AIMTo investigate the diversity of bacterial lactase genes in the intestinal contents of mice with antibiotics-induced diarrhea.METHODSFollowing 2 d of adaptive feeding, 12 specific pathogen-free Kunming mice were randomly divided into the control group and model group. The mouse model of antibiotics-induced diarrhea was established by gastric perfusion with mixed antibiotics (23.33 mL·kg-1·d-1) composed of gentamicin sulfate and cephradine capsules administered for 5 days, and the control group was treated with an equal amount of sterile water. Contents of the jejunum and ileum were then collected and metagenomic DNA was extracted, after which analysis of bacterial lactase genes using operational taxonomic units (OTUs) was carried out after amplification and sequencing.RESULTSOTUs were 871 and 963 in the model group and control group, respectively, and 690 of these were identical. There were significant differences in Chao1 and ACE indices between the two groups (P < 0.05). Principal component analysis, principal coordination analysis and nonmetric multidimensional scaling analyses showed that OTUs distribution in the control group was relatively intensive, and differences among individuals were small, while in the model group, they were widely dispersed and more diversified. Bacterial lactase genes from the intestinal contents of the control group were related to Proteobacteria, Actinobacteria, Firmicutes and unclassified bacteria. Of these, Proteobacteria was the most abundant phylum. In contrast, the bacterial population was less diverse and abundant in the model group, as the abundance of Bradyrhizobium sp. BTAi1, Agrobacterium sp. H13-3, Acidovorax sp. KKS102, Azoarcus sp. KH32C and Aeromonas caviae was lower than that in the control group. In addition, of the known species, the control group and model group had their own unique genera, respectively.CONCLUSIONAntibiotics reduce the diversity of bacterial lactase genes in the intestinal contents, decrease the abundance of lactase gene, change the lactase gene strains, and transform their structures.

BackgroundQiweibaizhu powder (QWBZP) has been shown to be effective in treating antibiotic-associated diarrhea (AAD). Previous research has reported that plant polysaccharides can promote the growth of beneficial intestinal bacteria and inhibit the multiplication of pathogenic bacteria, thus effectively treating diarrhea. Here, we investigated the effect of QWBZP crude polysaccharide on the diversity of intestinal mucosal bacteria and their community structure composition in mice with AAD, and the aim of this study was to provide the scientific basis for the efficacy of QWBZP crude polysaccharide on diarrhea.Materials and MethodsEighteen Kunming (KM) mice were randomly divided into the normal (mn) group, the model (mm) group, and the QWBZP crude polysaccharide treatment (ma) group, with six mice in each group. An AAD model was constructed using a mixed antibiotic solution and treated with gavage crude polysaccharide solution of QWBZP. The intestinal mucosa was extracted from the jejunum to the ileum of mice, and the metagenome was extracted and then analyzed using MiSeq sequencing to characterize the intestinal mucosal bacteria in mice.ResultsThe spleen and thymus indices of each group of mice had no significant differences. The Chao1 and ACE indices of the mn and mm groups were similar, the Simpson index was the largest and the Shannon index was the smallest in the mm group, and there was no significant difference in the diversity indices of all three groups. In the PCA and PCoA, the mn and ma group samples were both relatively concentrated with a high similarity of community structure. In contrast, the samples in the mm group were more scattered and farther away from the samples in the mn and ma groups, i.e., the community structure similarity within and between the groups was low. Compared with the mm group, the relative abundance of Proteobacteria, Lactobacillus, and the Firmicutes/Bacteroidetes (F/B) ratio in the ma group was decreased, while that of Enterococcus continued to increase. In the LEfSe analysis, there were significant differences in the characteristic bacteria in the mn, mm, and ma groups.ConclusionThe single crude polysaccharide component is not very effective in treating AAD, so the clinical efficacy of the QWBZP crude polysaccharide is subject to further investigation.

