Dietary Exposure to Antibiotic Residues Facilitates Metabolic Disorder by Altering the Gut Microbiota and Bile Acid Composition

Dietary preservatives alter the gut microbiota in vitro and in vivo with sex-specific consequences for host metabolic development in a mouse model

BACKGROUND

Antibiotics in early life can promote adiposity via interactions with the gut microbiota but represent only one possible route of antimicrobial exposure. Dietary preservatives exhibit antimicrobial activity, contain chemical structures accessible to microbial enzymes, and may therefore similarly disrupt microbial contributions to metabolic development.

OBJECTIVE

Here we test the hypothesis that preservatives alter the gut microbiota with consequences for host metabolism.

METHODS

We screened common dietary preservatives for in vitro and ex vivo activity against a panel of gut bacteria and whole fecal microbial communities, profiling outcomes via optical density measurements and 16S rDNA sequencing. We then exposed adult mice to diet-relevant doses of 4 preservatives [acetic acid, BHA (butylated hydroxyanisole), EDTA (ethylenediaminetetraacetic acid), and sodium sulfite] or ampicillin (positive control) for 7 days. Finally, we examined the effects of early-life EDTA and low-dose ampicillin exposure starting in gestation in a mouse model, tracking differences in growth and metabolism.

RESULTS

Preservatives altered microbial growth and community structure in vitro, ex vivo, and in vivo, but with compound-specific changes in gut microbiota composition distinct from those of ampicillin. Long-term EDTA exposure from gestation reduced calorie absorption and cecal acetate, resulting in 32% lower gains in body fat in females for a given food intake (±12% standard error, linear mixed effects model). Females exposed to ampicillin exhibited a similar 42% (±11%) reduction in food-adjusted gains in adiposity, along with larger brains and smaller livers. By contrast, among males, EDTA had no detectable metabolic impacts while ampicillin exposure increased food-adjusted gain in body fat by 108% (±12%).

CONCLUSIONS

Our results highlight the potential for everyday doses of common preservatives to affect the gut microbiota and impact metabolism differently in males and females. Thus, despite their generally-regarded-as-safe designation, preservatives could have unintended consequences for consumer health via their impact on the gut microbiota.

An energetic framework for gut microbiome-mediated obesity induced by early-life exposure to antibiotics

Early-life antibiotic (ELA) exposure has garnered attention for its potential role in modulating obesity risk, although outcomes from mouse experiments and human epidemiological studies often vary based on dosage and sex. Low-dose (subtherapeutic) antibiotics can enhance energy availability through moderate alterations in gut microbiome profile, while high-dose (therapeutic) antibiotics substantially deplete the gut microbiota, thereby contributing to short-term negative energy balance. In this perspective, we propose a framework to understand how these distinct impacts of antibiotics on the gut microbiome during critical developmental windows shape long-term obesity risk through their influence on host energy balance. Using this framework, we then propose several hypotheses to explain variation in ELA-induced obesity outcomes across males and females. We conclude by discussing the evolutionary implications of ELAs, positing that the response of the gut microbiome to ELAs may signal energy availability and environmental volatility, influencing metabolic programming and adaptive traits across generations.

Antibiotic exposure and risk of overweight/obesity in children: a biomonitoring-based study from eastern Jiangsu, China

Objective

To describe antibiotic exposure in children and explore its association with overweight/obesity.

Methods

In June 2022, 328 kindergarten and primary school children were selected from Nantong city in Jiangsu Province. Questionnaires were distributed, and morning urine samples were obtained. Total urinary concentrations of 41 antibiotics were measured using ultra-performance liquid chromatography and tandem mass spectrometry. The rates of antibiotic exposure were expressed as percentages (%), specific percentiles (P 95 and P 99), and the maximum values were used to describe the concentration of antibiotics. The association between urinary antibiotic creatinine-adjusted and overweight/obesity was analyzed using logistic regression.

