Acinetobacter baumannii have emerged as important nosocomical pathogens especially in intensive care patients. Carbapenems are the choice of drug for their treatment but they started developing resistance to carbapenems predominatantly by producing Metallo beta-lactamases (MBL). Treatment of such carbapenem resistant Acinetobacter has led to reintroduction of polymyxins like colistin, polymyxin B and newer tetracycline group of drugs like tigecycline. As there were limited studies in on Minimum

more »

... inhibitory concentrations (MIC) of MBL producing Acinetobacter to polymyxins and tigecyclines from india, the present study was undertaken. MBL detection was done by combined disc test with imipenem and EDTA. MIC of the drugs was determined by Agar dilution method. MIC50 and MIC90 of tigecycline were found to be 0.5 μg/ml and 1 μg/ml respectively. Suseptibility MIC ranges for tigecycline were found to be 0.5 to 2 μg/ml. Resistance rates for tigecycline were found to be 6%. MIC50 and MIC90 of colistin was found to be 2 μg/ml. Susceptibility MIC ranges for colistin were found to be 0.25 to 1 μg/ml. MIC50 and MIC90 of polymyxinB were found to be 1 μg/ml and 2 μg/ml respectively. Susceptibility MIC ranges for polymyxin B were found to be between 0.5 to 2ug/ml. The susceptibility rates with colistin and polymyxin B were found to be 99.2% and 100% respectively. Polymyxin B and colistin are very good drugs of choice for treatment of MBL producing Acinetobacter baumannii with 0.8% and 0% resistance rates. Though good sensitivity was noticed with tigecycline, we found 6% resistance rate.