Project description:Both Aerococcus urinae (Au) and Globicatella sanguinis (Gs) colonize the human urinary tract and are in the Aerococcaceae family. These rarely pathogenic Gram-positive bacteria were identified in polymicrobial urethral catheter biofilms (CBs) using 16S rDNA and proteomic analyses in this study. For confirming the identities, Au and Gs strains were isolated from small blood agar colonies derived from the CB extracts. Longitudinal surveys of clinical urine specimens revealed their persistence in the urinary tract and recolonization of newly replaced catheters. Dominant CB cohabitating organisms were Enterobacteriaceae, especially Proteus mirabilis and Escherichia coli. The proteomes of Gs and Au profiled from the in vivo milieu suggest that their energy metabolisms rely on glycolytic, heterolactic fermentation and peptide catabolic pathways. Several PTS sugar uptake and oligopeptide ABC transport systems were also highly abundant in the in vivo proteomes of Au and Gs, indicative to adaptations to nutrients available in urine and exfoliated urothelial cells (protein and proteoglycan breakdown products). Differences in Au and Gs metabolisms pertained to citrate lyase and glycogen (only in the Gs proteome), use of Xfp to degrade D-xylulose-5’-phosphate, and synthesis pathways for enzyme cofactors pyridoxal 6’-phosphate and 4’-phosphopantothenate (the latter only in the Au proteome). Interestingly, predicted metal ion (ZnuA-like) uptake systems were abundant in Gs but not in Au in vivo. Au expressed two LPXTG-anchored surface proteins, one predicted to have a pilin D adhesion motif. We describe how two microorganisms not previously characterized metabolically adapt to the milieu in the catheterized human urinary tract. Whether they are true pathogens or bystanders in CBs needs further investigation.
