In vitro bactericidal activity of 0.6% povidone-iodine eye drops formulation

Antimicrobials and antiseptics: Lowering effect on ocular surface bacterial flora - A systematic review

Topical antimicrobials and antiseptics are used perioperatively to reduce the ocular surface bacteria flora (OSBF) that are involved in the development of post-operative infectious complications. However, their effectiveness is still a controversial topic. This systematic review, performed according to the PRISMA guidelines and registered in PROSPERO, aims to provide an overview of the efficacy of the agents currently used in peri-cataract surgery and -intravitreal injections (IVI) in lowering the OSBF. Although effective in lowering OSBF, perioperative topical antimicrobials are associated with the risk of resistance development, with no obvious additional benefit compared with topical antisepsis. Conversely, the effectiveness of topical antiseptics before cataract surgery and IVI is strongly supported. Based on the available evidence, perioperative antimicrobials are not recommended, whereas the perioperative use of antiseptics is strongly recommended as prophylactic treatment for lowering the infection due to OSBF. Post-operative antimicrobials may be considered in eyes at higher risk for infection.

Biocides in the Hospital Environment: Application and Tolerance Development

Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.

Solid-State Preparation and Characterization of 2-Hydroxypropylcyclodextrins-Iodine Complexes as Stable Iodophors

The use of iodine as antiseptic poses some issues related to its low water solubility and high volatility. Stable solid iodine-containing formulations are highly advisable and currently limited to the povidone-iodine complex. In this study, complexes of molecular iodine with 2-hydroxypropyl α-, β- and γ-cyclodextrins were considered water-soluble iodophors and prepared in a solid state by using three different methods (liquid-assisted grinding, co-evaporation and sealed heating). The obtained solids were evaluated for their iodine content and stability over time in different conditions using a fully validated UV method. The assessment of the actual formation of an inclusion complex in a solid state was carried out by thermal analysis, and the presence of iodine was further confirmed by SEM/EDX and XPS analyses. High levels of iodine content (8.3–10.8%) were obtained with all the tested cyclodextrins, and some influence was exerted by the employed preparation method. Potential use as solid iodophors can be envisaged for these iodine complexes, among which those with 2-hydroxypropyl-α-cyclodextrin were found the most stable, regardless of the preparation technique. The three prepared cyclodextrin–iodine complexes proved effective as bactericides against S. epidermidis.

p-Sulfonato-Calix[4]arene Micelles Stabilize a Povidone Iodine Solution: Supramolecular Interactions, Iodine Retention, and Bactericidal Activity

Povidone iodine (PVPI) is an antiseptic widely used against a broad spectrum of pathogens. However, undesired side-effects are still associated with PVPI treatment due to the irritant effect of iodine. Reducing the concentration of a PVPI formulation could provide safer and more friendly formulations, for routine use and applications in very delicate organs such as the eye. However, managing the storage of a low-concentration solution of PVPI is challenging due to the high iodine volatility. In this study, we demonstrated that an amphiphilic p-sulfonato-calix[4]arene derivative forming micelles (SC4OC6) improves the stability of a 0.1% PVPI aqueous buffered solution. UV-vis and NMR spectra as well as dynamic and electrophoretic light scattering measurements showed that SC4OC6 establishes non-covalent supramolecular interactions with PVPI, resulting in the formation of nanoaggregates with a negatively charged surface. Isothermal titration calorimetry provided the aggregation parameters and evidenced that the formation of the supramolecular assembly is an enthalpically favored process. The interaction of SC4OC6 with PVPI enhances the iodine retention and stability of the solution without affecting the rapid and effective bactericidal activity of PVPI, as demonstrated by a time-killing assay with Staphylococcus epidermidis.

Ophthalmic Solutions with a Broad Antiviral Action: Evaluation of Their Potential against Ocular Herpetic Infections

HSV-1 can be associated with severe and recurrent eye infections characterized by a strong inflammatory response that leads to blepharoconjunctivitis, epithelial and stromal keratitis, and retinal necrosis. The incidence of HSV-1 keratitis is 1.5 million every year worldwide, including more than 40,000 new cases exhibiting serious visual failures. Generally, the therapy uses antiviral drugs to promote healing; however, there are currently no compounds that are able to completely eradicate the virus. In addition, the phenomenon of resistance is rapidly spreading among HSV-1 strains, creating mutants developing resistance to the common antiviral drugs; therefore, deep research on this issue is warranted. The efficacy of different ophthalmic solutions already on the market was evaluated for reducing HSV-1 infection. Different plaque assays were set up on epithelial cells, revealing that two ophthalmic solutions were able to inhibit viral replication in the early stages of infection. The data were further confirmed by molecular tests analyzing the expression levels of the principal genes involved in HSV-1 infection, and a strong reduction was observed after only 1 min of eye-drop treatment. Collectively, these results suggested the use of ophthalmic solutions as potential antiviral options for the treatment of ocular herpetic infection.

