Table 4.

Examples of rapid detection used for Clostridioides difficile infection.

Biorecognition elements	Target (analyte)	Platform	Detection format	Applicability	LOD	Response time	References
Nucleic acid	Spores	Magnetic bead aggregation	LAMP coupled to PiBA	Selective media	N/A	N/A	DuVall et al. (2016)
	Toxins	Magnetic	NMR-based technology	Stool	<180 CFU/mL	45 min	Yang et al. (2017)
	TcdA/B	Magnetic	ELISA sandwich assays	Stool	1.35 𝜇g/mL	N/A	Hong et al. (2015)
	TcdA/B	MEF	Optical	Stool	10 CFU/mL	40 s	Joshi et al. (2014)
	TcdB	PEPS	Electrical impedance (PEPS) (direct detection)	Stool	150 CFU/mL	40 min	Han et al. (2019)
	TcdA/B	FMSM	Optical	Stool	1.12 ng/mL	20 min	Yang et al. (2020)
Aptamer (aptasensor)	TcdA/B, binary toxin	Magnetic Beads/SOMAmer	ELISA sandwich assays	Selective media	1 pg/mL to 300 pg/mL	N/A	Ochsner et al. (2013), Ochsner et al. (2014)
	GDH	Fuorescence emission structure-switching fluorescence signaling aptamer	Optical	Stool	1 pg/mL	60 min	Liu et al. (2018)
	TcdA	Colorimetric	Electrochemical impedance	Stool	1 pg/mL	N/A	Luo et al. (2014)
	TcdB	Colorimetric	Colorimetric assay	Stool	600 and 60 pg/mL	30 min	Liu et al. (2020)
	TcdB	Colorimetric	Colorimetric assay	Stool	5 ng/mL	30 min 60 min	Luo and Liu (2020)
	GDH	Colorimetric	Colorimetric assay	Selective media	10 𝜇g/mL	30 min	Hui et al. (2018)
Enzyme based	Specific protease, PPEP-1	Bioluminescent Sensor	Optical	Stool	10 𝜇g/mL	30 min	Ng et al. (2021)
Antibody	TcdB	Amperometric	Electrochemical	TcdB	0.3 ng/mL	30 min	Xu et al. (2014)
	TcdA/B	Impedance	Electrochemical	Stool	0.6 pg/mL	30 min	Zhu et al. (2014b)
	TcdB	DPV	Electrochemical	Stool	0.7 pg/mL	45 min	Fang et al. (2013)
	GDH	Lateral flow immunoassay	Optical, thermal	Selective media	1.0625 ng/mL 0.1328 ng/mL	N/A	Wang et al. (2016)
	TcdB	Magnetic and fluorescent particles	Automated ELISAs	Stool	45 pg/mL	30 min	Gite et al. (2018)
	Toxins	Single-molecule array technology	Automated ELISAs	Stool	45 pg/mL	N/A	Banz et al. (2018)
	TcdB	Impedance polyurethane (PU) nanospiked gold electrode	Electrochemical (DPV)	Stool	0.5 pg/mL	40 min	Cui et al. (2018)
	TcdA/B	Fluorescence	Optical	Stool	N/A	40 s	Joshi et al. (2014)
	SlpA, TcdB	SERS-based LFA	Optical	Stool	0.01 pg/mL	20 min	Hassanain et al. (2021)
	GDH, TcdB	Split-luciferase assay, luminescent	Optical	Stool	4.5 pg/mL 2 pg/mL	32 min	Adamson et al. (2022)

GDH, glutamate dehydrogenase; TcdA, toxin A; TcdB, toxin B; LAMP, microfluidic loop-mediated isothermal amplification; PiBA, product-inhibited bead aggregation; MEF, metal enhanced fluorescence; MAMEF, microwave accelerated metalenhanced fluorescence; PEPS, piezoelectric plate sensor; FMSM, fluorescent magnetic spore-based microrobot; ELISAs, enzyme-linked immunosorbent assays; PPEP-1, pro-pro endopeptidase 1; DPV, differential pulse voltammetry; SERS-based LFA, surface enhanced Raman scattering-based lateral flow assay; N/A, not available.