Table 2.

Examples of biofilm studies in clinical human DFU.

Model	N° of Patients	Biofilm Visualization	Findings	Reference
DFU	2	CLSM	Evidence of biofilms	[44]
DFU	162	Microtiter plate assay	Biofilms in 67.9% of infected DFUs	[45]
DFU	26	FISH and ESEM	Observation of the formed biofilms and their bacterial constitution	[48]
DFU	357	Crystal violet	Observation of the formed biofilms	[46]
DFU	100	Congo Red dye, tissue culture plates, and crystal violet staining	Biofilm formation in 46.3% of isolates, predominantly by S. aureus (38.8% of isolates) and MDR bacteria (46.3%)	[47]
DFU	49	Calgary biofilm pin lid device with resazurin and PCR of genes associated with biofilm formation	Biofilms are resistant to antibiotics at concentrations 10–1000 times higher than those required to kill planktonic cells	[53]
DFU	155	Microtiter plate assay and ELISA, XTT formazan, and SEM	Presence and importance of non-Candida albicans species in biofilms	[55]
DFU	95	Microtiter plate assay and FISH	Polymicrobial biofilms are thicker	[56]

DFU—diabetic foot ulcer; CLSM—confocal laser scanning microscopy; ELISA—enzyme-linked immunosorbent assay; ESEM—environmental scanning electron microscopy; FISH—fluorescent in situ hybridization; MDR—multidrug resistant; PIA—polysaccharide intercellular adhesin; SEM—scanning electron microscopy; XTT—2H-tetrazolium-5-carboxanilide.