Genomic Load from Sputum Samples and Nasopharyngeal Swabs for Diagnosis of Pneumococcal Pneumonia in HIV-Infected Adults
Genomic Load from Sputum Samples and Nasopharyngeal Swabs for Diagnosis of Pneumococcal Pneumonia in HIV-Infected Adults
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DOI：
10.1128/jcm.01553-14
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发表时间：
2014-12-01
影响因子：
9.4
通讯作者：
Klugman, Keith P.
中科院分区：
文献类型：
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作者：
Albrich, Werner C.;Madhi, Shabir A.;Klugman, Keith P.
鼻咽（NP）拭子的定量lytA实时PCR（rtPCR）结果可区分社区获得性肺炎球菌肺炎（CAP）和无症状定植。与传统的诊断方法相比，使用优化的临界值改善了肺炎球菌的病原学确定。在这里，我们比较了诱导痰和NP拭子中lytA rtPCR的实用性。如果血液培养、诱导痰培养或革兰氏染色、尿抗原检测或全血lytA rtPCR显示肺炎球菌，或如果NP拭子的lytA rtPCR结果> 8，000拷贝/ml，则认为肺炎球菌是感染HIV的南非成人CAP的原因。还对诱导痰进行lytA rtPCR。在222例有诱导痰的患者中，149例（67.1%）痰液lytA rtPCR阳性，而革兰染色或痰培养阳性者105例（45.9%; P < 0.001）。痰培养阳性时痰液的平均拷贝数高于痰培养阴性时（7.9对5.6 log（10）拷贝/ml; P < 0.001）。以10,000拷贝/ml为临界值，对高质量痰液lytA rtPCR检测的敏感性为78.1%，特异性为80.0%。该临界值与先前确定的NP拭子lytA rtPCR临界值8，000拷贝/ml相似（曲线下面积受试者工作特征[AUC-ROC]，任何质量痰液为80.4%，NP拭子为79.6%）。良好痰液的AUC-ROC为83.2%。总体而言，对于大多数患者，lytA rtPCR在诱导痰液上的表现与NP拭子相似，但如果可以获得高质量痰液，则表现略好。由于标本采集容易，NP拭子可能更适合诊断肺炎球菌性肺炎。
Quantitative lytA real-time PCR (rtPCR) results from nasopharyngeal (NP) swabs distinguish community-acquired pneumococcal pneumonia (CAP) from asymptomatic colonization. The use of an optimized cutoff value improved pneumococcal etiology determination compared to that of traditional diagnostic methods. Here, we compare the utility of lytA rtPCR from induced sputum and from NP swabs. Pneumococcus was considered the cause of CAP in HIV-infected South African adults if blood culture, induced-sputum culture or Gram stain, urine antigen test, or whole-blood lytA rtPCR revealed pneumococcus or if lytA rtPCR from NP swabs gave a result of >8,000 copies/ml. lytA rtPCR was also performed on induced sputum. Pneumococcus was detected by lytA rtPCR from sputum in 149 (67.1%) of 222 patients with available induced sputum, whereas the results of either Gram stain or culture of sputum were positive in 105 of 229 patients (45.9%; P < 0.001). The mean copy numbers from sputum were higher when the sputum cultures were positive than when the sputum cultures were negative (7.9 versus 5.6 log(10) copies/ml; P < 0.001). Against the composite diagnostic standard, a cutoff value of 10,000 copies/ml for good-quality sputum lytA rtPCR had a sensitivity of 78.1% and a specificity of 80.0%. This cutoff value performed similarly to the previously identified cutoff value of 8,000 copies/ml for NP swab lytA rtPCR (area under the curve receiver operating characteristic [AUC-ROC], 80.4% for sputum of any quality versus 79.6% for NP swabs). The AUC-ROC for good-quality sputum was 83.2%. Overall, lytA rtPCR performs similarly well on induced sputum as on NP swabs for most patients but performs slightly better if good-quality sputum can be obtained. Due to the ease of specimen collection, NP swabs may be preferable for the diagnosis of pneumococcal pneumonia.