Effect of antibiotics on gut microbiota, glucose metabolism and body weight regulation: a review of the literature

Applied physiology: gut microbiota and antimicrobial therapy

The gut microbiota plays an important role in maintaining human health and in the pathogenesis of several diseases. Antibiotics are among the most commonly prescribed drugs and have a significant impact on the structure and function of the gut microbiota. The understanding that a healthy gut microbiota prevents the development of many diseases has also led to its consideration as a potential therapeutic target. At the same time, any factor that alters the gut microbiota becomes important in this approach. Exercise and antibacterial therapy have a direct effect on the microbiota. The review reflects the current state of publications on the mechanisms of intestinal bacterial involvement in the pathogenesis of cardiovascular, metabolic, and neurodegenerative diseases. The physiological mechanisms of the influence of physical activity on the composition of the gut microbiota are considered. The mechanisms of the common interface between exercise and antibacterial therapy will be considered using the example of several socially important diseases. The aim of the study is to show the physiological relationship between the effects of exercise and antibiotics on the gut microbiota.

Risk of type 2 diabetes and long-term antibiotic use in childhood: Evidence from the UK Biobank

AIMS

This study aimed to investigate the association between long-term use of antibiotics during childhood and the risk of type 2 diabetes mellitus (T2DM) using a prospective cohort from the UK Biobank.

METHODS

Participants in the UK Biobank who completed the online survey for digestive health were included in this prospective cohort study. A Cox regression model adjusted for sociodemographic characteristics, general health factors, mental health, lifestyle factors, comorbidities, and medication use was used to estimate the hazard ratio (HR) and confidence interval (CI) of the association between long-term use of antibiotics in the childhood and incident T2DM.

RESULTS

The final analyses included 152,992 participants and 22,133 of them received long-term/recurrent antibiotics as children or teenagers. During the follow-up, 3370 and 681 incident T2DM cases occurred in the non-exposed and exposed groups respectively. Long-term use of antibiotics in childhood was associated with an increased risk of T2DM, with an HR of 1.16 (95 % CI, 1.07-1.27) after adjusting for potential confounders. Results in the subgroup analyses and sensitivity analyses were highly consistent with the primary analyses.

CONCLUSIONS

Long-term use of antibiotics in childhood is associated with the risk of T2DM in middle and old age in the UK Biobank population.

Antibiotics attenuate diet-induced nonalcoholic fatty liver disease without altering intestinal barrier dysfunction

To date the role of the alterations of intestinal microbiota in the development of intestinal barrier dysfunction in settings of nonalcoholic fatty liver disease (NAFLD) has not been fully understood. Here, we assessed the effect of antibiotics on development of NAFLD and their impact on intestinal barrier dysfunction. Male C57BL/6J mice were either pair-fed a liquid control diet (C) or fat- and fructose-rich diet (FFr) +/- antibiotics (AB, ampicillin/vancomycin/metronidazole/gentamycin) for 7 weeks. Fasting blood glucose was determined and markers of liver damage, inflammation, intestinal barrier function, and microbiota composition were assessed. The development of hepatic steatosis with early signs of inflammation found in FFr-fed mice was significantly abolished in FFr+AB-fed mice. Also, while prevalence of bacteria in feces was not detectable and TLR4 ligand levels in portal plasma were at the level of controls in FFr+AB-fed mice, impairments of intestinal barrier function like an increased permeation of xylose and iNOS protein levels persisted to a similar extent in both FFr-fed groups irrespective of AB use. Exposure of everted small intestinal tissue sacs of naïve mice to fructose resulted in a significant increase in tissue permeability and loss of tight junction proteins, being not affected by the presence of AB, whereas the concomitant treatment of tissue sacs with the NOS inhibitor aminoguanidine attenuated these alterations. Taken together, our data suggest that intestinal barrier dysfunction in diet-induced NAFLD in mice may not be predominantly dependent on changes in intestinal microbiota but rather that fructose-induced alterations of intestinal NO-homeostasis might be critically involved.

Effects of Glucosinolate-Enriched Red Radish (Raphanus sativus) on In Vitro Models of Intestinal Microbiota and Metabolic Syndrome-Related Functionalities

The gut microbiota profile is determined by diet composition, and therefore this interaction is crucial for promoting specific bacterial growth and enhancing the health status. Red radish (Raphanus sativusL.) contains several secondary plant metabolites that can exert a protective effect on human health. Recent studies have shown that radish leaves have a higher content of major nutrients, minerals, and fiber than roots, and they have garnered attention as a healthy food or supplement. Therefore, the consumption of the whole plant should be considered, as its nutritional value may be of greater interest. The aim of this work is to evaluate the effects of glucosinolate (GSL)-enriched radish with elicitors on the intestinal microbiota and metabolic syndrome-related functionalities by using an in vitro dynamic gastrointestinal system and several cellular models developed to study the GSL impact on different health indicators such as blood pressure, cholesterol metabolism, insulin resistance, adipogenesis, and reactive oxygen species (ROS). The treatment with red radish had an influence on short-chain fatty acids (SCFA) production, especially on acetic and propionic acid and many butyrate-producing bacteria, suggesting that consumption of the entire red radish plant (leaves and roots) could modify the human gut microbiota profile toward a healthier one. The evaluation of the metabolic syndrome-related functionalities showed a significant decrease in the gene expression of endothelin, interleukin IL-6, and cholesterol transporter-associated biomarkers (ABCA1 and ABCG5), suggesting an improvement of three risk factors associated with metabolic syndrome. The results support the idea that the use of elicitors on red radish crops and its further consumption (the entire plant) may contribute to improving the general health status and gut microbiota profile.

Early-life antibiotic exposure increases the risk of childhood overweight and obesity in relation to dysbiosis of gut microbiota: a birth cohort study

Background

Early-life antibiotic exposure is associated with the development of later obesity through the disruption of gut microbiota in the animal models. However, the related epidemiological evidence is still conflicting.

Methods

A birth cohort was consisted of 2140 mother-infant pairs in Chaoyang District Maternal and Child Health Care Hospital in this study. Here, their available antibiotic exposure during the first one year of life was ascertained using a open-ended questionnaire and related anthropometric parameters from the health screening program. The compositions of gut microbiota were comprehensively analyzed by16S rRNA high throughput sequencing. Then the spearman correlations were performed by the multiple covariance-adjusted regressions between the antibiotic exposure with anthropometric parameters and compositions of gut microbiota.

Results

Among the 2140 subjects, the antibiotic exposure during the first one year of life was 53.04%, mainly by Cephalosporins (53.39%) and Erythromycins(27.67%) for the treatment of respiratory tract infection (79.56%), which were not significantly different among the subgroups. Compared to the control group, both childhood overweight and obesity at two and a half years were higher in the antibiotic exposed group, with higher percents of Faecalibacterium, Agathobacter and Klebsiella, and lower percentage of Bifidobacterium. Moreover, there were positively potential associations between early-life antibiotic exposure with the accelerated anthropometric parameters and disruption of Faecalibacterium, Agathobacter, Klebsiella and Bifidobacterium at two and a half years.

Conclusion

These above results proved that early-life antibiotic exposure was positively associated with the accelerated childhood overweight and obesity from one year to two and a half years by impacting the disorders of Faecalibacterium, Agathobacter, Klebsiella and Bifidobacterium, which would propose the theoretical basis for rationalizing the personalized antibiotic exposure among the infants to truly reflect the fairness of public health.

Supplementary information

The online version contains supplementary material available at 10.1186/s12941-022-00535-1.

Topical and Oral Oestrogen for Recurrent Urinary Tract Infection-Evidence-based Review of Literature, Treatment Recommendations, and Correlation with the European Association of Urology Guidelines on Urological Infections

CONTEXT

Urinary tract infection (UTI) represents a significant disease for women, with 20-40% suffering from recurrent UTIs (rUTIs) across their lifetime.

