Kais Madeleine, Spindler Carl, Kalin Mats, Ortqvist Ake, Giske Christian G
Clinical Microbiology, Microbiology and Tumor Biology Center, Karolinska Institutet, Karolinska University Hospital Solna, SE-17176 Stockholm, Sweden.
Diagn Microbiol Infect Dis. 2006 Jul;55(3):169-78. doi: 10.1016/j.diagmicrobio.2006.01.007. Epub 2006 Apr 19.
The limitation of polymerase chain reaction (PCR) in diagnosis of lower respiratory tract infections (LRTIs) caused by Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis has been a distinguishing colonization from infection. We assess here the usefulness of real-time quantitative PCR (RQ-PCR) performed on lower respiratory tract samples to overcome this problem. Consecutive respiratory tract samples from patients with and without signs of infection (n = 203) were subjected to RQ-PCR, targeting the genes pneumolysin (S. pneumoniae), fumarate reductase (H. influenzae), and outer membrane protein B (M . catarrhalis). DNA from positive controls with predefined colony forming units (CFUs) per milliliter were included to allow estimation of CFU per milliliter for the test samples. In parallel, assessment of quantitative cultures from all samples was performed. In the group of patients with LRTI, significant pathogens (>/=10(5) CFU/mL) were found in 32/135 samples (23.7%) with culture, in 51/135 (37.7%) with RQ-PCR, and in 59/135 (43.7%) when combining the methods.
聚合酶链反应（PCR）在诊断由肺炎链球菌、流感嗜血杆菌和卡他莫拉菌引起的下呼吸道感染（LRTIs）时，其局限性在于难以区分定植与感染。我们在此评估对下呼吸道样本进行实时定量PCR（RQ-PCR）以克服这一问题的实用性。对有或无感染迹象的患者的连续呼吸道样本（n = 203）进行RQ-PCR，检测肺炎溶素（肺炎链球菌）、延胡索酸还原酶（流感嗜血杆菌）和外膜蛋白B（卡他莫拉菌）的基因。纳入每毫升具有预定义菌落形成单位（CFU）的阳性对照的DNA，以便估计测试样本的每毫升CFU。同时，对所有样本进行定量培养评估。在LRTI患者组中，通过培养在32/135个样本（23.7%）中发现显著病原体（≥10⁵CFU/mL），通过RQ-PCR在51/135个样本（37.7%）中发现，联合两种方法在59/135个样本（43.7%）中发现。
