Infections and Cystic Fibrosis Unit, Milano, Italy.
Emerging Bacterial Pathogens Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy.
J Infect Dis. 2018 Mar 5;217(6):933-942. doi: 10.1093/infdis/jix621.
Staphylococcus aureus and Pseudomonas aeruginosa are key bacterial pathogens of the respiratory tract in patients with cystic fibrosis (CF). Although P. aeruginosa chronic bronchial infection is associated with a poorer prognosis, the consequences of S. aureus colonization on CF outcomes are controversial.
In this paper, murine models of infection resembling traits of the CF human airways disease have been revisited using an infection schedule that mimics the sequence of events of pulmonary disease in CF patients. First, mice were infected with S. aureus, embedded in agar beads; this was followed by P. aeruginosa infection and analysis of bacterial load, leukocyte infiltration, and lung tissue damage.
We reveal that (1) S. aureus promotes severe lesions including abscess formation, (2) S. aureus increases the risk of subsequent chronic P. aeruginosa respiratory infection, and (3) once the chronic infection has been established, P. aeruginosa influences most of the inflammatory responses independent of S. aureus.
Our findings established the significance of S. aureus colonization per se and the impact on the subsequent P. aeruginosa infection. This would point towards a thorough assessment for the need of treatment against S. aureus.
金黄色葡萄球菌和铜绿假单胞菌是囊性纤维化（CF）患者呼吸道的主要细菌性病原体。虽然铜绿假单胞菌慢性支气管感染与预后较差相关，但金黄色葡萄球菌定植对 CF 结局的影响仍存在争议。
本研究通过模拟 CF 患者肺部疾病发生顺序的感染方案，重新研究了类似于 CF 人类气道疾病特征的感染小鼠模型。首先，将金黄色葡萄球菌嵌入琼脂珠中感染小鼠；然后感染铜绿假单胞菌，并分析细菌负荷、白细胞浸润和肺组织损伤。
我们揭示了金黄色葡萄球菌（1）促进包括脓肿形成在内的严重病变；（2）增加了随后慢性铜绿假单胞菌呼吸道感染的风险；（3）一旦慢性感染确立，铜绿假单胞菌独立于金黄色葡萄球菌影响大多数炎症反应。
我们的研究结果确立了金黄色葡萄球菌定植本身的重要性及其对随后铜绿假单胞菌感染的影响。这将表明需要彻底评估针对金黄色葡萄球菌的治疗需求。
