A study of the carbapenemases produced by imipenem-resistant Acinetobacter baumannii and the changes in drug resistance in these strains.

Objective To study the carbapenemases produced by imipenem-resistant Acinetobacter baumannii and the changes in drug resistance in these strains.Methods The carbapenemases produced by imipenem-resistant A.baumannii were detected with a modified Hodge test and the susceptibility of imipenem-resistant strains of A.baumannii was analyzed with KB disk diffusion to ascertain the potential these changes had to lead to resistance.Results Of 62 strains of imipenem-resistant A.baumannii isolated from clinics,15 were positive according to a modified Hodge test,indicating a rate of 24.19%.The rate of carbapenemase production by imipenem-resistant A.baumannii increased yearly.The clinically isolated strains were mainly from sputum and secretions primarily from patients in ICU(20.97%),followed by patients in the Emergency Department and Neurosurgery.The drug resistance of imipenem-resistant A.baumannii to 17 types of commonly used antimicrobials increased yearly.A.baumannii was least resistant to cefoperazone/sulbactam,followed by polymyxin E.Conclusion The increased resistance of imipenem-resistant A.baumannii is mainly due to carbapenemase.Cefoperazone/sulbactam has more potent antibacterial activity against carbapenem-resistant A.baumannii and may be effective in treating such a bacterial infection.