Efficacy of Three Povidone Iodine Formulations against Cutibacterium acnes Assessed through In Vitro Studies: A Preliminary Study

Cutibacterium acnes (C. acnes, formerly known as Propionibacterium acnes) is the major causative agent of prosthetic joint infections (PJI). Treatment of PJI with antibiotics is difficult due to antibiotic resistance and adverse side effects on patients’ health. Proper disinfection of the surgical site using a variety of povidone iodine formulations could prevent C. acnes infection. In the current study, the efficacy of the three povidone iodine (PVP-I) formulations, viz: PVP-I 10% dermic solution, PVP-I 5% alcoholic solution and PVP-I 4% scrub, was tested against C. acnes, in vitro, in the presence of interfering substances mimicking soiling conditions. C. acnes strain ATCC 6919 was used to test the bactericidal activity of the povidone iodine formulations according to the modified dilution-neutralization method described in French Norm EN standard 13727. A 3-log reduction in the bacterial cell count in 60 s was considered to be significant. The results showed that under experimental conditions, the three PVP-I formulations displayed bactericidal activity against the micro-organism, Cutibacterium acnes, and that the lowest concentration of povidone-iodine active against C. acnes was 0.4%. These results are encouraging as PVP-I offers a low-cost and efficient method of disinfection.

Efficacy and tolerability of polyvinylpyrrolidone-iodine 0.6% treatment in adenoviral keratoconjunctivitis: a Prospective Randomized Controlled Study

OBJECTIVES

To analyze the effect of the employment of polyvinylpyrrolidone-iodine (PVP-I) 0.6% eye drop on the clinical course of patients affected by Adenoviral Keratoconjunctivitis (AKC).

METHODS

Consecutive patients with clinical signs of AKC and positive results of AdenoPlus test were enrolled from four Italian Centres. Patients were randomized to receive: PVP-I 0.6% eye drops four times/daily for 20 days (Group A) or hyaluronate-based tear substitutes four times/daily for 20 days (Group B). Best-corrected visual acuity (BCVA), optical coherence tomography (OCT) Optovue iVue pachymetry map; corneal haze; conjunctival injection and chemosis; subepithelial corneal infiltrates (SEIs); corneal and conjunctival staining and corneal densitometry were recorded at diagnosis and at every follow-up visit. The primary outcome was the resolution time of AKC.

RESULTS

Overall, 59 AKC patients (34 for Group A and 25 for Group B) completed the study. Patients of Group A showed a significantly shorter resolution time and lower incidence of SEIs compared to patients of Group B. In particular, SEIs were present at the last visit in 3/34 (8.82%) patients of the Group A vs 11/25 (44%) of the Group B (p = 0.005). Patients of Group A showed a significantly lower incidence of corneal haze compared to patients of Group B (0/34 vs 3/25; p = 0.038). No side effects were reported for both groups.

CONCLUSIONS

Although further clinical evaluations are needed, according to our data the use of PVP-I 0.6% eye drop in the setting of AKC reduces the risk of SEIs as well as the resolution time of the disease.

In vivo antimicrobial activity of 0.6% povidone-iodine eye drops in patients undergoing intravitreal injections: a prospective study

To investigate the antimicrobial activity of a preservative-free 0.6% povidone-iodine eye drop as an antiseptic procedure in decreasing the conjunctival bacterial load in eyes scheduled for intravitreal treatment and to compare its efficacy to the untreated fellow eye used as the control group. Prospective cohort analysis in which 208 patients received preservative-free 0.6% povidone-iodine eye drops three times a day for three days before intravitreal injection. Before and after the prophylactic treatment, a conjunctival swab was collected from both the study eye and the untreated contralateral eye, used as control. The swab was inoculated on different culture media and the colony-forming units were counted. Bacteria and fungi were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Treatment with 0.6% povidone-iodine eye drops significantly reduced the conjunctival bacterial load from baseline (p < 0.001 for blood agar and p < 0.001 for chocolate agar) with an eradication rate of 80%. The most commonly isolated pathogen at each time-point and in both groups was coagulase-negative Staphylococci, isolated in 84% of the positive cultures. The study provides evidence about the effectiveness of 0.6% povidone-iodine eye drops treatment in reducing the conjunctival bacterial load in eyes scheduled for intravitreal treatment.

