Effect of dosing interval on the efficacy of topical ophthalmic gatifloxacin against Enterococcus faecalis in an in vitro pharmacokinetic model simulating the local eye compartment

Vitrectomy using 0.025% povidone-iodine irrigation for treating post-traumatic endophthalmitis due to intraocular foreign bodies: Two case reports

Traumatic eye injury-related endophthalmitis is a serious traumatic complication that threatens the vision of many patients worldwide. Herein, we present two cases of traumatic endophthalmitis that underwent 0.025% povidone-iodine treatment and hoped to introduce the bactericidal effect of 0.025% povidone-iodine in balanced salt solution PLUS (0.025% PI-BSS PLUS) and its use in vitrectomy for traumatic endophthalmitis. The 0.025% PI-BSS PLUS solution is bactericidal and nontoxic when used as an irrigation solution in pars plana vitrectomy. The two cases of traumatic endophthalmitis were resolved by pars plana vitrectomy using 0.025% PI-BSS PLUS.

Intravitreal Injection of 1.25% Povidone Iodine Followed by Vitrectomy Using 0.025% Povidone Iodine Irrigation for Treating Endophthalmitis

Purpose

To investigate the safety and effectiveness of intravitreal injection (IVI) of 1.25% povidone iodine (PI) followed by vitrectomy using 0.025% PI irrigation for treating endophthalmitis.

Methods

Prospective case series study. Nine eyes of 8 patients with postoperative or endogenous endophthalmitis treated at the Nihon University Hospital between April 2015 and October 2017 were studied. First, IVI of 0.1 mL/1.25%PI was conducted, followed by anterior chamber irrigation and vitrectomy using 0.025%PI irrigation solution. Corneal epithelial damage, anterior chamber inflammation, and vitreous inflammation were assessed and fundus examinations were performed, using a slit-lamp microscope and indirect ophthalmoscopy. A specular microscope, Goldmann perimetry, and electroretinography (ERG) were also used.

Results

In all but case 7, endophthalmitis resolved rapidly and good visual acuity was maintained. No adverse events were noted. Furthermore, the perioperative ERG showed improvements in the oscillatory potentials amplitudes on ERG and flicker ERG, as well as in the implicit time of the a-wave, suggesting functional recovery in the retinal outer and inner layers after therapy.

Conclusions

IVI of PI followed by vitrectomy was thought to be a safe and effective treatment for endophthalmitis.

Translational Relevance

We succeeded in proving the clinical safety of IVI of PI followed by vitrectomy with PI irrigation as well as previous experimental reports. PI is available in world widely, therefore this method will be optimal treatment for endophthalmitis.

Persistently Vitreous Culture-Positive Exogenous Bacterial Endophthalmitis

PURPOSE

To report the clinical settings, bacterial isolates, antibiotic sensitivities, and visual acuity outcomes of patients with persistently positive vitreous cultures after intravitreal antibiotics.

DESIGN

Consecutive, noncomparative case series.

METHODS

setting: Tertiary care center.

PATIENT POPULATION

Thirty-six eyes of 36 patients with exogenous endophthalmitis with the same bacterial organism identified on at least 2 consecutive vitreous cultures from 1981 to 2015.

OBSERVATION PROCEDURES

Vitreous cultures with intravitreal injections of antibiotics and pars plana vitrectomies with intravitreal antibiotics.

MAIN OUTCOME MEASURES

Bacterial isolates, antibiotic sensitivities, visual outcomes.

RESULTS

Thirty-six eyes of 36 patients met the study criteria. The mean follow-up was 26.5 months. The most common clinical settings were after cataract extraction (18/36, 50%) and glaucoma surgery (11/36, 31%). The mean initial visual acuity was 2.16 ± 0.77 logMAR (Snellen equivalent ≈20/2900), and there was no statistically significant change at the final evaluation (2.08 ± 0.97 logMAR, ≈20/1900, P = .72). The most common bacteria were Staphylococcus (11/36, 31%) and Streptococcus (9/36, 25%). Gram-positive bacteria were sensitive to vancomycin (27/27, 100%); gram-negative bacteria were sensitive to amikacin (5/5, 100%). The antibiotic sensitivities were the same on repeat cultures in 34 of 36 patients (94%). The initial treatment was a vitreous culture and intravitreal injection of antibiotics in 28 of 36 patients (78%). The vision at the last follow-up was 20/200 or better in 12 patients (33%) and no light perception in 11 of 36 patients (31%).

CONCLUSIONS

The most commonly identified organisms were gram-positive bacteria. There was good concordance in the antibiotic sensitivities between initial and subsequent cultures. Patients with persistently vitreous culture-positive endophthalmitis had poor visual outcomes.

The antibacterial activity of levofloxacin eye drops against staphylococci using an in vitro pharmacokinetic model in the bulbar conjunctiva

The incidence of fluoroquinolone-resistant staphylococcal isolates from the conjunctival sac is increasing. We compared pharmacological effects of levofloxacin (LVFX) against Staphylococcus epidermidis using an in vitro pharmacokinetic (PK) model simulating the concentration in the bulbar conjunctiva after applying eye drops of 0.5% and 1.5% LVFX. We used S. epidermidis conjunctival sac isolates [minimum inhibitory concentrations (MICs) of LVFX, 0.125 μg/mL]. LVFX-resistant strains were obtained from parental strains after culture with LVFX. The in vitro PK model simulated the concentration in the bulbar conjunctiva following three topical applications of 0.5% or 1.5% LVFX ophthalmic solution (0, 4, and 8 h) to rabbit eyes. Parental and LVFX-resistant strains were exposed to LVFX in the in vitro PK model, and changes in viable bacterial counts were evaluated for 12 h. The MICs of LVFX for the resistant isolates were 2-32 times higher than the parental strain, and those with MICs ≥2 ug/mL had mutations in the quinolone resistance-determining region. The PK model simulation predicts that 1.5% LVFX exerts bactericidal and bacteriostatic effects against strains with MICs of 0.125-2 and 4 μg/mL, respectively, whereas 0.5% LVFX would only be effective against strains with MICs of 0.125-1 μg/mL. The PK model predicts that the 1.5% LVFX ophthalmic solution exhibits a stronger bactericidal effect against resistant staphylococci in the bulbar conjunctiva than the 0.5% LVFX ophthalmic solution.

In vitro simulation of in vivo pharmacokinetic model with intravenous administration via flow rate modulation

The aim of this paper was to propose a method of flow rate modulation for simulation of in vivo pharmacokinetic (PK) model with intravenous injection based on a basic in vitro PK model. According to the rule of same relative change rate of concentration per unit time in vivo and in vitro, the equations for flow rate modulation were derived using equation method. Four examples from literature were given to show the application of flow rate modulation in the simulation of PK model of antimicrobial agents in vitro. Then an experiment was performed to confirm the feasibility of flow rate modulation method using levo-ornidazole as an example. The accuracy and precision of PK simulations were evaluated using average relative deviation (ARD), mean error and root mean squared error. In vitro model with constant flow rate could mimic one-compartment model, while the in vitro model with decreasing flow rate could simulate the linear mammillary model with multiple compartments. Zero-order model could be simulated using the in vitro model with elevating flow rate. In vitro PK model with gradually decreasing flow rate reproduced the two-compartment kinetics of levo-ornidazole quite well. The ARD was 0.925 % between in vitro PK parameters and in vivo values. Results suggest that various types of PK model could be simulated using flow rate modulation method without modifying the structure. The method provides uniform settings for the simulation of linear mammillary model and zero-order model based on in vitro one-compartment model, and brings convenience to the pharmacodynamic study.