| Objective:To understand the carrying condition and infective distribution characteristics of New Delhi metal beta lactamase-1 (NDM 1) of Acinetobacter baumannii in local areas, and provide basis for clinical infection control and medical management. The selected Acinetobacter baumannii with NDM-1 and E.coli J53 were experimented with plasmid combining method, to research the blaNDM-1 in the transmission mechanism between different species. To screen out the pan-drug resistant Acinetobacter baumannii with NDM-1 from the whole genome sequencing, to understand its genome characteristics and the study of drug resistance gene island.Methods:1. Collect the Acinetobacter baumannii strains of four local hospitals between 2013.01-2014.12, to identify the strains and vertificate the drug susceptibility with VIKET COMPACT 2 automatic bacteria identification of the French bioMerieux company, and sceen the Acinetobacter baumannii strains. To confirm the phenotype with MBL E-test, and amplify the blaNDM-1 with PCR as to select the Acinetobacter baumannii with NDM-1,and using the pulsed field gel electrophoresis for homologous research.2. The Acinetobacter baumannii with NDM-1 were selected as donor bacteria and E.coli J53 was selected as receptors, and plasmid conjugation experiment was performed.3. To perform the whole genome sequencing of the pan-drug resistant Acinetobacter baumannii with NDM-1.Results: 5 Acinetobacter baumannii strains carried the blaNDM-1 and belonged to different types. blaNDM-1 is located in a plasmid and can be conjuncted to E.coli J53 with plasmid, resulted the resistance of the conjuncted J53. Whole genome sequencing results:the total length of pan-drug resistant Acinetobacter baumannii strain A02 was about 4.12 Mbp, the GC content is 38.97%,16 gene islands were calculated.The insertion sequence ISAba125 was inserted upstream and downstream of the blaNDM-i and blaNDM-1 was on the Tn125 transposon.Conclusions:The Acinetobacter baumannii with NDM-1 had appeared in local hospitals, and were resistant to β- lactams, carbapenems and aminoglycosides, so antibiotics should be selected reasonably. They have strong resistance and result in huge difficulties for clinical treatment. The patients with blaNDM-1 did not have medical tourism history abroad, showed that the production of the metal enzyme may be independent evolution process. The plasmid with blaNDM-1 can be spread from the Acinetobacter baumannii with NDM-1 to the E.coli J53, indicating that the blaNDM-1 has the ability of spread across species.The detection of NDM-1 should be enhanced to prevent its outbreak. The whole genome sequencing of a pan-drug resistant Acinetobacter baumannii showed that the insertion sequence ISAbal25 was inserted upstream and downstream of the blaNDM-1 and blaNDM-1 was on the plasmid 1. |
