2週間頻回交換型ソフトコンタクトレンズの細菌学的汚染と管理方法との関連について : ケースを乾燥させることの重要性

type:text

コンタクトレンズ(CL)の細菌学的汚染を防ぐために効果的な管理方法について示唆を得る目的で,2週間頻回交換型SCL(FRSCL)を装着している大学生31名のレンズケアの実施状況と2週間使用後のレンズおよびその消毒に使用するマルチパーパスソリューション(MPS),ケースの細菌学的汚染状況を調査した.その結果,31名中22名でCL,MPS,ケースのいずれかの検体から,また全186検体のうち91検体から菌が検出された.CL,MPS,ケースの菌数は相関があり,またCLに比べMPS,ケースの方が汚染されていた.36株を分離し,そのうち27株はブドウ糖非発酵菌を中心とするグラム陰性桿菌であった.レンズケアでは,レンズ着脱時の手洗い,こすり洗い,ケースの乾燥を行なっているものは半数以下で,細菌学的検査との関連をみるとレンズ着脱時の手洗い,こすり洗い,ケースの洗浄・乾燥,より多くの手順を遵守したものでCLの汚染が少なく,特にケースの乾燥が汚染の有無に関係していた.検出細菌数の多かったもの6名について,指定した方法に従ってケースを乾燥するようにしてもらった.その結果,5名でMPS,ケースからの検出菌数が減少した.また,ケースを検体から分離した Serratia marcescens で汚染して,乾燥状態と湿潤状態で保管して菌数の変動をみたところ,乾燥状態で菌数が減少した.介入効果のみられなかった1名のMPSから Serratia marcescens が検出されたため,分離した株につい4種のMPSの消毒効果について検討した.その結果,消毒効果のない株が存在すること,MPSにより消毒効果が異なることが示された.以上より2週間頻回交換型SCLの汚染を防ぐには,従来いわれているこすり洗いやすすぎだけでなく,ケ

In order to acquire suggestions about the contributable regimen steps for preventing bacterial contamination of contact lenses(CL), we examined the compliance of each regimen steps and bacterial contamination of frequently replaceable soft contact lenses, multipurpose solutions (MPS) used for disinfection of soft contact lenses, and lens cases of 31 university students after 2 weeks application. As a result we found that one or more of CLs, MPSs and lens cases of 22 students, and 91 of 186 samples were contaminated. The number of bacteria detected CLs, MPSs and lens cases correlated with each other and MPSs and lens cases were contaminated more severely. 27 of 36 isolated strains were gram negative rods, most of which were identified as glucose non-fermentative gram negative rods. Subjects who performed hands wash before and after CL application, rub of CLs and drying of lens cases were less than 50 per cent. Analysis of relationships between bacterial contamination and regimen steps revealed that CLs obtained form subjects who performed hands wash before and after CL application, rub of CLs, and washing and drying of lens cases, especially lens case drying, were less contaminated. Six subjects whose CLs were severely contaminated were asked to perform designated lens case drying. After 2 weeks intervention, number of bacteria detected in MPSs and lens cases of 5 subjects decreased. In addition, the number of bacteria in lens cases contaminated by isolated Serratia marcescens experimentally decreased more when they kept in drying condition than in wet condition. Since Serratia marcescens was isolated from one subject in whom lens case drying was not effective, disinfectant ability of 4 MPSs against isolated 11 strains were evaluated and it was found that some stains were resistant to MPSs and MPSs differed in their disinfectant abilities. In conclusion, lens case drying was suggested to be important for reducing bacterial contamination.

source:Journal of School of Nursing, Chiba University