[Nosocomial infection by new quinolone resistant Enterobacter cloacae].

For the past two years, five strains of new quinolone resistant Enterobacter cloacae have been isolated from three patients in our hospital; strain A was isolated from patient A, strain B from patient B, and strains C1, C2, C3 from patient C. These five strains were resistant to new quinolones and other antimicrobial agents including ampicillin, piperacillin, methicillin, cefotaxime, cefoperazone, kanamycin, gentamicin, tetracycline, minocycline, and chloramphenicol. Plasmid DNA profiles on agarose gel indicated that strain B and C3 carried completely the same plasmid pattern, but strain A gave a different plasmid pattern. Furthermore chromosomal DNAs extracted from strains A, B and C3 were digested with restriction endonucleases EcoR I, BamH I and Sma I. They were separated by pulsefield gel electrophoresis. The banding profiles of strains B and C3 showed the same pattern. It is, therefore, highly suggested that strains B and C3 are the same E. cloacae strain, although isolated from different patients at different time. The possible route of nosocomial infection between these two patients who were hospitalized in the same room after an interval of 4 months was discussed.