School of Medicine, The University of Queensland, Brisbane, QLD, Australia.
Adult Cystic Fibrosis Centre, Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, QLD, Australia.
BMC Pulm Med. 2017 Nov 2;17(1):138. doi: 10.1186/s12890-017-0482-7.
Pulmonary exacerbations in cystic fibrosis (CF) remain poorly understood and treatment is usually targeted at Pseudomonas aeruginosa. Within Australia a predominant shared P. aeruginosa strain (AUST-02) is associated with greater treatment needs. This single centre study assessed temporal shared strain population dynamics during and after antibiotic treatment of exacerbations.
Sputum was collected from 12 adult patients with a history of chronic AUST-02 infection at four time-points during and after treatment of an exacerbation. Forty-eight P. aeruginosa isolates within each sample underwent AUST-02 allele-specific PCR and SNP-based strain genotyping.
Various commonly shared Australian strains (AUST-01, 0.1%; AUST-02, 54.3%; AUST-06, 36.6%; AUST-07, 4.6%; AUST-11, 4.3%) and two unique strains (0.1%) were identified from 45 sputum samples (2160 isolates). Based on within-patient relative abundance of strains, a "single-strain infection" (n = 7) or "mixed-strain infection" (n = 5) was assigned to each patient. A significant temporal variation in the P. aeruginosa population composition was found for those with mixed-strain infection (P < 0.001). Patients with mixed-strain infections had more long-term treatment requirements than those with single-strain infection. Moreover, despite both groups having similar lung function at study entry, patients with single-strain infection had greater improvement in FEV% predicted following their exacerbation treatment (P = 0.02).
Pulmonary exacerbations may reveal multiple, unrelated P. aeruginosa strains whose relative abundance with one another may change rapidly, in a sustained and unpredictable manner.
囊性纤维化（CF）中的肺部恶化仍然了解甚少，治疗通常针对铜绿假单胞菌。在澳大利亚，一种主要的共同铜绿假单胞菌菌株（AUST-02）与更大的治疗需求相关。这项单中心研究评估了在 CF 患者肺部恶化期间和恶化后抗生素治疗时，共享菌株的种群动态。
在 CF 患者肺部恶化期间和恶化后，从 12 名慢性 AUST-02 感染史的成年患者中采集 4 个时间点的痰液。对每个样本中的 48 个铜绿假单胞菌分离株进行 AUST-02 等位基因特异性 PCR 和 SNP 基于的菌株基因分型。
从 45 个痰液样本（2160 个分离株）中鉴定出各种常见的澳大利亚菌株（AUST-01，0.1%；AUST-02，54.3%；AUST-06，36.6%；AUST-07，4.6%；AUST-11，4.3%）和两种独特的菌株（0.1%）。根据患者内菌株的相对丰度，将每位患者分配为“单菌株感染”（n=7）或“混合菌株感染”（n=5）。对于混合菌株感染的患者，发现铜绿假单胞菌种群组成有显著的时间变化（P<0.001）。混合菌株感染的患者比单菌株感染的患者有更多的长期治疗需求。此外，尽管两组患者在研究开始时的肺功能相似，但单菌株感染的患者在其肺部恶化治疗后 FEV%预测值的改善更大（P=0.02）。
肺部恶化可能揭示多个不相关的铜绿假单胞菌菌株，它们之间的相对丰度可能以持续和不可预测的方式迅速变化。
