Ex-post verification analysis
During the first trial, discordance between the results obtained with reference method and MBS AST POCT was observed for 1 patient out of 13 patients analyzed for both levofloxacin and amoxicillin-clavulanic acid. In this case, with the MBS AST POCT, the infecting bacteria resulted resistant to both the tested antibiotic, whereas the hospital report testified such bacteria as susceptible. Ex-post verification was thus carried out on frozen urine samples. The MBS AST POCT results were coherent with those obtained previously, confirming the presence of bacteria, resistant to both of the tested antibiotics. The Kirby-Bauer diffusion disk test showed the presence of two distinct bacterial strains displaying different susceptibility to both antibiotics, one being susceptible and one resistant. Because of the presence of a resistant strain and the ultimate ineffectiveness of the antibiotic in preventing bacteria multiplication in urine, the sample was considered resistant.In the second trial, discordant AST results were obtained for 16 patients, samples of which underwent verification analysis according to the previously described operating protocol. Of these, 9 discordant results were obtained for amoxicillin-clavulanic acid. After ex-post verification, agreement between MBS AST POCT and reference method’s results was achieved for 5 samples, confirming MBS AST POCT initial results, and such data were then used for statistical analysis; in the 4 remaining cases, discordance between results persisted, thus MBS AST POCT results were included into statistical analysis as either false positive or false negative results. Considering ciprofloxacin, 3 discordant results were obtained, but verification analysis confirmed agreement for all samples, which led to complete agreement between MBS AST POCT and reference method’s results. Lastly, for trimethoprim-sulfamethoxazole, discordant results between methods were obtained for 4 samples. After ex-post verification, agreement was achieved for 2 samples (3%), while for the other 2 samples no agreement was obtained (3%), so these results were included into statistical analysis either as false positive or false negative.The overall performance of the MBS AST POCT is showed in Tables 