Ferguson A W, Scott J A, McGavigan J, Elton R A, McLean J, Schmidt U, Kelkar R, Dhillon B
Department of Ophthalmology, Stirling Royal Infirmary, Forth Valley Acute Hospitals NHS Trust, Livilands, Stirling, FK8 2AL, UK.
Br J Ophthalmol. 2003 Feb;87(2):163-7. doi: 10.1136/bjo.87.2.163.
BACKGROUND/AIM: Povidone-iodine (PI, Betadine) is routinely used as a preoperative topical antiseptic in cataract surgery as it has been shown to reduce the incidence of postoperative endophthalmitis. However, the concentration used clinically is variable. In vitro studies have shown that PI is paradoxically more effective at lower concentration. This study was undertaken to determine if this effect was reproducible in vivo.
A prospective randomised double blind study was carried out in the ophthalmic theatre in a district general hospital. 105 patients attending for routine cataract surgery were randomly allocated to have their conjunctival fornices irrigated preoperatively with either PI 1% (group A) or PI 5% (group B). Conjunctival swabs were taken, in identical fashion, both before and 1 minute after irrigation. The number and species of bacterial colonies cultured from each swab was counted. The difference in the median number of bacterial colonies from pre-irrigation to post-irrigation cultures was then compared between the groups.
Bacterial cultures were gained from 100 patients (33 male, 67 female, mean age 74 years, range 30-95 years). Group B (5% PI) showed a decrease in median colony forming units (CFU) pre-irrigation from 100 to 40 CFU post-irrigation (a drop of 60%). This was greater than in group A (1% PI) where the reduction was 120 CFU pre-irrigation to 100 CFU post-irrigation (a drop of 16.7%) (Mann-Whitney test, p<0.05). At higher initial bacterial loads (CFU pre-irrigation >1000), the difference in median between the two groups became larger as the number of pre-irrigation bacteria increased. In group B pre-irrigation CFU reduced from 3340 to 110 post-irrigation (a drop of 96.7%) compared with group A: 5000 CFU pre-irrigation to 3000 post-irrigation (a drop of 40%) (Mann-Whitney test, p=0.0014).
Despite in vitro evidence of higher bactericidal efficacy of PI at more dilute concentrations, 5% PI is more effective than 1% PI in decreasing the human conjunctival bacterial flora in vivo, particularly in the presence of heavier initial bacterial load.
背景/目的：聚维酮碘（PI，碘伏）在白内障手术中常规用作术前局部防腐剂，因为已证明它可降低术后眼内炎的发生率。然而，临床使用的浓度并不一致。体外研究表明，PI在较低浓度下反而更有效。本研究旨在确定这种效应在体内是否可重现。
在一家地区综合医院的眼科手术室进行了一项前瞻性随机双盲研究。105例接受常规白内障手术的患者被随机分配，术前用1%聚维酮碘（A组）或5%聚维酮碘（B组）冲洗结膜穹窿。冲洗前和冲洗后1分钟以相同方式采集结膜拭子。对每个拭子培养的细菌菌落数量和种类进行计数。然后比较两组冲洗前至冲洗后培养的细菌菌落中位数的差异。
从100例患者（33例男性，67例女性，平均年龄74岁，范围30 - 95岁）获取了细菌培养物。B组（5%聚维酮碘）冲洗前菌落形成单位（CFU）中位数从100降至冲洗后40（下降60%）。这一降幅大于A组（1%聚维酮碘），A组冲洗前为120 CFU，冲洗后为100 CFU（下降16.7%）（曼-惠特尼检验，p<0.05）。在初始细菌载量较高时（冲洗前CFU>1000），随着冲洗前细菌数量增加，两组中位数差异变得更大。B组冲洗前CFU从3340降至冲洗后110（下降96.7%），而A组冲洗前为5000 CFU，冲洗后为3000 CFU（下降40%）（曼-惠特尼检验，p = 0.0014）。
尽管体外证据表明PI在更稀释浓度下具有更高的杀菌效力，但5%聚维酮碘在体内降低人结膜细菌菌群方面比1%聚维酮碘更有效，尤其是在初始细菌载量较高的情况下。
