Abstract
Escherichia coli is one the most common bacteria responsible of uropathogenic diseases, which motives the search for rapid and easy methods of detection. By taking advantage of the specific interactions between mannose and type 1 fimbriae, in this work two fluorescent phenyleneethynylene (PE) trimers bearing one or two 4-aminophenyl-α-D-mannopyranoside termini groups were synthesized for the detection of E. coli. Three bacterial strains: ORN 178 (fimbriae I expression), ORN 208 (mutant serotype with no fimbriae expression) and one obtained from a local hospital (SS3) were used. Laser Scanning Confocal Microscopy (LSCM) and Surface Plasmon Resonance (SPR) were applied for the interaction studies following two different approaches: (1) mixing the oligomer solutions with the bacterial suspension, which permitted the observation of stained bacteria and by (2) biosensing as thin films, where bacteria adhered on the surface-functionalized substrate. LSCM allows one to easily visualize that two mannose groups are necessary to have a specific interaction with the fimbriae 1. The sensitivity of SPR assays to E. coli was 104 colony forming unit (CFU)/mL at 50 µL/min flow rate. The combination of PE units with two mannose groups results in a novel molecule that can be used as a specific fluorescent marker as well as a transducer for the detection of E. coli.
Highlights
Escherichia coli is one of the most common bacteria responsible for urinary tract infections (UTIs).Uropathogenic E. coli uses type 1 fimbriae for adhering and colonizing the host [1] through specific binding of their top adhesin (FimH) to a high-weight mannose glycoprotein, uroplakin Ia, which is present in the differentiated uroepithelial cells [2,3,4]
All of these works demonstrate the specificity of the molecules to uropathogenic Escherichia coli compared to other bacteria or even other E. coli strains that do not express type 1 fimbriae
We report in this paper the synthesis of two phenyleneethynylene oligomers bearing one or two mannose termini groups that could allow the specific detection of uropathogenic Escherichia coli by fluorescence microscopy and its biosensing by Surface Plasmon
Summary
Escherichia coli is one of the most common bacteria responsible for urinary tract infections (UTIs).Uropathogenic E. coli uses type 1 fimbriae for adhering and colonizing the host [1] through specific binding of their top adhesin (FimH) to a high-weight mannose glycoprotein, uroplakin Ia, which is present in the differentiated uroepithelial cells [2,3,4]. Sensors 2017, 17, 1025 poly(phenylenevinylidene)s [13] functionalized with mannose or other carbohydrates were reported All of these works demonstrate the specificity of the molecules to uropathogenic Escherichia coli compared to other bacteria or even other E. coli strains that do not express type 1 fimbriae. Disney and Bunz [7] obtained the detection limit of the bacteria by fluorescence microscopy Despite these excellent results as markers, a real biosensing, i.e., the quantification of a signal towards E. coli concentration is not feasible by fluorescence techniques. In the previous works, sensing by fluorescence spectroscopy is limited to a model protein (concanavalin A), or, when E. coli bacteria is used, only the quenching of the fluorescence intensity of the conjugated polymer in presence of a certain bacterial number, typically 107 –108 CFU/mL equal to O.D. at 600 nm of 0.05–1) is reported
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
