ABSTRACT
This study evaluated the efficacy of glycone (myricitrin, hesperidin and phloridzin) and aglycone flavonoids (myricetin, hesperetin and phloretin) in inhibiting biofilm formation by Staphylococcus aureus RN4220 and S. aureus SA1199B that overexpress the msrA and norA efflux protein genes, respectively. The minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC50 - defined as the lowest concentration that resulted in ≥50% inhibition of biofilm formation) of flavonoids were determined using microdilution in broth procedures. The flavonoids showed MIC >1024 µg/mL against S. aureus RN4220 and S. aureus SA1199B; however, these compounds at lower concentrations (1-256 µg/mL) showed inhibitory effects on biofilm formation by these strains. Aglycone flavonoids showed lower MBIC50 values than their respective glycone forms. The lowest MBIC50 values (1 and 4 µg/mL) were observed against S. aureus RN4220. Myricetin, hesperetin and phloretin exhibited biofilm formation inhibition >70% for S. aureus RN4220, and lower biofilm formation inhibition against S. aureus SA1199B. These results indicate that sub-MICs of the tested flavonoids inhibit biofilm formation by S. aureus strains that overexpress efflux protein genes. These effects are more strongly established by aglycone flavonoids.
Subject(s)
Bacterial Proteins/genetics , Biofilms/drug effects , Flavonoids/antagonists & inhibitors , Gene Expression Regulation, Bacterial/genetics , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Anti-Bacterial Agents/pharmacology , Biofilms/growth & development , Flavonoids/administration & dosage , Flavonoids/chemistry , Glycosylation/drug effects , Hesperidin/administration & dosage , Hesperidin/antagonists & inhibitors , Hesperidin/chemistry , Membrane Transport Proteins/genetics , Microbial Sensitivity Tests , Multidrug Resistance-Associated Proteins/genetics , Phloretin/administration & dosage , Phloretin/antagonists & inhibitors , Phloretin/chemistry , Phlorhizin/administration & dosage , Phlorhizin/antagonists & inhibitors , Phlorhizin/chemistryABSTRACT
INTRODUCTION: S. aureus is of great importance to public health due to its pathogenicity. This study aimed to evaluate lipase production by S. aureus isolates from different sources. METHODOLOGY: Lipolytic activity was determined using Tween-Calcium agar (48 hours; 35°C). RESULTS: Eighty-six percent of the isolates from human wounds were positive for lipase production. The frequencies of isolates positive for lipase production were 33.3% from cow udders, 15.4% from the nasal cavities of cattle, 82.9% from ricotta cheeses, and 100% and 91.7% from meat- and vegetable-contact surfaces, respectively. CONCLUSION: The production of lipase varied among the isolates according to their source.
