Comparative efficacy of two different topical povidone-iodine 5% regimens in reducing conjunctival bacterial flora: A randomized parallel double-masked clinical trial

Effects of chloramphenicol, povidone-iodine 1% and 5% eye drops on the colonisation of conjunctival flora in patients undergoing cataract surgery

Objectives

the aim was to compare 2 drops of either 5% chloramphenicol, 1% povidone-iodine or 5% povidone-iodine before cataract surgery on reducing the colonisation of bacterial flora in the conjunctiva.

Design

This was a double-blind, randomised clinical trial study.

Setting

Patients referred to Shahid Sadoughi Hospital in Yazd, Iran, for cataract surgery were studied.

Participants

Totally 260 patients were enrolled.

Intervention

The affected lower fornix was gently sampled with a sterile swab and cultured on appropriate microbiological media. Then one of the 3 solutions mentioned above was instilled into the conjunctival sac of the cases in groups 1, 2 and 3, respectively. After thirty minutes, new conjunctival swabs were taken and cultured.

Main outcome measures

The type of bacteria isolated and their colony-forming unit per mL (CFU/mL) number were primary end-points. The statistical tests of Phi and Cramer's V and Wilcoxon and Kruskal-Wallis were applied to evaluate the relationship between the studied variables and culture results as the secondary end-point.

Results

The studied patients were 129 (49.6%) males and 131 (50.4%) females. Bacterial growth was observed in 49 cases (18.85%); the most commonly isolated bacteria were Staphylococcus epidermidis (71.42%). In the povidone-iodine 5% and chloramphenicol groups (but not the povidone-iodine 1%), the decrease in the number of CFU/mL was statistically significant (P = 0.032 and P = 0.005, respectively, Wilcoxon test).

Conclusion

A single dose of povidone-iodine 5% and chloramphenicol effectively reduces the colonisation of normal conjunctival bacteria and can be used as effective prophylaxis.

Funding

This study was part of an MSc thesis of Nasrin Tofighi. Shahid Sadoughi University of Medical Sciences, Yazd, Iran, funded this work.

Effect of topical povidone-iodine 10% plus levofloxacin 0.5% 1 hour before cataract surgery in eliminating perioperative conjunctival flora: randomized clinical trial

PURPOSE

To evaluate the effect of a single administration of topical povidone-iodine (PVI) 10% plus levofloxacin 0.5% at 1 hour before cataract surgery on perioperative elimination rate of conjunctival flora.

SETTING

Poostchi Ophthalmology Research Center, Shiraz, Iran.

DESIGN

Randomized controlled trial.

METHOD

Patients who required cataract surgery were randomly assigned to 1 of 2 groups: intervention (administration of PVI 10% plus levofloxacin 0.5% at 1 hour preoperatively) or control. The patients in both groups received PVI just before the operation. Conjunctival cultures were obtained using thioglycollate broth at 4 timepoints: T1, before intervention; T2, before the second application of PVI; T3, 3 minutes after the second administration of PVI; and T4, just postoperatively.

RESULTS

The study comprised 142 patients. The comparative rates of positive cultures in the intervention vs control groups were as follows: T1 (70.4% vs 73.2%, P = .709); T2 (15.5% vs 71.8%, P < .001); T3 (7.0% vs 19.7%, P = .027); and T4 (5.6% vs 4.2%, P = .698). Coagulase-negative Staphylococci was the most common isolated microorganism.

CONCLUSIONS

Results showed that a single adjuvant application of PVI 10% plus levofloxacin 0.5% eyedrops at 1 hour before operation leads to a further increase in the rate of sterile conjunctiva just preoperatively.

Use of an ultra-clean air flow for surgical field asepsis when performing intravitreous injections in an ambulatory surgical environment

Background

Intravitreal injection of medications is one of the most common procedures performed in ophthalmology. Intravitreal anti-VEGF agents are currently the chosen treatment for ocular fundus diseases, including age-related macular degeneration and diabetic retinopathy. As an invasive procedure it involves risks. The most serious complication from intravitreal injection of anti-VEGF agents is endophthalmitis (EO). Although rare, EO can result in devastating loss of vision. This article evaluates whether the use of an ultra-clean air flow (UA) can be another useful tool in the prevention of EOs. Accordingly, the maintenance of asepsis of the surgical field of intravitreal injections was verified with and without the use of UA.

