Department of Laboratory Medicine.
Department of Laboratory Medicine Department of Microbiology Department of Medicine, University of Washington, Seattle.
Clin Infect Dis. 2014 Sep 1;59(5):643-50. doi: 10.1093/cid/ciu400. Epub 2014 May 27.
Guidelines currently provide conflicting recommendations regarding the diagnosis of group A streptococcal (GAS) pharyngitis in adults. Clinical guidelines state that negative rapid antigen detection tests (RADTs) do not require confirmation by a backup method in adults, whereas laboratory-based guidelines mandate confirmation of a negative RADT in patients of all ages. The objective of this study was to assess the utility of reflexive culture following a negative RADT in adolescents and adults with suspected GAS pharyngitis.
A retrospective analysis of 726 patients, aged ≥13 years, with negative RADTs and positive GAS throat cultures, was performed between 1 January 2000 and 31 December 2011 at 2 academic medical centers in Seattle, Washington. Complication rates, treatment, modified Centor score, and bacterial burden in patients with negative RADTs and positive GAS throat cultures were assessed.
Modified Centor scores ≥2 were observed in 55% of patients with a negative RADT and positive GAS culture. Of these, 77% of patients had a moderate or heavy bacterial burden (≥2+). RADTs failed to detect some patients who presented with serious complications of GAS pharyngitis: 29 (4.0%) had peritonsillar abscesses and 2 (0.28%) were diagnosed with acute rheumatic fever. Providers found culture results to be useful for initiating antibiotic therapy or confirming a clinical diagnosis. Antibiotic treatment was prescribed in 68.7% of patients, with culture-directed initiation of therapy documented in 43.5%.
Reflexive GAS culture is clinically useful when RADTs are negative. RADTs fail to detect a substantial number of adult patients with clinically significant pharyngitis who can benefit from treatment.
目前，关于成人 A 组链球菌（GAS）咽炎的诊断，临床指南提供了相互矛盾的建议。临床指南指出，阴性快速抗原检测（RADT）在成人中无需通过备用方法进行确认，而基于实验室的指南则要求在所有年龄段的患者中确认阴性 RADT。本研究的目的是评估在疑似 GAS 咽炎的青少年和成人中，阴性 RADT 后进行反射性培养的效用。
对 2000 年 1 月 1 日至 2011 年 12 月 31 日期间在华盛顿州西雅图的 2 所学术医疗中心就诊的年龄≥13 岁、RADT 阴性且 GAS 咽拭子培养阳性的 726 例患者进行了回顾性分析。评估了阴性 RADT 和阳性 GAS 咽拭子培养患者的并发症发生率、治疗、改良 Centor 评分和细菌负荷。
55%的阴性 RADT 和阳性 GAS 培养患者的改良 Centor 评分≥2。其中，77%的患者细菌负荷中等或较重（≥2+）。RADT 未能检测到一些出现 GAS 咽炎严重并发症的患者：29 例（4.0%）患有扁桃体周围脓肿，2 例（0.28%）被诊断为急性风湿热。临床医生发现培养结果有助于开始抗生素治疗或确认临床诊断。68.7%的患者接受了抗生素治疗，43.5%的患者记录了基于培养的治疗起始。
当 RADT 阴性时，GAS 培养具有临床意义。RADT 未能检测到大量具有临床意义的咽炎的成年患者，这些患者可以从治疗中受益。
