| Part One:Molecular epidemiologic analysis of MDR Acinetobacter baumanniiOBJECT:To identify the characteristics of molecular epidemiology for MDR Acinetobacter baumannii isolated during an outbreak of nosocomial infections at General hospital of People's Liberation Army in 2007.METHOD:Three representative strains, previously identified by PFGE, were analysed with recently described MLST that based on Minimum Spanning Tree analysis.RESULTS:Strains 37,34 and 42 showed the allelic profile 2-2-2-2-2-2-2 (sequence type ST2), characteristic of A. baumannii ECâ…¡clone (clonal complex 2).CONCLUSION:The outbreak of nosocomial infections was caused by three subclones of A.baumannii ECâ…¡clone.Part Two:Molecular epidemiologic analysis of genomic data for Acinetobacter baumannii from Genome Project databaseOBJECT:To identify the characteristics of molecular epidemiology for genomic data of Acinetobacter baumannii from Genome Project database.METHOD:Genomic data of Acinetobacter baumannii from Genome Project database were analysed with the MLST.RESULTS:Six strains showed the allelic profile 2-2-2-2-2-2-2 (sequence type ST2), characteristic of A.baumannii ECâ…¡clone (clonal complex 2). Three additional strains showed the allelic profile 1-1-1-1-5-1-1 and 3-1-1-1-5-1-1 (sequence type ST1 and ST20), characteristic of A.baumannii EC I clone (clonal complex 1). The other isolates showed other sequence types.CONCLUSION:There are genomic data for several strains of ECâ… andâ…¡clones in Genome Project database. Part Three:The AbaR genomic island in strain 42 of ECâ…¡cloneOBJECT:To test the hypothesis that strain 42 of ECâ…¡clone harbours a structure related to AbaR genomic island.METHOD:(1) First, strain 42 was tested by PCR with primers derived from ATPase gene, J1, J2 and J4. (2) Then the AbaR genomic island in strain 42 was totally sequenced, based on the sequence of AbaR genomic island in strain 6014059 from Genome Project database. (3) At last the AbaR in strain 42 was annotated and compared with the previously reported AbaRs. The structures of standard AbaRs and non-standard AbaRs also were compared.RESULTS:(1) There is an AbaR in strain 42. (2) A continuous region of 10kb was completely sequenced. This transposon was formed by backbone transposon Tn6021 and identical to that of 6014059, except for a regions of 2.8kb was missing from strain 42. (3) The unique region in Tn6021 is a 1.2 segment which is repleced by an arsenate resistance operon (arSHBRC) in Tn6019. The partial uspA and adjacent sup of Tn6021 share a significantly lower similarity to their counterparter in Tn6019, indicating a homologous recombination within this region. And the relationship between the recombination and insertion of MARR related structure remains for further investigation.CONCLUSION:The AbaR-type genomic islands were more complicated in ECâ…¡clone and they might be not important in the epidemic spread of ECâ…¡clone.Part Four:The antibiotics resistant genomic islands in ECâ… clone of A.baumanniiOBJECT:To identify the antibiotics resistant genomic islands in ECâ… clone.METHOD:The genomic data of MDR ECâ… strain AYE was first analysed by Barcode software. Then the results were compared with the genomic sequences of MDR ECâ… strain AB0057 and antibiotics susceptible ECâ… strain AB307-0294 to identify antibiotics resistant genomic islands.RESULTS:There were 217 sequence fragments with different barcodes in the genome of strain AYE. The region of 2904291bp to 2925291bp harbours a class 1 integrase. Partial sequence of this region also presented in strain AB0057, but missed from strain AB307-0294, indicating multi-drug-resistance acquisition through integron.CONCLUSION:The region of 2904291bp to 2925291bp in strain AYE may be an antibiotics resistant genomic island.
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