OBJECTIVE

This review aims to provide evidence for current European Association of Urology (EAU) guidance that topical, but not oral, oestrogen is a worthwhile preventative therapy for rUTIs in postmenopausal women. We also aim to establish whether a relationship exists between oestrogen dosage and treatment efficacy.

EVIDENCE ACQUISITION

A literature search was performed across databases for this review. All studies that included oral or topical oestrogen in females with urinary tract infections were selected. Studies were inspected to establish treatment and follow-up duration, average weekly oestrogen dosage, efficacy of treatment, and reasons for dropout.

EVIDENCE SYNTHESIS

Clinical resolution and reduction of UTIs were evaluated. Six studies (seven treatment groups) using topical oestrogen as a treatment arm (258 patients total) and four studies using oral oestrogen as the treatment arm were included (1376 patients total). Topical oestrogen was administered as creams, pessaries, or per-vaginal tablets with follow-up spanning 2-12 mo. Of the patients, 51-100% remained UTI free throughout the duration of follow-up with minimal dropouts. Patients enrolled and treated with oral oestrogen were generally given higher weekly doses and had follow-up between 3 mo and 4.1 yr. All included studies agreed that topical oestrogen is an effective prophylaxis for rUTIs in women, with higher efficacy associated with weekly doses of ≥850 µg. Conversely, only one study arrived at the same conclusion for oral oestrogen.

CONCLUSIONS

Our review concurs with current EAU guidance that topical but not oral oestrogen therapy can be a valid treatment for women suffering from rUTIs. Administration weekly topical doses of ≥850 µg is associated with the best outcomes.

PATIENT SUMMARY

In this study, we look at the role of oral and topical oestrogens for the treatment of urinary tract infections and their adherence to European Association of Urology guidelines. We found that administration of weekly topical doses of ≥850 µg is associated with the best outcomes.

Antibiotics in urine from general adults in Shenzhen, China: Demographic-related difference in exposure levels

Misuse or overuse of antibiotics can have a variety of detrimental microbial effects. However, the body burden of antibiotics in the general population is currently unclear. In this cross-sectional study, we determined four classes of widely-applied antibiotics (3 imidazoles, 2 sulfonamides, 5 quinolones, and 2 chloramphenicols) in urine samples from 1170 adult residents in Shenzhen, China. Antibiotics were detected in 30.8 % of all urine samples with concentrations ranging from <LOD to 3517 μg/mL, among which metronidazole, ofloxacin and florfenicol were predominant. Notably, antibiotics prohibited for human or veterinary use were detected in 21.0 % of samples, indicating that these antibiotics may still be overused in daily life. We found that the presence of antibiotics in urine is associated with being overweight (OR: 1.386, 95 % CI: 1.056-1.819, p = 0.019) and obesity (OR: 1.862, 95 % CI: 1.103-3.146, p = 0.020) in the adult population. Multilinear regression analysis showed that a percent increase of hydroxy metronidazole was related to 9.86 % positive change of body mass index (p = 0.029). Interestingly, we also found total antibiotic concentration higher in the unmarried group (p = 0.006). Besides, consumption of smoked foods was correlated with urinary antibiotic levels (p = 0.001), indicating smoked meat may be a potential exposure source of veterinary antibiotics. These results highlight the need to reduce human exposure to banned antibiotics. Future research could focus on assessing the health risk and other outcomes of antibiotic overuse.

Construction of Electrochemical Sensors for Antibiotic Detection Based on Carbon Nanocomposites

Excessive antibiotic residues in food can cause detrimental effects on human health. The establishment of rapid, sensitive, selective, and reliable methods for the detection of antibiotics is highly in demand. With the inherent advantages of high sensitivity, rapid analysis time, and facile miniaturization, the electrochemical sensors have great potential in the detection of antibiotics. The electrochemical platforms comprising carbon nanomaterials (CNMs) have been proposed to detect antibiotic residues. Notably, with the introduction of functional CNMs, the performance of electrochemical sensors can be bolstered. This review first presents the significance of functional CNMs in the detection of antibiotics. Subsequently, we provide an overview of the applications for detection by enhancing the electrochemical behaviour of the antibiotic, as well as a brief overview of the application of recognition elements to detect antibiotics. Finally, the trend and the current challenges of electrochemical sensors based on CNMs in the detection of antibiotics is outlined.

Antibiotics-induced disruption of gut microbiota increases systemic exposure of clopidogrel active metabolite in type 2 diabetic rats

Gut microbiota play an important role in the pathophysiology of type 2 diabetic mellitus (T2DM) and biodisposition of drugs. Our previous study demonstrated that T2DM rats had the decreased plasma exposure of clopidogrel active metabolite (Clop-AM) due to upregulation of P-glycoprotein (P-gp). However, whether the change to clopidogrel (Clop) disposition under T2DM condition is associated with gut microbiota needs to be elucidated. In the study, we used an antibiotic cocktail consisting of ampicillin, vancomycin, metronidazole, and neomycin to disrupt gut microbiota and observed their influence on pharmacokinetic profiles of Clop-AM. Antibiotic administration markedly alleviated T2DM rats' phenotype including hyperglycemia, insulin resistance, oxidative stress, inflammation, hyperlipidemia, and liver dysfunction. Meanwhile, treatment with antibiotics significantly reversed the reduced systemic exposure of Clop-AM in T2DM rats relative to control rats, which was associated with the decreased intestinal P-gp level that might promote Clop absorption, resulting in more Clop transformation to Clop-AM. Fecal microbiome analysis exhibited a serious disruption of gut microbiota after antibiotic treatment with the sharply reduced microbial load and the altered microbial composition. Interestingly, an in vitro study showed that antibiotics had no influence on P-gp mRNA leve in SW480 cells, suggesting the microbiome disruption, not the direct role of antibiotics on P-gp expression, contributes to the altered P-gp level and Clop disposition in T2DM rats. The findings add new insights into the potential impact of gut microbiota on Clop biodisposition. Significance Statement 1.Antibiotics increase systemic exposure of Clop-AM in T2DM rats, which is associated with the downregulation of P-gp level.2.Antibiotics-induced disruption of gut microbiota, not direct effect of antibiotics on P-gp and CYPs expression, contributes to the altered Clop disposition.3.Antibiotics also alleviate T2DM phenotype including hyperglycemia, hyperlipidemia, insulin resistance, liver dysfunction and inflammation.

A short review of human exposure to antibiotics based on urinary biomonitoring

Antibiotics play a role in preventing and treating infectious diseases and also contribute to other health risks for humans. With the overuse of antibiotics, they are widely distributed in the environment. Long-term exposure to multiple antibiotics may occur in humans through medication and dietary intake. Therefore, it is critical to estimate daily intake and health risk of antibiotics based on urinary biomonitoring. This review compares the strengths and weaknesses of current analytical methods to determine antibiotics in urine samples, discusses the urinary concentration profiles and hazard quotients of individual antibiotics, and overviews correlations of antibiotic exposure with the risk of diseases. Liquid chromatography-tandem mass spectrometry is most applied to simultaneously determine multiple types of antibiotics at trace levels. Solid-phase extraction with a hydrophilic-lipophilic balance adsorbent is commonly used to extract antibiotics in urine samples. Fifteen major antibiotics with relatively higher detection frequencies and concentrations include sulfaclozine, trimethoprim, erythromycin, azithromycin, penicillin V, amoxicillin, oxytetracycline, chlortetracycline, tetracycline, doxycycline, ofloxacin, enrofloxacin, ciprofloxacin, norfloxacin, and florfenicol. Humans can be easily at microbiological effect-based risk induced by florfenicol, ciprofloxacin, azithromycin, and amoxicillin. Positive associations were observed between specific antibiotic exposure and obesity, allergic diseases, and mental disorders. Overall, the accessible, automated, and environmentally friendly methods are prospected for simultaneous determinations of antibiotics at trace level in urine. To estimate human exposure to antibiotics more accurately, knowledge gaps need to be filled up, including the transformation between parent and metabolic antibiotics, urinary excretion proportions of antibiotics at low-dose exposure and pharmacokinetic data of antibiotics in humans, and the repeated sampling over a long period in future research is needed. Longitudinal studies about antibiotic exposure and the risk of diseases in different developmental windows as well as in-depth research on the pathogenic mechanism of long-term, low-dose, and joint antibiotic exposure are warranted.

