An R plasmid of Serratia marcescens transferable to Pseudomonas aeruginosa

Chemotherapy. 1982;28(1):6-17. doi: 10.1159/000238054.


Hospital isolates of Serratia marcescens able to transfer resistance to up to 11 antibiotics were found to contain conjugative R plasmids. One set of strains harbors only a single R plasmid with a mass of 89 megadaltons (Mdal). This plasmid codes for resistance to nine antibiotics including ampicillin, carbenicillin, cephalothin, streptomycin, kanamycin, gentamicin, tobramycin, sisomycin, and sulfonamides. The 2nd set of strains harbors 2 R plasmids, 1 with a mass of 89 Mdal, the other 57 Mdal. Analysis of progeny from genetic crosses indicates that the larger R plasmid codes for resistance to the same antibiotics as does the 89-Mdal plasmid described above. The 57-Mdal species codes for resistance to ampicillin, carbenicillin, cephalothin, kanamycin, neomycin, and tetracycline. The 89- and 57-Mdal R plasmids appear unrelated by a number of genetic and physical criteria. The 89-Mdal plasmid, but not the 57-Mdal species, is transferable by conjugation to Pseudomonas aeruginosa, and renders this species stably resistant to carbenicillin, streptomycin, kanamycin, gentamicin, tobramycin, and sisomycin.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Conjugation, Genetic
  • Culture Media
  • DNA Restriction Enzymes / isolation & purification
  • DNA, Bacterial / isolation & purification
  • Escherichia coli / genetics
  • Nucleic Acid Hybridization
  • Pseudomonas aeruginosa / genetics*
  • R Factors*
  • Serratia marcescens / genetics*


  • Culture Media
  • DNA, Bacterial
  • DNA Restriction Enzymes