Is it possible to extrapolate the rates of resistance of Escherichia coli from asymptomatic bacteriuria in pregnant women to those of E. coli in uncomplicated community-acquired UTI?

Abstract

Treatment of uncomplicated urinary tract infections in primary care is generally empirical without requesting urine culture and based on biased resistance data collected from selected patients, most of them having risk factors for the isolation of resistant microorganisms. In order to overcome the lack of information on the real resistance rates in uncomplicated UTI, we compared antimicrobial phenotype and genotype of Escherichia coli isolated from pregnant women with asymptomatic bacteriuria (culture always performed) with those from women with uncomplicated acute cystitis (culture rarely performed) of different age groups. Between September 2017 and March 2018, 103 urines were randomly collected from pregnant women aged between 16 and 47 with asymptomatic bacteriuria (AB) (n=42), not hospitalized women in the same age range with uncomplicated acute cystitis (UAC) (n=31) and women older than 47 not hospitalized with UAC (n=30). Bacteria identification was performed using mass spectrometry and the antibiogram by broth microdilution. Genetic typification was carried out by pulsed-field gel electrophoresis. There are no significant differences between the groups of patients in the antibiotic susceptibility. Likewise, as expected, a wide genetic diversity is observed among the strains of E. coli studied without significant differences between the three groups. We propose a simple model that could provide better guidance for selection of empirical antimicrobial therapy for non-pregnant women with UAC than do generic hospital antibiogram data based on reliably extrapolating the susceptibility data of strains isolated from pregnant women with AB as representation of women with community-acquired UAC.