The current investigation is trying to study the impact of the mixture of Chinese herbs Qi Wei Bai Zhu San (QWBZS) on bacterial
lactase gene from
antibiotics-induced
diarrhea (AAD) mice, as the good curative effect of QWBZS on
diarrhea. Mice (6 mice per group) were randomly selected as control, model and treatment groups. To induce
diarrhea, mice in both model and treatment groups were intragastrically injected with mixture of
gentamycin sulfate and
cefradine (23.33 mL kg-1 day-1) twice per day and continuously for totally 5 days. After the success of establishing
diarrhea model, the mice in treatment group were gavaged with QWBZS for 3 days. Intestinal contents in all three groups were then collected and
DNA was extracted in aseptic environment for the following sequencing. The results showed that mice from QWBZS treatment group had obviously detectable levels of intestinal bacteria, such as Actinobacteria, Firmicutes and Proteobacteria, which produce phyla
lactase specifically. In comparison with other groups, the mice in treatment group had more abundant expression of
lactase gene from Acidovorax sp. KKs102, Stenotrophomonas sp. LMG11000, Pseudomonas oleovorans, Eggerthella and Burkholderia. Interestingly, the Shannon index decreased significantly after the treatment with QWBZS (P < 0.01 or P < 0.05). 63.1% of
lactase genes detected in the mice in treatment group were unclassified, and 32.8% of them were non-homologous to any fragments in the gene bank, which means that most of
lactase-producing bacteria are novel. Our results indicate that treatment with QWBZS did not increase the diversity of bacterial
lactase gene. Its curative effect on
diarrhea may be relevant to its role in facilitating the growth of novel or some key
lactase-producing strains.