Results

A total of 328 children were initially recruited, of which 295 aged 3-8 years met the inclusion criteria and were finally included in the study. The biomonitoring results revealed that 35 antibiotics were detected, with a total detection frequency of 98.31%. Among the included children, 24.75% were classified as overweight/obesity. Multinomial logistic regression analyses revealed significant associations between overweight/obese and exposure to veterinary antibiotics (VAs) and preferred veterinary antibiotics (PVAs). After adjusting for various overweight/obesity-relevant variables, higher exposure to sulfamethoxazole [OR = 2.35, 95% confidence interval (CI):1.17-4.70], norfloxacin (OR = 2.66, 95% CI: 1.01-7.08), and fluoroquinolones (OR = 1.97, 95% CI: 1.02-3.78) were significantly associated with overweight/obesity (p < 0.05). In addition, after stratification by sex and adjustment for confounding variables, sex-specific differences were observed in the association between antibiotic exposure and overweight/obesity. Notably, these associations were predominantly observed among boys.

Conclusion

Children were extensively exposed to antibiotics. Exposure to certain types of veterinary antibiotics and preferred veterinary antibiotic exposure, mainly through food or drinking water, are associated with an increased risk of overweight/obesity in children.

Dietary Exposure to Pesticide and Veterinary Drug Residues and Their Effects on Human Fertility and Embryo Development: A Global Overview

Drug residues that contaminate food and water represent a serious concern for human health. The major concerns regard the possible irrational use of these contaminants, since this might increase the amplitude of exposure. Multiple sources contribute to the overall exposure to contaminants, including agriculture, domestic use, personal, public and veterinary healthcare, increasing the possible origin of contamination. In this review, we focus on crop pesticides and veterinary drug residues because of their extensive use in modern agriculture and farming, which ensures food production and security for the ever-growing population around the world. We discuss crop pesticides and veterinary drug residues with respect to their worldwide distribution and impacts, with special attention on their harmful effects on human reproduction and embryo development, as well as their link to epigenetic alterations, leading to intergenerational and transgenerational diseases. Among the contaminants, the most commonly implicated in causing such disorders are organophosphates, glyphosate and antibiotics, with tetracyclines being the most frequently reported. This review highlights the importance of finding new management strategies for pesticides and veterinary drugs. Moreover, due to the still limited knowledge on inter- and transgenerational effects of these contaminants, we underlie the need to strengthen research in this field, so as to better clarify the specific effects of each contaminant and their long-term impact.

Dietary bile acids supplementation decreases hepatic fat deposition with the involvement of altered gut microbiota and liver bile acids profile in broiler chickens

BACKGROUND

High-fat diets (HFD) are known to enhance feed conversion ratio in broiler chickens, yet they can also result in hepatic fat accumulation. Bile acids (BAs) and gut microbiota also play key roles in the formation of fatty liver. In this study, our objective was to elucidate the mechanisms through which BA supplementation reduces hepatic fat deposition in broiler chickens, with a focus on the involvement of gut microbiota and liver BA composition.

RESULTS

Newly hatched broiler chickens were allocated to either a low-fat diet (LFD) or HFD, supplemented with or without BAs, and subsequently assessed their impacts on gut microbiota, hepatic lipid metabolism, and hepatic BA composition. Our findings showed that BA supplementation significantly reduced plasma and liver tissue triglyceride (TG) levels in 42-day-old broiler chickens (P < 0.05), concurrently with a significant decrease in the expression levels of fatty acid synthase (FAS) in liver tissue (P < 0.05). These results suggest that BA supplementation effectively diminishes hepatic fat deposition. Under the LFD, BAs supplementation increased the BA content and ratio of Non 12-OH BAs/12-OH BAs in the liver and increased the Akkermansia abundance in cecum. Under the HFD, BA supplementation decreased the BAs and increased the relative abundances of chenodeoxycholic acid (CDCA) and cholic acid (CA) in hepatic tissue, while the relative abundances of Bacteroides were dramatically reduced and the Bifidobacterium, Escherichia, and Lactobacillus were increased in cecum. Correlation analyses showed a significant positive correlation between the Akkermansia abundance and Non 12-OH BA content under the LFD, and presented a significant negative correlation between the Bacteroides abundance and CA or CDCA content under the HFD.