Infections and antibiotic use in early life, and obesity in early childhood: a mediation analysis

BACKGROUND/OBJECTIVE

Literature shows a positive association between antibiotics and obesity in childhood, but fails to account for confounding by indication. We evaluate the direct effect of infection on obesity and the indirect effect mediated by antibiotics by performing a mediation analysis of the infection-obesity association.

METHODS

A Medicaid cohort of children age 2-14 years old between 2015-2019 (n = 61,330) is used to perform mediation analysis of infections and antibiotic use in the first year of life, and obesity in childhood in Missouri, U.S.A.

RESULTS

An additional infection increases the risk of obesity in childhood (aIRR = 1.050, p < 0.001); however, mediation by antibiotic use is clinically and statistically insignificant. If the number of infections is not considered in the analysis, then antibiotic use as a risk factor for obesity is overstated (aIRR = 1.037 vs. 1.013 p < 0.001).

CONCLUSIONS

The number of infections exhibits a significant relationship with obesity and is a stronger risk factor for obesity than antibiotic use. In particular, a greater number of bronchitis, otitis media, and upper respiratory infections in the first year of life are associated with a significant increased risk of obesity in childhood. We find only weak evidence that an additional antibiotics claim increases the risk of obesity in childhood and this risk may not be clinically meaningful. Further research is needed to explore the association between early childhood infections, especially in the first 6 months of life, and obesity including the biological mechanism and environmental factor of early life infections associated with obesity.

Altered Gut Structure and Anti-Bacterial Defense in Adult Mice Treated with Antibiotics during Early Life

The association between prolonged antibiotic (AB) use in neonates and increased incidence of later life diseases is not yet fully understood. AB treatment in early life alters intestinal epithelial cell composition, functioning, and maturation, which could be the basis for later life health effects. Here, we investigated whether AB-induced changes in the neonatal gut persisted up to adulthood and whether early life AB had additional long-term consequences for gut functioning. Mice received AB orally from postnatal day 10 to 20. Intestinal morphology, permeability, and gene and protein expression at 8 weeks were analyzed. Our data showed that the majority of the early life AB-induced gut effects did not persist into adulthood, yet early life AB did impact later life gut functioning. Specifically, the proximal small intestine (SI) of adult mice treated with AB in early life was characterized by hyperproliferative crypts, increased number of Paneth cells, and alterations in enteroendocrine cell-specific gene expression profiles. The distal SI of adult mice displayed a reduced expression of antibacterial defense markers. Together, our results suggest that early life AB leads to structural and physiological changes in the adult gut, which may contribute to disease development when homeostatic conditions are under challenge.

Different approaches to change gut microbiota and its influence on metabolic disorders

Obesity and type 2 diabetes mellitus (T2D) are two non-infectious pandemics of the XXI century. Despite a large number of studies devoted to the development of obesity and T2D, it seems complicated to overcome the ongoing growth in the number of cases. In these situations it is necessary to investigate new approaches for the prevention and treatment of such diseases. One of these approaches is to study the role of gut microbiota in the disturbance of carbohydrate and lipid metabolism. This manuscript describes the role of the microbiota in obesity and T2D. The aim of the review was to describe various approaches to change the composition of the gut microbiota and to determine its impact on metabolic risks. To assess the relationship between T2D development and changes of microbiota composition we considered a number of studies devoted to the consequence of these pathophysiologic mechanisms in various situations: the effect of drug treatment, bariatric surgery and microbiota transplantation. Possible metabolically protective gut microbiota composition is discussed.

Antibiotic exposure and risk of type 2 diabetes mellitus: a systematic review and meta-analysis

To investigate the association between antibiotic exposure and risk of type 2 diabetes mellitus (T2DM). Four electronic databases, including PubMed, MEDLINE, EMBASE, and Cochrane Library, were searched for all relevant studies, from inception until May 2021, without restrictions. Pooled odds risk (OR) with 95% confidence intervals (CI) was applied to evaluate the effect value. Nine studies counting a total of 3,924,272 participants were assessed in the systematic review and meta-analyses. By meta-analysis using no antibiotic exposure as the reference, antibiotic exposure has a higher risk for T2DM (OR=1.16; 95% CI, 1.10-1.22). Subgroup analyses suggested that the antibiotic exposure could significantly enhance the risk of T2DM in those whose age were more than 50 (OR=1.17; 95% CI, 1.08-1.25). Further stratified analysis indicated that the association was likely attributed to the chemical structure of antibiotics, but not to antibacterial type and mechanism of action. Our results may further support the possibility that antibiotic use in recent years was associated with increased risk of T2DM. More attentions and cautions should be taken by the physicians when prescribing antibiotics.

Soil exposure accelerates recovery of the gut microbiota in antibiotic-treated mice

Environmental exposure to low cleanliness prevents the occurrence of allergic diseases and increases the richness and diversity of the intestinal microbiota. Antibiotics are widely used in clinical infection therapy but destroy the balance of the gut microbiota. In this study, the effects of cleanliness of the living environment on the gut microbiota are evaluated after administration of antibiotics. The patterns of gut microbiota are compared before and after antibiotic treatment in mice living in a higher standard clean environment with those of mice living in an unclean environment. The results show that dust exposure prevents the reduction in gut microbiota diversity following antibiotic treatment in mice and impaired structural changes in the gut microbiota. Additionally, dust exposure accelerates the recovery of the gut microbiota, regardless of consumption of a high-fat or normal diet. An unsanitary environment can reduce the effects of antibiotics on intestinal microecology in mice. These findings provide insights into approaches for regulating antibiotic-induced symbiosis of the gut microbiota and preventing diseases.

Legend of Weight Loss: a Crosstalk Between the Bariatric Surgery and the Brain

In recent years, plenty of researches have reported in obese individuals with abnormal brain processes implicated in homeostatic regulation, reward, emotion, memory, attention, and executive function in eating behaviors. Thus, treating obesity cannot remain "brainless." Behavioral and psychological interventions activate the food reward, attention, and motivation system, leading to minimal weight loss and high relapse rates. Pharmacotherapy is an effective weight loss method and regulate brain activity but with concerns about its brain function safety problems. Obesity surgery, the most effective therapy currently available for obesity, shows pronounced effects on brain activity, such as deactivation of reward and attention system, and activation of inhibition control toward food cues. In this review, we present an overview of alterations in the brain after the three common weight loss methods.

Changes in maternal anthropometric measurements in the first postpartum month and associated factors

OBJECTIVE

Maternal anthropometry offers a rapid, inexpensive, and non-invasive method for assessing nutritional status during pregnancy. We aimed to assess the changes in maternal anthropometric measurements in the first month after delivery and to investigate the factors associated with longitudinal changes in maternal postpartum nutritional status.

DESIGN

This prospective longitudinal study included 147 mothers who were on the 5th postpartum day applied to outpatient clinics, from January 2018 through January 2020. Each mother completed a structured questionnaire and baseline anthropometric measurements were performed at the postpartum 5th day and re-evaluated at the end of the first month after delivery.

PARTICIPANTS

Mother-infant pairs (n = 147).

RESULTS

At the end of the first postpartum month, maternal body weight (relative change -5.1%, 95% CI: -5.6%;-4.6%), muscle mass ratio (-1.6%, 95% CI: -2.4%;-0.9%) and body fluid ratio (-2.4%, 95% CI: -3.1%;-1.7%) decreased, whereas fat mass ratio increased (10.3%, 95% CI: 9.0%;11.6%).There was a significant association between infants' feeding type and maternal BMI, weight, muscle mass ratio, body fluid ratio, triceps, and biceps skinfold thickness in mothers (p < .05). We also found a significant relationship between maternal smoke exposure and BMI, maternal weight, fat-mass ratio (p < .05).

