Centre for Respiratory Medicine, University College London, London, UK.
Thorax. 2012 Dec;67(12):1075-80. doi: 10.1136/thoraxjnl-2012-201924. Epub 2012 Aug 3.
Prevalence and load of airway bacteria in stable and exacerbated chronic obstructive pulmonary disease (COPD) has been previously studied using microbiological culture. Molecular techniques, such as quantitative PCR (qPCR), may be more informative.
In this study, 373 sputum samples from 134 COPD outpatients were assessed for prevalence and load of typical airway bacteria (Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis) by multiplex qPCR, with 176 samples analysed for atypical bacteria. Paired stable and exacerbation typical bacteria data were compared in 52 patients. We compared routine culture with qPCR in 177/373 samples.
Typical bacteria were more prevalent in exacerbation than stable-state paired samples: 30/52 (57.7%) vs. 14/52 (26.9%); p=0.001. In patients who were bacteria-positive at both time points, mean (±1 SEM) load was significantly higher at exacerbation than stable state (108.5(±0.3) vs. 107.2(±0.5) cfu/ml), constituting a 20-fold increase (p=0.011). qPCR was more discriminatory at detecting typical bacteria than microbiological culture (prevalence 59.3% vs. 24.3%; p<0.001). At stable state, higher airway bacterial load correlated with more severe airflow limitation (FEV(1)%predicted) (r=-0.299; p=0.033) and higher inhaled corticosteroid dosage (r=0.382; p=0.008). Mean C-reactive protein was higher in bacterial-associated exacerbations (35.0 Vs 25.1 mg/L; p=0.032).
Airway bacterial prevalence and load increase at COPD exacerbations and are an aetiological factor. qPCR is more discriminatory than culture, identifying higher airway bacterial prevalence. Exacerbations associated with bacterial detection showed a higher mean C-reactive protein level. In the stable state, airway bacterial load is related to more severe airflow limitation and higher inhaled corticosteroid dosage used.
先前已经使用微生物培养法研究了稳定期和加重期慢性阻塞性肺疾病（COPD）患者气道细菌的流行率和负荷。定量 PCR（qPCR）等分子技术可能更具信息量。
本研究对 134 例 COPD 门诊患者的 373 份痰标本进行了多重 qPCR 检测，以评估典型气道细菌（流感嗜血杆菌、肺炎链球菌、卡他莫拉菌）的流行率和负荷，其中 176 份标本分析了非典型细菌。比较了 52 例患者稳定期和加重期的典型细菌数据。我们在 177/373 份标本中比较了常规培养和 qPCR。
在稳定期和加重期配对样本中，典型细菌在加重期的流行率高于稳定期：30/52（57.7%）比 14/52（26.9%）；p=0.001。在两个时间点均为细菌阳性的患者中，加重期的平均（±1 SEM）负荷明显高于稳定期，分别为 108.5（±0.3）cfu/ml 和 107.2（±0.5）cfu/ml），构成 20 倍的增加（p=0.011）。qPCR 比微生物培养法更能检测出典型细菌（流行率 59.3%比 24.3%；p<0.001）。在稳定期，气道细菌负荷越高，气流受限越严重（FEV1%predicted）（r=-0.299；p=0.033），吸入皮质激素剂量越高（r=0.382；p=0.008）。与细菌相关的加重期患者的 C 反应蛋白平均值较高（35.0 比 25.1 mg/L；p=0.032）。
COPD 加重期气道细菌的流行率和负荷增加，是一种病因。qPCR 比培养法更具鉴别力，可识别更高的气道细菌流行率。与细菌检测相关的加重期患者的平均 C 反应蛋白水平较高。在稳定期，气道细菌负荷与更严重的气流受限和更高的吸入皮质激素剂量有关。
