Sagerfors Susanna, Karakoida Chrysoula, Sundqvist Martin, Ejdervik Lindblad Birgitta, Söderquist Bo
Department of Ophthalmology, Faculty of Medicine and Health, Örebro University, SE 701 82 Örebro, Sweden.
Department of Laboratory Medicine, Clinical Microbiology, Faculty of Medicine and Health, Örebro University, SE 701 82 Örebro, Sweden.
J Clin Med. 2021 Apr 21;10(9):1810. doi: 10.3390/jcm10091810.
To compare two different methods of corneal culture in infectious keratitis: multiple sampling for direct inoculation and enrichment (standard method) and a single sample via transport medium for indirect inoculation (indirect inoculation method).
Prospective inclusion of patients fulfilling predefined criteria of infectious keratitis undergoing corneal culture according to both studied methods in a randomized order.
The standard method resulted in a significantly higher proportion of positive culture outcomes among the 94 included episodes of infectious keratitis (61%; 57/94) than the indirect inoculation method (44%; 41/94) ( = 0.002) and a significantly higher proportion of microorganisms than the indirect inoculation method, with a Cohen's kappa of 0.38 (95% CI: 0.28-0.49) for agreement between the methods. Subanalysis of culture results showed that direct inoculation on gonococcal agar only combined with the indirect inoculation method resulted in a similar rate of culture positive patients and proportion of detected microorganisms to the standard method.
Indirect inoculation of one corneal sample cannot replace direct inoculation of multiple corneal samples without loss of information. A combination of directly and indirectly inoculated samples can reduce the number of corneal samples by four without statistically significant differences in culture outcome or in the proportion of detected microorganisms.
比较感染性角膜炎两种不同的角膜培养方法：多次取样直接接种和富集培养（标准方法）以及通过转运培养基单次取样进行间接接种（间接接种法）。
前瞻性纳入符合感染性角膜炎预定义标准的患者，按照两种研究方法以随机顺序进行角膜培养。
在纳入的94例感染性角膜炎病例中，标准方法培养结果阳性的比例（61%；57/94）显著高于间接接种法（44%；41/94）（P = 0.002），且检测到的微生物比例也显著高于间接接种法，两种方法结果一致性的Cohen's kappa值为0.38（95%CI：0.28 - 0.49）。培养结果的亚分析表明，仅在淋球菌琼脂上直接接种并结合间接接种法，培养阳性患者的比例和检测到的微生物比例与标准方法相似。
对一个角膜样本进行间接接种无法替代对多个角膜样本进行直接接种而不损失信息。直接接种和间接接种样本相结合可将角膜样本数量减少四分之三，且培养结果或检测到的微生物比例无统计学显著差异。
