比较 qPCR 和培养方法在孕妇 B 族链球菌定植检测中的应用：一种新 qPCR 检测方法的评估。
Comparison of qPCR and culture methods for group B Streptococcus colonization detection in pregnant women: evaluation of a new qPCR assay.
机构信息
Laboratorio de Microbiología, Universidad de Granada-Instituto de Investigación Biosanitaria de Granada, Av. de la Investigación n°11, 18071, Granada, Spain.
Laboratorio de Microbiología, Universidad de Granada, Hospital General Virgen de las Nieves- Instituto de Investigación Biosanitaria de Granada, Granada, Spain.
出版信息
BMC Infect Dis. 2018 Jul 5;18(1):305. doi: 10.1186/s12879-018-3208-4.
BACKGROUND
Streptococcus Group B (GBS) colonization in pregnant women is the most important risk factor for newborn disease due to vertical transmission during delivery. GBS colonization during pregnancy has been implicated as a leading cause of perinatal infections. Traditionally, pregnant women are screened for GBS between 35 and 37 weeks of gestation. However, antenatal culture-based screening yields no information on GBS colonization status and offers low predictive value for GBS colonization at delivery. Numerous assays have been evaluated for GBS screening in an attempt to validate a fast and efficient method. The aim of this study was to compare bacteria isolation by culture and two qPCR techniques, targeting sip and cfb genes, respectively, for detecting colonizing GBS.
METHODS
Cultures - the gold-standard technique, a previous qPCR technique targeting the sip gene, and a new proposed qPCR assay targeting the cfb gene were evaluated as diagnostic tools on 320 samples.
RESULTS
Considering cultures as the gold standard, the evaluated qPCR method detected 75 out of 78 samples, representing a sensitivity of 93.58% (95% confidence interval (CI), 90.89-96.27) and specificity of 94.62% (95% CI, 91.78-97.46). However, an additional analysis was performed for true positives that included not only samples showing positives by culture but samples showing positive for both qPCR assays. The sensitivity and specificity were recalculated including these discrepant samples and a total of 89 samples were considered as positive, giving a prevalence of 27.81%. With this new analysis, the qPCR targeting the cfb gene showed a sensitivity of 95.5% (95% CI, 88.65-98.59) and specificity of 99.13% (95% CI, 96.69-99.97).
CONCLUSIONS
The new qPCR method is a sensitive and specific assay for detecting GBS colonization and represents a valuable tool for identifying candidates for intrapartum antibiotic prophylaxis. Cultures should be retained as the reference and the routine technique because of its specificity and cost analysis ratio, but it would be convenient to introduce PCR techniques to check negative culture samples or when an urgent detection is required to reduce risk of infection among infants.
背景
孕妇中 B 群链球菌（GBS）定植是导致新生儿垂直传播疾病的最重要危险因素。怀孕期间 GBS 定植已被认为是围产期感染的主要原因。传统上，孕妇在妊娠 35 至 37 周时进行 GBS 筛查。然而，基于产前培养的筛查无法提供 GBS 定植状态的信息，并且对分娩时 GBS 定植的预测价值较低。已经评估了许多检测方法来进行 GBS 筛查，以验证一种快速有效的方法。本研究旨在比较培养物分离和两种 qPCR 技术，分别针对 sip 和 cfb 基因，用于检测定植的 GBS。
方法
培养物 - 金标准技术、以前针对 sip 基因的 qPCR 技术和新提出的针对 cfb 基因的 qPCR 检测方法，对 320 个样本进行了评估。
结果
以培养物为金标准，评估的 qPCR 方法检测到 78 个样本中的 75 个，敏感性为 93.58%（95%置信区间（CI），90.89-96.27），特异性为 94.62%（95% CI，91.78-97.46）。然而，还对包括培养物阳性和两种 qPCR 检测方法均阳性的样本在内的真阳性进行了额外分析。重新计算了包括这些不一致样本的敏感性和特异性，共有 89 个样本被认为是阳性，患病率为 27.81%。通过这种新的分析，针对 cfb 基因的 qPCR 显示出 95.5%（95% CI，88.65-98.59）的敏感性和 99.13%（95% CI，96.69-99.97）的特异性。
结论
新的 qPCR 方法是一种敏感和特异的检测 GBS 定植的方法，是识别有必要进行分娩时抗生素预防的候选者的有价值的工具。由于其特异性和成本分析比率，培养物应保留为参考和常规技术，但引入 PCR 技术检查阴性培养物样本或在需要紧急检测以降低婴儿感染风险时将非常方便。
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