CONCLUSIONS

There are some important alterations in maternal anthropometric parameters during the postpartum period. This study will help further our understanding of the factors influencing changes in maternal body composition after delivery.

Gut Microbiota Bacterial Species Associated with Mediterranean Diet-Related Food Groups in a Northern Spanish Population

The MD (Mediterranean diet) is recognized as one of the healthiest diets worldwide and is associated with the prevention of cardiovascular and metabolic diseases. Dietary habits are considered one of the strongest modulators of gut microbiota, which seem to play a significant role in health status of the host. The purpose of the present study was to evaluate interactive associations between gut microbiota composition and habitual dietary intake in 360 Spanish adults from the Obekit cohort (normal weight, overweight, and obese participants). Dietary intake and adherence to the MD tests were administered and fecal samples were collected from each participant. Fecal 16S rRNA (ribosomal Ribonucleic Acid) gene sequencing was performed and checked against the dietary habits. MetagenomeSeq was the statistical tool applied to analyze data at the species taxonomic level. Results from this study identified several beneficial bacteria that were more abundant in the individuals with higher adherence to the MD. Bifidobacterium animalis was the species with the strongest association with the MD. Some SCFA (Short Chain Fatty Acids) -producing bacteria were also associated with MD. In conclusion, this study showed that MD, fiber, legumes, vegetable, fruit, and nut intake are associated with an increase in butyrate-producing taxa such as Roseburia faecis, Ruminococcus bromii, and Oscillospira (Flavonifractor) plautii.

Removal of sulfadiazine in a modified ultrafiltration membrane (PVDF-PVP-TiO2-FeCl3) filtration-photocatalysis system: parameters optimizing and interferences of drinking water

The addition of Fe³⁺ to TiO₂ is one of the effective methods to inhibit the recombination of photogenerated electrons and holes and thus improve the photocatalytic activity of TiO₂. The effect of PVDF-PVP-TiO₂-FeCl₃ (PPTFe) membrane filtration-photocatalytic system on the removal of trace concentration of sulfadiazine (SD) in water was evaluated. A two-factor four-level experiment was established to optimize 16 self-made modified membranes. The optimal membrane was then characterized in seven tests (SEM, EDS, membrane pure water flux, contact angle, porosity, mean pore size, ATR-FTIR), resulting in the optimal ratio (PPTFe membrane with 1.2 wt%TiO₂ and 0.8 wt%FeCl₃). Compared with the original membrane, the pore number, pore size, permeability, and hydrophilicity of the PPTFe membrane were all enhanced. The removal efficiency (92.63%) of SD by PPTFe membrane filtration-photocatalysis system was investigated. The reaction rate (0.0214 min^-1) of the removal SD of the system was determined according to the pseudo-first-order kinetic model. The removal performance of membrane type, pH, and water quality parameters (Cl^-, SO₄^2-, NO₃^-, HA) on PPTFe membrane filtration-photocatalytic system were also made a deep inquiry. The results reflected that acidic conditions (pH = 3) were beneficial to SD removal, the presence of Cl^-, SO₄^2-, and HA could inhibit SD removal, while the existence of NO₃^- was unaffected. Furthermore, the removal rate of SD in the actual water body was displayed well in this system. Finally, the possible photocatalytic degradation mechanism was proposed.Graphical abstract.

Educating Patients on Unnecessary Antibiotics: Personalizing Potential Harm Aids Patient Understanding

INTRODUCTION

Antibiotic resistance is a public health emergency fueled by inappropriate antibiotic use. Public education campaigns often focus on global antibiotic resistance or societal harm of antibiotic misuse. There has been little research into what messages have the greatest impact on patient preferences for nonindicated antibiotics in ambulatory clinics.

METHODS

We administered a survey at a primary care clinic in Baltimore, MD. A total of 250 participants rated 18 statements about potential harm from antibiotics on how each statement changed their likelihood to request antibiotics for an upper respiratory tract infection. Statements focused on potential harm either to the individual, to contacts of the individual, to society, and related or not to antibiotic resistance. Initial and final likelihood of requesting antibiotics was measured, and the impact of the statements in each category were compared using general linear models and Wilcoxon rank sum or Kruskal-Wallis tests.

RESULTS

All statements decreased patient likelihood to request antibiotics. Statements about harm to the individual or contacts of the individual decreased participant likelihood to request antibiotics significantly more than statements about societal harm of antibiotic misuse. Statements not discussing antibiotic resistance decreased participant likelihood of requesting antibiotics significantly more than statements discussing antibiotic resistance. Overall likelihood to request antibiotics decreased after the survey by 2.2 points on an 11-point Likert scale (P < .001).

CONCLUSION

When dissuading patients from requesting nonindicated antibiotics, providers and public health campaigns should focus on potential harm of nonindicated antibiotics to the individual rather than societal harm or antibiotic resistance.

Antibiotic-induced changes in the human gut microbiota for the most commonly prescribed antibiotics in primary care in the UK: a systematic review

OBJECTIVE

The gut microbiota influences many aspects of human health. We investigated the magnitude and duration of changes in gut microbiota in response to antibiotics commonly prescribed in UK primary care.

METHODS

We searched MEDLINE, EMBASE and AMED, all years up to May 2020 including all study designs, collecting and analysing data on the effect of antibiotics prescribed for respiratory and urinary tract infections. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane standard methods. Risk of bias was evaluated using the Critical Appraisal Skills Programme. Narrative synthesis was used to report the themes emerging from the data.

MAIN OUTCOME MEASURES

Primary outcomes were antibiotic-induced changes in the composition and/or diversity of the gut microbiota. Secondary outcome was the time for the microbiota to return to baseline.

RESULTS

Thirty-one articles with low or unclear risk of bias showed that antibiotics impact the gut microbiota by causing rapid and diminished levels of bacterial diversity and changes in relative abundances. After cessation of treatment, gut bacteria recover, in most individuals, to their baseline state within a few weeks. Some studies suggested longer term effects from 2 to 6 months. Considerable heterogeneity in methodology makes the studies prone to biases and other confounding factors. Doxycycline was associated with a marked short-term decrease in Bifidobacterium diversity. Clarithromycin decreased the populations of Enterobacteria, and the anaerobic bacteria Bifidobacterium sp and Lactobacillus sp in numbers and diversity for up to 5 weeks. Phenoxymethylpenicillin, nitrofurantoin and amoxicillin had very little effect on the gut microbiome.

CONCLUSIONS

Despite substantial heterogeneity of the studies and small sample sizes, there is evidence that antibiotics commonly used in primary care influence the composition of the gastrointestinal microbiota. Larger population-based studies are needed to fully understand how antibiotics modulate the microbiota, and to determine if these are associated with (longer term) health consequences.

PROSPERO REGISTRATION NUMBER

CRD42017073750.

Crosstalk between the growth hormone/insulin-like growth factor-1 axis and the gut microbiome: A new frontier for microbial endocrinology

Both the GH/IGF-1 axis and the gut microbiota independently play an important role in host growth, metabolism, and intestinal homeostasis. Inversely, abnormalities in GH action and microbial dysbiosis (or a lack of diversity) in the gut have been implicated in restricted growth, metabolic disorders (such as chronic undernutrition, anorexia nervosa, obesity, and diabetes), and intestinal dysfunction (such as pediatric Crohn's disease, colonic polyps, and colon cancer). Over the last decade, studies have demonstrated that the microbial impact on growth may be mediated through the GH/IGF-1 axis, pointing toward a potential relationship between GH and the gut microbiota. This review covers current research on the GH/IGF-1 axis and the gut microbiome and its influence on overall host growth, metabolism, and intestinal health, proposing a bidirectional relationship between GH and the gut microbiome.

