Metal ionzeolite materials against resistant bacteria, MRSA

Abstract

Metal ionzeolite materials based on different zeolite structuresFAU (NaY, 100750 nm), LTA (4400 nm), and MFI (ZSM5, >100, 760, and 2500 nm) were studied for developing antimicrobial agents using a simple method. These zeolite structures were loaded with silver, copper, or zinc ions using an ion-exchange method and tested for antimicrobial activity against three bacteriaEscherichia coli, methicillin-sensitive Staphylococcus aureus, and methicillin-resistant Staphylococcus aureus (MRSA), a clinical isolate. Sample characterization confirmed the presence of metal ions and the stability of the zeolite structures. All mono- and bimetallic ionzeolite materials loaded with silver displayed higher antimicrobial activity than zinc- or copper-containing samples. The inhibitory effect of metal ionzeolite materials was even higher than the action of antibiotics, especially against MRSA. These findings show that silver ionzeolite materials have potential applications to combat bacterial infections and further prevent the prevalence of resistant microorganisms. The antimicrobial activity seems to be related to the acidity and Si/Al ratio of zeolites, according to the following scale: MFI > FAU > LTA. Particularly, the inhibitory effect against MRSA is a very promising result considering the difficulty of effective eradication of this resistant strain, the principal agent of nosocomial or healthcare-associated infections, which affect 3.2\% of all hospitalized patients in the United States and 6.5\% in the European Union.