Groupe d'étude des interactions hôte-pathogène, UPRES EA 3142, Université d'Angers, France.
Can J Microbiol. 2012 Mar;58(3):311-7. doi: 10.1139/w11-131. Epub 2012 Feb 22.
The aim of this study was to unravel, by focusing on cell surface properties, the underlying virulence factors contributing to the difference in the pathogenicity observed in two Acinetobacter baumannii strains isolated from the same patient. The two strains were phenotypically different: (i) a mucoid strain (AB-M), highly virulent in a mouse model of pneumonia, and (ii) a nonmucoid strain (AB-NM), moderately virulent in the same model. The study of the cell surface properties included the microbial adhesion to solvents method, the measurement of the electrophoretic mobility of bacteria, the analysis of biofilm formation by calcofluor white staining, the adherence to silicone catheters, and scanning electron microscopy. The AB-NM strain was more hydrophobic, more adherent to silicone catheters, and produced more biofilm than the AB-M strain. Scanning electron microscopy showed bacterial cells with a rough surface and the formation of large cell clusters for AB-NM whereas the AB-M strain had a smooth surface and formed only a few cell clusters. Contrary to the results of most previous studies, cell surface properties were not correlated to the virulence described in our experimental model, indicating that mechanisms other than adherence may be involved in the expression of A. baumannii virulence.
本研究旨在通过研究细胞表面特性，揭示导致从同一患者中分离的两种鲍曼不动杆菌菌株致病性差异的潜在毒力因子。这两种菌株表型不同：（i）粘液型菌株（AB-M），在肺炎小鼠模型中具有高度致病性，（ii）非粘液型菌株（AB-NM），在相同模型中具有中度致病性。细胞表面特性研究包括微生物对溶剂的粘附性方法、细菌电泳迁移率的测量、钙荧光白染色分析生物膜形成、对硅酮导管的粘附性以及扫描电子显微镜观察。AB-NM 菌株比 AB-M 菌株更具疏水性、更易粘附于硅酮导管、并形成更多的生物膜。扫描电子显微镜显示 AB-NM 菌株的细菌细胞表面粗糙，形成大的细胞簇，而 AB-M 菌株的表面光滑，仅形成少量细胞簇。与大多数先前研究的结果相反，细胞表面特性与我们实验模型中描述的毒力无关，这表明在鲍曼不动杆菌毒力的表达中可能涉及其他粘附机制。