Clinical Features and Molecular Characteristics of Methicillin-Susceptible Staphylococcus aureus Ocular Infection in Taiwan

This study analyzed the clinical features and molecular characteristics of methicillin-susceptible Staphylococcus aureus (MSSA) ocular infections in Taiwan and compared them between community-associated (CA) and health-care-associated (HA) infections. We collected S. aureus ocular isolates from patients at Chang Gung Memorial Hospital between 2010 and 2017. The infections were classified as CA or HA using epidemiological criteria, and the isolates were molecularly characterized using pulsed-field gel electrophoresis, multilocus sequence typing, and Panton-Valentine leukocidin (PVL) gene detection. Antibiotic susceptibility was evaluated using disk diffusion and an E test. A total of 104 MSSA ocular isolates were identified; 46 (44.2%) were CA-MSSA and 58 (55.8%) were HA-MSSA. Compared with HA-MSSA strains, CA-MSSA strains caused a significantly higher rate of keratitis, but a lower rate of conjunctivitis. We identified 14 pulsotypes. ST 7/pulsotype BA was frequently identified in both CA-MSSA (28.3%) and HA-MSSA (37.9%) cases. PVL genes were identified in seven isolates (6.7%). Both CA-MSSA and HA-MSSA isolates were highly susceptible to vancomycin, teicoplanin, tigecycline, sulfamethoxazole–trimethoprim, and fluoroquinolones. The most common ocular manifestations were keratitis and conjunctivitis for CA-MSSA and HA-MSSA, respectively. The MSSA ocular isolates had diverse molecular characteristics; no specific genotype differentiated CA-MSSA from HA-MSSA. Both strains exhibited similar antibiotic susceptibility.

Efficacy of a New Commercial Ocular Spray Containing Oftasecur Citrus Extract for Reducing Microbial Load in the Conjunctiva of Patients Receiving Intravitreal Injections

INTRODUCTION

The control of conjunctival microbial load is crucial for patients receiving intravitreal injections (IVTs) in order to reduce the risk of endophthalmitis. The purpose of this work was to assess the antimicrobial activity of a new commercial ocular spray containing Biosecur citrus extract (Oftasecur^®, Off Health, Florence, Italy).

METHODS

This prospective cross-sectional pilot study included patients receiving IVTs who were instructed to apply Oftasecur spray onto the eye to be injected four times daily starting 4 days before surgery. The contralateral eye was considered the control. A conjunctival swab for microbiological analysis was performed in both eyes before starting study treatment and at the time of the injection. The Brief Ocular Discomfort Inventory (BODI) questionnaire was administered to patients based on an 11-point scale (0 for no discomfort and 10 for maximum discomfort).

RESULTS

Thirty patients (15 male, 15 female; mean age 64.7 ± 11.6 [standard deviation, SD] years) were included. Before starting treatment, 53.3% of the total eyes tested positive during the microbiological analysis. After the treatment period, only 20% of the eyes tested positive at the time of injection, showing a significant reduction in the microbial load (p < 0.01). Moreover, in the treated arm, the positive swabs before and after the prophylactic treatment with Oftasecur ocular spray showed a significant reduction (from 70.4% to 29.6%; p = 0.003, McNemar's test). Oftasecur ocular spray was well tolerated, with an average BODI score of 1.2 (± 0.70 SD).

CONCLUSION

Oftasecur ocular spray showed antimicrobial activity that significantly reduced the microbial load in patients receiving intravitreal injections. Therefore, it may have a role in the prophylaxis of infection in the setting of IVTs.

Bactericidal activity of three different antiseptic ophthalmic preparations as surgical prophylaxis

Purpose

In the era of antibiotic resistance, there is an increased interest in antiseptic solutions that might represent a reliable option for ocular surface disinfection. The objective of this study is to compare for the first time three different antiseptic ophthalmic preparations to assess their in vitro antimicrobial activity.

