Effectiveness of 1.25 % povidone-iodine combined with topical levofloxacin against conjunctival flora in intravitreal injection.

PURPOSE

To compare the effect of a reduced concentration (1.25 %) of povidone-iodine (PI) eye drops, combined with 0.5 % topical levofloxacin (LVFX), with that of the standard of care (5 % PI) on conjunctival flora before intravitreal injections (IVT).

METHODS

A prospective, randomized, single-blind clinical trial. One hundred eyes from 100 patients who underwent IVT were included. Eyes were randomly assigned to two groups and underwent different preparatory procedures before therapeutic IVT. LVFX drops were instilled three times every 5 min and then either 1.25 % PI drops were instilled three times every few minutes in group A or 5 % PI drops were instilled three times every few minutes in group B, the control. Conjunctival flora and the injection needles were collected for culture both before and after preparation. The number of positive cultures, the species isolated, and the minimum inhibitory concentrations (MIC) of the antibiotics were assessed.

RESULTS

The pretreatment culture was positive for 45 eyes (86.5 %) in group A (n = 52) and for 37 eyes (77.1 %) in group B (n = 48). After the preparatory procedure, the cultures were positive for 25 eyes (48.1 %) in group A and for 27 eyes (56.3 %) in group B (P = 0.43). After preparation, the number of positive cultures decreased by 46.7 % in group A and by 33.4 % in group B (P = 0.48). No needle samples were contaminated in either group. The most common isolate in both groups after preparation for surgery was Propionibacterium acnes. Among the different antibiotics, vancomycin and oxacillin had the lowest MIC >90 for overall isolates.

CONCLUSIONS

1.25 % PI with LVFX is as effective as 5 % PI. P. acnes was the most common conjunctival flora detected. Vancomycin has been confirmed as the best choice for treating infectious endophthalmitis after IVT.