Bharathi M J, Ramakrishnan R, Meenakshi R, Mittal S, Shivakumar C, Srinivasan M
Aravind Eye Hospital & Postgraduate Institute of Ophthalmology, Tirunelveli, Tamil Nadu, India.
Br J Ophthalmol. 2006 Oct;90(10):1271-6. doi: 10.1136/bjo.2006.096230. Epub 2006 Jul 12.
To determine the sensitivity, specificity and predictive values of potassium hydroxide (KOH) wet mount, Gram stain, Giemsa stain and Kinyoun's acid-fast stain in the diagnosis of infective keratitis.
A retrospective analysis of all patients with clinically diagnosed infective keratitis presenting between September 1999 and September 2002 was carried out. Corneal scrapes were taken and subjected to direct microscopy and culture.
3298 eyes of 3295 consecutive patients with infective keratitis were evaluated, of which 1138 (34.51%) eyes had fungal growth alone, 1069 (32.41%) had bacterial growth alone, 33 (1%) had Acanthamoeba growth alone, 83 (2.5%) had mixed microbial growth and the remaining 975 (29.56%) had no growth. The sensitivity of KOH wet mount was higher (99.3%; 95% confidence interval (CI) 98.6 to 99.6) in the detection of fungi, 100% (95% CI 90.4 to 100) in the detection of Nocardia and 91.4% (95% CI 75.8 to 97) in the detection of Acanthamoeba) than that of Gram-stained smears (89.2% (95% CI 87.3 to 90.8) in fungi, 87% (95% CI 73.0 to 94.6) in Nocardia and 60% (95% CI 42.2 to 75.6) in the detection of Acanthamoeba) in the detection of fungi, Nocardia and Acanthamoeba. 1764 of 3295 (53.54%) patients presented more than 7 days after onset of illness and 84.69% of the eyes had corneal ulcers with size >2 mm in diameter. Positivities of KOH (44.46%; p<0.001) and Gram-stained smears (77.37%; p<0.001) were found to be higher among eyes with larger ulcers (>2 mm) than among eyes with smaller ulcers (<2 mm).
KOH smear is of greater diagnostic value in the management of infective keratitis, and it is recommended in all clinics without exception for establishing timely treatment.
确定氢氧化钾（KOH）湿片法、革兰氏染色、吉姆萨染色及金胺O染色在感染性角膜炎诊断中的敏感性、特异性及预测价值。
对1999年9月至2002年9月间临床诊断为感染性角膜炎的所有患者进行回顾性分析。采集角膜刮片进行直接显微镜检查及培养。
对3295例连续感染性角膜炎患者的3298只眼进行评估，其中1138只眼（34.51%）仅培养出真菌，1069只眼（32.41%）仅培养出细菌，33只眼（1%）仅培养出棘阿米巴，83只眼（2.5%）为混合微生物生长，其余975只眼（29.56%）未培养出微生物。在检测真菌、诺卡菌及棘阿米巴时，KOH湿片法的敏感性高于革兰氏染色涂片，检测真菌时KOH湿片法敏感性为99.3%（95%可信区间[CI] 98.6至99.6），检测诺卡菌时为100%（95% CI 90.4至100），检测棘阿米巴时为91.4%（95% CI 75.8至97），而革兰氏染色涂片检测真菌时敏感性为89.2%（95% CI 87.3至90.8），检测诺卡菌时为87%（95% CI 73.0至94.6），检测棘阿米巴时为60%（95% CI 42.2至75.6）。3295例患者中有1764例（53.54%）在发病7天后就诊，84.69%的患眼角膜溃疡直径>2 mm。在溃疡较大（>2 mm）的眼中，KOH染色阳性率（44.46%；p<0.001）及革兰氏染色涂片阳性率（77.37%；p<0.001）高于溃疡较小（<2 mm）的眼。
KOH涂片在感染性角膜炎的诊断中具有更大的诊断价值，建议所有诊所均采用以建立及时治疗。
