Transferable trimethoprim resistance in three Finnish hospitals

Abstract

Resistance to trimethoprim in urinary tract isolates was studied in the Turku City Hospital in 1979 and 1980–81 and in the Turku and Kuopio University Central Hospitals in 1980–81. In the Turku City Hospital no changes occurred during this time in the frequency of strains highly-resistant to trimethoprim (MIC> 1000 mg/1) or of those in which transferable resistance was demonstrated. However, the nature of resistance has changed since 1979, when the only transferable pattern was trimethoprim-ampicillin resistance. In 1980–81 over half of the transfer-positive strains transferred only trimethoprim resistance. In the university hospitals the strains highly-resistant to trimethoprim occurred in 36.8% of strains resistant to >8 mg/1. This is significantly less than 68.7% observed at the same time in the Turku City Hospital. Among the highly-resistant strains the frequency of those transferring resistance was the same in the university hospitals as in the Turku City Hospital.