title: Aeromonas salmonicida subsp. salmonicida strains isolated from Chinese freshwater fish contain a novel genomic island and possible regional-specific mobile genetic elements profiles.
abstract: Two strains of Aeromonas salmonicida, YK and BG, were isolated from largemouth bronze gudgeon and northern whitefish in China, and identified as A. salmonicida subsp. salmonicida based on phylogenetic analysis of vapA and 16S rRNA gene sequences. YK and BG originated from freshwater fish, one of which belonged to the cyprinid family, and the strains showed a difference in virulence. Subsequently, we performed whole genome sequencing of the strains, and comparison of their genomic sequences to the genome of the A449 reference strain revealed various genomic rearrangements, including a new variant of the genomic island AsaGEI in BG, designated as AsaGEI2c This is the first report on a GEI of A. salmonicida strain from China. Furthermore, both YK and BG strains contained a Tn7 transposon inserted at the same position in the chromosome. Finally, IS-dependent rearrangements on pAsa5 are deemed likely to have occurred, with omission of the resD gene in both strains as well as omission of genes related to the IncF conjugal transfer system in the YK isolate. This study demonstrates that A. salmonicida subsp. salmonicida can infect non-salmonids (cyprinids) in addition to salmonids, and that AsaGEI2c might be useful as a geographical indicator of Chinese A. salmonicida subsp. salmonicida isolates.
authors: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Meng
authors: M
authors: Long
authors: Section for Environmental Microbiology and Biotechnology, Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors: Tue K
authors: TK
authors: Nielsen
authors: Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Grønnegårdsvej 15, 1870 Frederiksberg C, Denmark.
authors: Jørgen J
authors: JJ
authors: Leisner
authors: Section for Environmental Microbiology and Biotechnology, Department of Environmental Science, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors: Lars H
authors: LH
authors: Hansen
authors: Qinghai Provincial Fishery Environmental Monitoring Center, Xining 810000, China.
authors: Zhi X
authors: ZX
authors: Shen
authors: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
authors: Qian Q
authors: QQ
authors: Zhang
authors: State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China liaihua@ihb.ac.cn.
authors: Aihua
authors: A
authors: Li
mesh_terms: D048409:Aeromonas salmonicida / Q000235:genetics* / Q000302:isolation & purification; D000818:Animals; D002347:Carps / Q000382:microbiology; D002681:China / Q000453:epidemiology; D003530:Cyprinidae / Q000382:microbiology; D004251:DNA Transposable Elements; D005393:Fish Diseases / Q000453:epidemiology / Q000382:microbiology; D005399:Fishes / Q000382:microbiology*; D005618:Fresh Water; D016680:Genome, Bacterial; D044404:Genomic Islands; D023281:Genomics; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary; D059014:High-Throughput Nucleotide Sequencing; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S; D012487:Salmonidae / Q000382:microbiology; D014774:Virulence
chemical_list: D004251:DNA Transposable Elements; D012336:RNA, Ribosomal, 16S
keywords: Aeromonas salmonicida subsp. salmonicida; AsaGEI2c; China; Tn7 transposon; genome sequencing; genomic island