Influence of exposure time on the release of bacteria from a biofilm on Ti6Al4V discs using sonication: An in vitro model.

Implant sonication is considered a useful method for the diagnosis of implant-related infections. We designed an in vitro study using Ti6Al4V discs and 5 different bacteria to determine the optimal sonication time for recovery of most bacteria tested to enable use of sonication in clinical practice for microbiological diagnosis of implant-related infections. We carried out a specific protocol for the adherence and subsequent biofilm formation on the materials used. The discs were then sonicated and the retrieved bacteria were quantified. From minute 1 to 5, the amount of recovered organisms grew progressively for all bacteria. Between minute 6 and minute 10, the number was irregular for all strains except E. coli, though no pattern was evidenced. E. coli was the only microorganism with a progressive increase in liberation throughout the process. Significant differences were observed in each of the 10minutes analyzed as concerns the release of the 5 strains (P<0.021) as well as in the mean dislodgement (of the 10minutes) of all tested strains (P<0.00001). Considering that infections in which biofilms are involved could be polymicrobial, we concluded that 5minutes is the optimal time of sonication in order to recover the maximum amount of most bacteria attached to Ti6Al4V discs.