Abstract
Microemulsions (MEs), isotropic mixture of water, oil, surfactant and most frequently cosurfactant, have gained great interest in the pharmaceutical industries and food technology due to their great potential to act as antimicrobials as well as nanocarriers for antibiotics. In this study, the antibacterial activities of a ME, composed of 23.5% Cremophor EL, 12.5% transcutol, 30% ethyl decanoate and 34% distilled water, against Gram-positive and Gram-negative bacteria and its potential as a nanocarrier for cephalosporine (CEPH/ME) were assessed. The morphological structures of the ME and CEPH/ME, revealed by transmission electron microscopy, were spherical and their droplet diameters were 15.55 ± 3.17 nm and 10.56 ± 2.32 nm, respectively. ME was found to have great antibacterial activity against
Staphylococcus aureus
. According to the mechanism of action study of ME, free cephalosporine (CEPH) and CEPH/ME against
S. aureus
, the minimum inhibitory concentrations (MICs) were 2 mL/10 mL of nutrient broth for ME and 1 mL/10 mL of nutrient broth for both of CEPH and CEPH/ME. The ME, CEPH and CEPH/ME have affected the
S. aureus
through changing cell morphology, cell wall composition (sugar, protein and phosphorus), potassium leakage and cellular respiration. They enhanced the cellular permeability, decreased the hydrophobicity and viability of the bacterial cells. This study suggests that ME formula has a good potential as an antibacterial agent and as a nanocarrier for CEPH.