Abstract: Objective To explore the relationship between Helicobacter pylori (H. pylori) infection and lower esophageal diseases
in light of the changes of the bacterial flora in the lower esophagus. Methods Thirty BALB/C mice were randomized into
negative control group and H. pylori infection group, and in the latter group, the mice were subjected to intragastric
administration of solution containing H. pylori. After 4 weeks of administration, all the mice were sacrificed, and the V6 areas
in 16S rDNA were amplified from the bacterial DNA extracted from the lower esophagus using polymerase chain
reaction-denaturing gradient gel electrophoresis. The bacterial floras were analyzed on DGGE atlas with Quantity-One 1-D
analysis software, and the differential bands between the two groups were amplified using a 16S rDNA v6 area primer
followed by DNA sequencing and BLAST analysis. Results DGGE finger-prints showed a significantly greater number of DNA
bands in the infection group than in the negative control group (P<0.01). The diversity index and richness index were also
significantly higher in the infection group (0.01<P<0.05). Bacterium cluster class analysis well separated the dendrogram in the
infection group. Principal component analysis showed that different groups of bacteria gathered in different locations, and
BLAST analysis revealed the presence of special bacteria in the infection group. Conclusions In normal mice, Lactobacillus and
the Bacteroides are the predominant bacterial flora colonizing in the lower esophagus, and Staphylococcus, Acinetobacter and
Bacteridium become the predominant bacteria after H. pylori infection.