Microbial contamination in eye drops of patients in glaucoma treatment

Abstract Objetives: To assess the degree of fungal and bacterial contamination of hypotensive eye drops and the way these are preserved by the patients at the Glaucoma outpatient clinic of Santa Casa Hospital in Ribeirão Preto. Methods: Fifty-five patients were randomly assigned to follow-up in the outpatient clinic and, after their consent, an eye drop was collected per patient and later sent by mail for analysis by microbiologist and pathologist in up to 72 hours. Approximately 0.5ml of the medications were analyzed and the patients were asked to answer a simple questionnaire on the method of drug conservation and whether they considered it adequate. Results: Of the 55 analysed eye drops, five (9.01%) had their liquid contents contaminated. Among the microorganisms isolated there were 4 Gram negative bacteria, 1 (1.8%) by Serratia marcenses, 1 (1.8%) Pseudomonas aeruginosa and 2 (3.6%) Stenotrophomas maltophilia. An eye drop was contaminated by the fungus Candida ssp. All the patients in the study judged their methods of storage and instillation appropriate. The patients who had the positive coliria were summoned for clinical examination and passed through a new questionnaire by the investigator. Conclusion: The time and methods of preservation influence the contamination of medicinal products. All the eye drops that presented growth of microorganisms in the present study were open between 30 and 90 days. The fact that most patients take their eye drops on daily tasks increases the exposure of the bottles and can be a relevant fact to determine the contamination of these medications.

【摘要】研究目的：评估里贝朗普雷图圣卡萨医院青光眼门诊患者所使用的降眼压滴眼液（hypotensive eye drops）的真菌与细菌污染程度，以及患者对滴眼液的日常保存方式。
研究方法：本研究随机纳入55名门诊随访患者，在获取患者知情同意后，每名受试者提供1瓶滴眼液，随后通过邮寄方式将样本在72小时内送至微生物学家与病理学家处开展检测。对约0.5mL的药物样本进行分析，并要求患者填写一份简易问卷，内容涵盖药物保存方法以及患者自身对该保存方式是否恰当的主观判断。
研究结果：55份受检滴眼液中，共5份（9.01%）的药液被污染。分离得到的污染微生物共计4株革兰氏阴性菌：其中1株（1.8%）为粘质沙雷菌（Serratia marcenses），1株（1.8%）为铜绿假单胞菌（Pseudomonas aeruginosa），2株（3.6%）为嗜麦芽窄食单胞菌（Stenotrophomonas maltophilia）；另有1份滴眼液被念珠菌属（Candida ssp.）真菌污染。所有参与本研究的患者均认为自身的药物储存与滴用方法恰当。检测结果呈阳性的滴眼液对应的患者被召回接受临床检查，并由研究者重新发放问卷进行调研。
研究结论：药物的保存时长与方式会显著影响药品的污染风险。本研究中所有检出微生物生长的滴眼液均为开封后30~90天使用的。多数患者会在日常活动中携带滴眼液，此举会增加药瓶的暴露概率，或是导致此类药物发生污染的相关影响因素之一。