Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis

Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the “anti-biotic era”. Although, we have expeditiously developed our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts required for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins.In this review article, we provide an overview of the established diagnostic techniques and therapeutics for keratitis caused by various bacteria. We extensively report the recent in-roads through novel tools for accurately diagnosing mono- and poly-bacterial corneal infections. Furthermore, we outline the recent progress by our groups and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discuss in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.     

应用硝酸还原酶法检测HSK患者血清一氧化氮水平

目的 探讨单疱病毒性角膜炎（HSK）患者血清一氧化氮（NO）的变化及其临床意义。方法 对43例HSK患者（其中活动期15例，非活动期28例）用硝酸还原酶法测定血清NO含量；并用同样方法对45例正常献血员作正常对照。结果所有HSK患者血清NO水平较正常对照高；HSK活动期患者N0水平较HSK非活动期患者高；HSK非活动期患者血清α肿瘤坏死因子（TNF-α）、α干扰素（IFN-α）、外周血淋巴细胞CD4／CD8比值（CD4／CD8）与正常对照比较无明显差异（P值均〉0．05）；HSK活动期患者TNF-α、IFN-α、CD4／CD8与正常对照比较有显著差异（P均〈0．01）；HSK活动期患者血清N0水平与TNF-α水平正相关（r=0．89），与IFN-α、CD4／CD8负相关（r分别为-0．79和-0．87）。结论 HSK非活动期患者血清NO水平轻度增加是机体对炎症的正常应答，对角膜细胞起保护作用；HSK活动期患者血清NO水平明显增高，对角膜组织有损伤作用。血清NO水平异常增高是活动期HSK的成因之一；用硝酸还原酶法检测HSK患者的NO水平，可为HSK患者愈后评估提供参考指标。     

First case of Tropicoporus tropicalis keratitis in an immunocompetent host from India and review of the literature

Tropicoporus tropicalis is an environmental basidiomycete that has been implicated in nine cases of cutaneous (n = 7) and pulmonary (n = 2) human infections predominantly in chronic granulomatous disease patients. We report here the first case of keratitis caused by Tropicoporus tropicalis in a 40-year-old immunocompetent patient, who presented with sudden diminution of vision in right eye. Corneal scrapings revealed hyaline, septate hyphae in microscopy and culture showed growth of white non-sporulating mycelial growth which was confirmed as Tropicoporus tropicalis by sequencing of ITS region of 28S rDNA. The patient was initiated on topical voriconazole along with natamycin, gatifloxacin and atropine drops. However, despite treatment, corneal ulcer perforated, for which penetrating keratoplasty was performed. Thereafter, he was prescribed amphotericin B (AMB) drops sixteen times a day and ketoconazole 200 mg twice a day with no recurrence reported over one year of follow up. The case represents the first case of infection by this fungus from India and also is the first case to be reported in an immunocompetent host.     

76例中西医结合治疗树枝状角膜炎的疗效及护理

目的观察中西医结合用药对树枝状角膜炎的治疗效果。方法76例（90眼）树枝状角膜炎患者分成观察组40例（46眼）和对照组36例（44眼）；对照组按常规局部用无环鸟苷眼药水及静脉滴注无环鸟苷，观察组常规加中药方剂治疗，进行疗效对比观察。结果观察组治愈44眼，显效2眼，治愈时间（12．3±2．5）d，1年复发率为13.95％；对照组治愈22眼，显效13眼，无效9眼，治愈时间（19．7±3．6）d，1年复发率为26．64％。2组治疗结果、治愈时间、复发率差异有显著性（p〈0．01；p〈0．05；p〈0.01）。结论中西医结合治疗树技状角膜炎，结合动态护理。可提高疗效、缩短疗程、减少复发。     

中西医结合治疗单纯疱疹病毒性角膜炎64例

目的:观察中西医结合治疗单纯疱疹病毒性角膜炎的临床疗效.方法:选取单纯疱疹病毒性角膜炎患者128例,随机分为观察组和对照组,每组64例.对照组应用0.1％阿昔洛韦滴眼液与0.1％羟苄唑眼液交替滴眼治疗,对于深层角膜炎患者,阿昔洛韦0.5g加至0.9％葡萄糖注射液500 mL中静脉滴注;观察组在对照组治疗的基础上加服中药治疗.结果:观察组有效率为95.59％,对照组有效率为78.26％,观察组显著优于对照组(P＜0.01);观察组平均治愈时间、复发率均优于对照组(P均＜0.05).结论:中西医结合治疗单纯疱疹病毒性角膜炎疗效显著.     

Case of keratitis caused by Streptomyces thermocarboxydus

We describe a case of keratitis caused by Streptomyces thermocarboxydus and report the usefulness of molecular analysis in identifying the exact species of Streptomyces. A 50-year-old man was diagnosed with keratitis caused by Streptomyces sp. which was identified as S. thermocarboxydus by sequencing the 16S rDNA. He had no history of trauma or systemic diseases. He was initially treated with topical beta-lactams and fluoroquinolones, and systemic beta-lactams but the keratitis did not improve. His vision improved significantly after topical erythromycin (5 mg/ml) and oral minocycline (200 mg/day) therapy. Our findings demonstrate that molecular analysis can be used to identify the exact Streptomyces species causing the keratitis. This then allowed us to determine the susceptibility of this species to different antibacterial drugs which were used to treat our patient successfully.     

角膜浅基质层针刺术联合软性角膜接触镜治疗丝状角膜炎临床观察

目的探讨角膜浅基质层针刺术联合软性角膜接触镜治疗丝状角膜炎的安全性和有效性。方法选择25例丝状角膜炎患者,表麻后刮除丝状物,间距0．5ram密集针刺病灶3ram范围内上皮层至浅基质层,术毕佩戴软性角膜接触镜,眼水点眼治疗原发病,随访观察。结果25例患者中21例症状完全消失,一次性治愈率84％,有效率100％。结论角膜浅基质层针刺联合软性角膜接触镜治疗丝状角膜炎是一种安全有效的方法,具有临床实用价值。     

环孢霉素A在眼科应用中的研究分析

目的探讨环孢霉素A在眼科中的应用,以供临床参考。方法分析环孢霉素A在眼科干眼病、防止翼状胬肉复发、角膜移植以及带状疱疹引起的角膜炎的应用效果,对环孢霉素A进行研究,总结其药物应用。结果环孢霉素A在眼科干眼病、防止翼状胬肉复发、角膜移植以及带状疱疹引起的角膜炎的应用效果均较为显著,患者不良反应较少,疗效较好,安全性较高。临床应用时可采用滴眼液、脂质体、眼膏等制剂。结论环孢霉素A在眼科中的应用范围较为广泛,如何研制新的载体材料,减少其毒副作用,是该药物研究的方向。