AnTIC: Uro-associated E. coli Genome Analysis

Background: AnTIC trial data showed continuous low-dose antibiotic prophylaxis to be effective in reducing symptomatic urinary tract infections (UTIs) compared to no treatment, in clean intermittent self-catheterisation (CISC) users. Antibiotic prophylaxis was however associated with increased antibiotic resistance. The mechanisms by which prophylaxis benefitted such patients are not known. Prophylactic treatments involving ß-lactam based antibiotics and nitrofurantoin appeared to select against E. coli. However, 17 patients were characterised by uro-associated E.coli that acquired multi drug resistance (MDR) during the trial. Sequencing of these E. coli isolates, associated with bacterial loads (>104 CFU/ml), showed patients prescribed prophylactic antibiotics tended to harbour one E. coli strain while patients in the non-prophylactic study arm were colonised by >1 E. coli strain. Interpretation: These findings suggest that continuous low-dose antibiotic treatments in some CISC patients selected for MDR bacteria, which resulted in a stable personalised uromicrobiota and a lower rate of symptomatic UTIs.