Obesity, Xenobiotic Intake and Antimicrobial-Resistance Genes in the Human Gastrointestinal Tract: A Comparative Study of Eutrophic, Overweight and Obese Individuals.

Marjorie Raquel Anariba Sarmiento,Claudio Galuppo Diniz,Dioneia Evangelista Cesar,Thais Oliveira de Paula,Sheila Cristina Potente Dutra Luquetti,Ana Paula Boroni Moreira,Vânia Lúcia da Silva,Alessandra Barbosa Ferreira-Machado,Francis Moreira Borges,Juliana Alves Resende

doi:10.3390/genes10050349

Marjorie Raquel Anariba Sarmiento, Claudio Galuppo Diniz + Show 8 more

Open Access

https://doi.org/10.3390/genes10050349

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Abstract

Although lifestyle and physiology in obese individuals are accepted to lead to changes in the intestinal microbiota, uncertainty remains about microbiota dysbiosis, and xenobiotics intake, as a source of selective pressure, independent of antimicrobial chemotherapy. The aim of this study was to compare the occurrence of antimicrobial resistance genetic markers (ARG) in faecal specimens of eutrophic, overweight and obese individuals, and their correlation with xenobiotic intake and gut bacteria density. Methods: This was a cross-sectional case-controlled study including 72 adult participants with no record of intestinal or systemic diseases, or recent use of antimicrobials, grouped as eutrophic, overweight, or obese. Anthropometric profile, eating habits and oral xenobiotics intake were recorded. Faecal metagenomic DNA was used to screen for ARG by PCR, and to measure bacterial groups by fluorescence in situ hybridization (FISH). Student’s t and Wilcoxon tests were used to compare means and differences in ARG detection (95% confidence intervals). Correlation analyses (odds ratio) and relationships between bacteria density and ARG were determined. Results: Increase in abdominal circumference, waist circumference, hip, waist-hip ratio, BMI, carbohydrate, fibres, and total calorie intakes were different from eutrophic to obese participants. Habitual use of antihypertensive and anti-inflammatory drugs, antacids, and artificial sweeteners were associated mainly with obesity and overweight. Nutritional supplements were associated to the eutrophic group. ARG screening showed differences being more frequent among obese, and positive for 27 genetic markers related to β-lactams, tetracyclines, the macrolide lincosamide and streptogramin group, quinolones, sulfonamides, aminoglycosides, and efflux pump. Positive correlation between ARG and BMI, caloric intake, and intake of xenobiotics, was observed for obese individuals. Relationships among ARG detection and bacteria densities were also different. Conclusions: This study reinforces the hypothesis that obese individuals may harbour an altered gut microbiota, if compared to eutrophic. The overweight individuals display a transitional gut microbiota which seems to be between eutrophic and obese. Furthermore, the increased xenobiotic intake associated to obesity may play an important role in the antimicrobial resistance phenomenon.

Highlights

The functionality of the human body depends on its dynamic ecological balance with resident microbiota, which create essential physiological characteristics for an individual’s survival [1,2].In humans and other warm-blooded animals, the microbiota associated with the gastrointestinal tract is responsible for several fundamental functions in host physiology, including processing of non-digestible dietary components, development, and maturation of the immune system, and processing of xenobiotics [1,3,4].It is accepted that gastrointestinal tract provides a large reservoir of antibiotic resistance genes through the microbiota, defined as the intestinal resistome
The 72 adult volunteers selected from the community and from a nutrition clinic at the University of Juiz de Fora (UFJF)
There was a gradual increase in the abdominal circumference, waist circumference, hip, waist-hip ratio, and body mass index from eutrophic to obese participants

Summary

Introduction

It is accepted that gastrointestinal tract provides a large reservoir of antibiotic resistance genes through the microbiota, defined as the intestinal resistome. This includes genes of clinical relevance defined, in turn, as the clinical resistome [5]. Resistance determinants in the gut have been documented in the microbiota of isolated indigenous populations that have never received antibiotic treatment, and they are not related with the synthesis of secondary metabolites, that might suggest they are constitutively expressed [8,9]

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