An exegesis of bacteriophage therapy: An emerging player in the fight against anti-microbial resistance

Bacteriophages (simply referred to as Phages) are a class of viruses with the ability to infect and kill prokaryotic cells (bacteria), but are unable to infect mammalian cells. This unique ability to achieve specific infectiousness by bacteriophages has been harnessed in antibacterial treatments dating back almost a decade before the antibiotic era began. Bacteriophages were used as therapeutic agents in treatment of dysentery caused by Shigella dysenteriae as far back as 1919 and in the experimental treatment of a wide variety of other bacterial infections caused by Vibriocholerae, Staphylococcussp., Pseudomonas sp. etc, with varying degrees of success. Phage therapy and its many prospects soon fell out of favour in western medicine after the Second World War, with the discovery of penicillin. The Soviet Union and other countries in Eastern Europe however mastered the craft of bacteriophage isolation, purification and cocktail preparation, with phage-based therapeutics becoming widely available over-the-counter. With the recent rise in cases of multi-drug resistant bacterial infections, the clamour for a return to phage therapy, as a potential solution to the anti-microbial resistance (AMR) crisis has grown louder. This review provides an extensive exposé on phage therapy, addressing its historical use, evidences of its safety and efficacy, its pros and cons when compared with antibiotics, cases of compassionate use for treating life-threatening antibiotic-resistant infections, the limitations to its acceptance and how these may be circumvented.

Colonization of Mice With Amoxicillin-Associated Klebsiella variicola Drives Inflammation via Th1 Induction and Treg Inhibition

β-Lactam antibiotics can increase the resistance and virulence of individual intestinal microorganisms, which may affect host physiology and health. Klebsiella, a crucial gut inhabitant, has been confirmed to be resistant to most β-lactam antibiotics and contributes to the etiology of inflammatory bowel disease (IBD). In this study, the influence of amoxicillin (AMO) on Klebsiella and its role in colitis was investigated in an antibiotic cocktail (ABx) murine model. The results suggested that a 7-day AMO treatment significantly enriched the abundance of Klebsiella and enhanced serum resistance, antibiotic resistance, and biofilm formation ability of Klebsiella variicola (K. variicola) compared to the wild-type strain in the control group mice. Colonization of mice with the AMO-associated K. variicola could induce Th1 cells and inhibit Treg differentiation to promote inflammation in ABx murine model. In addition, inoculation of AMO-associated K. variicola in dextran sodium sulfate (DSS)-induced colitis murine model mice also confirmed that K. variicola colonization exacerbated inflammation as assessed by increased TNF-α, IFN-γ, IL-17a, and disease activity (DAI) levels; decreased colon length and bodyweight; and a disrupted Th1/Treg balance. The results of our study demonstrate that AMO enhances Klebsiella virulence in mice by disrupting the T cell equilibrium to exacerbate colitis, thereby providing a reference for proper antibiotic prescription.

Amoxicillin-induced gut dysbiosis influences estrous cycle in mice and cytokine expression in the ovary and the caecum

PROBLEM

Gut dysbiosis is caused by several factors, including the use of antibiotics. Since intestinal dysbiosis is associated with a wide range of immunopathological and reproductive conditions, the main goal of this study was to evaluate amoxicillin-induced gut dysbiosis and its influence on the oestrous cycle in mice.

METHOD OF STUDY

Mice were treated with amoxicillin or PBS, and faecal microbiota was evaluated by 16S rDNA metagenomic sequencing. The oestrous cycle was evaluated by vaginal cytology, vaginal opening and flow cytometry. After the induction of gut dysbiosis, the ovaries and the caecum were analysed to differential expression of IL-1β and IL-10 genes and histological analysis.

RESULTS

Amoxicillin-treated mice presented differing bacterial groups in the faecal microbiota when compared to the PBS-treated group indicating that amoxicillin treatment-induced gut dysbiosis and they gained weight. The vaginal cytology analysis showed that amoxicillin-induced gut dysbiosis decreased the number of cells but increased the relative number of leucocytes and altered the oestrous cycle. IL-1β was shown to be upregulated in the caecum and in the ovary of the dysbiotic mice. On the other hand, IL-10 expression was shown to be diminished in both organs of the dysbiotic mice. The oocyte area from dysbiotic group presented lower than non-dysbiotic mice with increasing thickness of the pellucid zone. The follicular teak from dysbiotic mice showed lower thickness than non-dysbiotic mice.

CONCLUSION

The results indicate that amoxicillin induces gut dysbiosis and influences the oestrous cycle and the inflammatory status of the ovary and the caecum.

Reduced environmental bacterial load during early development and gut colonisation has detrimental health consequences in Japanese quail

Gastrointestinal colonisation by commensal microbiota is essential for the health and well-being of the host. We aimed to evaluate the influence of a reduced bacterial load environment on microbiota development and maturation, and the possibility of targeted colonisation via at-hatch administration of a selected bacterial strain. Japanese quail (Coturnix japonica) were inoculated within 1 h of hatch with a freshly grown culture of a Lactobacillus agilis isolate derived from a healthy adult quail. Hatchlings were kept in a mouse isolator for one week and then housed between one and four weeks of age, with a flock of normally grown adult quail to expose the bacteria-restricted birds to normal commensal quail bacteria. The bacterial isolate used to inoculate the birds was found to completely dominate the microbiota of the intestine of L.agilis at-hatch inoculated birds. Despite 3 weeks of co-housing of the test birds with an adult flock harbouring normal rich gut microbiota, neither the Lactobacillus inoculated nor PBS inoculated birds reached the level of bacterial diversity seen in birds raised under normal conditions. Neither PBS nor Lactobacillus inoculated birds were able to adopt normal quail microbiota after one week of restricted exposure to bacteria, indicating that contact with diverse microbiota during the early days of gut development in birds is critical for the establishment of healthy intestinal community. Very early intervention in the form of a suitable bacterial probiotic inoculant immediately post-hatch protected birds grown in extreme hygiene conditions from developing anomalous gut microbiota and intestinal damage. Our data shows that it is possible to induce dominance of desired strain using simple timed manipulation.

Uso temprano de antibióticos en la infancia y obesidad pediátrica: revisión sistemática de la literatura

Introducción: la prevalencia de obesidad en el mundo es creciente y específicamente la obesidad en niños se ha convertido en un problema de salud pública que preocupa a varios países. La evidencia ha señalado al uso de antibióticos en la infancia como un factor relacionado con la presencia de obesidad infantil.Objetivo: Analizar sistemáticamente la evidencia reciente acerca de la relación entre el uso temprano de antibióticos en la infancia y la presencia de obesidad infantil.Métodos: Se realizó una búsqueda bibliográfica en las bases de Pubmed, Ovid, EBSCO, Lilacs, JAMA pediatrics de estudios observacionales en los últimos diez años que abordaran la relación entre el uso de antibióticos antes de los 24 meses de edad y la obesidad infantil.Resultados: Luego de realizar el tamizaje de los artículos, se seleccionaron 9 para la síntesis cualitativa. Con dos excepciones, los estudios analizados muestran una relación estadísticamente significativa entre el uso temprano de antibióticos y la obesidad o sobrepeso infantil, medido como peso para la edad o mediante el índice de masa corporal y aún con el ajuste por las potenciales variables de confusión, esta asociación permanece siendo estadísticamente significativa, debido a algunos de los diseños epidemiológicos, no se puede verificar la relación de antecedencia temporal de la exposición. 

Effects of grape pomace and seed polyphenol extracts on the recovery of gut microbiota after antibiotic treatment in high-fat diet-fed mice

The widespread use of antibiotics all over the world increases the risk of many metabolic diseases by altering the gut microbiota. Grape by-products are of particular interest in the prevention of metabolic diseases, while only minimum amounts of these wastes are up-graded or recycled at present. The study investigated the effect of grape pomace (GPE) and seed (GSE) polyphenol extracts on the recovery of gut microbiota after antibiotic cocktail treatment in high-fat diet-fed (HFD) mice. C57BL/6J mice were fed HFD together with antibiotic treatment by drinking water for 3 weeks. Then, GPE and GSE were supplemented for 7 days after withdrawal of antibiotics. The gut microbiota was characterized by a significant loss of diversity and certain important taxon after a 3-week antibiotic cocktail treatment. The GPE and GSE supplementation during the restore period of gut microbiota had some positive effects. The relative abundance of gut microbiota was improved by GPE and GSE compared to the spontaneous recovery group. And gut microbiota diversity was also greatly changed by GPE and GSE, being indicated by the changes of Verrucomicrobia and Akkermansia in feces. These findings suggested that grape polyphenol extracts have a great influence on the recovery of gut microbiota after antibiotics and high-fat diet treatment.

