Investigation of the effect of the association of iontophoresis with polymyxin on resistant bacteria.

• Grant number: 24/21255-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Renata Fonseca Vianna Lopez
• Grantee: Thalita Isabel Barbosa Rochael
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 22/03521-0 - Investigation of physical methods associated with drug delivery systems in the local immune and antimicrobial response, AP.TEM

Abstract

The mechanisms of antibiotic resistance are rising to dangerously high levels worldwide. Therefore, the search for alternatives to help combat resistant strains is of vital importance. Applying a constant low-intensity electric current to the skin enhances cellular activity and shows evidence of inhibiting microbial growth. However, changes in the electric circuit, the presence of components in the medium that may disrupt the bacterial cell membrane upon electrical current application, as well as the mechanisms by which iontophoresis inhibits microbial growth, have not yet been clarified and require further investigation. Polymyxin B is an antimicrobial that acts by competitively displacing divalent cations interacting with phosphates present in bacterial cell walls. It is hypothesized that the application of iontophoresis in media containing polymyxin B and bacteria will modulate ion movement and reduce bacterial resistance to this antibiotic. This study aims to understand the mechanisms involved in the antimicrobial activity of electric current. Gram-positive and Gram-negative bacteria will be used, initially in monoculture, and modifications will be made to the electrical circuit, the electrode polarity in contact with the bacteria, constant electric current density, and bacterial viability. Modified E. coli, with reduced peptidoglycan content, will be employed to assess the influence of zeta potential and the presence of polymyxin B and other cationic substances on the viability of bacteria exposed to electric current. The production of hydrogen peroxide and other free radicals in bacterial cultures subjected to electric current application will also be investigated.