RESUMO
BACKGROUND: Drug combination is a new therapy to improve antibiotic deficiency treatment towards biofilm resistance. OBJECTIVE: This study was conducted to determine the potential effect of sodium oleate to inhibit established biofilms of two strains, methylotrophic bacteria Methylophilus quaylei in combination with ampicillin. Minimum inhibitory concentration (MIC) of ampicillin was determined and added in combination with sodium oleate and examined on planktonic and established biofilms of two strains M. quaylei were characterized by different properties of cell surface hydrophobicity. METHODS: The effect on biofilms was evaluated by the number of colony forming units (CFUs), crystal violet assay, light and scanning electron microscopy. RESULTS: The study demonstrates that sodium oleate has a promoting activity against planktonic growth of M. quaylei strains and has a slight inhibitory effect on biofilm. Addition of sodium oleate enhances the bactericidal effect of ampicillin against biofilm cells. Combination of ampicillin 0.1 mg/ml (MIC) and sodium oleate 0.03 mg/ml showed a remarkable destruction effect on established biofilms. DISCUSSION: Combination of ampicillin 0.1 mg/ml (MIC) and sodium oleate 0.03 mg/ml showed a remarkable destruction effect on established biofilms. Overall, results indicated that sodium oleate in combination with ampicillin enhances the inhibition of M. quaylei biofilms and this combination can be utilized for combating bacterial biofilm resistance. CONCLUSION: Overall, results indicated that sodium oleate in combination with ampicillin enhances the inhibition of M. quaylei biofilms and this combination can be utilized for combating bacterial biofilm resistance.
