Avaliação microbiológica da associação do biopolímero de fibrina com nitrato de prata

Abstract

Fibrin sealants, also known as fibrin biopolymer (BPF), are biological matrixes from human plasma, fully resorbable, that mimic the last stages of the coagulation cascade during which fibrinogen is converted into a structured and insoluble fibrin clot. BPF developed from the snake venom Crotalus durissus terrificus, presents an excellent alternative for tissue engineering and cell modulation. Its use as a healer for venous ulcers in the lower limbs proved to be safe and potentially effective in a phase II clinical study. Objective: To investigate the antimicrobial effect of the association of fibrin biopolymer with silver nitrate. This association will allow its use in contaminated and colonized wounds, which currently leads to suspension of treatment with BPF. Methods: BPF is prepared from 2 active components and a diluent. Different concentrations of silver nitrate were mixed with the BPF components. The clots containing silver nitrate were inserted into the wells drilled on the agar in Petri dishes containing the culture medium of Mueller Hilton agar previously seeded with cultures of Staphylococcus aureus and Escherichia coli. Silver nitrate concentrations were used, forming the following groups: Control - NP1 = 1mg / mL; NP2 = 2.5mg / mL and NP3 = 5mg / mL silver nitrate; Experimental group: the same concentrations used in the control group associated with BPF and positive control with antibiotics. The presence was verified and the inhibition halo present in each of the tested plates was measured. Tests of minimum inhibitory concentration (CIM) and minimum bactericide (CBM) were carried out to establish the lowest concentration of BPF + NP and NP capable of inhibiting the tested strains. Mean and median values of diameters with measures of central tendency and standard deviation and interquartile range were considered as measures of sample dispersion and verification of antimicrobial efficacy. Results: A significant difference was observed in the halos of inhibition of treatments with NP when compared with BPF + NP. There was a statistical difference in the inhibition halos of the gram-negative bacteria in relation to the gram-positive bacteria, in the treatment with NP, NP3 showed a significant difference in relation to NP2 compared to E. coli while S. aureus did not present a statistically significant difference. BPF alone did not form an inhibition halo. BPF + NP had an inhibitory effect on the antimicrobial action of NP by 18.2% for E. coli and 13.5% for S. aureus when compared to NP treatment. The CIM found for E. coli and S. aureus when tested with GMP + NP were 7.81 and 250 µg / mL and with NP 3.9 and 7.81 µg / mL. While CBM found for BPF + NP they were 15.62 and 1000 µg / mL and for treatment with NP 7.81 and 15.62 µg / mL respectively. Conclusion: It was possible to verify by the results that the NP and BPF + NP showed antibacterial effect on the species of gram-negative and grampositive bacteria, demonstrating greater efficacy for E. coli and that the antibacterial activity of the NP was more effective than the BPF + NP. He observed that GMP when isolated has no antibacterial effect.