "new frontier"

In recent years the metagenomics techniques have allowed to study composition and function of the intestinal microbiota. The microbiota is a new frontier of biomedical research to be explored and there is growing evidence of its fundamental health-promoting activity. The present review gives a synthetic overview on the characteristics and the role of the microbiota in the adult with particular reference to physiology, pathophysiology and relationships with the host and the environment.

The effect of a multispecies probiotic on microbiota composition in a clinical trial of patients with diarrhea-predominant irritable bowel syndrome

BACKGROUND

Although probiotics are increasingly used in irritable bowel syndrome (IBS), their mechanism of action has not been elucidated sufficiently. We aimed to evaluate the impact of a multispecies probiotic on enteric microbiota composition in women with diarrhea-predominant-IBS (IBS-D) and to determine whether these effects are associated with changes in IBS symptoms or inflammatory markers.

METHODS

In a double-blind, placebo-controlled study, Rome III IBS-D women completed a two-week run-in period and eligible women were assigned at random to a probiotic capsule (BIO-25) or an indistinguishable placebo, twice daily for 8 weeks. IBS symptoms and stool consistency were rated daily by visual analogue scales and the Bristol stool scale. High sensitivity C-reactive protein, fecal calprotectin and microbial composition were tested at baseline and at 4 and 8 weeks. Microbial sequencing of the 16S rRNA was performed and data were analyzed to compare patients who responded to treatment with those who did not.

KEY RESULTS

172 IBS-D patients were recruited and 107 eligible patients were allocated to the intervention (n = 54) or placebo (n = 53) group. Compared to placebo, BIO-25 did not result in changes in microbial diversity or taxa proportions, except for higher relative proportions of Lactobacillus in the BIO-25 group (P = 0.002). Symptomatic responders to BIO-25 showed a reduction in the proportion of Bilophila(P = 0.003) posttreatment. Patients with beneficial inflammatory-marker changes had higher baseline proportions of Faecalibacterium(P = 0.03), Leuconostoc (P = 0.03), and Odoribacter (P = 0.05) compared to corresponding non-responders.

CONCLUSIONS & INFERENCES

Identifying patients with a more amenable microbiome at treatment initiation may result in better treatment response.

Biomarkers of inflammation - LBP and TLR- predict progression of knee osteoarthritis in the DOXY clinical trial

OBJECTIVE

To evaluate systemic inflammatory biomarkers in symptomatic knee osteoarthritis (OA) and their association with radiographic and biochemical OA progression.

METHODS

Lipopolysaccharide (LPS) binding protein (LBP), soluble Toll-like receptor 4 (sTLR4) and interleukin 6 (IL-6) were measured in plasma of 431 knee OA patients from the doxycycline (DOXY) trial at baseline and 18 months. Plasma lipopolysaccharide and lipopolysaccharide binding protein (LBP) were also measured at 12 months. As a biochemical indicator of disease activity and OA progression, urinary (u) C-telopeptide of Type II collagen (uCTX-II) was measured in samples collected at baseline and 18 months. Change over 16 months in radiographic tibiofemoral joint space width (JSW in mm) and joint space narrowing (JSN≥0.5 mm) were used to indicate radiographic OA progression. Change over 18 months for uCTX-II was used as a secondary outcome. Both univariate and multivariable regression analyses were performed to test the association between Z-score transformed biomarkers and outcomes.

RESULTS

Baseline LBP and time-integrated concentration (TIC) of LBP over 12 and 18 months were associated with worsening joint space width (JSW) (parameter estimates: -0.1 to -0.07) and JSN (OR: 1.32 to 1.42) adjusting for treatment group, age, body mass index (BMI) and corresponding baseline radiographic measures. Baseline sTLR4 and TIC over 18 months were associated with change in uCTX-II over 18 months (adjusted parameter estimates: 0.0017 to 0.0020). Results were not modified by treatment with doxycycline.

CONCLUSION

Plasma LBP and sTLR4 were associated with knee OA progression over 16-18 months. These results lend further support for a role of systemic low-grade inflammation in the pathogenesis of knee OA progression.

The role of the gut microbiota in schizophrenia: Current and future perspectives

OBJECTIVES

Schizophrenia is a poorly understood chronic disease. Its pathophysiology is complex, dynamic, and linked to epigenetic mechanisms and microbiota involvement. Nowadays, correlating schizophrenia with the environment makes sense owing to its multidimensional implications: temporal and spatial variability. Microbiota involvement and epigenetic mechanisms are factors that are currently being considered to better understand another dimension of schizophrenia.

METHODS

This review summarises and discusses currently available information, focussing on the microbiota, epigenetic mechanisms, technological approaches aimed at performing exhaustive analyses of the microbiota, and psychotherapies, to establish future perspectives.

RESULTS

The connection between the microbiota, epigenetic mechanisms and technological developments allows for formulating new approaches objectively oriented towards the development of alternative psychotherapies that may help treat schizophrenia.

CONCLUSIONS

In this review, the gut microbiota and epigenetic mechanisms were considered as key regulators, revealing a potential new aetiology of schizophrenia. Likewise, continuous technological advances (e.g. culturomics), aimed at the microbiota-gut-brain axis generate new evidence on this concept.

