Clegg Herbert W, Dallas Steven D, Roddey Oliver F, Martin Edward S, Swetenburg Raymond L, Koonce Elizabeth W, Felkner Mary B, Ryan Amy G
Department of Pediatrics, Eastover Pediatrics, Presbyterian Hospital, Charlotte, NC, USA.
Pediatr Infect Dis J. 2003 Aug;22(8):726-31. doi: 10.1097/01.inf.0000078835.72497.ab.
Antigen tests have been well-studied and are widely used in pediatric practice for rapid detection of group A Streptococcus (GAS) infections in the throat, but they have not been examined sufficiently for the detection of infection of skin sites, such as the perineal region or impetiginous lesions.
During the 3-year period 1999 to 2002, we evaluated 239 patients with suspected GAS skin infection, in 5 pediatric practices, using 3 Dacron swabs for each site. The first swab was tested in the pediatric office laboratory with an antigen detection kit. For the first 91 patients, the Abbott Test Pack Plus antigen detection test (ADT) was used. The Abbott Signify Strep A ADT was used to test subsequent patients. The second swab was tested with BD Directigen 1-2-3 ADT in the hospital laboratory. The third swab was placed in modified Stuart's transport medium for comparison of recovery of GAS from culture in broth or on agar. A positive culture served as the reference standard. Test performance and test accuracy were determined for each ADT.
Of the 247 ADTs and cultures performed on 239 patients, 91 with suspected skin infection were tested with the Test Pack Plus test, 149 with the Signify Strep A test and 247 with the Directigen test. Eighty-six (35%) cultures were positive, 73 from perineal sites (54 rectal, 13 vaginal, 6 penile) and 13 from impetiginous lesions. There was 100% concordance for the 86 cultures positive for GAS in a comparison between dry Dacron swabs and swabs that had been placed in modified Stuart's transport medium. Test Pack Plus and Signify Strep A ADTs had similar performance characteristics for skin infections: sensitivity, 92 and 88%; specificity, 99 and 97%; positive predictive value, 96 and 94%; and negative predictive value, 97 and 93%. Directigen ADT had sensitivity 78%, specificity 100%, positive predictive value 100% and negative predictive value 89%. Accuracy for the tests varied from 92 to 97%.
Tests designed to detect GAS carbohydrate antigen in patients with pharyngitis can be used rapidly and accurately to detect GAS antigen in patients with cutaneous lesions suspected of GAS infection.
抗原检测已得到充分研究，并广泛应用于儿科实践中，用于快速检测咽喉部的A组链球菌（GAS）感染，但对于皮肤部位感染的检测，如会阴区域或脓疱病损，尚未进行充分研究。
在1999年至2002年的3年期间，我们在5家儿科诊所对239例疑似GAS皮肤感染的患者进行了评估，每个部位使用3根涤纶拭子。第一根拭子在儿科门诊实验室用抗原检测试剂盒进行检测。对于前91例患者，使用雅培测试包加强型抗原检测试验（ADT）。后续患者使用雅培Signify A组链球菌ADT进行检测。第二根拭子在医院实验室用BD Directigen 1-2-3 ADT进行检测。第三根拭子置于改良的Stuart运送培养基中，用于比较肉汤或琼脂培养中GAS的回收率。阳性培养作为参考标准。确定每种ADT的检测性能和检测准确性。
对239例患者进行了247次ADT检测和培养，其中91例疑似皮肤感染患者用测试包加强型试验检测，149例用Signify A组链球菌试验检测，247例用Directigen试验检测。86份（35%）培养结果为阳性，73份来自会阴部位（54份直肠、13份阴道、6份阴茎），13份来自脓疱病损。在干燥涤纶拭子与置于改良Stuart运送培养基中的拭子之间的比较中，86份GAS阳性培养结果的一致性为100%。测试包加强型和Signify A组链球菌ADT对皮肤感染具有相似的性能特征：敏感性分别为92%和88%；特异性分别为99%和97%；阳性预测值分别为96%和94%；阴性预测值分别为97%和93%。Directigen ADT的敏感性为78%，特异性为100%，阳性预测值为100%，阴性预测值为89%。各试验的准确性在92%至97%之间。
设计用于检测咽炎患者中GAS碳水化合物抗原的试验可快速、准确地用于检测疑似GAS感染的皮肤病变患者中的GAS抗原。
