Curing of Serratia marcescens Plasmid by High Temperature and by Acridine Orange and Urea

The present study was conducted on five isolates of S. marcescens from septicemic patients in Al-Salam Hospital in Mosul. Isolates were identified by using cultural and biochemical characteristics as well as the Api 20E system Resistance of the isolates to Chloramphenicol, Tetracycline, Ampicillin, Erythromycin and Gentamycin was checked. Curing the Isolates of their plasmids was performed by using high temperature (45c), acridine orange (40 g/ml) and urea (100 g/ml). When S. marcescens isolates were grown at 45C cured and sensitive bacterial colonies were observed at a frequency of 1094%. These, however, were resistant to Erythromycin. Treating the isolates with Acridine orange cured them of all them resistance except Erythromycin at 1092% .Urea treatment cured their of all resistance phenotypes except Ampicline and Chloramphenicol , also at a frequency of 1093%.