Microbiology Research Centre, Aravind Eye Hospital & Postgraduate Institute of Ophthalmology, Tirunelveli 627 001, Tamil Nadu, India.
Indian J Med Res. 2009 Dec;130(6):749-57.
BACKGROUND & OBJECTIVE: Infective keratitis is rare in the absence of predisposing factors. The pattern of risk factors predisposing to infective keratitis varies with geographical regions and also influences the type of infection that occurs. The present study was aimed to identify the specific risk factors that predispose the infective keratitis (non viral) and to determine the association between the risk factors identified and the microbial aetiology of infective keratitis in a geographic region (south India).
A retrospective analysis of all patients clinically diagnosed infective keratitis (non viral) presenting between September 1999 and September 2002 was performed to identify risk factors. After diagnosing infective keratitis clinically, corneal scrapes were performed and subjected to microscopy and culture.
A total of 3295 patients with infective keratitis were evaluated, of whom, 1138 (34.5%) patients had fungal growth alone, 1066 (32.4%) had bacterial growth alone, 33 (1%) had Acanthamoeba growth alone, 83 (2.5%) had mixed microbial growth and the remaining 975 (29.6%) had no growth. Corneal injury was identified in 2356 (71.5%) patients and it accounted for 91.9 per cent in fungal keratitis (P<0.0001) (OR: 73.5; 95%CI: 61.3-98.5), 28.1 per cent in bacterial keratitis and 100 per cent in Acanthamoeba keratitis (P<0.0001). Injuries due to vegetative matter (61.2%) was identified as significant risk for fungal keratitis (P<0.0001) (OR: 15.73; 95%CI: 12.7-19.49) and mud (84.85%) for Acanthamoeba keratitis (P<0.0001) (OR: 16.52; 95%CI: 6.35-42.99). Co-existing ocular diseases predisposing to bacterial keratitis accounted for 724 (69%) patients (P<0.0001) (OR: 33.31; 95%CI: 26.98-41.12). Bacterial pathogens alone were recovered from all 35 patients with contact lens associated keratitis (100%). Co-existing ocular diseases (78.3%) were frequently documented among patients older than 50 yr (P<0.0001) (OR: 27.0; 95%CI: 25.0-28.0) and corneal injury (89.7%) was frequently recorded among patients younger than 51 yr (P<0.0001) (OR: 72.0; 95%CI: 70.0-73.0).
INTERPRETATION & CONCLUSION: Corneal injury was found to be the principal risk factor for fungal and Acanthamoeba keratitis, while co-existing ocular diseases for bacterial keratitis. Corneal injury with vegetative matter was more often associated with fungal keratitis and injury with mud with Acanthamoeba keratitis.
在不存在诱发因素的情况下，感染性角膜炎很少见。导致感染性角膜炎的风险因素模式因地域不同而有所差异，也会影响发生的感染类型。本研究旨在确定导致（非病毒性）感染性角膜炎的具体风险因素，并确定在一个地域（印度南部）确定的风险因素与感染性角膜炎的微生物病因之间的关系。
对 1999 年 9 月至 2002 年 9 月期间临床诊断为（非病毒性）感染性角膜炎的所有患者进行回顾性分析，以确定风险因素。在临床诊断为感染性角膜炎后，进行角膜刮片并进行显微镜检查和培养。
共评估了 3295 例感染性角膜炎患者，其中 1138 例（34.5%）患者仅存在真菌感染，1066 例（32.4%）仅存在细菌感染，33 例（1%）仅存在棘阿米巴感染，83 例（2.5%）存在混合微生物感染，其余 975 例（29.6%）无生长。2356 例（71.5%）患者存在角膜损伤，真菌性角膜炎中占 91.9%（P<0.0001）（OR：73.5；95%CI：61.3-98.5），细菌性角膜炎中占 28.1%，棘阿米巴角膜炎中占 100%（P<0.0001）。因植物性物质（61.2%）引起的损伤被确定为真菌性角膜炎的显著风险因素（P<0.0001）（OR：15.73；95%CI：12.7-19.49），而泥（84.85%）是棘阿米巴角膜炎的显著风险因素（P<0.0001）（OR：16.52；95%CI：6.35-42.99）。导致细菌性角膜炎的共同眼部疾病占 724 例（69%）患者（P<0.0001）（OR：33.31；95%CI：26.98-41.12）。所有 35 例接触镜相关角膜炎患者均单独分离出细菌病原体（100%）。年龄大于 50 岁的患者（78.3%）更常伴有共同眼部疾病（P<0.0001）（OR：27.0；95%CI：25.0-28.0），年龄小于 51 岁的患者（89.7%）更常记录到角膜损伤（P<0.0001）（OR：72.0；95%CI：70.0-73.0）。
角膜损伤被认为是真菌和棘阿米巴角膜炎的主要危险因素，而共同的眼部疾病是细菌性角膜炎的主要危险因素。角膜损伤合并植物性物质更常与真菌性角膜炎有关，而损伤合并泥土则更常与棘阿米巴角膜炎有关。