Antibiotic use during pregnancy and childhood overweight: A population-based nationwide cohort study

Studies in mice suggest that early life represents a critical time window, where antibiotics may exert profound and lasting effects on the gut microbiota and metabolism. We aimed to test the hypothesis that prenatal antibiotic exposure is associated with increased risk of childhood overweight in a population-based cohort study. We linked 43,365 mother-child dyads from a nationwide cohort of pregnant women and their offspring to the Danish National Prescription Registry. Linear and logistic regression models were used to examine associations between prenatal exposure to antibiotics and BMI z-score and overweight (including obesity) at age seven and 11 years. Prenatal antibiotic exposure and childhood overweight were both associated with high pre-pregnancy BMI, maternal diabetes, multi-parity, smoking, low socioeconomic status, high paternal BMI, and short duration of breastfeeding. After adjustment for confounders, no associations were observed between prenatal antibiotic exposure and odds of overweight at age seven and 11 years. Whereas no association was observed between broad-spectrum antibiotics and overweight at age 11 years, exposure to broad-spectrum antibiotics was associated with higher odds of overweight at age seven years with an odds ratio of 1.27 (95% CI, 1.05–1.53) for ampicillin and an odds ratio of 1.56 (95% CI, 1.23–1.97) for amoxicillin. As we did not account for underlying infections, the observed associations with early childhood overweight could be explained by confounding by indication. In conclusion, our population-based study suggests that prenatal exposure to narrow-spectrum antibiotics is not associated with overweight in offspring. Exposure to some broad-spectrum antibiotics may increase the odds of overweight in early childhood, but the association does not persist in later childhood.

Inhibitory effects of selected antibiotics on the activities of α-amylase and α-glucosidase: In-vitro, in-vivo and theoretical studies

Antibiotics are effective drugs that are used to treat infectious diseases either by killing bacteria or slowing down their growth. The well-adapted structural features of antibiotics for the inhibition/activation of enzymes include several available hydrogen bond (H-bond) acceptors and donors, flexible backbone and hydrophobic nature. The substrates of α-amylase and α-glucosidase, known as key absorbing enzymes, have functional groups (OH groups) rembling antibiotics. Given the possibility of developing in diabetics and the significant association between diabetes and infection, the present study was conducted to investigate the influences of tetracycline (TET), kanamycin (KANA), lincomycin (LIN), erythromycin (ERM) and azithromycin (AZM) on α-glucosidase and α-amylase activities with calculating IC₅₀ and K_i values. Also, the efficacy of antibiotics after oral administration was evaluated by analysis of blood glucose concentrations in rats, as well as a molecular docking analysis was explored. α-glucosidase and α-amylase activities were inhibited in a dose dependent fashion by TET with an IC₅₀ of 38.7 ± 1.4 and 47.8 ± 3.2 μM respectively, by KANA with an IC₅₀ of 46.2 ± 1.6 and 65.1 ± 1.6, by LIN with an IC₅₀ of 59.1 ± 2.1 and 51.3 ± 4.1, by ERM with an IC₅₀ of 94.9 ± 4.7 and 65.7 ± 3.8 and by AZM with an IC₅₀ of 69.4 ± 4.4 and 103.6 ± 6.2. Moreover, the K_i values of TET were calculated as 4.4 ± 0.6 and 8.4 ± 0.8 μM for α-glucosidase and α-amylase in a competitive-mode and mixed-mode inhibition. In addition, to communicate with the active site of α-glucosidase and α-amylase respectively, TET presented a binding energy of -9.8 and -8.8 kcal/mol, KANA -7.9 and -7.1, LIN -7.8 and -6.7, ERM -6.8 and -6.4, and AZM -6.4 and -7.5 kcal/mol. In-vivo studies also suggested a decrease in the blood glucose concentration after administering TET compared to the positive controls (P < 0.01). The results obtained from the present research can therefore help the scientific community explore the possible interconnection between the clinical side-effects of antibiotics and their α-glucosidase and α-amylase inhibitory properties, as the target enzymes in hypoglycemia conditions.

Gut microbiota and obesity: An opportunity to alter obesity through faecal microbiota transplant (FMT)

Obesity is a global pandemic with immense health consequences for individuals and societies. Multiple factors, including environmental influences and genetic predispositions, are known to affect the development of obesity. Despite an increasing understanding of the factors driving the obesity epidemic, therapeutic interventions to prevent or reverse obesity are limited in their impact. Manipulation of the human gut microbiome provides a new potential therapeutic approach in the fight against obesity. Specific gut bacteria and their metabolites are known to affect host metabolism and feeding behaviour, and dysbiosis of this biosystem may lead to metabolic syndrome. Potential therapies to alter the gut microbiota to treat obesity include dietary changes, supplementation of the diet with probiotic organisms and prebiotic compounds that influence bacterial growth, and the use of faecal microbiota transplant, in which gut microbiota from healthy individuals are introduced into the gut. In this review, we examine the growing scientific evidence supporting the mechanisms by which the human gut microbiota may influence carbohydrate metabolism and obesity, and the various possible therapies that may utilize the gut microbiota to help correct metabolic dysfunction.

The Contribution of Complementary and Alternative Medicine to Reduce Antibiotic Use: A Narrative Review of Health Concepts, Prevention, and Treatment Strategies

AIM

The aim of this narrative review was to explore the potential contributions of CAM to reduce antibiotic use.

METHODS

We searched PubMed, Embase, and Cochrane Database of Systematic Reviews with a specific, limited set of search terms and collected input from a group of expert CAM researchers to answer the question: What is known about the contribution of CAM health and health promotion concepts, infection prevention, and infection treatment strategies to reduce antibiotic use? Results. The worldview-related CAM health concepts enable health promotion oriented infection prevention and treatment aimed at strengthening or supporting the self-regulating ability of the human organism to cope with diseases. There is some evidence that the CAM concepts of health (promotion) are in agreement with current conceptualization of health and that doctors who practice both CAM and conventional medicine prescribe less antibiotics, although selection bias of the presented studies cannot be ruled out. There is some evidence that prevention and some treatment strategies are effective and safe. Many CAM treatment strategies are promising but overall lack high quality evidence.

CONCLUSIONS

CAM prevention and treatment strategies may contribute to reducing antibiotic use, but more rigorous research is necessary to provide high quality evidence of (cost-)effectiveness.

Microbial regulation of organismal energy homeostasis

The gut microbiome has emerged as a key regulator of host metabolism. Here we review the various mechanisms through which the gut microbiome influences the energy metabolism of its host, highlighting the complex interactions between gut microbes, their metabolites and host cells. Among the most important bacterial metabolites are short-chain fatty acids, which serve as a direct energy source for host cells, stimulate the production of gut hormones and act in the brain to regulate food intake. Other microbial metabolites affect systemic energy expenditure by influencing thermogenesis and adipose tissue browning. Both direct and indirect mechanisms of action are known for specific metabolites, such as bile acids, branched chain amino acids, indole propionic acid and endocannabinoids. We also discuss the roles of specific bacteria in the production of specific metabolites and explore how external factors, such as antibiotics and exercise, affect the microbiome and thereby energy homeostasis. Collectively, we present a large body of evidence supporting the concept that gut microbiota-based therapies can be used to modulate host metabolism, and we expect to see such approaches moving from bench to bedside in the near future.

