Antimicrobial efficacy of 45S5 and borosilicate bioglasses against multidrug-resistant bacteria: an in vitro assay.

Several bioceramics have been developed to promote bone repair. However, postoperative infections in the implanted area may led to in bone resorption. The widespread use of antimicrobials has contributed to the increased prevalence of multidrug-resistant bacteria, posing an additional challenge to therapeutics. This study aimed to evaluate the antimicrobial activity and resistance-inducing potential of two bioceramic formulations, 45S5 bioglass and borosilicate bioglass (BVBS), against multidrug-resistant strains of methicillin-resistant Staphylococcus pseudintermedius (MRSP), Escherichia coli, and Pseudomonas aeruginosa. Antibacterial activity was determined by the minimum inhibitory concentration (MIC) and time-kill kinetics. Resistance-inducing capacity was assessed by bacterial growth after 48 h of exposure to 800 mg/mL of each bioceramic. Bioglass 45S5 demonstrated greater antimicrobial activity, with an MIC of 50 mg/mL for E. coli and P. aeruginosa and 100 mg/mL for MRSP, and complete eradication of the strains after 8 h. BVBS presented an MIC of 100 mg/mL for E. coli and P. aeruginosa, and 200 mg/mL for MRSP, with complete bacterial elimination within 24 h. No resistance induction was observed for 45S5 in any of the strains, and BVBS showed this effect only on E. coli and P. aeruginosa strains. The results indicate that both formulations were effective against multidrug-resistant bacteria, with bioglass 45S5 being the most promising alternative due to its greater antimicrobial efficacy and lack of resistance induction.