Methods

The antiseptic activity of three commercial ophthalmic solutions, IODIM (povidone-iodine 0.6% in hyaluronic acid vehicle—Medivis, Catania, Italy), OZODROP (nanoemulsion with ozonated oil—concentration not specified—FBVision, Ophthalmic Pharmaceuticals, Rome, Italy), and DROPSEPT (chlorhexidine 0.02% and vitamin E 0.5% Tocopherol Polyethylene Glycol 1000 Succinate—TPGS, Sooft Italia, Montegiorgio, Italy), was tested in vitro on six reference strains by time-killing assays. Viable cells were evaluated after 1, 15, 30 min; 2, 6, and 24 h exposure by seeding 100 µl of the suspension (or appropriate dilutions) on LB agar or Sabouraud-dextrose agar. All plates were incubated at 37 °C for 24 h and evaluated by manually counting the colonies.

Results

IODIM solution showed a very rapid microbicidal activity: the number of viable cells for all the tested strains was under the detection limit (less than 10 CFU/ml) already after 1 min exposure, and this result was maintained at every incubation time. The rapid antimicrobial activity of povidone-iodine was not replicated when testing the other two antiseptics.

Conclusions

The study reports the great efficacy in reducing bacterial load in a very short time of povidone-iodine 0.6% compared with other antiseptic preparations.

Cataract Surgery by Intraoperative Surface Irrigation with 0.25% Povidone-Iodine

Postoperative endophthalmitis after cataract surgery is typically caused by the patient's own conjunctival normal bacterial flora. A three-step approach is recommended to prevent endophthalmitis: (1) "border control" to prevent microorganisms from entering the eye by disinfecting the ocular surface is the most important measure; (2) bacteria that have gained access into the anterior chamber are reduced by irrigation; (3) bacteria remaining in the anterior chamber and vitreous at the end of surgery are controlled by antibacterial drugs. We have devised a method, "the Shimada technique", for irrigating the ocular surface with povidone-iodine, a disinfectant with potent microbicidal effect and established effective and safe concentrations for eye tissues. Povidone-iodine exhibits a bactericidal effect for a wide concentration range of 0.005-10%, but 0.1% povidone-iodine has the highest activity and requires the shortest time of only 15 s to achieve microbicidal effect. When used to irrigate the ocular surface every 20-30 s during cataract surgery, 0.25% povidone-iodine is conceivably diluted to around 0.1%. Irrigation with 0.25% povidone-iodine during cataract surgery significantly reduced bacteria contamination rate in the anterior chamber compared with saline (p = 0.0017) without causing corneal endothelial damage.

In Vitro Antimicrobial Activity of a New Ophthalmic Solution Containing Hexamidine Diisethionate 0.05% (Keratosept)

PURPOSE

To assess the in vitro antimicrobial activity of a new commercial ophthalmic solution containing hexamidine diisethionate 0.05% (Keratosept).

METHODS

Staphylococcus aureus American Type Culture Collection (ATCC 43300), Pseudomonas aeruginosa ATCC 27853, 3 ocular bacterial isolates (1 Staphylococcus epidermidis, 1 S. aureus, and 1 P. aeruginosa), and 5 Candida species were used. The bacterial and fungal isolates were cultured on Columbia blood agar base and Sabouraud-dextrose agar plates, respectively, and incubated overnight at 37°C. Suspensions were prepared in a sterile saline solution with optical density equal to 0.5 McFarland standard (∼10 CFU/mL). Isolate suspensions were made in Keratosept solution to obtain a concentration of 10 CFU/mL. The suspensions were then distributed in conical tubes with a final volume of 1 mL and incubated at 37°C. After 1, 5, 10, 15, 20, 25, 30 minutes, and 24 hours, 10 μL of each suspension was removed, seeded on Columbia blood agar base and Sabouraud-dextrose agar plates and then incubated for 24 hours at 37°C.

RESULTS

After 1-minute incubation, there was no growth on the plates seeded with S. aureus ATCC 43300, S. aureus clinical isolate, S. epidermidis clinical isolate, and all 5 Candida species tested. Conversely, Keratosept solution failed to kill the Pseudomonas isolates after 30 minutes exposure and needed 24 hours to eradicate the organisms.

CONCLUSIONS

Keratosept ophthalmic solution showed in vitro antimicrobial activity against S. epidermidis, S. aureus, and Candida species. Results suggest that it may be a potential candidate for the treatment of staphylococcal and Candida infections of the ocular surface and have some role in antimicrobial prophylaxis before intravitreal injections.

