Savoia Dianella, Zucca Mario
Department of Clinical and Biological Sciences, University of Torino, S. Luigi Gonzaga Hospital, 10043, Orbassano, Torino, Italy.
Curr Microbiol. 2007 Jun;54(6):440-4. doi: 10.1007/s00284-006-0601-9. Epub 2007 Apr 24.
Bacteria belonging to the Burkholderia species are important pulmonary pathogens in cystic fibrosis (CF) patients. Their ability to establish chronic and sometimes fatal infections seems linked to the quorum sensing-regulated expression of virulence factors. We examined 23 Burkholderia isolates, 19 obtained from CF patients and 4 from the environment, to evaluate their ability to form biofilm and to penetrate and replicate inside J774 macrophagic cells. Our results indicate that biofilm formation and intracellular survival are behavioral traits frequently expressed by Burkholderia strains isolated from CF patients. Successive isolates obtained from each of four chronically infected patients yielded bacteria consistently belonging to the same strain but showing increasing ability to replicate intracellularly and to produce biofilm, possibly due to in vivo bacterial microevolution driven by the selective lung environmental conditions. Protection against antimicrobials granted to burkholderiae by the expression of these two virulence factors might account for the frequent failures of antibiotic treatment in CF patients.
伯克霍尔德菌属细菌是囊性纤维化（CF）患者重要的肺部病原体。它们建立慢性感染甚至有时是致命感染的能力似乎与群体感应调节的毒力因子表达有关。我们检测了23株伯克霍尔德菌分离株，其中19株来自CF患者，4株来自环境，以评估它们形成生物膜以及在J774巨噬细胞内渗透和复制的能力。我们的结果表明，生物膜形成和细胞内存活是从CF患者分离出的伯克霍尔德菌菌株经常表现出的行为特征。从四名慢性感染患者中分别获得的连续分离株产生的细菌始终属于同一菌株，但细胞内复制和产生生物膜的能力不断增强，这可能是由于肺部选择性环境条件驱动的体内细菌微进化所致。这两种毒力因子的表达赋予伯克霍尔德菌的抗菌保护作用可能是CF患者抗生素治疗频繁失败的原因。
