Study On The Relationship Between Multidrug Resistance And Class â…  Integron In Acinetobacter Baumannii Clinical Isolates

Objective:To study the resistance,characterization of the class I integrongenes (intI1) and integrated gene cassettes in Acinetobacter baumanniiisolates from our hospital, analyze the relationship between class Iintegron and multidrug resistance.So as to provide the science basis forthe prevention,control and cure of the clinical infection and spread ofdrug resistant Acinetobacter baumannii.Method:We have Collected90strains of Bauman Acinetobacter randomlyFrom January,2011to June,2011.Firstly Class I integrons weredetected by polymerase chain reaction of the class I integrase genes (intI1)in these isolates, so as to investigate the positive rate of Class I integrongenes. Then The integrated gene cassettes were detected by polymerasechain reaction of the Class I integron positive ones.The PCR productswas observed by electrophoresis,and randomly selected2products ofclass I integron genes (intI1)and5of integrated gene cassettes products tobe sequenced.Statisticing the positive rate of class I integron, To studythe characterization of the class I integron genes (intI1) and integratedgene cassettes in Acinetobacter baumannii isolates from our hospital.AnalyzIing the relationship between class Ⅰintegron and multidrug resistance by statistical analysis of class I integron positive and negativeones in drug resistance.Result：1、63of90strains were detected type1integrase gene, the specific bandsbeteeen200bp and300bp were detected by electrophoretics. It issuggested that these strains carrying class I integrons, and the positiverate was70.0%. Sequencing results in Pubmed through BLASTcomparative analysis, finding that it is100%homology with the genewhich number is AM283490and coding type1integration enzyme genesequence in GenBank..2、Amplifing cassettes variable region genes of63type I integrase genepositive strains,52strains (of82.5%)were amplified different sizefragments,they are beween1000and3000bp by electrophoresis.5PCRproducts were randomly selected to be purified and sequenced. Thesequencing results were be compared in Pubmed and be found99%similarly with the gene of code HQ880273.1,98%similarly with the geneof code JN415765.1in GenBank which codes integrated genecassettes.The gene cassettes harbor arr-3-aacA4and aacA4-catB8-aadA1.arr-3gene encods ADP ribosyltransferase，causing drug resistance toRifampicin.AacA4gene encods6’-N-aminoglycoside acetyltransferase,causing drug resistance to Amikacin, netilmicin and tobramycin. aadA1gene codes aminoglycoside nucleotide transferase which is leading toresistance to spectinomycin and streptomycin. catB8gene codeschloramphenicol acetyltransferase, leading to chloramphenicol resistance. 3、In recent years, the multiple antibiotic resistance rate of BaumanAcinetobacter is rised obviously in our hosital. The multiple drugresistance rate of class I integron positive strains(79.4%) wassignificantly higher than that of negative ones(11.1%)(P<0.01).Conclusion:The infections of Acinetobacter baumannii were often ocuuered inpatients in poor conditions of immuno-compressed,with exogenouscatheter or tracheal intubation. It is often separated from respiratorysamples.The most of separation is from Department of neurosurgery,secondly Department of respiration, thirdly Department of cardiology.Class I integron in Acinetobacter baumannii is closely related withmultiple antibiotic resistance, The multiple drug resistance rate of class Iintegron positive strains was significantly higher than that of negativeones. The gene cassettes are arr-3-aacA4,aacA4-catB8-aadA1.Toinvestigated the class I integron genes (intI1) and integrated genecassettes in Acinetobacter baumannii isolates provides rational scientificbaisis for prevention of bacterial drug-resistance and pharmacypractions.