Effectiveness of 0.66% Povidone-Iodine Eye Drops on Ocular Surface Flora before Cataract Surgery: A Nationwide Microbiological Study

A multicenter, nonrandomized, prospective, controlled study was conducted to evaluate, as perioperative prophylactic treatment, the anti-infective effectiveness of 0.66% povidone-iodine eye drops (IODIM^®) against the bacterial flora of the conjunctival surface of patients who undergo cataract surgery. Eye drops containing 0.66% povidone-iodine were applied to the eye undergoing cataract surgery; the untreated contralateral eye was used as control. One hundred and twenty patients set to receive unilateral cataract surgery were enrolled in 5 Italian Ophthalmology Centers and pretreated for three days with 0.66% povidone-iodine eye drops. The contralateral eye, used as control, was left untreated. Conjunctival swabs of both eyes were collected at the baseline visit and after three days of treatment, just before the cataract surgery. A qualitative and quantitative microbiological analysis of bacterial presence was evaluated by means of bacterial culture, followed by identification. Methicillin resistance determination was also performed on staphylococci isolates. Bacterial load before and after treatment of the eye candidate for cataract surgery was evaluated and compared to the untreated eye. A reduction or no regrowth on the culture media of the bacterial load was observed in 100% of the study subjects. A great heterogenicity of bacterial species was found. The 0.66% povidone-iodine eye drops, used for three days prior to cataract surgery, were effective in reducing the conjunctival bacterial load. The 0.66% povidone-iodine eye drops (IODIM^®) might represent a valid perioperative prophylactic antiseptic adjuvant treatment to protect the ocular surface from microbial contamination in preparation of the surgical procedure.

Low-Concentration (0.66%) Povidone Iodine Treatment of a Corneal Ulcer in a Rheumatoid Arthritis Patient

Patient: Female, 89-year-old

Final Diagnosis: Corneal ulcer

Symptoms: Low vision

Medication:—

Clinical Procedure: —

Specialty: Ophthalmology

Bactericidal and virucidal activity of ethanol and povidone-iodine

Ethanol and povidone‐iodine (PVP‐I) are important microbicides that inactivate bacteria and viruses. The present study provides a review of literature data on the concentration‐dependent bactericidal and virucidal activity of ethanol and PVP‐I in vitro. A systematic search was performed using the meta‐database for biomedicine PubMed. Eventually, 74 studies with original data on the reduction of bacterial and viral infectivity using in vitro tests were analyzed. A safe bactericidal effect of ethanol can be expected at concentrations between 60% and 85%, and the exposure times vary between ≤0.5 and ≥5 min. Within an exposure of up to 5 min, 80%–90% ethanol also exerts virucidal/low‐level activity, which includes its action against enveloped viruses plus adeno‐, noro‐, and rotaviruses. For PVP‐I, the best bactericidal and virucidal/high‐level effect is present at a concentration range of approx. 0.08%–0.9% depending on the free iodine concentration. The maximum exposure times are 5 min for bacteria and 60 min for viruses. The available data may help optimize the significant inactivation of bacteria and viruses in various areas. However, as the conditions in application practice can vary, concrete recommendations for the application can only be derived to a limited extent.

In vitro antimicrobial activity of a new ophthalmic solution containing povidone-iodine 0.6% (IODIM® )

PURPOSE

To assess the in vitro antimicrobial activity of a new commercial ophthalmic solution containing povidone-iodine 0.6% (IODIM^® ).

METHODS

Staphylococcus aureus ATCC 43300, Pseudomonas aeruginosa ATCC 27853, three ocular bacterial isolates (1 S. epidermidis, 1 S. aureus, 1 P. aeruginosa) and five Candida species were used. The bacterial and fungal isolates were cultured on Columbia blood agar base plates and Sabouraud-dextrose agar plates, respectively and incubated overnight at 37°C. Bacterial and fungal suspensions in sterile saline solution were prepared to an optical density equal to 0.5 McFarland standard (approximately 10⁸ CFU/ml). Suspensions of the isolates were made in IODIM^® solution to obtain a final concentration of 10⁶ CFU/ml. The suspensions were then distributed in conical tubes in a final volume of 1 ml and incubated at 37°C. At different time-points (1, 5, 10, 15, 20, 25, 30 min and 24 hr), 10 μl of each suspension was removed, seeded on Columbia blood agar base and Sabouraud-dextrose agar plates and then incubated for 24 hr at 37°C. Positive and negative controls were included in all experiments.

