Kuhn S, Davies H D, Katzko G, Jadavji T, Church D L
Department of Pediatrics, University of Calgary, Alberta, Canada.
Diagn Microbiol Infect Dis. 1999 Aug;34(4):275-80. doi: 10.1016/s0732-8893(99)00027-9.
The Strep A OIA assay by Biostar (Boulder, Co., USA) is a unique optical immunoassay system for the rapid detection of Group A streptococcal carbohydrate. As part of a community-based pediatric cohort study of Group A Streptococcus (GAS) persistence following antibiotic therapy of pharyngitis, the performance of the Strep A OIA assay was compared with the amount of growth from standard throat swab culture methods. A total of 363 throat swabs taken over the course of the study was evaluated from 248 children between 2 and 18 years of age. Two culture methods were performed: an agar plate with the throat swab using Columbia agar base with 5% sheep blood incubated under an anaerobic environment for 48 h and Todd-Hewitt broth (THB) enhancement. The Strep A OIA was then performed. A total of 144 of 363 (39.7%) samples was positive for GAS by one or more of the laboratory tests across study visits: agar culture detected 132 of 144 (91.7%), THB culture detected 128 of 144 (88.9%), and the Strep A OIA assay detected 129 of 144 (89.6%). Complete agreement among all three laboratory tests was found for 333 of 363 (91.7%) of the samples. Agar culture results were comparable to THB cultures with a sensitivity of 96.9%, specificity of 96.6%, a positive predictive value of 93.9%, and a negative predictive value of 98.3%. Although the performance of the Strep A OIA assay had similar specificity (96.5%) and positive predictive value (93.8%) compared with the combined results of the two culture methods, the sensitivity (89.0%) and negative predictive value (93.6%) were lower. A significant difference (p < 0.001) was found in the ability of the Strep A OIA assay to detect agar culture-positive swabs that had a light growth (1+ or 2+) (63.0%) versus a moderate (3+) or heavy (4+) growth (98.1%) of GAS. Although the Strep A OIA assay allows GAS throat swab results to be reported an average of 24 h sooner than either of the cultures, the rapid assay was not as sensitive in detecting light growth GAS-positive cultures.
美国科罗拉多州博尔德市的Biostar公司生产的A群链球菌光学免疫分析（OIA）检测是一种独特的光学免疫分析系统，用于快速检测A群链球菌碳水化合物。作为一项基于社区的关于咽炎抗生素治疗后A群链球菌（GAS）持续存在情况的儿科队列研究的一部分，将A群链球菌OIA检测的性能与标准咽拭子培养方法的生长量进行了比较。在研究过程中，共对248名2至18岁儿童的363份咽拭子进行了评估。采用了两种培养方法：一种是将咽拭子接种在含5%羊血的哥伦比亚琼脂培养基平板上，在厌氧环境下培养48小时，并进行托德-休伊特肉汤（THB）增菌培养。然后进行A群链球菌OIA检测。在整个研究访问期间，363份样本中有144份（39.7%）通过一种或多种实验室检测呈GAS阳性：琼脂培养法检测出144份中的132份（91.7%），THB培养法检测出144份中的128份（88.9%），A群链球菌OIA检测法检测出144份中的129份（89.6%）。在363份样本中的333份（91.7%）中，所有三种实验室检测结果完全一致。琼脂培养结果与THB培养结果相当，敏感性为96.9%，特异性为96.6%，阳性预测值为93.9%，阴性预测值为98.3%。尽管A群链球菌OIA检测的性能与两种培养方法的综合结果相比，特异性（96.5%）和阳性预测值（93.8%）相似，但其敏感性（89.0%）和阴性预测值（93.6%）较低。A群链球菌OIA检测法在检测GAS轻度生长（1+或2+）的琼脂培养阳性拭子（63.0%）与中度（3+）或重度（4+）生长的拭子（98.1%）的能力上存在显著差异（p < 0.001）。尽管A群链球菌OIA检测法能够比任何一种培养方法平均提前24小时报告GAS咽拭子检测结果，但这种快速检测方法在检测轻度生长的GAS阳性培养物时不够敏感。
