A C-Type Lectin from Bothrops jararacussu Venom Disrupts Staphylococcal Biofilms

Bovine mastitis is a major threat to animal health and the dairy industry. Staphylococcus aureus is a contagious pathogen that is usually associated with persistent intramammary infections, and biofilm formation is a relevant aspect of the outcome of these infections. Several biological activities have been described for snake venoms, which led us to screen secretions of Bothrops jararacussu for antibiofilm activity against S . aureus NRS155. Crude venom was fractionated by size-exclusion chromatography, and the fractions were tested against S . aureus . Biofilm growth, but not bacterial growth, was affected by several fractions. Two fractions (15 and 16) showed the best activities and were also assayed against S . epidermidis NRS101. Fraction 15 was identified by TripleTOF mass spectrometry as a galactose-binding C-type lectin with a molecular weight of 15 kDa. The lectin was purified from the crude venom by D-galactose affinity chromatography, and only one peak was observed. This pure lectin was able to inhibit 75% and 80% of S . aureus and S . epidermidis biofilms, respectively, without affecting bacterial cell viability. The lectin also exhibited a dose-dependent inhibitory effect on both bacterial biofilms. The antibiofilm activity was confirmed using scanning electron microscopy. A pre-formed S . epidermidis biofilm was significantly disrupted by the C-type lectin in a time-dependent manner. Additionally, the lectin demonstrated the ability to inhibit biofilm formation by several mastitis pathogens, including different field strains of S . aureus , S . hyicus , S . chromogenes , Streptococcus agalactiae , and Escherichia coli . These findings reveal a new activity for C-type lectins. Studies are underway to evaluate the biological activity of these lectins in a mouse mastitis model.