Infectious Diseases Service, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
J Med Microbiol. 2020 May;69(5):705-711. doi: 10.1099/jmm.0.001190. Epub 2020 Apr 28.
pneumonia (PCP) is a severe disease affecting immunocompromised patients. Diagnosis is difficult due to the low sensitivity of direct examination and inability to grow the pathogen in culture. Quantitative PCR in bronchoalveolar lavage fluid (BAL) has high sensitivity, but limited specificity for distinguishing PCP from colonization. To assess the performance of an in-house quantitative PCR to discriminate between PCP and colonization. This was a single-centre retrospective study including all patients with a positive PCR result for in BAL between 2009 and 2017. Irrespective of PCR results, PCP was defined as the presence of host factors and clinical/radiological criteria consistent with PCP and (i) the presence of asci at direct examination of respiratory sample or (ii) anti-PCP treatment initiated with clinical response and absence of alternative diagnosis. Colonization was considered for cases who did not receive anti-PCP therapy with a favourable outcome or an alternative diagnosis. Cases who did not meet the above mentioned criteria were classified as 'undetermined'. Seventy-one patients with positive PCR were included (90 % non-HIV patients). Cases were classified as follows: 37 PCP, 22 colonization and 12 undetermined. Quantitative PCR values in BAL were significantly higher in patients with PCP versus colonization or undetermined (<0.0001). The cut-off of 5×10 copies/ml was able to discriminate PCP cases from colonization with 97 % sensitivity, 82 % specificity, 90 % positive predictive value and 95 % negative predictive value. Our quantitative PCR for in BAL was reliable to distinguish PCP cases from colonization in this predominantly non-HIV population.
卡氏肺孢子虫肺炎（PCP）是一种影响免疫功能低下患者的严重疾病。由于直接检查的敏感性低，且病原体无法在培养中生长，因此诊断较为困难。支气管肺泡灌洗液（BAL）中的定量 PCR 具有较高的敏感性，但对区分 PCP 与定植的特异性有限。评估一种内部定量 PCR 区分 PCP 和定植的性能。这是一项单中心回顾性研究，包括 2009 年至 2017 年间所有 BAL 中阳性 PCR 结果的患者。无论 PCR 结果如何，PCP 的定义为存在宿主因素和符合 PCP 的临床/放射学标准，并且 (i) 呼吸道样本的直接检查中存在有丝分裂或 (ii) 抗 PCP 治疗开始后具有临床反应且无其他诊断。对于未接受抗 PCP 治疗且预后良好或有其他诊断的患者，考虑为定植。未满足上述标准的病例被归类为“不确定”。共纳入 71 例阳性 PCR 的患者（90%为非 HIV 患者）。病例分为以下几类：37 例 PCP、22 例定植和 12 例不确定。与定植或不确定相比，PCP 患者的 BAL 定量 PCR 值显著更高（<0.0001）。5×10 拷贝/ml 的截止值能够以 97%的敏感性、82%的特异性、90%的阳性预测值和 95%的阴性预测值区分 PCP 病例与定植。我们在 BAL 中针对 的定量 PCR 能够可靠地区分非 HIV 人群中 PCP 病例与定植。