CONCLUSIONS

The results indicate that supplementation of BAs in both LFD and HFD may ameliorate hepatic fat deposition in broiler chickens with the involvement of differentiated microbiota-bile acid profile pathways.

Impact of low-level exposure to antibiotics on bile acid homeostasis in adults: Implication for human safety thresholds

Bile acid homeostasis is critical to human health. Low-level exposure to antibiotics has been suggested to potentially disrupt bile acid homeostasis by affecting gut microbiota, but relevant data are still lacking in humans, especially for the level below human safety threshold. We conducted a cross-sectional study in 4247 Chinese adults by measuring 34 parent antibiotics and their metabolites from six common categories (i.e., tetracyclines, qinolones, macrolides, sulfonamides, phenicols, and lincosamides) and ten representative bile acids in fasting morning urine using liquid chromatography coupled to mass spectrometry. Daily exposure dose of antibiotics was estimated from urinary concentrations of parent antibiotics and their metabolites. Urinary bile acids and their ratios were used to reflect bile acid homeostasis. The estimated daily exposure doses (EDED) of five antibiotic categories with a high detection frequency (i.e., tetracyclines, qinolones, macrolides, sulfonamides, and phenicols) were significantly associated with urinary concentrations of bile acids and decreased bile acid ratios in all adults and the subset of 3898 adults with a cumulative ratio of antibiotic EDED to human safety threshold of less than one. Compared to a negative detection of antibiotics, the lowest EDED quartiles of five antibiotic categories and four individual antibiotics with a high detection frequency (i.e., ciprofloxacin, ofloxacin, trimethoprim, and florfenicol) in the adults with a positive detection of antibiotics had a decrease of bile acid ratio between 6.6% and 76.6%. Except for macrolides (1.2×102 ng/kg/day), the medians of the lowest EDED quartile of antibiotic categories and individual antibiotics ranged from 0.32 ng/kg/day to 10 ng/kg/day, which were well below human safety thresholds. These results suggested that low-level antibiotic exposure could disrupt bile acid homeostasis in adults and existing human safety thresholds may be inadequate in safeguarding against the potential adverse health effects of low-level exposure to antibiotics.

Potential Probiotic Weizmannia coagulans WC10 Improved Antibiotic-Associated Diarrhea in Mice by Regulating the Gut Microbiota and Metabolic Homeostasis

Antibiotic-associated diarrhea (AAD) is a common side effect of long-term and heavy antibiotic therapy. Weizmannia coagulans (W. coagulans) is an ideal probiotic because of its high viability, stability, and numerous health benefits to the host. In this study, the strains were first screened for W. coagulans WC10 (WC10) with a high combined ability based on their biological properties of gastrointestinal tolerance, adhesion, and short-chain fatty acid production ability. The effect of WC10 on mice with AAD was further evaluated. The results showed that WC10 was effective in improving the symptoms of AAD, effectively restoring antibiotic-induced weight loss, and reducing diarrhea status score and fecal water content. In addition, WC10 decreased the expression of pro-inflammatory cytokines and increased the expression of anti-inflammatory cytokines, alleviated intestinal tissue damage and inflammation, and improved intestinal epithelial barrier function by decreasing serum levels of enterotoxin, DAO, and D-lactic acid, and by increasing the expression of the intestinal mucosal immune factors sIgA and occludin. Importantly, the composition and function of the gut microbiota gradually recovered after WC10 treatment, increasing the number of SCFAs-producing Bifidobacterium and Roseburia. Subsequently, the short-chain fatty acid (SCFA) content was examined and WC10 significantly increased acetate, propionate, and butyrate production. Additionally, metabolomic analysis also showed that WC10 reversed the antibiotic interference with major metabolic pathways. These findings provide a solid scientific basis for the future application of W. coagulans WC10 in the treatment of AAD.