Chemoprophylaxis against group A streptococcus during military training

Chemoprophylaxis with intramuscular benzathine penicillin G has been used widely by the U.S. military to prevent epidemics of group A streptococcus infections during basic training. The recent global shortage of benzathine penicillin prompted a detailed analysis of this issue in 2017 by military preventive medicine and infectious disease authorities in San Antonio, Texas, and San Diego, California, USA. This paper explores the history of group A streptococcus and chemoprophylaxis in the U.S. military training environment, current policy and practice, and challenges associated with widespread chemoprophylaxis. In light of the history presented, preventive medicine authorities at basic training centers should be extremely cautious about discontinuing benzathine penicillin chemoprophylaxis.

Pleiotropic effects of metformin: Shaping the microbiome to manage type 2 diabetes and postpone ageing

Metformin is the first-choice therapy to lower glycaemia and manage type 2 diabetes. Continuously emerging epidemiological data and experimental models are showing additional protective effects of metformin against a number of age-related diseases (ARDs), e.g., cardiovascular diseases and cancer. This evidence has prompted the design of a specific trial, i.e., the Targeting Aging with Metformin (TAME) trial, to test metformin as an anti-ageing molecule. However, a unifying or prevailing mechanism of action of metformin is still debated. Here, we summarize the epidemiological data linking metformin to ARD prevention. Then, we dissect the deeply studied mechanisms of action explaining its antihyperglycemic effect and the putative mechanisms supporting its anti-ageing properties, focusing on studies using clinically pertinent doses. We hypothesize that the molecular observations obtained in different models with metformin could be indirectly mediated by its effect on gut flora. Novel evidence suggests that metformin reshapes the human microbiota, promoting the growth of beneficial bacterial species and counteracting the expansion of detrimental bacterial species. In turn, this action would influence the balance between pro- and anti-inflammatory circulating factors, thereby promoting glycaemic control and healthy ageing. This framework may reconcile diverse observations, providing information for designing further studies to elucidate the complex interplay between metformin and the metabiome harboured in mammalian body compartments, thereby paving the way for innovative, bacterial-based therapeutics to manage type 2 diabetes and foster a longer healthspan.

Recovery of gut microbiota of healthy adults following antibiotic exposure

To minimize the impact of antibiotics, gut microorganisms harbour and exchange antibiotics resistance genes, collectively called their resistome. Using shotgun sequencing-based metagenomics, we analysed the partial eradication and subsequent regrowth of the gut microbiota in 12 healthy men over a 6-month period following a 4-day intervention with a cocktail of 3 last-resort antibiotics: meropenem, gentamicin and vancomycin. Initial changes included blooms of enterobacteria and other pathobionts, such as Enterococcus faecalis and Fusobacterium nucleatum, and the depletion of Bifidobacterium species and butyrate producers. The gut microbiota of the subjects recovered to near-baseline composition within 1.5 months, although 9 common species, which were present in all subjects before the treatment, remained undetectable in most of the subjects after 180 days. Species that harbour β-lactam resistance genes were positively selected for during and after the intervention. Harbouring glycopeptide or aminoglycoside resistance genes increased the odds of de novo colonization, however, the former also decreased the odds of survival. Compositional changes under antibiotic intervention in vivo matched results from in vitro susceptibility tests. Despite a mild yet long-lasting imprint following antibiotics exposure, the gut microbiota of healthy young adults are resilient to a short-term broad-spectrum antibiotics intervention and their antibiotics resistance gene carriage modulates their recovery processes.

Antibiotic-induced microbiome depletion alters metabolic homeostasis by affecting gut signaling and colonic metabolism

Antibiotic-induced microbiome depletion (AIMD) has been used frequently to study the role of the gut microbiome in pathological conditions. However, unlike germ-free mice, the effects of AIMD on host metabolism remain incompletely understood. Here we show the effects of AIMD to elucidate its effects on gut homeostasis, luminal signaling, and metabolism. We demonstrate that AIMD, which decreases luminal Firmicutes and Bacteroidetes species, decreases baseline serum glucose levels, reduces glucose surge in a tolerance test, and improves insulin sensitivity without altering adiposity. These changes occur in the setting of decreased luminal short-chain fatty acids (SCFAs), especially butyrate, and the secondary bile acid pool, which affects whole-body bile acid metabolism. In mice, AIMD alters cecal gene expression and gut glucagon-like peptide 1 signaling. Extensive tissue remodeling and decreased availability of SCFAs shift colonocyte metabolism toward glucose utilization. We suggest that AIMD alters glucose homeostasis by potentially shifting colonocyte energy utilization from SCFAs to glucose.

Antibiotic-induced microbiome depletion is one of the most common approaches to modulate the gut microbiome. Here the authors demonstrate that it affects gut homeostasis and glucose metabolism by decreasing luminal short chain fatty acids and leading to a shift of energy utilization by colonocytes.

Antibiotic exposure in early life and childhood overweight and obesity: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis of observational studies investigating the association between antibiotic exposure in infancy and risk of childhood overweight and obesity. Thirteen studies, including a total of 527 504 children, were included in the systematic review and 8 were included in meta-analyses. Exposure to antibiotics in infancy was associated with an increased odds ratio (OR) of childhood overweight and obesity (OR 1.11, 95% confidence interval [CI] 1.02-1.20). Whereas exposure to 1 treatment only and exposure between 6 and 24 months were not associated with increased risk of childhood overweight and obesity, exposure to >1 treatment was associated with an OR of 1.24 (95% CI 1.09-1.43) and exposure within the first 6 months of life was associated with an OR of 1.20 (95% CI 1.04-1.37). In conclusion, antibiotic exposure in infancy was associated with a slightly increased risk of childhood overweight and obesity, mainly if children were exposed to repeated treatments or treatment within the first 6 months of life. It is unclear whether this association is mediated via direct effects of antibiotics on the gut microbiota.

Antibiotics, gut microbiome and obesity

Antibiotics have been hailed by many as "miracle drugs" that have been effectively treating infectious diseases for over a century, leading to a marked reduction in morbidity and mortality. However, with the increasing use of antibiotics, we are now faced not only with the increasing threat of antibiotic resistance, but also with a rising concern about potential long-term effects of antibiotics on human health, including the development of obesity. The obesity pandemic continues to increase, a problem that affects both adults and children alike. Disruptions to the gut microbiome have been linked to a multitude of adverse conditions, including obesity, type 2 diabetes, inflammatory bowel diseases, anxiety, autism, allergies, and autoimmune diseases. This review focuses on the association between antibiotics and obesity, and the role of the gut microbiome. There is strong evidence supporting the role of antibiotics in the development of obesity in well-controlled animal models. However, evidence for this link in humans is still inconclusive, and we need further well-designed clinical trials to clarify this association.

Antibiotics in a general population: Relations with gender, body mass index (BMI) and age and their human health risks

Recently, increasing regulatory and public attention has been paid to the exposure risks of antibiotics due to their occurrence and antibiotic resistance worldwide. However, limited information on antibiotic levels in general populations is available. Forty antibiotics, including 9 sulfonamides, 5 fluoroquinolones, 4 macrolides, 4 tetracyclines, 3 chloramphenicols, 12 β-lactams and 3 others, were analyzed in 107 serum samples of normal adults collected from a hospital in Dalian, North China, between 2015 and 2016 using solid-phase extraction (SPE) coupled with HPLC-MS/MS. The results clearly showed that antibiotics were present in the serum of these adults. Specifically, 28 antibiotics were detected in the samples, with detection frequencies ranging from 0.9% to 17.8%. The total antibiotic concentrations in 26.2% of the serum samples were between the LOD and 20.0ng/mL. Importantly, the maximum concentrations of 5 antibiotics (trimethoprim, ciprofloxacin, cefaclor, lincomycin and erythromycin) were above 1000ng/mL in 3.7% of the samples. Furthermore, the detection frequencies of 5 veterinary antibiotics, 7 human antibiotics and 16 human/veterinary antibiotics in the serum samples were 23.4%, 17.8% and 29.0%, respectively. Significant differences of the veterinary antibiotics between female and male adults and of the sulfonamides between different BMI (body mass index) groups were observed (p<0.05). The concentrations of sulfonamides in elderly individuals were significantly higher (p<0.05) than those in young people. Finally, our results showed that almost all of the adults had no health risks related to exposure to antibiotics at such levels despite the high effect ratio (ER=1.74) for azithromycin in one sample. This study is the first to report the current status of antibiotics in human blood, which can help in better understanding the long-term effects of antibiotics on general populations and in identifying susceptible populations that are at high risk to antibiotic exposure.

