Characterisation of streptomycin resistance determinants in Danish isolates of Salmonella Typhimurium

Vet Microbiol. 2000 Jul 3;75(1):73-82. doi: 10.1016/s0378-1135(00)00207-8.


Fifty six Danish streptomycin (Sm) resistant isolates of Salmonella enterica serotype Typhimurium from pigs (n=34), calves (n=3) and humans (n=19) were characterised with respect to co-resistances (14 drugs), transferability of Sm-resistance by conjugation, genetic determinants encoding Sm-resistance and diversity with respect to localisation of genes in the genome and DNA-sequences. Forty-six strains carried resistance(s) other than Sm-resistance. Nineteen different co-resistance patterns were observed and tetracycline was the most commonly observed resistance in these patterns. In 22 of the strains, Sm-resistance was transferred by conjugation. Eleven strains contained the gene aadA only, six strains contained aadA+strA+strB, and 35 strains contained strA+strB. Partial sequences of aadA were obtained from four strains. Three strains showed identical sequences to a published aadA sequence from the transposon Tn7, and in one strain the sequence showed one synonymous substitution compared to this sequence. Partial sequences were obtained of strA and strB in seven strains. The sequence of strB was identical to the published sequence of the plasmid RSF1010 in all strains. All seven sequences of strA were identical and differed from the sequence of strA in RSF1010 by two non-synonymous substitutions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Southern / veterinary
  • Cattle
  • Cattle Diseases / drug therapy*
  • Cattle Diseases / microbiology
  • Colony Count, Microbial
  • Conjugation, Genetic / genetics
  • DNA Primers / chemistry
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / isolation & purification
  • Denmark
  • Drug Resistance, Microbial / genetics
  • Electrophoresis, Agar Gel / veterinary
  • Genetic Variation / genetics*
  • Humans
  • Nucleotidyltransferases / chemistry
  • Nucleotidyltransferases / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / chemistry
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Polymerase Chain Reaction / veterinary
  • Salmonella Infections, Animal / drug therapy*
  • Salmonella typhimurium / chemistry
  • Salmonella typhimurium / drug effects
  • Salmonella typhimurium / genetics*
  • Sequence Analysis, DNA
  • Streptomycin / pharmacology*
  • Swine
  • Swine Diseases / drug therapy*
  • Swine Diseases / microbiology


  • DNA Primers
  • DNA, Bacterial
  • Phosphotransferases (Alcohol Group Acceptor)
  • streptomycin 6-kinase
  • streptomycin 3''-kinase
  • Nucleotidyltransferases
  • streptomycin 3''-adenylyltransferase
  • Streptomycin