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.
Project description:Globicatella sanguinis is a rare cause of acute meningitis. We demonstrated human carriage of Globicatella by identifying cefotaxime-resistant strains in groin and rectal specimens 9 months after invasive infection. The pathogenic strain isolated from the cerebrospinal fluid and the carriage strains were accurately identified by sodA gene sequence analysis.
Project description:BackgroundGlobicatella are streptococcus-like organisms that have been rarely isolated from clinical specimens. Their epidemiology and clinical significance remain largely unknown.AimsTo describe two cases of Globicatella bacteraemia identified by 16S ribosomal RNA (rRNA) gene sequencing.MethodsTwo unidentified streptococcus-like bacteria isolated from blood cultures of patients were subject to 16S rRNA gene sequencing.ResultsTwo cases of Globicatella bacteraemia were identified by 16S rRNA gene sequencing. In the first case, a gram positive coccus was isolated from the blood culture of an 80 year old woman with diabetes mellitus and nosocomial sepsis, who died the day after developing the bacteraemia. The bacterium was unidentified by conventional phenotypic tests, the Vitek (gram positive identification) and the ATB expression (ID32 Strep) systems. In the second case, a similar bacterium was isolated from the blood culture of a 92 year old woman with polymicrobial acute pyelonephritis complicated by septic shock, who subsequently recovered after antibiotic treatment. 16S rRNA gene sequencing of the two isolates showed 0.5% nucleotide difference from that of G. sulfidifaciens and 0.7% nucleotide difference from that of G. sanguinis, indicating that they were Globicatella species.ConclusionsBecause Globicatella is rarely encountered in clinical microbiology laboratories, it may have been overlooked or misidentified in these cases. 16S rRNA gene sequencing is a useful tool to better characterise the epidemiology and clinical significance of Globicatella.