According to data published in the International Journal of Antimicrobial Agents, there is an association between general practitioners’ prescribing habits for urinary tract infections (UTIs) and UTI-related Escherichia coli bacteremia incidence at the practice level, and higher prescribing of trimethoprim is associated with higher incidence of trimethoprim-resistant bacteremia.
This national ecologic study was carried out with data aggregated at the general practitioner practice level on all adult female patients with reported UTI-related E coli bacteremia in England from 2012 to 2014. A total of 20,274 patients were included from 5916 practices.
The overall incidence of UTI-related E coli bacteremia in the study population demonstrated no significant change over the study duration (1.3% increase; 95% CI, .1%-2.7%, P =.074). An adjustment for practice characteristics showed that the incidence increased by 3.0 % (P <.001) and 1.5% (P <.01) with each increasing quintile in trimethoprim and nitrofurantoin prescribing, respectively. The incidence of trimethoprim-resistant bacteremia increased by 4.5% (P =.032) with each increasing quintile in trimethoprim prescribing. However, this was not associated with nitrofurantoin prescribing.
Limitations of an ecologic study do not allow patient level conclusions to be drawn, but reporting results at the general practioner practice level did allow practice level policy recommendations. The completeness of data reporting was another limitation that is common to routinely collected data. Antibiotic susceptibility data from blood cultures were limited because these data were collected under a voluntary scheme. However, participation was approximately 90% across all testing years. It was also not possible to know specifically which patient received a prescription for antibiotics, nor was it possible to imply a direct causal relationship between prescribing and total E coli bacteremia incidence.
The findings supported recommendations from the National Health Service England to reduce the total antibiotics and the proportion of broad-spectrum antibiotics prescribed in primary care. The recommendation for use of nitrofurantoin when antibiotics for a UTI are necessary is also supported. Investigators suggest future work should seek to validate these findings at the patient level, allowing for adjustments for comorbidities such as UTI severity, previous antibiotic use, and other patient-level characteristics.
Lishman H, Costelloe C, Hopkins S, et al. Exploring the relationship between primary care antibiotic prescribing for urinary tract infections, Escherichia coli bacteraemia incidence and antibiotic resistance: an ecological study [published online August 23, 2018] Int J Antimicrob Agents. doi: 10.1016/j.ijantimicag.2018.08.013