| The intestinal flora affects the host's basic functions such as metabolism,digestion and other basic functions.by regulating host immune,metabolic,and neural pathways.Current research shows that intestinal microbes are related to cancer,diabetes,cardiovascular disease,obesity,intestinal inflammation and many other diseases.The intestinal flora has been studied to predict and treat some clinical diseases that are difficult to cure or easy to relapse.Some fecal microbiological research results such as fecal microbiota transplantation(FMT)have been put into clinical treatment The intestinal flora is affected by many factors,and antibiotics are one of the main reasons,especially some oral antibiotics with broad-spectrum antibacterial effects.While killing or inhibiting pathogenic bacteria,antibiotics also affect the composition,structure and function of the intestinal flora.The effects of antibiotics on the intestinal flora may last for several years,leading to some bacteria have completely disappeared from the intestine.Antibiotics affect many diseases related to the intestinal flora through the intestinal flora.Antibiotic resistance caused by the use of antibiotics is also an important hidden danger that threatens human health.The World Health Organization has listed antibiotic resistance as one of the three major threats to health.Some multi-drug resistant bacteria,(MDR)such as Methicillin resistant Staphylococcus aureus(MRSA),Vancomycin resistant Enterococcus(VRE),Enterobacter carrying the NDM-1 gene,the emergence of these bacteria has made the treatment of some easily curable diseases more difficult,more costly,and accompanied by more side effects.Antibiotic resistance has led to the loss of nearly ten million people and caused a lot of economic losses.In recent years,many researchers have focused on the effects of antibiotics on intestinal flora and antibiotic resistance.The impact of antibiotics on intestinal flora can provide a reference for the use of clinical antibiotics to avoid diseases caused by improper use of antibiotics that cause disturbances in the intestinal flora.In this paper,C57/BL6 mice were used as models.Mice were administered gastric ampicillin(AMP)and imipenem(IMP).The feces were collected and the selective media is used to culture Enterobacter,Enterococcus and Lactobacillus in feces,then different bacteria were counted.the fecal microbial genome was extracted,Quantitative Real-time PCR(qPCR)was used to detect the content of broad-spectrum ?-lactamase gene blaTEM,a common carbapenem antibiotic resistance gene blaIMP-1,and 16S rDNA genes in fecal microorganisms.16S high-throughput technology was used to analyze changes in the structure and function of the floraThe results showed that compared with the control group,the number of Enterobacter bacteria in the feces of mice taking imipenem and ampicillin antibiotics increased significantly,and the number of lactobacillus did not change significantly before and after treatment.The number of Enterobacter decreased significant around the 10th day of administration,and returned to the level before the administration during the ten-day recovery period.The change trend of Enterococcus was similar to that of Enterobacter,and it was a process of rising and then decreasing.It was found after administration of ampicillin The number of antibiotic-resistant Enterobacter in mouse stools increased significantly.According to the Antimicrobial susceptibility test,the minimum inhibitory concentration of the isolated Enterobacter strains was about 1024?g/mL on the 3rd to 6th days of administration.The minimum inhibitory concentration(MIC)of Enterobacter strains isolated at other time points during the administration period was significantly higher than that of the control group.Resistance to ampicillin of Enterococcus did not change significantly compared with the control group.For the group of mice given imipenem gavage,imipenem gavage may increase the number of imipenem-resistant Enterococcus in the intestine of some mice.MIC results showed that the resistance of Enterococcus and Enterobacter to imipenem did not increase.The results of real-time quantitative PCR showed that after administration of imipenem and ampicillin,the copy number of 16SrDNA in gene per gram of mouse stool was significantly higher than that of the control group,indicating that the number of bacterias in the feces of mice increased after gavage of two antibiotics.The copies of integrin(intll)gene and blaTEM gene were also tested,and and it was found that the two antibiotics did not affect the abundance of intll gene and blaTEM gene in the intestine.No blaIMP-1 gene was detected in fecal microbial genome.The results of 16S rDNA Amplicon Sequencing revealed a decrease in the abundance of Bacteroidetes,an increase in the abundance of Proteobacteria and Verrucomicrobia.Further analysis of the flora Changes in the levels of families,genera,and species,it was found that the abundance of some bacterial families in Bacteroidetes and Firmicutes decreased,and the abundance of some bacterial families in Proteobacteria and Verrucomicrobia increased.The changes in genera and species levels were similar to the levels of their families and phyla.The abundance of the dominant genera in some families with higher abundance was higher than that in the control group.Among them,the bacterial abundance of Enterobacter and Enterococcus first increased and then decreased with time.And antibiotics also affect the expression of some genes related to human diseases,organ development,cell activity,and bacterial resistance in the intestinal flora. |
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