Global concerns have been raised due to upward trend of Multi-drug Resistant (MDR) Pseudomonas aeruginosa reports in ocular infections. Our aim was to characterize the virulence determinants of MDR P. aeruginosa causing ocular infections. P. aeruginosa strains were isolated from 46 patients with conjunctivitis (2), endophthalmitis (11) and active keratitis (25) seen at our Institute, between 2016 and 2020. The isolates were identified by Vitek-2 and characterized based on growth kinetics, biofilm formation, motility, pyoverdine and pyocyanin production, phospholipase and catalase activity, urease production along with expression of exotoxins (exo-A, exo-U and exo-S) and correlated to its antibiotic profiles. Of the 46 P. aeruginosa isolates, 23 were MDR and were significantly (p = 0.03) associated with older (> 65) patients, along with higher production of pyoverdine (58.3%), pyocyanin (30.4%), phospholipase (91.6%) and protease (62.5%) activity, formed strong biofilms and exo-A (30.4%). No significant relation between motility, urease and catalase production with antibiotic susceptibility was observed. Heatmap and PCoA analysis confirmed this unique virulence profile associated with MDR-PA strains. Phenotypic characteristics of P.aeruginosa might be responsible for increased colonization and antibiotic resistance observed in vivo and understanding these differences may lead to development of clinical guidelines for the management of MDR infections.

中文翻译：

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多药 (MDR) 和泛耐药 (XDR) 铜绿假单胞菌的毒力因子：对印度南部高发病率环境中眼部感染分离株的横断面研究

由于眼部感染中多药耐药 (MDR) 铜绿假单胞菌报告呈上升趋势，引起了全球关注。我们的目的是表征引起眼部感染的 MDR 铜绿假单胞菌的毒力决定因素。铜绿假单胞菌菌株是从 2016 年至 2020 年间在我们研究所发现的 46 名患有结膜炎 (2)、眼内炎 (11) 和活动性角膜炎 (25) 的患者中分离出来的。生物膜形成、运动性、pyoverdine 和绿脓素产生、磷脂酶和过氧化氢酶活性、脲酶产生以及外毒素（exo-A、exo-U 和 exo-S）的表达，并与其抗生素谱相关。在 46 个铜绿假单胞菌分离株中，23 个是 MDR，并且与老年 (> 65) 患者显着 (p = 0.03) 相关，随着pyoverdine (58.3%)、绿脓素(30.4%)、磷脂酶(91.6%)和蛋白酶(62.5%)活性的增加，形成了强大的生物膜和exo-A (30.4%)。没有观察到运动性、脲酶和过氧化氢酶的产生与抗生素敏感性之间存在显着关系。热图和 PCoA 分析证实了这种与 MDR-PA 菌株相关的独特毒力谱。铜绿假单胞菌的表型特征可能是体内观察到的定植和抗生素耐药性增加的原因，了解这些差异可能会导致制定 MDR 感染管理的临床指南。观察到具有抗生素敏感性的脲酶和过氧化氢酶的产生。热图和 PCoA 分析证实了这种与 MDR-PA 菌株相关的独特毒力谱。铜绿假单胞菌的表型特征可能是体内观察到的定植和抗生素耐药性增加的原因，了解这些差异可能会导致制定 MDR 感染管理的临床指南。观察到具有抗生素敏感性的脲酶和过氧化氢酶的产生。热图和 PCoA 分析证实了这种与 MDR-PA 菌株相关的独特毒力谱。铜绿假单胞菌的表型特征可能是体内观察到的定植和抗生素耐药性增加的原因，了解这些差异可能会导致制定 MDR 感染管理的临床指南。