Background: There is increasing focus on the development of bacterial antibiotic resistance.
Materials and methods: We conducted a retrospective study of urine samples from patients resident in a Norwegian county, comparing 9121 samples culture-positive in 2003-04 with 28 066 samples in 1997-99. Determination of resistance was done with the MAST automatic multipoint inoculator system.
Results: Escherichia coli was found in 68% and 56% of out-patient and in-patient isolates respectively. Significant declines in mecillinam sensitivity (from 96% to 94%), nitrofurantoin sensitivity (from 97% to 95%) and sulfonamide sensitivity (from 73% to 71%) in in-patient E. coli isolates were found. In out-patients we found significant reductions in sensitivity to ampicillin (from 78% to 76%) and trimethoprim (from 83% to 82%). For urinary tract infection isolates as a whole, the greatest sensitivity was observed for nitrofurantoin: 85% in in-patient isolates and 75% in out-patient isolates, but there was a significant decline in resistance to several antibiotics.
Interpretation: Increasing antibiotic resistance may be related to increasing antibiotic use. Mecillinam and nitrofurantoin may be considered first-choice preparations as E. coli is the dominant etiological agent and shows the greatest sensitivity to these two antibiotics.