Levofloxacin liposomal form creation and its effectiveness evaluation against Listeria monocytogenes

The dynamics of the increase in antibiotic-resistant strains of microorganisms is growing daily, although over the past few decades, new antibiotic molecules have not been developed. As a result, animal husbandry bears great losses. One of the solutions to the problem of antibiotic resistance in bacteria can be to improve existing antimicrobials by encapsulating the active substance in nanocontainers. The aim of the study is to obtain a liposomal form of levofloxacin and evaluate its effectiveness against Listeria monocytogenes. In the course of the work, approaches to the creation of liposomes as structures that deliver antibiotics to the site of action are considered. Empty liposomes were obtained by the convection method. To reduce the size of the liposomes, ultrasonic bath treatment at a temperature of 20±2 °C and a sound frequency of 35 kHz was used. The inclusion of levofloxacin in liposomes was carried out by the active loading method, by creating an ammonium sulfate concentration gradient. Levofloxacin was dissolved in 1 % acetic acid solution, after which it was incubated with previously prepared liposomes. Liposomes of levofloxacin with a concentration of 1 mg/ml were obtained and the effectiveness of liposomal levofloxacin was evaluated in comparison with the usual form of the antibiotic and liposomes not loaded with the antibiotic in relation to Listeria monocytogenes cells. To assess the effectiveness of the antibacterial effect, a bacterial suspension of Listeria monocytogenes 766 microorganisms was co-incubated in LMX Broth for 24 hours at 37 °C. It was shown that the effectiveness of the liposomal form differs from the classical one. The decrease in the viability of the test-object when using nanocapsulated levofloxacin is 27.5 % in comparison with the use of classical levofloxacin. Liposomes without antibiotic showed no antibacterial effect at all.