Tetracycline resistance in staphylococci from free-living rodents and insectivores

One hundred and fifty-eight staphylococcal strains isolated from wild rodents and insectivores were analysed for plasmid-borne resistance to tetracycline (Tc). Only 10 isolates, six Staphylococcus saprophyticus isolates and single isolates of S. xylosus, S. equorum, S. warneri and S. cohnii subsp. cohnii carried a Tc resistance plasmid of approximately 4.4 kb as confirmed by protoplast transformation. All 10 plasmids harboured a Tc resistance gene of hybridization class K [tet(K)] as confirmed by polymerase chain reaction (PCR). The plasmid was assigned to the pT181 family as it revealed a high degree of restriction map homology to pT181 and other members of this family. Macrorestriction analysis with the enzyme SmaI showed that three of the six isolates identified as S. saprophyticus shared the same pulsed-field gel electrophoresis (PFGE) pattern.