Factors associated with trimethoprim-resistant bacteria isolated from urine samples

Urine samples with trimethoprim-resistant or trimethoprim-sensitive Gram-ne gative bacteria and samples with no bacterial growth (NG) were identified. Age-sex matched community controls were generated with each trimethoprim-re sistant case. These four groups were evaluated for exposure. Prior trimetho prim use was significantly more common in the trimethoprim-resistant group when compared with the trimethoprim-sensitive or the NG group. Prior hospit alization was significantly less common in the trimethoprim-resistant than the trimethoprim-sensitive group, but not with the NG group. Prior oestroge n exposure was associated with trimethoprim resistance. There were no assoc iations found for diabetes or prior corticosteroid exposure. Community cont rols were found to be inappropriate controls for the study of trimethoprim- resistant bacteria in urine samples.