Antibiofilm activity of cell-free supernatants from bacteria isolated from chronic wounds against Staphylococcus aureus.

AIMS: Staphylococcus aureus is a commensal bacterium and an opportunistic pathogen for humans, as one of the main species in chronic wounds. Seeking alternative strategies against S. aureus in chronic wounds, this study aimed to evaluate the anti-biofilm activity of cell-free supernatants (CFS) from cultures of Morganella morganii and Corynebacterium striatum isolated from chronic wounds.

MATERIALS AND

METHODS

Growth in the presence and absence of CFS was evaluated, and biofilm formation was measured through bacterial growth on 96-well plates, followed by staining with safranin. Biofilm-associated genes were analyzed by qPCR, and a molecular fingerprinting of the CFS was performed.

RESULTS

The CFS could inhibit biofilm formation on S. aureus at a 50% concentration without interfering with growth. At a 25% concentration, the bioactivity was not maintained for some strains of S. aureus. M. morganii CFS could inhibit biofilm formation genes, while C. striatum genes could not. Molecules different from the control were detected by HPLC-MS, which were not affected by heat or proteinase K.

CONCLUSIONS

M. morganii and C. striatum appear as potential producers of bioactive molecules against biofilm formation on S. aureus, and future studies may help to identify these molecules and broaden the comprehension of their mechanism of action.