Metal-loaded zeolite remediation of soils contaminated with pandrug-resistant Acinetobacter baumannii

Abstract

<jats:title>Abstract</jats:title><jats:p>Due to the development of resistance to antimicrobial agents, bacterium <jats:italic>Acinetobacter baumannii</jats:italic> is nowadays a leading cause of nosocomial outbreaks. Clinically relevant <jats:italic>A. baumannii</jats:italic> outside hospital settings including natural soils affected by human waste represents a public-health risk for humans and animals. The aim of this study was to investigate the potential of metal-loaded zeolites to eliminate viable <jats:italic>A. baumannii</jats:italic> from artificially contaminated natural soils. <jats:italic>A. baumannii</jats:italic> isolate was subjected to the activity of natural zeolitised tuff (NZ) and Cu-modified (CuNZ) or Ag-modified zeolite (AgNZ) in wet, slightly acidic <jats:italic>terra rossa</jats:italic> and slightly alkaline red palaeosol. <jats:italic>A. baumannii</jats:italic> survived in <jats:italic>terra rossa</jats:italic> and red palaeosol supplemented with 1 wt% of NZ for seven days and four months, respectively. The addition of 1 wt% of CuNZ to <jats:italic>terra rossa</jats:italic> and red palaeosol shortened the survival of <jats:italic>A. baumannii</jats:italic> to three and 14 days, respectively. The addition of 0.1 wt% of AgNZ to both soils resulted in complete removal of viable <jats:italic>A. baumannii</jats:italic> within 1 h of contact, while the total native heterotrophic bacterial counts remained high. Since AgNZ is prepared with a simple modification of cost-effective and environmentally friendly natural zeolite, it is a promising material for the remediation of soils contaminated with pandrug-resistant <jats:italic>A. baumannii</jats:italic>.</jats:p>

Advances in the Applications of Clinoptilolite-Rich Tuffs

“…Except in water media, Ag-ZT and Cu-ZT were tested for the elimination of A. baumannii from artificially contaminated natural soils [ 36 ]. Adding 1wt.% of Cu-ZT shortened the survival of A. baumannii from seven to three days in slightly acidic terra rossa and from four months to 14 days in slightly alkaline red palaeosol.…”

“…An M-ZT with low leaching of metal cations, such as Cu- or Cu 2 O-containing ZT [ 32 , 33 ], is recommended for disinfection. The bactericidal activity of ZT with Cu(II), Ag(I), or BC can be applied in the disinfection of water or wet surfaces [ 34 ] but also in the remediation of soils contaminated with human pathogens [ 36 ].…”

“…In recent decades, the adsorption, catalytic, and antibacterial characteristics of clinoptilolite-rich tuffs (ZT) from two deposits, Vranjska Banja and Slanci (Serbia), containing up to 80 wt.% clinoptilolite, with quartz and feldspar as the primary mineral impurities, have been extensively studied [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. This review compares these results with ZTs from other regions.…”