Ozlem Aydemir, Department of Microbiology, Sakarya University, Training and Research Hospital, Sakarya, Turkey.
Yusuf Aydemir, Department of Pulmonology, Faculty of Medicine, Sakarya University, Sakarya, Turkey.
Pak J Med Sci. 2014 Sep;30(5):1011-6. doi: 10.12669/pjms.305.5098.
Lower respiratory tract infection is one of the most important causes of morbidity and mortality. However establishing a microbial diagnosis for patients with lower respiratory tract infection is still challenging and is often achieved in only half of cases by conventional methods. This study was designed to compare the fast responsive PCR method with the culture method in lower respiratory tract infections and to evaluate the reliability of multiplex PCR method.
One hundred ninety seven patients with the symptoms of acute lower respiratory tract infection, and diagnosed with community-acquired pneumonia, acute exacerbation of chronic obstructive pulmonary disease and exacerbations of bronchiectasis were included in the study. Both culture and PCR methods was performed for the isolation of most commonly seen bacteria, from sputum, nasopharyngeal swabs and bronchoalveolar lavage fluid samples.
While at least one bacterial isolation was determined in 62 (31.5%) of all patients with culture method, this number increased to 125 (63.5%) with multiplex PCR. The bacteria most commonly identified by PCR were S. pneumoniae (32%) and H. influenzae (31%). There was a significant difference between PCR and culture in terms of multi-factor detection rates (p<0.005). Multiple bacteria were detected in only two cases in cultures; however, multiple pathogens were detected in 47 cases with PCR.
Conventional methods, such as culture and serology are not always adequate to detect the pathogens in lower respiratory tract. Real-time PCR assays proved highly sensitive and rapid. The prevalence of bacteria and multiple agent detected by real-time PCR compared with culture was substantially higher. Widespread use of PCR methods, by providing the immediate and appropriate ''agent specific antibiotic treatment'' of LRTI, will help reduce failure and contributes to a reduction in antibiotic resistance.
下呼吸道感染是发病率和死亡率的最重要原因之一。然而，对于下呼吸道感染患者，建立微生物诊断仍然具有挑战性，并且通过常规方法通常仅能在一半的病例中实现。本研究旨在比较快速响应 PCR 方法与培养方法在下呼吸道感染中的应用，并评估多重 PCR 方法的可靠性。
本研究纳入了 197 例具有急性下呼吸道感染症状并诊断为社区获得性肺炎、慢性阻塞性肺疾病急性加重和支气管扩张症加重的患者。从痰、鼻咽拭子和支气管肺泡灌洗液样本中，同时进行培养和 PCR 方法以分离最常见的细菌。
在培养方法中，有 62 例（31.5%）至少确定了一种细菌分离，而在多重 PCR 中，这一数字增加到 125 例（63.5%）。通过 PCR 最常鉴定的细菌是肺炎链球菌（32%）和流感嗜血杆菌（31%）。PCR 和培养在多因素检测率方面存在显著差异（p<0.005）。在培养中仅在两种情况下检测到多种细菌，但在 47 例 PCR 中检测到多种病原体。
传统方法，如培养和血清学，并不总是足以检测下呼吸道的病原体。实时 PCR 检测法证明具有高度敏感性和快速性。实时 PCR 检测到的细菌和多种病原体的流行率明显高于培养。广泛应用 PCR 方法，通过提供下呼吸道感染的即时和适当的“针对病原体的抗生素治疗”，将有助于减少治疗失败，并有助于减少抗生素耐药性的产生。
