Analytical performance of the LAMP assays

The specificity of LAMP assays targeting P. mirabilis, E. coli, K. pneumoniae and E. faecalis were performed using DNA extracts obtained from 16 different bacterial species reference strains belonging to genera frequently isolated from UTI and 20 other anaerobic and facultative anaerobic strains isolated from UTI cases and particularly with 38 P. mirabilis clinical isolates for LAMP P. mirabilis (Table ​(Table1).1). Products were examined visually by staining with SG I and after electrophoresis on a 1.5% agarose gel—120 Volts—45 min. The assays were performed in triplicate to ensure its repeatability. The sensitivity of the five LAMP assays (E. coli, K. pneumoniae, P. mirabilis, E. faecalis and CTX-M group 1) was assessed in quintuplicate on a 10-fold serial dilution of spiked urine samples ranging from 10¹ to 10⁷ CFU/mL. Products were examined visually by staining with SG I and analyzed by electrophoresis on a 1.5% agarose gel—120 Volts—45 min. The sensitivity was defined as the lowest concentration detected by the assay in four out of the five experiments.