Deparments of Surgery (Ophthalmology) and Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire.
MedImmune LLC, Gaithersburg, Maryland.
JAMA Ophthalmol. 2016 Apr;134(4):383-9. doi: 10.1001/jamaophthalmol.2015.5956.
Bacterial virulence factors are increasingly recognized as important in the understanding of clinical infections.
To determine whether 2 potential virulence factors, in vitro biofilm formation and Psl exopolysaccharide (EPS) expression, influence clinical presentation or outcomes in Pseudomonas aeruginosa keratitis.
DESIGN, SETTING, AND PARTICIPANTS: Laboratory investigation using P aeruginosa clinical isolates from the double-blind Steroids for Corneal Ulcers Trial (SCUT), which included patients at Aravind Eye Hospital, Proctor Foundation, University of California, San Francisco, and Dartmouth-Hitchcock Medical Center. SCUT was conducted from September 1, 2006, through February 22, 2010. All data used in this study were obtained during this period. Pseudomonas aeruginosa clinical isolates from SCUT were evaluated for in vitro biofilm formation, and Psl EPS expression was assessed using an anti-Psl monoclonal antibody (mAb) enzyme-linked immunosorbent assay. Planktonic growth kinetics and the susceptibility to anti-Psl mAb-mediated opsonophagocytic killing (OPK) were also evaluated in a subset of isolates. Linear regression assessed associations between SCUT patients' visual acuity and their corresponding biofilm formation and Psl EPS expression. Generalized estimating equation regression models were used to assess whether the change in visual acuity among SCUT patients was associated with Psl EPS expression or biofilm formation.
Biofilm formation, Psl production, OPK, and visual acuity.
The P aeruginosa SCUT strains produced a mean (SD) in vitro biofilm score of 1.06 (0.32) (range 0.17-2.12). A 1-unit increase in biofilm was associated with a worse visual acuity of 2 lines measured in SCUT patients at baseline (0.20 logMAR; 95% CI, -0.03 to 0.44; P = .09) and 3 months (0.21 logMAR; 95% CI, 0.003 to 0.44; P = .047). Of 101 confirmed P aeruginosa SCUT isolates, 100 expressed Psl EPSs. In addition, all Psl-positive strains evaluated in the OPK assay were susceptible to anti-Psl mAb-mediated OPK.
The ability of P aeruginosa keratitis isolates to form biofilms in vitro was correlated with worse vision at presentation and after 3 months in SCUT. Ninety-nine percent of P aeruginosa keratitis isolates from SCUT produced Psl EPSs, and 100% of these evaluated Psl-positive isolates were susceptible to anti-Psl mAb-mediated OPK. These data indicate that biofilm formation and Psl EPSs may be candidate targets for novel therapeutics against P aeruginosa keratitis.
细菌毒力因子在理解临床感染方面的重要性日益得到认识。
确定 2 种潜在的毒力因子，即体外生物膜形成和 Psl 胞外多糖（EPS）表达，是否会影响铜绿假单胞菌角膜炎的临床表现或结局。
设计、地点和参与者：这是一项使用来自类固醇治疗角膜溃疡试验（SCUT）的临床分离株进行的实验室研究，该试验包括来自阿拉文眼科医院、普罗克特基金会、加利福尼亚大学旧金山分校和达特茅斯-希区柯克医疗中心的患者。SCUT 于 2006 年 9 月 1 日至 2010 年 2 月 22 日进行。本研究中使用的所有数据均在此期间获得。使用抗 Psl 单克隆抗体（mAb）酶联免疫吸附试验评估了 SCUT 中的铜绿假单胞菌临床分离株的体外生物膜形成情况，并评估了 Psl EPS 表达情况。还在部分分离株中评估了浮游生物生长动力学和抗 Psl mAb 介导的调理吞噬杀伤（OPK）的敏感性。线性回归评估了 SCUT 患者的视力与相应的生物膜形成和 Psl EPS 表达之间的关联。广义估计方程回归模型用于评估 SCUT 患者的视力变化是否与 Psl EPS 表达或生物膜形成有关。
生物膜形成、Psl 产生、OPK 和视力。
铜绿假单胞菌 SCUT 株的体外生物膜评分平均（SD）为 1.06（0.32）（范围 0.17-2.12）。生物膜增加 1 个单位与基线时 SCUT 患者视力下降 2 行相关（0.20 logMAR；95%CI，-0.03 至 0.44；P = .09）和 3 个月时（0.21 logMAR；95%CI，0.003 至 0.44；P = .047）。在 101 株确认的铜绿假单胞菌 SCUT 分离株中，有 100 株表达了 Psl EPSs。此外，在 OPK 测定中评估的所有 Psl 阳性菌株均对 Psl mAb 介导的 OPK 敏感。
铜绿假单胞菌角膜炎分离株在体外形成生物膜的能力与 SCUT 中初始和 3 个月后的视力下降有关。SCUT 中 99%的铜绿假单胞菌角膜炎分离株产生了 Psl EPSs，并且在评估的 100%的 Psl 阳性分离株中，它们都对 Psl mAb 介导的 OPK 敏感。这些数据表明，生物膜形成和 Psl EPSs 可能是针对铜绿假单胞菌角膜炎的新型治疗药物的候选靶标。
