A recent study, led by Dr. Menghui Zhang from the State Key Laboratory of Microbial Metabolism at Shanghai Jiao Tong University (China), has shown that gut resistome of obese children is reduced after a dietary intervention.
The resistome refers to the collection of all the antibiotic resistant genes (ARGs) in a specific environment. The human gut microbiota includes a reservoir of ARGs and allows for the exploration of the human gut resistome at the whole microbial community level. Although it is a well-known fact that diet shapes the composition and function of the gut microbiota, its influence on the gut resistome has not yet been studied.
By using deep metagenomic sequencing, Wu and colleagues studied the gut resistome of 35 obese children with either Prader-Willi syndrome (a rare genetic disorder that is associated with – among many other developmental problems – severe obesity) or with simple obesity before and after dietary intervention, at different levels including ARGs, gene types and resistance potential to corresponding antibiotics and antibiotic classes. The dietary intervention consisted of a diet rich in non-digestible carbohydrates (based on whole grains, traditional Chinese medicinal foods and prebiotics) for 30 days. The nutritional composition of the diet can be found here.
Both the richness and diversity of the gut resistome were significantly reduced after the dietary intervention. The intervention eliminated up to 48 ARGs and reduced the abundance of more than 77% of ARGs. Specifically, the abundance of 36 different resistant gene types was significantly altered after dietary intervention. When studying gene types assigned to their corresponding antibiotic compounds, a total of 10 ARG types related to antibiotic compounds in faecal samples were reduced after the intervention: namely chloramphenicol, norfloxacin, puromycin, erythromycin, fosfomycin, vancomycin, polymicin, enoxacin, fosmidomycin and kasugamycun. At the antibiotic class level, the abundances of 8 ARG types linked to different antibiotic classes, including streptogramin, macrolide, polypepetides, sulfonamide, quinolone, amphenicols and glycopeptide, were significantly reduced in post-intervention faecal samples. The researchers also constructed an ARG distribution network that provided the types and numbers of ARGs in each bacterium of their dataset. The intervention reduced up to 69% of ARG carriers, which include Klebsiella, Enterobacter and Escherichia, which are bacteria known to be involved in multidrug resistance. All together these data show that shifting the dominant fermentation of gut bacteria from protein to carbohydrate by a diet rich in non-digestible carbohydrates significantly diminished the gut resistome of obese children.
In conclusion, the striking finding of this study is that a dietary intervention can reduce antibiotic resistance genes in the intestines of obese children. Therefore, managing the gut resistome by dietary interventions emerges as a useful tool to fight against the threat of antibiotic resistance.
Wu G, Zhang C, Wang J, et al. Diminution of the gut resistome after a gut microbiota-targeted dietary intervention in obese children. Sci Rep. 2016; 6:24030. doi:10.1038/srep24030.
Zhang C, Yin A, Li H, et al. Dietary modulation of gut microbiota contributes to alleviation of both genetic and simple obesity in children. EBioMedicine. 2015; 2(8):968-84.