RESULTS

After 5-min incubation, there was no bacterial growth on any plate. Conversely, IODIM^® failed to kill the Candida isolates after 30 min' exposure and needed 24 hr to eradicate the organisms.

CONCLUSION

IODIM^® ophthalmic solution showed in vitro antimicrobial activity against S. epidermidis, S. aureus, P. aeruginosa and Candida species. Results suggest that it may be a potential candidate for the treatment of ocular surface infections and antimicrobial prophylaxis before intravitreal injections.

Corneal Ulcer Treated with 0.66% Nanoemulsion Povidone-Iodine: A Case Report

Patient: Male, 61-year-old

Final Diagnosis: Corneal ulcer

Symptoms: Pain • redness • watering • photophobia

Medication: —

Clinical Procedure: IODIM therapy

Specialty: Ophthalmology

The efficacy of diluted topical povidone-iodine rinses in the management of recalcitrant chronic rhinosinusitis: a prospective cohort study

PURPOSE

Recalcitrant chronic rhinosinusitis is a persistent inflammatory condition of the sinonasal mucosa despite adequate medical therapy and sinus surgery. This study aimed to demonstrate the effectiveness and safety of dilute povidone-iodine (PVP-I) sinonasal rinses as an adjunctive therapy.

METHODS

Prospective cohort study. Twenty-nine recalcitrant CRS patients with endoscopic evidence of ongoing inflammation and purulent discharge were prescribed 0.08% diluted PVP-I rinses. Changes to endoscopic modified Lund-Kennedy (MLK) scores at 7 weeks post-PVP-I rinsing served as the primary outcome measure.

RESULTS

The median MLK-discharge score significantly decreased in all patients by 1.50 points post-PVP-I rinsing (p value < 0.01). The total MLK score significantly decreased in all patients by 1.50 points (p value = 0.01). Up to a 17% reduction in serum inflammatory markers was measured post-PVP-I rinsing. Sinonasal culture revealed a shift from moderate-heavy growth to lighter bacterial growth overall. Subjective SNOT-22 scores significantly improved overall by ≥ 1 minimal clinically important difference (MCID > 12; baseline median = 33; follow-up median = 20; p value < 0.01; n = 22). TSH levels increased non-significantly within normal ranges (baseline median = 1.59 mU/L; follow-up median = 1.92 mU/L; p = 0.10; n = 15). Mucociliary clearance time increased non-significantly within normal ranges (baseline median = 9 min; follow-up median = 10 min; p value = 0.53; n = 17). Olfactory Sniffin'16 scores non-significantly decreased within age-related normal ranges (baseline median = 14; follow-up median = 13; p value = 0.72; n = 18).

CONCLUSION

A dilute 0.08% PVP-I sinonasal rinse as an ancillary therapy in recalcitrant CRS significantly reduces signs of infection alongside notable symptom improvement, without affecting thyroid function, mucociliary clearance or olfaction.

The Effectiveness of 0.6% Povidone Iodine Eye Drops in Reducing the Conjunctival Bacterial Load and Needle Contamination in Patients Undergoing Anti-VEGF Intravitreal Injection: A Prospective, Randomized Study

The study purpose was to assess the efficacy of a preservative-free 0.6% povidone iodine eye drops as perioperative prophylactic treatment for reducing conjunctival bacterial load and the rate of needle contamination in patients undergoing intravitreal anti-vascular endothelial growth factor injection. Enrolled patients were randomized to either the study group (0.6% povidone iodine, three day-prophylactic treatment before the injection) or to the control group (placebo, three day-prophylactic treatment). Conjunctival swabs were obtained before and after the prophylactic treatment in both groups. Intravitreal injections were performed in a sterile fashion. The injection needle and a control needle were collected for microbiological culture. Data from 254 and 253 eyes in the study group and control group, respectively, were analyzed. Bacterial growth from conjunctival swab cultures was significantly lower after 0.6% povidone iodine prophylaxis compared to baseline and to placebo prophylaxis (p < 0.001), showing an 82% eradication rate in the study group. No injection needle showed bacterial contamination in the study group, whereas six needles were culture-positive in the control group (p = 0.015). No serious ocular and non-ocular adverse events were recorded. The 0.6% povidone iodine solution proved an effective treatment in reducing conjunctival bacterial load and risk of needle contamination.