Department of Pediatrics, Faculty of Medicine, Centre for Understanding and Preventing Infection in Children, University of British Columbia Vancouver, BC, Canada.
Front Cell Infect Microbiol. 2012 May 28;2:67. doi: 10.3389/fcimb.2012.00067. eCollection 2012.
Burkholderia cepacia complex (BCC) bacteria can cause devastating chronic infections in people with cystic fibrosis. Of particular concern is "cepacia syndrome," a rapidly progressive and usually fatal decline in health, characterized by a necrotizing bacteremic pneumonia. An important component of defense against bloodstream infections is the bactericidal action of serum. Traditional methods to determine the capacity of bacterial isolates to resist the bactericidal effects of serum are relatively low-throughput viability assays. In this study, we developed a novel growth-based assay for serum susceptibility, which allows for high throughput analysis. We applied this assay to a range of clinical isolates of BCC as well as isolates comprising the BCC experimental strain panel. Our data demonstrate that isolates from all species of BCC examined can possess serum resistant or serum sensitive/intermediate phenotypes. Of particular clinical significance, we also found no direct link between the last saved pulmonary isolate from patients who subsequently developed "cepacia syndrome" and their capacity to resist the inhibitory effects of human serum, suggesting serum resistance cannot be used as a marker of an isolate's capacity to escape from the lung and cause bacteremia.
洋葱伯克霍尔德菌复合群 (BCC) 细菌可引起囊性纤维化患者的破坏性慢性感染。特别令人关注的是“洋葱伯克霍尔德菌综合征”，这是一种迅速进展且通常致命的健康下降，其特征为坏死性菌血症性肺炎。抵抗血流感染的防御的一个重要组成部分是血清的杀菌作用。用于确定细菌分离株抵抗血清杀菌作用能力的传统方法是相对低通量的生存能力测定。在这项研究中，我们开发了一种新的基于生长的血清药敏测定法，可实现高通量分析。我们将该测定法应用于一系列临床分离株的 BCC 以及包含 BCC 实验菌株组的分离株。我们的数据表明，所检查的 BCC 所有种的分离株都可能具有血清抗性或血清敏感/中介表型。特别具有临床意义的是，我们还发现随后发生“洋葱伯克霍尔德菌综合征”的患者的最后保存的肺部分离株与它们抵抗人血清抑制作用的能力之间没有直接联系，这表明血清抗性不能用作分离株逃避肺部并引起菌血症的能力的标志物。
