Exploring the relationship between primary care antibiotic prescribing for urinary tract infections, Escherichia coli bacteraemia incidence and antimicrobial resistance: an ecological study.

This study quantified the association between antibiotic prescribing for urinary tract infections (UTIs) and the incidence/antimicrobial susceptibility of UTI-related Escherichia coli bacteraemia in adult women in England. A national ecological study was conducted with data aggregated at GP practice level. The study population was adult female patients (>18 years) with reported UTI-related E. coli bacteraemia in England (2012-2014). Reports of bacteraemia from the national mandatory surveillance scheme were linked with E. coli blood culture susceptibility data (where available) and the correlation with primary care exposure to trimethoprim and nitrofurantoin was quantified using longitudinal multilevel models. The study included 19 874 patients from 5916 practices. The overall incidence of UTI-related E. coli bacteraemia in the study group did not change significantly (1.3% increase, 95% CI 0.1-2.7%; P = 0.074). However, after adjusting for practice characteristics, UTI-related E. coli bacteraemia incidence increased by 3.0% (P < 0.001) and 1.5% (P < 0.01) with each increasing quintile in trimethoprim and nitrofurantoin prescribing, respectively. The incidence of trimethoprim-resistant bacteraemia increased by 4.5% (P = 0.032) with each increasing quintile in trimethoprim prescribing and was not associated with nitrofurantoin prescribing. This study demonstrated an association between GP prescribing for UTIs and UTI-related E. coli bacteraemia incidence at the practice level and showed that higher prescribing of trimethoprim is associated with higher incidence of trimethoprim-resistant bacteraemia. Evidence is provided of the importance of prudent antibiotic prescribing in primary care to prevent the development of antibiotic resistance, placing patients at risk of subsequent severe infections.