Rapid diagnostic assay for detection of cellulose in urine as biomarker for biofilm-related urinary tract infections

Abstract

The ability of uropathogenic Escherichia coli (UPEC) to adopt a biofilm lifestyle in the urinary tract is suggested as one cause of recurrent urinary tract infections (UTIs). A clinical role of UPEC biofilm is further supported by the presence of bacterial aggregates in urine of UTI patients. Yet, no diagnostics exist to differentiate between the planktonic and biofilm lifestyle of bacteria. Here, we developed a rapid diagnostic assay for biofilm-related UTI, based on the detection of cellulose in urine. Cellulose, a component of biofilm extracellular matrix, is detected by a luminescent-conjugated oligothiophene, which emits a conformation-dependent fluorescence spectrum when bound to a target molecule. We first defined the cellulose-specific spectral signature in the extracellular matrix of UPEC biofilm colonies, and used these settings to detect cellulose in urine. To translate this optotracing assay for clinical use, we composed a workflow that enabled rapid isolation of urine sediment and screening for the presence of UPEC-derived cellulose in <45 min. Using multivariate analysis, we analyzed spectral information obtained between 464 and 508 nm by optotracing of urine from 182 UTI patients and 8 healthy volunteers. Cellulose was detected in 14.8% of UTI urine samples. Using cellulose as a biomarker for biofilm-related UTI, our data provide direct evidence that UPEC forms biofilm in the urinary tract. Clinical implementation of this rapid, non-invasive and user-friendly optotracing diagnostic assay will potentially aid clinicians in the design of effective antibiotic treatment.

Optotracing for selective fluorescence-based detection, visualization and quantification of live S. aureus in real-time

“…When used as nontoxic medium additives, photostable optotracers incorporated into the growing biofilm emit target-specific optical signals as the target is produced, thus allowing true real-time analysis. Optotracing also enabled the development of a diagnostic assay for biofilm-related urinary tract infections by detection of native cellulose produced by uropathogenic E. coli (UPEC) in urine from infected patients 15 . We expanded optotracing to become a versatile method for nondisruptive analysis of polysaccharides 16 .…”

Conjugated Oligo- and Polymers for Bacterial Sensing

“…Cellulose-positive (WT) and cellulose-negative (△bcsA) biofilm controls are also indicated. Panel (C) was reproduced from Choong et al (2016a), Panel (D) was reproduced from Choong et al (2018) and Panel (E) was reproduced from Antypas et al (2018), licensed under CC BY 4.0 (http://creativecommons.org/licenses/by/4.0/).…”

“…Similar to Salmonella , the ECM of UPEC biofilms is mainly composed of cellulose and curli. This inspired Antypas et al to investigate whether cellulose can be detected in urine by optotracing, as a diagnostic biomarker for UTI (Antypas et al, 2018). Analysis of spectra from LCOs interacting with relevant control strains showed the ability of the LCO to identify cellulose in UPEC biofilms.…”

Unraveling Escherichia coli’s Cloak: Identification of Phosphoethanolamine Cellulose, Its Functions, and Applications

“…Many UPEC, however, do produce curli and cellulose at 37°C, and studies have detected or strongly supported their production in vivo. [14][15][16][17][18][19] Thus, functional studies of curli and cellulose will help to more fully understand the roles of the various ECM components in E coli pathogenesis. Finally, many other bacterial species contain the cellulose modification machinery and research is needed to understand what benefits might be conferred to these bacteria that have evolved to produce a modified cellulose.…”