Postoperative endophthalmitis (PE) is the devastating complication that frequently results in vision loss. Recently, enterococcus have emerged as a major cause of PE in several countries and resulted in poor visual outcome. However, the reason remains elusive. We investigate whether selection pressure of fluoroquinolone exerts effects on microorganism profiles isolated from PE. Medical records of patients who were diagnosed with PE at eight resident training institutions between January 2004 and December 2015 were reviewed. The most common isolate was Enterococcus faecalis (28.0%), followed by Staphylococcus epidermidis (18.6%) and other coagulase negative Staphylococci (7.6%). However, the rates of E. faecalis isolated from conjunctival microbes were 6.2% (16/257) and their resistance to fluoroquinolones was higher than those of S. epidermidis. In vitro and in vivo co-culture models of E. faecalis and S. epidermidis were established for survival assays after administration of fourth-generation fluoroquinolone. In in vitro co-culture model, the survival assay of E. faecalis and S. epidermidis against the treatment of moxifloxacin showed that E. faecalis survived significantly better than S. epidermidis in the presence of moxifloxacin 1 µg/mL and more. In in vivo co-culture model, E. faecalis survived significantly better than S. epidermidis after topical treatment of moxifloxacin (5 mg/mL). E. faecalis has been the most common causative strain of PE in Korea. We suggest that the increase of E. faecalis in PE could be associated with the selection pressure of fourth-generation fluoroquinolone.

Summary: Enterococcus spp. have emerged as a leading causative strain of postoperative endophthalmitis in 11-year clinical data. We suggest that the increase of Enterococcus spp. is associated with the selection pressure of fourth-generation fluoroquinolone.

术后眼内炎（PE）是破坏性并发症，经常导致视力下降。近来，肠球菌已经在一些国家成为PE的主要原因，并导致不良的视觉效果。但是，原因仍然难以捉摸。我们调查氟喹诺酮的选择压力是否对分离自PE的微生物谱产生影响。回顾了2004年1月至2015年12月间在八家居民培训机构诊断为PE的患者的病历。最常见的分离株是粪肠球菌（28.0％），其次是表皮葡萄球菌（18.6％）和其他凝固酶阴性葡萄球菌（7.6％）。然而，粪肠球菌的发生率从结膜微生物中分离出的细菌为6.2％（16/257），其对氟喹诺酮类药物的抵抗力高于表皮葡萄球菌。在施用第四代氟喹诺酮后，建立粪肠球菌和表皮葡萄球菌的体外和体内共培养模型以进行存活测定。在体外共培养模型中，粪肠球菌和表皮葡萄球菌对莫西沙星治疗的存活率分析表明，在存在1 µg / mL或更高的莫西沙星时，粪肠球菌比表皮葡萄球菌的存活率显着提高。在体内在共培养模型中，粪肠球菌在莫西沙星（5 mg / mL）的局部治疗后存活率明显优于表皮葡萄球菌。粪肠球菌是韩国最常见的PE致病菌。我们认为，PE中粪肠球菌的增加可能与第四代氟喹诺酮的选择压力有关。

摘要： 肠球菌。在11年的临床数据中，已成为术后眼内炎的主要致病菌。我们建议增加肠球菌的种类。与第四代氟喹诺酮的选择压力有关。