Influence of dietary status on the obesogenic effects of erythromycin antibiotic on Caenorhabditis elegans

As emerging pollutants, antibiotics were widely detected in water bodies and dietary sources. Recently, their obesogenic effects raised serious concerns. So far, it remained unclear whether their obesogenic effects would be influenced by water- and diet-borne exposure routes. In present study, Caenorhabditis elegans, nematodes free-living in air-water interface and feeding on bacteria, were exposed to water- and diet-borne erythromycin antibiotic (ERY). The statuses of the bacterial food, inactivated or alive, were also considered to explore their influences on the effects. Results showed that both water- and diet-borne ERY significantly stimulated body width and triglyceride contents. Moreover, diet-borne ERY's stimulation on the triglyceride levels was greater with alive bacteria than with inactivated bacteria. Biochemical analysis showed that water-borne ERY inhibited the activities of enzymes like adipose triglyceride lipase (ATGL) in fatty acid β-oxidation. Meanwhile, diet-borne ERY inhibited the activities of acyl-CoA synthetase (ACS) and carnitine palmitoyl transferase (CPT) in lipolysis, while it stimulated the activities of fatty acid synthase (FAS) in lipogenesis. Gene expression analysis demonstrated that water-borne ERY with alive bacteria significantly upregulated the expressions of daf-2, daf-16 and nhr-49, without significant influences in other settings. Further investigation demonstrated that ERY interfered with bacterial colonization in the intestine and the permeability of the intestinal barrier. Moreover, ERY decreased total long-chained fatty acids (LCFAs) in bacteria and nematodes, while it decreased total short-chained fatty acids (SCFAs) in bacteria but increased them in nematodes. Collectively, the present study demonstrated the differences between water- and diet-borne ERY's obesogenic effects, and highlighted the involvement of insulin and nhr-49 signaling pathways, SCFAs metabolism and also the interaction between intestinal bacteria and the host.

Exposure to prescribed medication in early life and impacts on gut microbiota and disease development

The gut microbiota during early life plays a crucial role in infant development. This microbial-host interaction is also essential for metabolism, immunity, and overall human health in later life. Early-life pharmaceutical exposure, mainly referring to exposure during pregnancy, childbirth, and infancy, may change the structure and function of gut microbiota and affect later human health. In this Review, we describe how healthy gut microbiota is established in early life. We summarise the commonly prescribed medications during early life, including antibiotics, acid suppressant medications and other medications such as antidepressants, analgesics and steroid hormones, and discuss how these medication-induced changes in gut microbiota are involved in the pathological process of diseases, including infections, inflammatory bowel disease, metabolic diseases, allergic diseases and neurodevelopmental disorders. Finally, we review some critical methods such as dietary therapy, probiotics, prebiotics, faecal microbiota transplantation, genetically engineered phages, and vagus nerve stimulation in early life, aiming to provide a new strategy for the prevention of adverse health outcomes caused by prescribed medications exposure in early life.

Alternatives to antibiotics in pig production: looking through the lens of immunophysiology

In the livestock production system, the evolution of porcine gut microecology is consistent with the idea of "The Hygiene Hypothesis" in humans. I.e., improved hygiene conditions, reduced exposure to environmental microorganisms in early life, and frequent use of antimicrobial drugs drive immune dysregulation. Meanwhile, the overuse of antibiotics as feed additives for infectious disease prevention and animal growth induces antimicrobial resistance genes in pathogens and spreads related environmental pollutants. It justifies our attempt to review alternatives to antibiotics that can support optimal growth and improve the immunophysiological state of pigs. In the current review, we first described porcine mucosal immunity, followed by discussions of gut microbiota dynamics during the critical weaning period and the impacts brought by antibiotics usage. Evidence of in-feed additives with immuno-modulatory properties highlighting probiotics, prebiotics, and phytobiotics and their cellular and molecular networking are summarized and reviewed. It may provide insights into the immune regulatory mechanisms of antibiotic alternatives and open new avenues for health management in pig production.

