Vidas c difficile toxin a bassay

PCR assays for toxin genes (tcdB, tcdA, ctdA and ctdB) were performed using primers according to previous study^{20 , 31 (link), 32 (link)}. The total toxin production was quantitatively evaluated via enzyme immunoassays using the VIDAS C. difficile Toxin A & Bassay (BioMerieux, France)^{11 (link)}. Vegetable cells were inoculated in brain heart infusion (BHIS) at 72 hours at 37 °C in an anaerobic environment. The culture samples was adjusted to OD600 = 0.3 and centrifuged. The supernatant (300 μL) was transferred to the sample well according to the manufacturer’s instructions. The concentration of the total A and B toxins was proportioned to the final fluorescence intensity.

Diagnosis of CDI was based on a combination of clinical presence of diarrhea and laboratory findings. The patients enrolled all presented with diarrhea, and laboratory diagnosis of CDI was performed by detection of fecal CDAB through enzyme immunoassays (EIAs). Fecal samples were collected and sent to the Laboratory of Clinical Microbiology and stored at 2–8 °C, and then prepared for testing with the VIDAS C. difficile Toxin A&B Assay (BioMerieux, Marcy l’Etoile, France) [13 (link)]. Toxin concentrations were tested as relative fluorescence values (RFV) and the results were reported in terms of negative, equivalent and positive.