Effect of Ultraviolet Light Irradiation Combined with Riboflavin on Different Bacterial Pathogens from Ocular Surface Infection.

Jing Shen,Qingfeng Liang,Hong Liang,Guanyu Su,Antoine Labbé,Yang Zhang,Christophe Baudouin,Zhiqun Wang

doi:10.1155/2017/3057329

Abstract

In order to study Staphylococcus epidermis and Staphylococcus aureus in vitro viability after the exposure to ultraviolet (UV) light and riboflavin, twelve strains of Staphylococcus epidermis and twelve strains of Staphylococcus aureus were isolated from patients with bacterial keratitis. The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions was qualitatively observed. The number of colonies surviving bacteria was counted under different UV light power and different exposure time. The experiment showed that there was no inhibition effect on the growth of bacteria using riboflavin alone. In UV alone group and UV-riboflavin group, inhibition effect on the bacteria growth was found. The UV-riboflavin combination had better inhibition effect on bacteria than UV irradiation alone. The amount of bacteria in the UV-riboflavin group was decreased by 99.1%~99.5% and 54.8%~64.6% in the UV alone group, when the UV light power was 10.052 mW/cm2 and the irradiation time was 30 min. Moreover, with the increase of the UV power or irradiation time, the survival rates of bacteria were rapidly reduced. Compared with Staphylococcus aureus, Staphylococcus epidermis was more easily to be killed under the action of UV light combined with riboflavin.

Highlights

Infectious keratitis is a vision-threatening condition, which can be caused by bacteria, virus, fungus, parasites, and so forth
Four different samples were prepared which are UV-riboflavin treated sample (Group 1), control treated with UV alone (Group 2), control treated with riboflavin alone (Group 3), and control untreated. 200 μL bacterial suspension (0.5 MCF) was aseptically transferred into the 9 cm blood agar plates with properly labeled test positions of control samples and UV-riboflavin treated sample. 10 μL diluent riboflavin solution (0.1% wt) was added in each labeled test position of UV-riboflavin treated sample and riboflavin alone treated control sample
The growth situation of Staphylococcus epidermidis and Staphylococcus aureus under different experimental conditions is shown in Figures 2 and 3

Summary

Introduction

Infectious keratitis is a vision-threatening condition, which can be caused by bacteria, virus, fungus, parasites, and so forth. In China, there are 3 million corneal blind patients, and infectious corneal blindness has an annual increase rate of 100,000 cases [2]. Bacterial keratitis is one of the most common ocular infections, which progresses rapidly and severely. With the extensive use of broad spectrum antibiotic, recent studies have shown increasing evidence of resistance of microbes to antimicrobial agents. Antibiotic resistance can cause continued progression of the disease process despite the use of broad spectrum antibiotics and some more severe consequences [3,4,5]. The occurrence of antibiotic-resistant bacteria has prompted ophthalmologists to study the antimicrobial activity of additional biological, chemical, and physical sources as adjunctive or alternative therapies for bacterial keratitis

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