From the Division of Academic General Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago.
Northwestern University Feinberg School of Medicine.
Pediatr Infect Dis J. 2019 Aug;38(8):769-774. doi: 10.1097/INF.0000000000002293.
Timely, accurate diagnosis of group A streptococci (GAS) pharyngitis prevents acute rheumatic fever and limits antibiotic overuse. The illumigene group A Streptococcus assay (Meridian Bioscience, Cincinnati, OH) is a molecular test for GAS pharyngitis with high sensitivity and specificity. We sought to determine whether the illumigene test is more likely than throat culture to be positive in patients without pharyngeal symptoms and explore the limits of detection of the test.
Patients 3-17 years of age were eligible if they had no history of pharyngitis or use of antibiotics within the previous 2 weeks; there were no upper respiratory infection symptoms, sore throat or fever and no signs of infection. Culture and illumigene were performed on duplicate throat swabs. Excess lysate from a subset of illumigene tests was evaluated by real-time polymerase chain reaction. Institutional Review Board approval was obtained.
We enrolled 385 patients from February 2016 to October 2017; mean age was 10 yr; 51% were male. Most visits were for health supervision (69%). Significantly more illumigene tests (78/385, 20.3%) than throat cultures (48/385, 12.5%) were positive (χ; P =0.0035). Illumigene was "indeterminate" for 3 patients, leaving 382 pairs of swabs for analysis. Results were discordant for 32 of 382 pairs (8.4%); 31 of 32 (97%) were illumigene-positive/culture-negative (McNemar test; P < 0.000001). Real-time polymerase chain reaction was negative in 4 of 13 (31%) tested illumigene-positive lysates; the paired culture had been negative in all four. The limit of detection for the illumigene test was 55 colony forming units/mL.
The illumigene test is significantly more likely than throat culture to yield positive results in patients without GAS pharyngitis. Failure to appropriately select patients for testing may negatively impact antimicrobial stewardship efforts without benefit to patients.
及时、准确地诊断 A 组链球菌（GAS）咽炎可预防风湿热和限制抗生素的过度使用。Illumigene 组 A 链球菌检测（Meridian Bioscience，俄亥俄州辛辛那提）是一种用于 GAS 咽炎的分子检测方法，具有高灵敏度和特异性。我们旨在确定与咽拭子培养相比，Illumigene 检测在无咽症状的患者中呈阳性的可能性，并探索该检测的检测下限。
如果患者在过去 2 周内无咽炎或使用抗生素史，无上呼吸道感染症状、咽痛或发热，无感染迹象，年龄在 3-17 岁之间，则符合入选条件。对双侧咽拭子进行培养和 Illumigene 检测。从亚组的 Illumigene 检测中获得的多余裂解液通过实时聚合酶链反应进行评估。获得机构审查委员会的批准。
我们于 2016 年 2 月至 2017 年 10 月期间共纳入 385 名患者；平均年龄为 10 岁；51%为男性。大多数就诊是为了健康检查（69%）。与咽拭子培养（48/385，12.5%）相比，Illumigene 检测（78/385，20.3%）阳性的患者明显更多（χ 2；P =0.0035）。3 名患者的 Illumigene 检测结果为“不确定”，其余 382 对拭子用于分析。382 对拭子中有 32 对（8.4%）结果不一致；31 对（97%）为 Illumigene 阳性/培养阴性（McNemar 检验；P < 0.000001）。对 13 个 Illumigene 阳性裂解液中的 4 个（31%）进行实时聚合酶链反应检测为阴性；所有 4 个配对培养均为阴性。Illumigene 检测的检测下限为 55 个菌落形成单位/mL。
与咽拭子培养相比，Illumigene 检测在无 GAS 咽炎的患者中更有可能产生阳性结果。不恰当地选择患者进行检测可能会对抗菌药物管理工作产生负面影响，而对患者无益。
