Department of Ophthalmology, Cantonal Hospital Lucerne, Lucerne, Switzerland
Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.
BMJ Open Ophthalmol. 2024 Jun 3;9(1):e001632. doi: 10.1136/bmjophth-2024-001632.
Unpreserved single-dose unit (SDU) eye drops are commonly used to avoid benzalkonium chloride-related toxicity. Although intended for single use, many patients report off-label repeated use of SDUs over a prolonged period. We investigated whether repeated use of dexamethasone 0.1% SDUs in the same patient increases the bacterial contamination rate.
We prospectively enrolled patients scheduled for inpatient corneal and glaucoma surgery receiving dexamethasone 0.1% SDU four times per day from the same vial. To assess contamination rates, one drop from the vial was cultured immediately after opening the SDU (t0), 10 hours later after four drop applications (t10) and 24 hours after opening without further drop applications (t24). Conjunctival swabs were taken before and after drop application. Contamination rate was assessed with a standard clinical culturing protocol without introducing a positive control.
110 eyes of 109 patients were evaluated. Drops collected immediately after opening the SDU (t0) were contaminated in 9/110 cultures (8.1%). At t10, 13/110 cultures were contaminated (11.8%; p=0.267) and 11/110 at t24 (10.0%; t24 vs t0; p=1.00). In 5 of 21 cases of contaminated drops at t10 and/or t24, the same isolates were cultured from the initial conjunctival swab and the SDU. In three cases, the same bacterial species was found in consecutive samples.
The contamination rate of the SDU did not increase after multiple use within 24 hours. Contamination from fingertip flora was more likely than from ocular surface flora. Reuse of dexamethasone 0.1% SDU in the same patient within 24 hours appears to be safe.
未保存的单剂量单位 (SDU) 滴眼剂常用于避免苯扎氯铵相关毒性。尽管旨在单次使用，但许多患者报告在较长时间内反复超适应证使用 SDU。我们研究了同一患者重复使用地塞米松 0.1% SDU 是否会增加细菌污染率。
我们前瞻性招募了计划住院进行角膜和青光眼手术的患者，他们每天从同一支小瓶中使用地塞米松 0.1% SDU 四次。为了评估污染率，在打开 SDU 后立即（t0）、滴用 4 次后 10 小时（t10）和打开后 24 小时（无进一步滴用）从小瓶中取出一滴进行培养。在滴用前后进行结膜拭子培养。使用标准临床培养方案评估污染率，不引入阳性对照。
共评估了 109 例患者的 110 只眼。立即从小瓶中取出的滴眼剂（t0）在 9/110 次培养中（8.1%）受到污染。在 t10 时，13/110 次培养受到污染（11.8%；p=0.267），在 t24 时 11/110 次培养受到污染（10.0%；t24 与 t0 相比；p=1.00）。在 t10 和/或 t24 时的 21 次污染滴眼剂中，有 5 次从小瓶和初始结膜拭子中培养出相同的分离株。在 3 例中，连续样本中发现了相同的细菌种类。
在 24 小时内多次使用后，SDU 的污染率没有增加。指尖菌群污染的可能性大于眼表菌群污染。同一患者在 24 小时内重复使用地塞米松 0.1% SDU 似乎是安全的。
