| PurposesTo compare the bacterial community distribution and diversity of conjunctival flora in patients accepting drug intervention or not before cataract surgery by the 16 S r DNA sequencing technology and to assess the medication value before cataract surgery. MethodsThe conjunctival flora samples were collected from 31 normal adults who were going to receive cataract surgery. Preoperative give levofloxacin 0.5% eye drops(q2h * 1d) and 0.5% povidone-iodine(PVP-I) irrigation. The total samples’ number of the three groups(before antibiotics group, after antibiotics group and after PVP-I(povidone iodine group)) was 93 samples. Total DNA was extracted and sequencd by Illumina Hiseque2000 which was a platform for a new generation of high-throughput 16 S r DNA. The V3-V4 hypervariable regions of bacterial 16 S r DNA were amplified, and the high throughput pyrosequencing was performed.Bioinformatics analysis(including the diversity and relative abundance of species) of the samples were obtained according to the sequence and microflora composition of the three groups were compared according to the species classification(phylum, family, genus). ResultsTotal optimized sequences of the 93 samples were 2420515 and 36 555 OTU(operational taxonomy unit) were obtained by cluster analysis. There were 27 phylum found in three group. and the dominant phylum of the three groups were: Proteobacteria, Actinobacteria, Bacteroidetes and Deinococcus-Thermus. Dominant phylum of the three groups were statistically analyzed, the relative abundance(%) of the before antibiotics group were: 46.54±20.41, 34.11±19.11, 34.11±19.11, 2.10±2.10, 0.67±0.86; those of the after antibiotic group were: 68.28±15.06, 19.37±15.90, 6.55±4.77, 2.38±2.65, 1.61±2.46 and those the after PVP-I group were: 87.29±10.77, 7.37±10.90, 1.84±1.48, 1.36±1.28, 1.28±1.52; the relative content of Proteobacteria was increasing(P<0.001), the relative content of both Actinobacteria and Bacteroidetes were decreasing(P<0.001) and the difference of Deinococcus-Thermus was not statistically significant(P=0.847). In the family level, there were 191 families in the three group. All of the Pseudomonadaceae, Corynebacteriaceae and Moraxellaceae were expressed a high relative abundance in each group, the relative abundance(%) of the before antibiotics group were: 28.23 ± 19.57, 26.89 ± 16.85, 5.24 ± 5.03, those of the after antibiotics group were: 15.02 ± 15.24, 43.25 ± 18.04, 6.29 ± 4.18 and those of the after PVP-I group were: 5.67 ± 10.53, 64.57 ± 18.48, 6.42 ± 3.11; the relative content of Pseudomonadaceae was increasing(P<0.001) and both Corynebacteriaceae and Moraxellaceae were decreasing(P<0.001). In the genus level, 587 genera were detected in the 93 samples of the three groups. There were 585 genera in the before antibiotics group, 505 genera in the after antibiotics group and 476 in the after PVI group. All of the Pseudomonas, Corynebacterium, Acinetobacter, Staphylococcus, Streptococcus. and Achromobacter were expressed a high relative abundance in each group, the relative abundance(%) of the before antibiotics group were: 26.75±17.20, 28.22±19.88, 4.74±2.77, 5.28±5.70, 2.85±4.7, 30.88±1.15, those of the after antibiotics group were: 43.55±18.66, 14.78±15.61, 5.53±4.04, 2.05±2.45, 1.30±2.61, 1.13±0.70 and those of the after PVP-I group were: 63.56±18.89, 5.74±10.75, 5.47±2.77, 0.43±0.43, 0.13±0.21, 2.03±1.19. The relative content of Pseudomonas was increasing(P<0.001) and both Corynebacterium and Staphylococcus were decreasing(P<0.001). There was not statistically significant in the relative abundance of the Acinetobacterwas neither in after antibiotics nor in after PVP-I group compared with the before antibiotics group(P<0.05). The relative abundance of Achromobacter had no obvious changes after antibiotics, but the relative abundance increased after PVP-I irrigation. ConclusionsThe results of the study which illustrated 16 S r DNA high-throughput sequencing technology find that the diversity of the bacteria community in conjunctival and the relative content of them, reveales that the 16 S r DNA high-throughput sequencing technology has obvious advantages than traditional culture-dependent method. The conjunctival sac containing abundance bacterial genome. We find 585 genera and 191 families belonged to 27 phyla. There are significant individual difference both in diversity and the relative abundance in bacteria community. Distribution of bacteria before and after treatment has undergone significant changes, both the 0.5% levofloxacin eye drops and 0.5%(the effective iodine concentration) povidone-iodine could effectively change the distribution of conjunctival flora. |
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