Abstract

The rapid growth of resistant bacteria to antibiotics has caused a worldwide public health crisis. Antibiotic resistance can result from bacteria evolving mutations in target proteins and obtaining mechanisms to inactivate, degrade, pump out, or block entry of antibiotics into the cell. An increase in antibiotic resistance makes bacterial infections harder to treat and has been attributed to the overuse, misuse, and the lack of new drug development of antibiotics. The discovery of new antibiotics is needed to combat this threat. Amino acid-surfactants have generated interest as antibacterial agents and as switchable surfactants. These surfactants are of particular interest because they are largely biodegradable, due to a relatively labile ester or amide bond. Two novel O-acylated amino acid surfactants with hydrophobic ω-alkenyl chains were previously synthesized using the leucine and phenylalanine amino acids. These surfactants are being tested for antimicrobial activity, using 2-fold dilutions of each surfactant in methanol. Two gram positive (Staphylococcus aureus and Enterococcus faecalis) and two gram negative (Escherichia coli and Acinetobacter baylyi) bacterial species are being tested against these surfactants using standard dilution assays, and the minimum inhibitory concentration (MIC) is determined by the lowest concentration of surfactant needed to inhibit bacterial growth. Experiments are done in triplicate to insure the validity of MIC results. All bacterial species that are being used are non-pathogenic representatives of antibiotic-resistant bacterial pathogens. Both surfactants have antimicrobial activity against both S. aureus and E. coli. The other bacterial strains are currently being tested along with the micelle-forming characteristics of these surfactants.