| Objecitve:To analyze the distribution of genotypes of quinolone and aminoglycosides in IMP-resistant Acinetobacter baumannii in Yanbian Area,to detect the carrying status of mutations of gyrA and parC,the aminoglycoside modifying enzyme and the 16s rRNA methylase gene.To explore the multi-drug resistance mechanism of Acinetobacter baumannii in our hospital,to provide theoretical basis for effectively guiding clinical treatment and controlling nosocomial infection,and to find new clues for the control of multidrug-resistant Acinetobacter baumannii.Methods:A total number of 285 strains of Acinetobacter baumannii isolated from clinical departments of our hospital from 2015.09 to 2017.12 were collected.Bacterial identification and drug susceptibility testing were performed on clinical isolates by BD automatic bacterial identification drug susceptibility tester.Acinetobacter baumannii was screened in bacterial culture at 42?,EDTA was used to identify whether the bacteria produced metalloenzymes,and Hodge test was used to detect bacteria whether carbapenemase is produced.Use the polymerase chain reaction method and sequencing analysingto detect the carrying status of quinolone gyrA and parC genes,aminoglycoside modifying enzyme and the 16s rRNA methylase gene.To gather statistics of bacterial drug sensitivity data,analysis of the resistance rate and distribution of Acinetobacter baumannii in our hospital.Results:1.Preliminary identification of bacterial strains:Acinetobacter baumannii was identified by bacterial susceptibility and bacterial culture at 42?.285 strains of imipenem-resistant Acinetobacter baumannii EDTA test were negative,suggesting that the bacteria did not produce metalloenzymes;improved Hodge All tests were positive,suggesting that the bacteria produce carbapenemase.2.Imipenem-resistant Acinetobacter baumannii isolated in our hospital is highly resistant to clinically used antibiotics.Levofloxacin is 100%;Amikacin is 70.2%,Gentamicin is 96.1%;Ceftazidime is 100%.Cefepime 98.2%;penicillin 100%,is a multi-drug resistant Acinetobacter baumannii.Among 285 strains,76.5%were derived from sputum samples and 74.4%were from intensive care units.3.The detection results of quinolone drug resistance genes:gyrA and parC genes were found in 285 isolates,Ser-Leu mutations were found in position 83 of gyrA geneand synonymous mutations of Gly in 71 and Arg in 162 amino acids respectively.There was a mutation in Ser-Leu at position 80 of the parC gene;in addition,52.3%of the strains had synonymous mutations of proline at 109 amino acids,and 47.7%of the strains had synonymous mutations of lysine and tryptophan at 124 and 126 amino acids respectively.4.Aminoglycoside drug resistance gene detection results:153 strains of 16s rRNA detected armA gene,the detection rate was 53.7%,rmtA,rmtB,rmtC,rmtD,rmtE and npmA were not detected.The detection rates of aac(3)-Ia,aac(6')-Ib,and aph(3')-Ia were 81(28.4%),101(31.4%),and 28(9.2%,respectively).).The same strain often has a combination of multiple drug resistance genes.Conclusion:1.Acinetobacter baumannii is more prevalent in the intensive care unit in our hospital,the control of Acinetobacter baumannii in the intensive care unit should be strengthened.Carbapenems,quinolones,and aminoglycoside antibiotics have a high rate of drug resistance and belong to the multi-drug resistant Acinetobacter baumannii,which is sensitive to polymyxin.2.The multi-drug resistant Acinetobacter baumannii gyrA and parC mutation rate is high in our hospital,which is the main reason for the resistance to quinolone antibiotics in our hospital.The 16s rRNA was detected mainly by armA.The presence of aminoglycoside modifying enzyme increased the resistance of the bacteria to aminoglycosides.The same drug-resistant strain could have multiple drug resistance genes coexisting together and they mediate a high degree of bacterial resistance to aminoglycosides. |
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