Grim Christopher J, Kozlova Elena V, Ponnusamy Duraisamy, Fitts Eric C, Sha Jian, Kirtley Michelle L, van Lier Christina J, Tiner Bethany L, Erova Tatiana E, Joseph Sandeep J, Read Timothy D, Shak Joshua R, Joseph Sam W, Singletary Ed, Felland Tracy, Baze Wallace B, Horneman Amy J, Chopra Ashok K
Food and Drug Administration, Laurel, Maryland, USA.
Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas, USA.
Appl Environ Microbiol. 2014 Jul;80(14):4162-83. doi: 10.1128/AEM.00486-14. Epub 2014 May 2.
The genomes of 10 Aeromonas isolates identified and designated Aeromonas hydrophila WI, Riv3, and NF1 to NF4; A. dhakensis SSU; A. jandaei Riv2; and A. caviae NM22 and NM33 were sequenced and annotated. Isolates NF1 to NF4 were from a patient with necrotizing fasciitis (NF). Two environmental isolates (Riv2 and -3) were from the river water from which the NF patient acquired the infection. While isolates NF2 to NF4 were clonal, NF1 was genetically distinct. Outside the conserved core genomes of these 10 isolates, several unique genomic features were identified. The most virulent strains possessed one of the following four virulence factors or a combination of them: cytotoxic enterotoxin, exotoxin A, and type 3 and 6 secretion system effectors AexU and Hcp. In a septicemic-mouse model, SSU, NF1, and Riv2 were the most virulent, while NF2 was moderately virulent. These data correlated with high motility and biofilm formation by the former three isolates. Conversely, in a mouse model of intramuscular infection, NF2 was much more virulent than NF1. Isolates NF2, SSU, and Riv2 disseminated in high numbers from the muscular tissue to the visceral organs of mice, while NF1 reached the liver and spleen in relatively lower numbers on the basis of colony counting and tracking of bioluminescent strains in real time by in vivo imaging. Histopathologically, degeneration of myofibers with significant infiltration of polymorphonuclear cells due to the highly virulent strains was noted. Functional genomic analysis provided data that allowed us to correlate the highly infectious nature of Aeromonas pathotypes belonging to several different species with virulence signatures and their potential ability to cause NF.
对10株气单胞菌分离株的基因组进行了测序和注释，这些分离株分别鉴定并命名为嗜水气单胞菌WI、Riv3以及NF1至NF4；达卡气单胞菌SSU；詹氏气单胞菌Riv2；豚鼠气单胞菌NM22和NM33。分离株NF1至NF4来自一名患有坏死性筋膜炎（NF）的患者。两株环境分离株（Riv2和Riv3）来自该NF患者感染源的河水。虽然分离株NF2至NF4是克隆性的，但NF1在基因上是不同的。在这10株分离株的保守核心基因组之外，还鉴定出了几个独特的基因组特征。毒性最强的菌株具有以下四种毒力因子之一或其组合：细胞毒性肠毒素、外毒素A以及3型和6型分泌系统效应蛋白AexU和Hcp。在败血症小鼠模型中，SSU、NF1和Riv2毒性最强，而NF2毒性中等。这些数据与前三株分离株的高运动性和生物膜形成相关。相反，在肌肉感染小鼠模型中，NF2的毒性比NF1强得多。分离株NF2、SSU和Riv2大量从肌肉组织扩散到小鼠内脏器官，而根据菌落计数和通过体内成像实时追踪生物发光菌株，NF1到达肝脏和脾脏的数量相对较少。组织病理学上，观察到由于高毒力菌株导致肌纤维变性并伴有多形核细胞的显著浸润。功能基因组分析提供的数据使我们能够将属于几种不同物种的气单胞菌致病型的高传染性与毒力特征及其导致NF的潜在能力联系起来。