Changes in the gut microbiota composition and the plasma ghrelin level in patients with Helicobacter pylori-infected patients with eradication therapy

Objective

To investigate the influence of antimicrobials on both the gut microbiota structure and the plasma ghrelin level using Helicobacter pylori-infected patients who underwent eradication therapy.

Design

Twenty H. pylori-infected patients (mean age 68.3 years old) who underwent eradication therapy participated in the study. For the therapy, patients had 1 week of triple therapy consisting of amoxicillin, clarithromycin and proton-pump inhibitors. Stool and blood samples were obtained before (S1), immediately after (S2) and/or 3 months after (S3) the therapies. The concentrations of ghrelin and leptin in the blood were assayed using an ELISA. The V3-V4 region of the 16S rRNA gene was amplified using bacterial DNA from the stool, and about 50 000 high-quality amplicons per sample were grouped into operational taxonomic units for bacteriological analyses.

Results

The Bacteroidetes:Firmicutes (B:F) ratio was significantly greater at S3 than S1 (P<0.01). This increase in the B:F ratio between S3 and S1 was found in 15 out of 20 patients. A significant decrease in the concentration of active ghrelin (P=0.003) in the plasma was observed between S3 and S1. There was a statistically significant correlation between the rate of patients whose B:F ratio increased and that of patients whose active ghrelin level decreased between S3 and S1 according to Fisher’s exact probability test (P=0.03).

Conclusions

Changes in the gut microbiota, such as the B:F ratio after treatment with antimicrobials, might cause a change in the plasma ghrelin level, as the direct and earliest target of antimicrobials would be the microbiota rather than the hormone-secreting system.

Antibiotic-Induced Alterations in Gut Microbiota Are Associated with Changes in Glucose Metabolism in Healthy Mice

The gut microbiome plays an important role in health and disease. Antibiotics are known to alter gut microbiota, yet their effects on glucose tolerance in lean, normoglycemic mice have not been widely investigated. In this study, we aimed to explore mechanisms by which treatment of lean mice with antibiotics (ampicillin, metronidazole, neomycin, vancomycin, or their cocktail) influences the microbiome and glucose metabolism. Specifically, we sought to: (i) study the effects on body weight, fasting glucose, glucose tolerance, and fasting insulin, (ii) examine the changes in expression of key genes of the bile acid and glucose metabolic pathways in the liver and ileum, (iii) identify the shifts in the cecal microbiota, and (iv) infer interactions between gene expression, microbiome, and the metabolic parameters. Treatment with individual or a cocktail of antibiotics reduced fasting glucose but did not affect body weight. Glucose tolerance changed upon treatment with cocktail, ampicillin, or vancomycin as indicated by reduced area under the curve of the glucose tolerance test. Antibiotic treatment changed gene expression in the ileum and liver, and shifted the alpha and beta diversities of gut microbiota. Network analyses revealed associations between Akkermansia muciniphila with fasting glucose and liver farsenoid X receptor (Fxr) in the top ranked host-microbial interactions, suggesting possible mechanisms by which this bacterium can mediate systemic changes in glucose metabolism. We observed Bacteroides uniformis to be positively and negatively correlated with hepatic Fxr and Glucose 6-phosphatase, respectively. Overall, our transkingdom network approach is a useful hypothesis generating strategy that offers insights into mechanisms by which antibiotics can regulate glucose tolerance in non-obese healthy animals. Experimental validation of our predicted microbe-phenotype interactions can help identify mechanisms by which antibiotics affect host phenotypes and gut microbiota.

Biochemistry of the menopause

The life of a human female is characterized from teenage years by monthly menstruation which ceases (the menopause) typically between the age of 40 and 60 years. The potential for reproduction declines and ceases as the ovaries become depleted of follicles. A transition period in mid-life, for 2 to 10 years, when menstruation is less regular is called the perimenopause. The menopause is associated with a significant decline in plasma concentrations of sex hormones, an increase in the concentrations of the gonadotrophins and changes in other hormones such as the inhibins. These changes are superimposed with effects of aging, social and metabolic factors, daily activity and well-being. Although the menopause is entirely natural, in some cases ovarian failure can occur earlier than usual; this is pathological and warrants careful biochemical investigations to distinguish it from conditions causing infertility. Elderly females are affected by a range of clinical disorders including endocrine, cardiovascular, skeletal, urogenital tract and immunological systems, body mass, vasomotor tone, mood and sleep pattern. Reference intervals for many diagnostic biochemical tests for the menopause need to be used when interpreting results in clinical investigations for patient management. The standardization and harmonization of assays are being addressed. Many women now choose to develop their career before bearing children, and the health service has had to change services around this. This review does not cover screening for and tests during pregnancy. The review is timely since the population is aging and there will be more demand on healthcare services.

Phage therapy: An alternative to antibiotics in the age of multi-drug resistance

The practice of phage therapy, which uses bacterial viruses (phages) to treat bacterial infections, has been around for almost a century. The universal decline in the effectiveness of antibiotics has generated renewed interest in revisiting this practice. Conventionally, phage therapy relies on the use of naturally-occurring phages to infect and lyse bacteria at the site of infection. Biotechnological advances have further expanded the repertoire of potential phage therapeutics to include novel strategies using bioengineered phages and purified phage lytic proteins. Current research on the use of phages and their lytic proteins against multidrug-resistant bacterial infections, suggests phage therapy has the potential to be used as either an alternative or a supplement to antibiotic treatments. Antibacterial therapies, whether phage- or antibiotic-based, each have relative advantages and disadvantages; accordingly, many considerations must be taken into account when designing novel therapeutic approaches for preventing and treating bacterial infection. Although much about phages and human health is still being discovered, the time to take phage therapy serious again seems to be rapidly approaching.

The Role of Supplemental Complex Dietary Carbohydrates and Gut Microbiota in Promoting Cardiometabolic and Immunological Health in Obesity: Lessons from Healthy Non-Obese Individuals

Dietary supplementation with complex carbohydrates is known to alter the composition of gut microbiota, and optimal implementation of the use of these so called "prebiotics" could be of great potential in prevention and possibly treatment of obesity and associated cardiometabolic and inflammatory diseases via changes in the gut microbiota. An alternative to this "microbiocentric view" is the idea that health-promoting effects of certain complex carbohydrates reside in the host, and could secondarily affect the diversity and abundance of gut microbiota. To circumvent this potential interpretational problem, we aimed at providing an overview about whether and how dietary supplementation of different complex carbohydrates changes the gut microbiome in healthy non-obese individuals. We then reviewed whether the reported changes in gut bacterial members found to be established by complex carbohydrates would benefit or harm the cardiometabolic and immunological health of the host taking into account the alterations in the microbiome composition and abundance known to be associated with obesity and its associated disorders. By combining these research areas, we aimed to give a better insight into the potential of (foods containing) complex carbohydrates in the treatment and prevention of above-mentioned diseases. We conclude that supplemental complex carbohydrates that increase Bifidobacteria and Lactobacilli, without increasing the deleterious Bacteroides, are most likely promoting cardiometabolic and immunological health in obese subjects. Because certain complex carbohydrates also affect the host's immunity directly, it is likely that host-microbiome interactions in determination of health and disease characteristics are indeed bidirectional. Overall, this review article shows that whereas it is relatively clear in which direction supplemental fermentable carbohydrates can alter the gut microbiome, the relevance of these changes regarding health remains controversial. Future research should take into account the different causes of obesity and its adverse health conditions, which in turn have drastic effects on the microbiome balance.