Dynamic of Biofilm Formation on Surgical Clamps by Staphylococcus aureus and Acinetobacter baumannii Strains

Background: Understanding biofilm formation and the interaction between bacterial species on surgical instrument surfaces is of great importance. Due to the scarcity of studies on this subject, the present study proposes to investigate this dynamic process.

Methods: Staphylococcus aureus and Acinetobacter baumannii reference strains, associated or not, were cultured on Cushing tissue dissecting forceps. In an attempt to compare and investigate biofilm in different anatomic parts of this surgical instrument, quantitative microbial culture and electronic microscopy were performed at different times.

Results and Discussion: The quantitative culture and electronic microscopy analysis of single-species biofilm showed that A. baumannii cells were more adherent and prevalent on the instruments’ surface at all examined times, whereas mixed-species biofilm results showed that S. aureus cells prevail after the sixth hour and represent the majority of the aggregated cells at 12 and 24 h.

Conclusions: Our results indicated a possible antagonistic interaction between the two tested species. The findings also showed that the biofilm formation occurred after the first analyzed time, reinforcing the need to follow the existing guidelines to process medical devices.