Background Antibiotic-associated diarrhea (AAD), defined as diarrhea that occurs in association with the administration of antibiotics and without another clear etiology, is one of the most common adverse drug events of antibiotics therapy. We established a diarrhea model induced by gentamycin and cefradine to investigate the microbiota characteristics in the intestinal lumen of mice with AAD and provide insights into noteworthy bacteria related to gentamicin and cefradine-associated diarrhea. Results The number of OTUs in the model group and the normal group was 983 and 2107, respectively, and 872 identical OTUs were shared between two groups. Species richness and species diversity of intestinal microbe were altered by antibiotics administration. PCoA showed a clear separation between AAD and health control. The dominant phyla of AAD mice were Firmicutes (52.63%) and Proteobacteria (46.37%). Among the genus with top 20 abundance, the relative abundance of 7 genera, Ruminococcus, Blautia, Enterococcus, Eubacterium, Clostridium, Coprococcus, and Aerococcus, were enriched in the model group. Based upon the LEfSe analysis, Enterococcus, Eubacterium, Ruminococcus, and Blautia were identified as potential biomarkers for AAD. Conclusions The bacterial diversity of the intestinal lumen was diminished after gentamicin and cefradine administration. The alterations in the abundance and composition of gut microbiota further led to the dysfunction of gut microbiota. More specifically, gentamicin and cefradine significantly increased the abundance of the opportunistic pathogens, of which Enterococcus and Clostridium were the most prominent and most worthy of attention.

To investigate the influence of treatment on intestinal microorganisms in mice with antibiotics-induced diarrhea, mouse model of antibiotics-induced diarrhea was created by gavaging mice with mixed antibiotics (23.33 mL/kg/days) composed of gentamycin sulfate and cefradine for 5 days. Mice with the symptom of diarrhea were then treated with by intragastric administration. The control group mice were given with sterile water. After 4 day treatment, total DNA of intestinal microflora of treated and control mice was extracted, and their quantities were measured by sequencing the V4 region of 16S rDNA. The results showed that when compared to the control (sterile water), treatment with increased the operational taxonomic units (OTUs) of intestinal bacteria. The Chao index in diarrhea treated group was higher than diarrhea control group and was similar to healthy control group, while all differences had no significance ( > 0.05). treatment increased the Shannon index but not significantly ( > 0.05). Moreover, there was not significant impact on density and diversity of intestinal bacterial population at phylum and genus levels ( > 0.05). Interestingly, treatment recovered the population density of certain bacterium species, such as (in family level) ( < 0.05). Our results indicate that has potency of adjusting the density and diversity of intestinal bacteria and recovering the population density of in family level.

The current study aimed at exploring the diversity of bacterial lactase genes in the intestinal mucosa of mice with dysbacterial diarrhea induced by antibiotics and to provide experimental basis for antibiotics-induced diarrhea. Mice model of dysbacterial diarrhea was established by gastric perfusion with mixture of cephradine capsules and gentamicin sulfate (23.33 mL kg d), twice a day and continuously for 5 days. Intestinal mucosa from jejunum to ileum was collected, and bacterial metagenomic DNA was extracted for Miseq metagenome sequencing to carry out diversity analysis. The results showed that specific operational taxonomic units (OTUs) were 45 in the control group and 159 in the model group. The Chao1, ACE, Shannon and Simpson indices in model group were significantly higher (< 0.01 or < 0.05) than control group. Principal component analysis (PCA) and box chart of the control group were relatively intensive, while in the model group, they were widely dispersed. Furthermore, the inter-group box area was higher than that in the intra-group. Compared with the model group, the abundance of bacterial lactase genes in Proteobacteria from the intestinal mucosa of the control group was higher, but lower in Actinobacteria and unclassified bacteria. At the genus level, the relative abundance of bacterial species and taxon units in model group was obviously increased (< 0.05). Our results indicate that antibiotics increased the diversity and abundance of bacterial lactase genes in the intestinal mucosa, as the abundance of ,, ,, and. In addition, antibiotics become an additional source for lactase genes of ,, ,, and.