Study On The Integrons In Acinetobacter Baumannii

ObjectiveTo analysis our hospital Acinetobacter bacteria infections and thecharacteristic of antimicrobial resistance;and to investigate the integrons inacinetobacter and the relationship with antibiotic resistance.MethodsThe identification and drug-sensitivity test were assayed by MicroScanWalk Away40; the detection, classification of integrons were performed by PCR.All integrons were determined by RFLP analysis. Product of variable region ofpositive strain was performed on sequencing.ResultsDuring the4-year infected surveillance,a total of174strains ofA．baumannii were isolated, which mainly came from the sputum samples ofpatients（149strains,85.6%）. In the distribution of hospital departments, ICUwas the most (61strains,35.1%),respiratory department was the second (46strains,26.4%).47.7%were older suffers. A．baumannii was resistant to14kinds of antibiotics increasingly, especially to imipenem,from17.6%to66.1%,and we found88strains was multidrug-resistant strains,the relevance ratio isincreasing sharply. The integrons were identified in31of the58isolates(53.4%). All integrons were classⅠas determined by RFLP analysis,neither classⅡ nor classⅢ integrin was detected. The rate of integrationpositive group was higher than the negative group. To augment the genecassettes of the multiple drug-resistant strains which are positive of integration, we find three fragments:500bp、1000bp、2500bp,500bp and2500bp clipscarry genes box for aadA1, aacA4and catB8, respectively, codingaminoglycoside and chloramphenicol resistance,1000bp clips carry genes boxas blaVIM-2, aadA1, aacA7, coding metal beta-lactamase genes andaminoglycoside resistance.ConclusionsThe antimicrobial resistance and the isolation rate of multidrug-resistantand pan drug-resistant Acinetobacter baumannii is increasing year by year,Integrons of multi-drug resistant strains in A. baumannii clinical isolates fromour hospital all belonged to class1integron. The cause of drug resistance ofintegron positive strain to aminoglycosides and chloramphenicol is drugresistance gene cassettes. Beta-lactams gene cassette plays the unimportantrole in integron-mediated drug-resistance.