Microorganisms Identified in the Maternal Bladder: Discovery of the Maternal Bladder Microbiota

Objective  The objective of this study was to characterize the bladder microbiota in pregnancy. Methods  A prospective observational study of 51 pregnant women, admitted to a tertiary care hospital, who underwent straight catheterization urine collection or transurethral Foley catheter placement. 16S rRNA gene sequencing and enhanced quantitative urine culture assessed the maternal bladder microbiota with comparisons made to standard urine culture results. Results  Enhanced quantitative urine culture and 16S rRNA gene sequencing detected bacteria in the majority of participants. Lactobacillus and Gardnerella were the most commonly detected microbes. In contrast, standard urine culture had a 100% false-negative rate and failed to detect several known or emerging urinary pathogens. Conclusion  There are live bacteria in the bladders of most pregnant women. This challenges the definition of asymptomatic bacteriuria.