Department of Ophthalmology and Laboratório Especial de Microbiologia Clínica, Infectious Diseases Division, Universidade Federal de São Paulo, São Paulo, Brazil.
J Cataract Refract Surg. 2011 Jul;37(7):1244-50. doi: 10.1016/j.jcrs.2011.01.025. Epub 2011 May 20.
To determine the usefulness of real-time polymerase chain reaction (PCR) assays in the diagnosis of postoperative bacterial endophthalmitis in clinically diagnosed infectious cases and to test for bacterial DNA in control samples collected from noninfected eyes.
Federal University of São Paulo, Brazil.
Evaluation of diagnostic test or technology.
This study comprised patients with clinically diagnosed infectious endophthalmitis after cataract surgery and vitreous samples (from noninflamed eyes obtained through vitrectomy) and aqueous samples (at end of phacoemulsification) from control patients at a single university setting. Universal and gram-specific real-time PCR, Gram staining, and culture were performed. Sensitivity and cycle thresholds were determined. Clinical and microbiologic data were also assessed.
The study evaluated 11 patients with infectious endophthalmitis (9 vitreous and 7 aqueous samples), 12 control vitreous samples, and 50 control aqueous samples. Gram and culture identified 80% and 75%, respectively, of patients with infectious endophthalmitis. Real-time PCR assays were positive in 91% of patients with a clinical diagnosis of endophthalmitis using aqueous samples, vitreous samples, or both. None of the 12 vitreous controls were positive by PCR. Two aqueous control samples were positive by real-time PCR. The cycle threshold cutoff value was 36 for universal PCR (sensitivity 93.8%; specificity 100%) and 38 for gram-specific PCR (sensitivity 93.8%; specificity 100%). Gram-positive microorganisms prevailed, and visual acuity varied according to the causative bacteria.
Real-time PCR provided fast and accurate diagnosis of bacterial endophthalmitis. As a quantitative technique, it may be useful in distinguishing between contamination and infection based on the cycle thresholds value.
确定实时聚合酶链反应（PCR）检测在临床诊断为感染性病例的术后细菌性眼内炎中的诊断价值，并检测来自非感染眼的对照样本中的细菌 DNA。
巴西圣保罗联邦大学。
诊断测试或技术的评估。
本研究包括在单一大学环境中，对白内障手术后临床诊断为感染性眼内炎的患者进行玻璃体样本（通过玻璃体切除术从非炎症眼获得）和对照患者的房水样本（在超声乳化结束时）采集。进行了通用和革兰氏菌特异性实时 PCR、革兰氏染色和培养。确定了灵敏度和循环阈值。还评估了临床和微生物学数据。
该研究评估了 11 例感染性眼内炎患者（9 例玻璃体和 7 例房水样本）、12 例对照玻璃体样本和 50 例对照房水样本。革兰氏染色和培养分别识别出 80%和 75%的感染性眼内炎患者。使用水样、玻璃体样或两者均对临床诊断为眼内炎的患者进行实时 PCR 检测，阳性率为 91%。12 例玻璃体对照均未通过 PCR 检测为阳性。2 例水样对照通过实时 PCR 检测为阳性。通用 PCR 的循环阈值截止值为 36（灵敏度 93.8%；特异性 100%），革兰氏菌特异性 PCR 的循环阈值截止值为 38（灵敏度 93.8%；特异性 100%）。革兰氏阳性微生物占优势，视力因致病细菌而异。
实时 PCR 快速准确地诊断细菌性眼内炎。作为一种定量技术，它可能有助于根据循环阈值值区分污染和感染。
