Atividade antimicrobiana e antibiofilme de um mel da Caatinga paraibana contra bactérias causadoras de infecções nosocomiais

Abstract

The aim of this study was to describe the available scientific evidence in the literature regarding the clinical applicability of honey as an antimicrobial agent, as well as to evaluate, in vitro, the antimicrobial and antibiofilm activity of a honey sample collected from the Caatinga biome in Paraíba, Brazil, against nosocomial microorganisms. Nine honey samples from the Caatinga region (labeled MC-1 to MC-9) were georeferenced, sterilized by filtration, and diluted in different concentrations (% w/v) for analysis. The antimicrobial activity was assessed by broth microdilution to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) against Staphylococcus aureus ATCC, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa ATCC 109246, Klebsiella pneumoniae ATCC 70063, and Escherichia coli ATCC 25922. Antibiofilm activity was evaluated on 48-hour pre-formed biofilms of S. aureus and MRSA using the honey sample that exhibited the best MIC values. Only MC-4 and MC-11 showed promising antimicrobial activity, with MC-4 standing out, presenting a MIC and MBC of 2.5% and 10% (w/v), respectively. All tested concentrations of honey exhibited effects on pre-formed biofilms, with viability reduction of at least 30% for S. aureus and 20% for MRSA, when compared to the untreated control (p < 0.05). Therefore, MC-4 exhibits both antimicrobial and antibiofilm activity against pathogens associated with hospital-acquired infections, particularly S. aureus and MRSA strains. This functional food may be considered a promising candidate to replace refined sugar in the diet, aiming to reduce the microbial load of non-oral pathogens in the oral cavity, and may serve as a source of bioactive compounds for the development of novel antimicrobial agents.