In Vivo Evaluation of Preoperative Topical Strategies in Reducing Conjunctival Microbial Load before Intravitreal...

Area of Science:

• Ophthalmology
• Microbiology
• Infectious Disease Prevention

Background:

• Intravitreal injections (IVIs) carry a risk of infection due to potential conjunctival microbial contamination.
• Standard preoperative disinfection protocols aim to minimize this risk, but alternative or adjunctive strategies are continuously explored.

Purpose of the Study:

• To evaluate the in vivo efficacy of different topical antiseptic strategies administered before IVIs in reducing conjunctival microbial load.
• To compare these strategies against standard 5% povidone-iodine (PI-5%) preoperative disinfection.

Main Methods:

• A prospective randomized comparative study involving 205 patients scheduled for IVIs.
• Patients received preoperative topical drops of 0.1% Polyquaternium-133, 0.6% povidone-iodine, 0.02% chlorhexidine digluconate, or no drops (control) three times daily for three days.
• Conjunctival swabs were collected at baseline, before standard disinfection, and after PI-5% application to assess microbial load (CFU count).

Main Results:

• 0.1% Polyquaternium-133 significantly reduced conjunctival bacterial load from baseline (T0) to before standard disinfection (T1).
• This reduction was further enhanced when Polyquaternium-133 was used in conjunction with standard PI-5% disinfection.
• While other agents showed limited efficacy, Polyquaternium-133 demonstrated activity against key pathogens like Corynebacterium macginleyi and Staphylococcus aureus.

Conclusions:

• No regimen achieved complete conjunctival sterility.
• 0.1% Polyquaternium-133 offers a significant reduction in conjunctival bacterial load and complements standard PI-5% disinfection.
• These findings suggest a potential clinical benefit of Polyquaternium-133 in the prophylaxis of infections associated with intravitreal injections.