Abstract
Purpose :
to evaluate the effectiveness of two topical antiseptics, povidone-iodine (PVI) and chlorhexidine (CHX) in reducing conjunctival bacterial microbiota
Methods :
Single-center, prospective, randomized clinical trial. 42 patients undergoing cataract surgery were randomly divided in two groups: one group (21 patients) used PVI 0.66% 4 times daily starting 3 days before surgery; the other (21 patients) used CHX 0.02% with the same posology. The contralateral eye was considered as control. Conjunctival swabs of both eyes at the baseline (T0) and after three days of treatment (T1) were collected all before cataract surgery with an eSwab with 1 mL of Liquid Amies Medium (Copan Brescia, Italy). DNA was extracted with a QIAamp DNA Microbiome Kit. Amplification was performed using 2 primer pools containing a primer to amplify the V2-4-8 region of 16S rDNA and the V3-6, 7–9 region of 16S rDNA. Libraries were pooled to obtain the final concentration at 26 pM. Template preparation was performed with Ion Chef. Sequencing of the amplicon libraries was carried out on 530 chip using the Ion Torrent S5 system. Raw reads were analyzed with GAIA (v 2.02). The richness and Shannon alpha diversity metrics, as well as Bray–Curtis beta diversity values, were computed with the R package phyloseq. The identification of ECSTs was carried out with the R package cluste. Principal coordinate analysis (PCoA) was performed using the function plot_ordination.
Results :
84 eye microbiome samples were analyzed. Taxonomy barplot by gender in represented in Figure 1. Microbiota of the 2 groups after treatment is showed in Figure 2. The vast majority of samples showed a reduction in Staphylococcus, Bacillus, Pseudomonas, and Corynebacterium predominate. We found an average of 88 genera with an average Shannon index of 0.65. ECSTs were characterized accordingly in each group (ECST-1 and ECST-2) The results will be presented as estimates of the effects (ratios or fold changes) and corresponding 95% confidence intervals. All tests will be two-sided and a 5% significance level will be used. Analyzes will be conducted using R (4.0.2 or later) and STATA (14.0).
Conclusions :
Both topical antiseptics were able to reduce conjunctival bacterial microbiota. PVI group lead to ECST-1 while CHX to ECST-2.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.