Background: Decontamination of umbilical cord is a critical phase before cryopreservation. We investigated the decontamination efficacy of the BASE.128 against the most frequent umbilical cord contaminants by an in vitro time-kill study.
Methods: F. magna (ATCC 29328), P. melaninogenica (ATCC 25845), and umbilical tissue clinical isolates E.coli, E. faecalis, and B. fragilis were cultivated under optimal growth conditions. Resistance to the antibiotics was determined by Kirby Bauer method. The inoculum concentrations were determined by Mc Farland method. BASE.128 and BASE as control (ALCHIMIA Srl) were inoculated with 10E5-10E6 cfu/ml of the selected microorganisms, each assessed in triplicate. All the strains were incubated at 37°C for 24 h, E. coli and E. faecalis were additionally incubated at +4°C for 48h and +22°C for 48h. Time kill of microorganisms by BASE.128 was determined at 0h, 3h, 6h, 16h, 24h (48h only for incubation at +4°C and 22°C).
Result: E. faecalis was resistant to cefuroxime, cetoconazol, clindamycin, quinupristin+dalfopristin, trimetoprim+sulfametoxazol. B. fragilis was penicillin resistant. A complete elimination of E. coli (6.56 log) was observed after 3h of incubation in BASE.128 at 37°C and 22°C and after 48h at 4°C. The initial inoculum of E. faecalis (5.7 log) was completely eliminated after 16h at 37°C, and 48h at 22°C. 5 log of F. magna and 6.6 log of P. melaninogenica were completely eliminated after 16h at 37°C. B. fragilis was reduced of 2.37 log after 16h at 37°C.
Conclusion: Decontamination with BASE.128 at 37°C for 16h allowed a complete elimination of at least 5 log of the most frequent umbilical cord contaminants (E. faecalis, E. coli, P. melaninogenica and F. magna).