Kadouri Daniel, Venzon Nel C, O'Toole George A
Department of Oral Biology, University of Medicine and Dentistry of New Jersey, Newark, NJ 07103, USA.
Appl Environ Microbiol. 2007 Jan;73(2):605-14. doi: 10.1128/AEM.01893-06. Epub 2006 Nov 10.
The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an approximately 100-fold reduction in biofilm cell viability was detected following a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as 30 min was sufficient to reduce a P. aeruginosa biofilm. The ability of Micavibrio to reduce an existing biofilm was confirmed by scanning electron microscopy. In static and flow cell experiments, M. aeruginosavorus was able to modify the overall P. aeruginosa biofilm structure and markedly decreased the viability of P. aeruginosa. The altered biofilm structure was likely caused by an increase in cell-cell interactions brought about by the presence of the predator or active predation. We also conducted a screen to identify genes important for P. aeruginosa-Micavibrio interaction, but no candidates were isolated among the approximately 10,000 mutants tested.
对革兰氏阴性外寄生捕食性细菌铜绿食菌微杆菌（Micavibrio aeruginosavorus）的宿主特异性进行了研究。如先前报道的那样，铜绿食菌微杆菌可捕食铜绿假单胞菌，此外还能捕食洋葱伯克霍尔德菌、肺炎克雷伯菌以及这些菌种的众多临床分离株。在静态试验中，早在接触铜绿食菌微杆菌3小时后就观察到生物膜生物量减少，在接触该捕食者24小时后，生物膜细胞活力检测到约100倍的降低。我们观察到，铜绿食菌微杆菌的初始滴度低至10 PFU/孔或接触捕食者的时间短至30分钟就足以减少铜绿假单胞菌生物膜。通过扫描电子显微镜证实了铜绿食菌微杆菌减少现有生物膜的能力。在静态和流动池实验中，铜绿食菌微杆菌能够改变铜绿假单胞菌生物膜的整体结构，并显著降低铜绿假单胞菌的活力。生物膜结构的改变可能是由于捕食者的存在或主动捕食导致细胞间相互作用增加所致。我们还进行了筛选以鉴定对铜绿假单胞菌与铜绿食菌微杆菌相互作用重要的基因，但在测试的约10000个突变体中未分离到候选基因。
