Comprehensive analysis of the bacterial spectrum for enhanced clinical insight in microbial ureteral stent colonization, uncomplicated urinary tract infections and catheter-associated urinary tract infections: a principal component analysis-based literature review

Abstract

Purpose: Controversies exist regarding the prevailing spectrum of microorganisms in microbial ureteral stent colonization (MUSC) and their clinical significance. The aim of this comprehensive review is to determine the predominant microbial spectrum in patients with an indwelling ureteral stent in comparison to catheter-associated urinary tract infections (CAUTI) and uncomplicated urinary tract infections (UTI).

Methods: Google scholar, PubMed, Embase, Medline, and Cochrane literature databases were searched from inception to April 2022 to identify manuscripts on MUSC, uncomplicated UTI and CAUTI. A principal component analysis (PCA) was performed to identify patterns of the pathogen spectrum of the different groups.

Results: We included 29 studies on MUSC, 28 studies on uncomplicated UTI and 23 CAUTI studies. The proportion of Staphylococci, Enterococci and Candida were significantly higher in MUSC and stent associated bacteriuria compared to their proportion in uncomplicated UTIs where E. coli dominates. By comparing MUSC, CAUTI and UTI with a PCA, the detected pathogen spectrum exhibited clearly distinguishable trends in the frequency of the main isolated pathogens influencing these three groups of urinary tract infections. With respect to MUSC and UTI, their 95% confidence interval ellipse only showed minimal overlap emphasizing that the spectrum of pathogens in the two groups is clearly distinct.

Conclusions: The frequency of detection of Staphylococci, Enterococci and Candida is more common in MUSC as compared to UTI. Thus, patients with indwelling ureteral stents should undergo an antimicrobial prophylaxis targeting this microbial spectrum in case of further surgery.

Keywords: Bacteriuria; Ureteral catheterization; Ureteroscopy; Urinary tract infections.

Fig. 1

A Pie figure showing the spectrum of pathogens in the different groups CAUTI, UTI, urine from stent patients, MUSC. Boxplot showing the variation in the proportion of each pathogen in the different studies. B Enterococcus. C Staphylococcus. D Candida. E E. coli

Fig. 2

Principal component analysis showing the grouping of UTI, stent colonization and CAUTI studies. Each point represents a study with the specific pathogen spectrum described in this study (numbers correspond to the number of the study see supplementary material for details); red UTI studies, blue stent colonization studies, grey CAUTI studies. Arrows show the projections of the original features on to the principal components. 95% confidence interval ellipses were also drawn for each group. With the use of the ellipses, the grouping of the different samples in the PCA projection can be observed. Such ellipses allow understanding which data deviate from the groups formed in this PCA projection