Burns J L, Jonas M, Chi E Y, Clark D K, Berger A, Griffith A
Division of Infectious Disease, Children's Hospital and Medical Center, Seattle, Washington 98105, USA.
Infect Immun. 1996 Oct;64(10):4054-9. doi: 10.1128/iai.64.10.4054-4059.1996.
Pulmonary infections caused by Burkholderia (Pseudomonas) cepacia are an important cause of morbidity and mortality in cystic fibrosis (CF) patients. Several features suggestive of cellular invasion and intracellular sequestration of B. cepacia in CF are persistence of infection in the face of antibiotic therapy to which the organism demonstrates in vitro susceptibility and a propensity to cause bacteremic infections in patients with CF. Epithelial cell invasion was demonstrated in vitro in A549 cells by a modified gentamicin protection assay. The kinetics of invasion appear to be saturable. Electron microscopy of invaded monolayers showed intracytoplasmic bacteria enclosed by membrane-bound vacuoles. No lysosomal fusion with these vacuoles was observed. Intraepithelial cell replication was suggested by electron microscopy and confirmed by both a quantitative assay and a visual assay. Cytochalasin D, but not colchicine, inhibited invasion, suggesting a role for microfilaments but not microtubules. The invasion phenotype in B. cepacia may be an important virulence factor for CF infections.
洋葱伯克霍尔德菌（假单胞菌属）引起的肺部感染是囊性纤维化（CF）患者发病和死亡的重要原因。CF患者中一些提示洋葱伯克霍尔德菌细胞侵袭和细胞内隐匿的特征包括：面对该菌在体外敏感的抗生素治疗时感染仍持续存在，以及在CF患者中引发菌血症感染的倾向。通过改良的庆大霉素保护试验在体外A549细胞中证实了上皮细胞侵袭。侵袭动力学似乎是可饱和的。对侵袭单层细胞的电子显微镜检查显示，胞浆内细菌被膜结合空泡包裹。未观察到溶酶体与这些空泡融合。电子显微镜检查提示上皮细胞内复制，并通过定量试验和视觉试验得到证实。细胞松弛素D而非秋水仙碱抑制侵袭，提示微丝而非微管起作用。洋葱伯克霍尔德菌的侵袭表型可能是CF感染的一个重要毒力因子。