Methods

The study was conducted in operating room of an ambulatory surgery center on four different surgical days when just intravitreal injections were scheduled. Two experiments using two Blood Agar and two Chocolate Agar plates (first 2 days; 4 plates by day) were carried out by positioning an UA directed to the surgical table and two other experiments (last 2 days; 4 plates per day) were carried out using similar plates without the use of the UA. All Blood Agar and four Chocolate Agar plates were positioned on the surgical table, close to the surgical filed. At the end of the day, after the conclusion of the intravitreous injections, the plates were sent for a biomolecular study that was carried out after 1 day of incubation at 37 °C.

Results

The sixteen plates, eight Blood Agar and eight Chocolate Agar, were analyzed qualitatively for the growth or not of microorganism’s colonies and identification of their species. The biomolecular study demonstrated the growth of bacteria of the genus Micrococcus sp. with the use of the UA and without the the UA bacterias of the genera Bacillus sp, Staphylococcus haemolyticus, Staphylococcus aureus and Staphylococcus cohnii ssp urealyticus were found.

Conclusion

The use of UA close to the operating table prevented the growth of pathogenic bacteria and should be considered as an alternative tool to avoid the contamination of materials and drugs used for intravitreal injections.

Povidone iodine treatment is deleterious to human ocular surface conjunctival cells in culture

Objective

To determine the effect of povidone iodine (PI), an antiseptic commonly used prior to ocular surgery, on viability of mixed populations of conjunctival stratified squamous and goblet cells, purified conjunctival goblet cells and purified conjunctival stromal fibroblasts in primary culture.

Methods and analysis

Mixed population of epithelial cells (stratified squamous and goblet cells), goblet cells and fibroblasts were grown in culture from pieces of human conjunctiva using either supplemented DMEM/F12 or RPMI. Cell type was evaluated by immunofluorescence microscopy. Cells were treated for 5 min with phosphate-buffered saline (PBS); 0.25%, 2.5%, 5% or 10% PI in PBS; or a positive control of 30% H₂O₂. Cell viability was determined using Alamar Blue fluorescence and a live/dead kit using calcein/AM and ethidium homodimer-1 (EH-1).

Results

Mixed populations of epithelial cells, goblet cells and fibroblasts were characterised by immunofluorescence microscopy. As determined with Alamar Blue fluorescence, all concentrations of PI significantly decreased the number of cells from all three preparation types compared with PBS. As determined by calcein/EH-1 viability test, mixed populations of cells and fibroblasts were less sensitive to PI treatment than goblet cells. All concentrations of PI, except for 0.25% used with goblet cells, substantially increased the number of dead cells for all cell populations. The H₂O₂ control also significantly decreased the number and viability of all three types of cells in both tests.

Conclusion

We conclude that PI, which is commonly used prior to ocular surgeries, is detrimental to human conjunctival stratified squamous cells, goblet cells and fibroblasts in culture.

Topical proparacaine eye drops to improve the experience of patients undergoing intravitreal injections: A randomized controlled trial

PURPOSE

We sought to evaluate whether additional topical anesthetic, specifically proparacaine 0.5%, improved patient experience with intravitreal injections without hindering antisepsis.

METHODS

A prospective, randomized controlled trial was conducted including 36 eyes of 36 patients undergoing intravitreal injections. Patients were randomized to treatment with additional topical proparacaine 0.5% versus control after undergoing informed consent. All patients prior to intravitreal injection underwent conjunctival culture after one drop of topical proparacaine 0.5% was placed. Half of patients then received an additional drop of proparacaine and then underwent a second conjunctival culture. The other half of patients had a drop of povidone iodine and then a second conjunctival culture. Intravitreal injection followed conjunctival cultures. To evaluate their experience, patients were provided with a survey.

RESULTS

In total, 36 patients were enrolled in the study. Three of 36 (8.3%) patients had positive conjunctival cultures after proparacaine eye drops alone. One of 17 (5.8%) patients had a positive conjunctival culture after a second drop of proparacaine. One of 19 (5.3%) patients had a positive culture after proparacaine and povidone iodine. By noninferiority analysis, proparacaine was inferior to povidone iodine (p = .28). Patient experience surveys did not differ between groups.

CONCLUSION

Patient perception did not significantly differ whether or not additional proparacaine drops were used prior to intravitreal injection in a randomized controlled trial. While proparacaine has some antiseptic properties, these were found to be inferior to those of povidone iodine. Therefore, while povidone iodine is essential for antisepsis, additional proparacaine drops should not interfere with antisepsis.