Urinary antibiotic levels and risk of overweight/obesity in preschool children: A biomonitoring-based study from eastern China

There is limited evidence linking antibiotic exposure, particularly from contaminated food or drinking water, to childhood obesity. The study aimed to investigate the association between urinary antibiotic levels and overweight/obesity in preschool children. In the case-control study, 121 overweight/obese preschoolers and 242 controls (aged 3-6 years) from eastern China were enrolled in 2022 based on age, sex, and study site matching. Overweight/obesity was determined using body mass index (BMI) and weight for height (WFH) criteria derived from national data. A total of 50 antibiotics from 8 categories were analyzed using ultra-performance liquid chromatography and tandem mass spectrometry (UPLC-MS/MS). We identified major dietary patterns using principal component analysis (PCA) and examined the associations of antibiotic exposure with childhood overweight/obesity using multivariate logistic regression. Twenty-four individual antibiotics were detected in more than 10 % of the samples, and overall detection rates were up to 100 %. Overweight/obese children had a higher exposure to veterinary antibiotics (VAs) than normal weight children. PCA analysis showed that children who were overweight/obese had higher scores of "Aquatic products preferred dietary pattern" and "Cereals preferred dietary pattern" compared to children with normal weight. Multivariate logistic regression analyses indicated that exposure to elevated levels of deoxytetracycline (OR: 1.72; 95 %CI: 1.00-2.93) and quinolones (OR: 1.63; 95 %CI: 1.04-2.57) was significantly related to an increased risk of BMI-based overweight/obesity. Quinolones exposure was also significantly associated with WFH-based overweight/obesity, primarily in boys. After adjustment for all covariates, higher exposure to ofloxacin (of the quinolones) was significantly related to overweight/obesity in girls. Exposure to certain antibiotics, especially quinolones, may increase the risk of overweight/obesity in preschoolers. More prospective, well-designed studies are needed to clarify these findings.

Revisiting the Intestinal Microbiome and Its Role in Diarrhea and Constipation

The gut microbiota represents a community of microorganisms (bacteria, fungi, archaea, viruses, and protozoa) that colonize the gut and are responsible for gut mucosal structural integrity and immune and metabolic homeostasis. The relationship between the gut microbiome and human health has been intensively researched in the past years. It is now widely recognized that gut microbial composition is highly responsible for the general health of the host. Among the diseases that have been linked to an altered gut microbial population are diarrheal illnesses and functional constipation. The capacity of probiotics to modulate the gut microbiome population, strengthen the intestinal barrier, and modulate the immune system together with their antioxidant properties have encouraged the research of probiotic therapy in many gastrointestinal afflictions. Dietary and lifestyle changes and the use of probiotics seem to play an important role in easing constipation and effectively alleviating diarrhea by suppressing the germs involved. This review aims to describe how probiotic bacteria and the use of specific strains could interfere and bring benefits as an associated treatment for diarrhea and constipation.

Effect of Changes in Veterinary Feed Directive Regulations on Violative Antibiotic Residues in the Tissue of Food Animals from the Inspector-Generated Sampling in the United States

The presence of antibiotic residues in the tissue of food animals is a growing concern due to the adverse health effects that they can cause in humans, such as antibiotic resistance bacteria. An inspector-generated sampling (IGS) dataset from the United States National Residue Surveillance Program, collected between 2014 and 2019, was analyzed to investigate the association of changes in the veterinary feed directive (VFD) regulations on the detection of violative penicillin, tetracycline, sulfonamide, desfuroylceftiofur, tilmicosin, and florfenicol, residues in the tissue of food animals. Multivariable logistic regression models were used for analysis. While the animal production class was significantly associated with residue violations for tetracycline, having a sample collection date after the implementation of change in VFD regulations was not. However, the odds of detecting violative sulfonamide and penicillin residues in the tissue of food animals following the implementation of the change in VFD regulations were 36% and 24% lower than those collected before the implementation of the change in VFD regulations period, respectively, irrespective of animal production class. Violative desfuroylceftiofur, tilmicosin, and florfenicol residues in the tissue of food animals were not significantly associated with the implementation of changes in the VFD regulations. Further investigation of the factors that influence the presence of violative antibiotic residues in the tissue of food animals following the change in VFD regulations would lend clarity to this critical issue.