The use of faecal microbiota transplant as treatment for recurrent or refractory Clostridium difficile infection and other potential indications: joint British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS) guidelines

Interest in the therapeutic potential of faecal microbiota transplant (FMT) has been increasing globally in recent years, particularly as a result of randomised studies in which it has been used as an intervention. The main focus of these studies has been the treatment of recurrent or refractory Clostridium difficile infection (CDI), but there is also an emerging evidence base regarding potential applications in non-CDI settings. The key clinical stakeholders for the provision and governance of FMT services in the UK have tended to be in two major specialty areas: gastroenterology and microbiology/infectious diseases. While the National Institute for Health and Care Excellence (NICE) guidance (2014) for use of FMT for recurrent or refractory CDI has become accepted in the UK, clear evidence-based UK guidelines for FMT have been lacking. This resulted in discussions between the British Society of Gastroenterology (BSG) and Healthcare Infection Society (HIS), and a joint BSG/HIS FMT working group was established. This guideline document is the culmination of that joint dialogue.

Child Weight Gain Trajectories Linked To Oral Microbiota Composition

Gut and oral microbiota perturbations have been observed in obese adults and adolescents; less is known about their influence on weight gain in young children. Here we analyzed the gut and oral microbiota of 226 two-year-olds with 16S rRNA gene sequencing. Weight and length were measured at seven time points and used to identify children with rapid infant weight gain (a strong risk factor for childhood obesity), and to derive growth curves with innovative Functional Data Analysis (FDA) techniques. We showed that growth curves were associated negatively with diversity, and positively with the Firmicutes-to-Bacteroidetes ratio, of the oral microbiota. We also demonstrated an association between the gut microbiota and child growth, even after controlling for the effect of diet on the microbiota. Lastly, we identified several bacterial genera that were associated with child growth patterns. These results suggest that by the age of two, the oral microbiota of children with rapid infant weight gain may have already begun to establish patterns often seen in obese adults. They also suggest that the gut microbiota at age two, while strongly influenced by diet, does not harbor obesity signatures many researchers identified in later life stages.

The use of antimicrobials as adjuvant therapy for the treatment of obesity and insulin resistance: Effects and associated mechanisms

The intestinal microbiota has come to be considered an additional risk factor for the development of metabolic diseases. Considering the potential role of antimicrobials as modulators of the intestinal microbiota, they have been investigated for use in the adjuvant treatment of obesity and insulin resistance (IR). In this regard, the present manuscript aimed to review the effect of regular use of antimicrobials on the treatment of obesity and/or IR, as well as its associated mechanisms. The regular use of antimicrobials does not seem to influence the body weight and adiposity of its consumer. Regarding IR, clinical trials did not observe positive effects, on the other hand, most of the experimental studies observed an increase in insulin sensitivity. The mechanisms used by antimicrobials that could lead to the improvement of insulin sensitivity are dependent on the modulation of the intestinal microbiota. This modulation would lead to a reduction in the stimulation of the immune system, as a consequence of improved intestinal barrier and/or the reduction of gram-negative bacteria in the microbiota. In addition, the secretion of glucagon-like peptide-1 would be modulated by metabolites produced by the intestinal microbiota, such as secondary bile acids and short-chain fatty acids. Based on the results obtained to date, more studies should be performed to elucidate the effect of these drugs on obesity and IR, as well as the mechanisms involved. In addition, the cost-benefit of the regular use of antimicrobials should be investigated, as this practice may lead to the development of antimicrobial-resistant microorganisms.

Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer

The microbiota consists of a dynamic multispecies community of bacteria, fungi, archaea, and protozoans, bringing to the host organism a dowry of cells and genes more numerous than its own. Among the different non-sterile cavities, the human gut harbors the most complex microbiota, with a strong impact on host homeostasis and immunostasis, being thus essential for maintaining the health condition. In this review, we outline the roles of gut microbiota in immunity, starting with the background information supporting the further presentation of the implications of gut microbiota dysbiosis in host susceptibility to infections, hypersensitivity reactions, autoimmunity, chronic inflammation, and cancer. The role of diet and antibiotics in the occurrence of dysbiosis and its pathological consequences, as well as the potential of probiotics to restore eubiosis is also discussed.

The delayed effects of antibiotics in type 2 diabetes, friend or foe?

An increasing amount of evidence suggests that the delayed effect of antibiotics (abx) on gut microbiota after its cessation is not as favorable as its immediate effect on host metabolism. However, it is not known how the diverse abx-dependent metabolic effects influence diabetic subjects and how gut microbiota is involved. Here, we treated db/db mice with abx cocktail for 12 days and discontinued for 24 days. We found that db/db mice showed decreased body weight and blood glucose after abx treatment, which rapidly caught up after abx cessation. Twenty-four days after abx withdrawal, db/db mice exhibit increased plasma, hepatic total cholesterol (TC) levels and liver weight. The gut microbiota composition at that time showed decreased relative abundances (RAs) of Desulfovibrionaceae and Rikenellaceae, increased RA of Erysipelotrichaceae and Mogibacteriaceae, which were correlating with the reduced short-chain fatty acids (SCFAs) in gut content, such as propionic acid and valeric acid and with the elevated fecal taurine-conjugated bile acids (BAs) levels. The molecular biology studies showed inhibited hepatic BA synthesis from cholesterol, impeded intracellular transportation and biliary excretion of cholesterol that all conferred to liver TC accumulation. The associations among alterations of gut microbiota composition, microbial metabolite profiles and host phenotypes suggested the existence of gut microbiota-linked mechanisms that mediate the unfavorable delayed effects of abx on db/db mice cholesterol metabolism. Thus, we call upon the caution of applying abx in diabetic animal models for studying microbiota-host interaction and in type 2 diabetes subjects for preventing chronic cardiovascular consequences.