作者：Bakiah Shaharuddin , K Wei Chan , Siti Suraiya Mohd Noor , Zunaina Embong 作者单位：16150 马来西亚吉兰丹州古邦阁亮，马来西亚理科大学医学院1眼科；2微生物与寄生虫学系
【摘要】 目的：确定抛弃型水凝胶接触镜及其护理液细菌定植的比率，并确定污染的病原体。方法：按目的抽样进行横断面研究。从马来西亚Sains大学健康校园的本科学生接触镜配戴者中收集100片水凝胶接触镜。所有的镜片和护理液均送微生物培养和革兰氏染色。结果：大多数的研究参与者为女性（98％）。平均年龄21。36±1.63岁。41片接触镜（82％）呈现阳性细菌定植，32％的护理液可见阳性细菌定植。最常见的病原体是凝固酶阴性葡萄球菌、金黄色葡萄球菌和链球菌，而在接触镜中能更频繁地分离出假单胞菌和沙雷氏菌。结论：配戴接触镜有导致镜片和护理液细菌定植的潜在危险。建议在镜片护理和配戴过程中采取最大程度的预防措施并严格遵守卫生做法。
【关键词】 水凝胶接触镜;细菌定植;大学学生的接触镜配戴
Bacterial colonization of hydrogel disposable contact lenses
Bakiah Shaharuddin , K Wei Chan , Siti Suraiya Mohd Noor , Zunaina Embong
1Department of Ophthalmology, 2Department of Microbiology and Parasitology, School of Medical Sciences, University Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
Correspondence to: Bakiah Shaharuddin. Department of Ophthalmology, School of Medical Sciences, University Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia. [email protected]
AbstractAIM: To determine the rate of bacterial colonization in hydrogel disposable contact lenses and solutions and to identify the contaminating rganisms.
METHODS: A cross sectional study with purposive sampling was carried out. One hundred hydrogel contact lenses were collected from wearers among undergraduate students of Health Campus, University Sains Malaysia. All lenses and storage solutions were sent for microbiological culture and gram staining.RESULTS: The majority of study participants were females (98%). The mean age was 21.36±1.63 years. Fortyone subject participants (82%) showed positive bacterial colonization of the lenses. From storage solutions 32% yielded positive colonization by bacteria. The most common organisms were coagulase negative staphylococcus, Staph aureus and streptococci while Pseudomonas sp. and Serratia sp. were isolated more frequently from contact lenses.CONCLUSION: Contact lens wearing is potentially dangerous as a result of high rate of bacterial colonization of the lenses and its storage solutions. Extreme precaution and adherence to strict hygienic practice is recommended during lens handling and wearing.
KEYWORDS: hydrogel contact lens; bacterial colonization; contact lens wearing in university students
INTRODUCTION
Contact lenses are worn for correction of refractive errors, tectonic support, prosthetic, cosmetic and therapeutic purposes. In recent years copolymers have been incorporated into the soft hydrogel lens materials, including silicone polymers for increased oxygen ermeability and phosphorylcholine to increase biocompatibility [1].
The problems associated with contact lens wear are potentially sight threatening, which require rapid diagnosis and treatment to prevent vision loss. Contact lens complications include acute red eye, peripheral ulcers, infiltrative keratitis and asymptomatic keratitis [1, 28].
We conduct a study in a group of young disposable hydrogel contact lens wearers who are also a subpopulation of biomedical and students of the Faculty of Medicine in the Health Campus of University Sains Malaysia, at the northeastern region part of Malaysia. The aim of this study was to determine the prevalence rate of bacterial colonization in hydrogel contact lenses among our study participants.
METHODS
Demographic data, type of contact lens, duration of lens wearing and wearing schedule were derived from a selfadministered questionnaire. Informed consent was obtained from all participants. All lenses which had been worn for a minimum period of 30 days were collected aseptically.
The contact lenses and solutions were cultured using the standard methods. Storage or washing solutions were obtained from the nozzle of the containers. Further gram staining is done if there were growths for the identification of microorganism. Gram positive organisms are identified using catalase and coagulase enzyme activity. If the organism showed positive reaction with catalase test, coagulase test is used to differentiate Staphylococcus aureus (coagulase positive) from coagulase negative staphylococcus. Negative result for catalase test would instigate further test to classify streptococci. Gram negative organismswere identified using biochemical tests such as Triple Sugar Iron agar, Sulfur Indole Motility test medium, Methyl Red test, Citrate utilization test and urease test.
RESULTS
One hundred disposable hydrogel contact lenses were cultured. The participants consist of one (2%) male student and 49 (98%) female students with a mean age of 21.36±1.63 years. Pattern of contact lens wearing which included the total duration of time the study participants had experience wearing contact lens, the duration of the current lens, and the daily average time the lens was being put on were analyzed (Table 1). Table 1Pattern of contact lens wear among study participants（略）
The duration of wearing of contact lenses has a median of 3 years and the contact lenses being collected for this study had been in use for a median value of 30 days. Most of the participants wore their contact lenses on a daily basis of an average of 9.86 hours.
All retrieved lenses were sent for microbiological cultures. Microorganisms were cultured from 68% of the lenses. Fortyone samples (82%) showed positive bacterial colonization with 27 samples (54%) having bacteria on both eyes and 14 samples (28%) on one eye. As for storage solutions, only 16 (32%) of the samples showed positive bacterial colonization (Table 2).Table 2Frequency of bacterial colonization on contact lenses and storage solutions（略）
The most common bacteria isolated were gram positive bacteria, including coagulase negative staphylococcus, Staphylococcus aureus, Streptococcus sp. and Bacillus sp. Of the gram negative bacteria isolated, Pseudomonas sp. and Serratia sp. were isolated more frequently from contact lenses. Bacteria were also isolated from storage solutions with coagulase negative staphylococcus predominating.
The mean bacterial count (in CFU/lens) of contact lenses and storage solutions is 31.4 (median: 14, IQR: 35) and 1。7 (median: 0, IQR: 2) respectively. The bacteria that were isolated from the storage solutions were of the same types of organisms of contact lenses.
Contact lenses were colonized predominantly by only one type of microorganism (60% contact lens and 68% storage solutions).
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