背景:定量(q)聚合酶链反应(PCR)循环阈值(Ct)值表示阳性PCR结果所需的扩增循环数,并且是测试样品中病原体数量的代表。Ct值对胃肠道感染的临床应用尚不清楚。目标:本系统综述评估了全球医学文献中胃肠道病原体的Ct值与患者表现和临床结果之间的关联。数据来源:MEDLINE,EMBASE,Cochrane图书馆数据库:搜索2020年1月14日至17日。研究合格标准:包括报告成人和儿科人群中Ct值与临床结果之间存在或不存在关联的研究。动物研究,reviews,荟萃分析,非英语语言研究被排除在外。参与者:感染胃肠道病原体的人类,用qPCR检测。干预措施:评估Ct值的诊断。提取的数据以叙述方式报告。结果:鉴定了33项合格研究;最常见的病原体是艰难梭菌(n=15),诺如病毒(n=10),和轮状病毒(n=9)。4/8(50%)研究报告了低艰难梭菌Ct值与症状严重程度增加或预后不良之间的统计学显著关联,在1/2(50%)研究中,死亡风险增加;在Ct值和症状持续时间或住院时间之间未发现显著关联.在诺如病毒的研究中,5/7(71%),主要是基因组II,报告的有症状病例的中位Ct值显着低于对照组。在有症状的病例中也观察到明显较低的轮状病毒Ct值与3/7(43%)研究中的对照,在2/2的研究中与更严重的症状有关。确定了非C的矛盾关联。艰难的细菌和寄生虫病原体。结论:总之,一些研究报告了Ct值与患者或医疗保健结果之间的临床有用关联;另外,精心设计,基于这些发现,需要进行大规模试验.系统审查注册:[PROSPERO],标识符[CRD42020167239]。
Background: Quantitative (q) polymerase chain reaction (PCR) cycle threshold (Ct) values represent the number of amplification cycles required for a positive PCR result and are a proxy of pathogen quantity in the tested sample. The clinical utility of Ct values remains unclear for gastrointestinal infections. Objectives: This systematic
review assesses the global medical literature for associations between Ct values of gastrointestinal pathogens and patient presentation and clinical outcomes. Data Sources: MEDLINE, EMBASE, Cochrane library databases: searched January 14-17, 2020. Study Eligibility Criteria: Studies reporting on the presence or absence of an association between Ct values and clinical outcomes in adult and pediatric populations were included. Animal studies, reviews, meta-analyses, and non-English language studies were excluded. Participants: Humans infected with gastrointestinal pathogens, detected with qPCR. Interventions: Diagnostics assessing Ct values. Extracted data were reported narratively. Results: Thirty-three eligible studies were identified; the most commonly studied pathogens were Clostridioides difficile (n = 15), norovirus (n = 10), and rotavirus (n = 9). Statistically significant associations between low C. difficile Ct values and increased symptom severity or poor outcome were reported in 4/8 (50%) studies, and increased risk of death in 1/2 (50%) studies; no significant associations were found between Ct value and duration of symptoms or length of hospital stay. Among studies of norovirus, 5/7 (71%), mainly genogroup II, reported symptomatic cases with significantly lower median Ct values than controls. Significantly lower rotavirus Ct values were also observed in symptomatic cases vs. controls in 3/7 (43%) studies, and associated with more severe symptoms in 2/2 studies. Contradictory associations were identified for non-C. difficile bacterial and parasitic pathogens. Conclusions: In conclusion, some studies reported clinically useful associations between Ct values and patient or healthcare outcomes; additional, well-designed, large-scale trials are warranted based on these findings. Systematic
Review Registration: [PROSPERO], identifier [CRD42020167239].