BACKGROUND Current diagnostic tests for pharyngitis do not distinguish between symptomatic group A Streptococcus (GAS) infection and asymptomatic colonization, resulting in over-diagnosis and unnecessary use of antibiotics. We assessed whether measures of host response could make this distinction. METHODS We enrolled 18 children with pharyngitis having Centor scores of 4 or 5 and 21 controls without pharyngitis or other acute infections. Both groups had throat cultures, molecular tests for GAS and respiratory viruses and IgM serology for Epstein-Barr virus. Host response was evaluated with white blood cell count (WBC), C-reactive protein (CRP), procalcitonin (PCT), and sequencing of RNA from peripheral blood leukocytes. RESULTS Of 18 cases, 11 had GAS pharyngitis, 3 had adenovirus pharyngitis and 4 had other pharyngitis. Among asymptomatic controls, 5 were positive for GAS. WBC, CRP, and PCT were higher in subjects with pharyngitis compared to asymptomatic controls including those with GAS. Transcriptional profiles from children with symptomatic GAS were clearly distinct from those of children in all other groups. The levels of two genes, CD177 and TLR5 each individually accurately distinguished between symptomatic and asymptomatic GAS. Optimal diagnostic sensitivity and specificity were achieved by the combination of CRP and PCT, and by each of the two gene markers. CONCLUSION In this exploratory study, we showed that traditional measures of inflammation and markers of host gene expression distinguish between symptomatic and asymptomatic GAS. These results point to future rapid molecular approaches for improving the diagnosis of GAS pharyngitis, that may help reduce unnecessary antibiotic use.

中文翻译：

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使用宿主反应改进 A 组链球菌性咽炎的诊断。

背景 目前的咽炎诊断测试无法区分有症状的 A 组链球菌 (GAS) 感染和无症状定植，导致过度诊断和不必要地使用抗生素。我们评估了宿主反应的措施是否可以做出这种区分。方法 我们招募了 18 名 Centor 评分为 4 或 5 的咽炎儿童和 21 名没有咽炎或其他急性感染的对照儿童。两组都进行了咽喉培养、GAS 和呼吸道病毒的分子检测以及 Epstein-Barr 病毒的 IgM 血清学检测。宿主反应通过白细胞计数 (WBC)、C 反应蛋白 (CRP)、降钙素原 (PCT) 和外周血白细胞 RNA 测序进行评估。结果18例中，GAS咽炎11例，腺病毒性咽炎3例，其他咽炎4例。在无症状对照中，5 例 GAS 呈阳性。与无症状对照组（包括 GAS 患者）相比，咽炎患者的 WBC、CRP 和 PCT 更高。有症状 GAS 儿童的转录谱明显不同于所有其他组的儿童。CD177 和 TLR5 这两个基因的水平分别准确地区分有症状和无症状的 GAS。CRP 和 PCT 的组合以及两种基因标记中的每一种都实现了最佳的诊断灵敏度和特异性。结论 在这项探索性研究中，我们发现传统的炎症测量和宿主基因表达标记物可以区分有症状和无症状的 GAS。这些结果指向未来用于改进 GAS 咽炎诊断的快速分子方法，