Converting organosulfur compounds to inorganic polysulfides against resistant bacterial infections

Abstract

The use of natural substance to ward off microbial infections has a long history. However, the large-scale production of natural extracts often reduces antibacterial potency, thus limiting practical applications. Here we present a strategy for converting natural organosulfur compounds into nano-iron sulfides that exhibit enhanced antibacterial activity. We show that compared to garlic-derived organosulfur compounds nano-iron sulfides exhibit an over 500-fold increase in antibacterial efficacy to kill several pathogenic and drug-resistant bacteria. Furthermore, our analysis reveals that hydrogen polysulfanes released from nano-iron sulfides possess potent bactericidal activity and the release of polysulfanes can be accelerated by the enzyme-like activity of nano-iron sulfides. Finally, we demonstrate that topical applications of nano-iron sulfides can effectively disrupt pathogenic biofilms on human teeth and accelerate infected-wound healing. Together, our approach to convert organosulfur compounds into inorganic polysulfides potentially provides an antibacterial alternative to combat bacterial infections.

Construction of Nanozyme‐Hydrogel for Enhanced Capture and Elimination of Bacteria

“…Therefore, great efforts have been devoted to developing alternative antibacterial materials in recent years . Particularly, inspired by natural enzymes for damaging bacteria through catalyzing the production of harmful reactive oxygen species (ROS), researchers diverted their attention to the construction of artificial enzymes with the functions of natural enzymes to combat bacteria . Different from high‐cost and instable natural enzymes, nanozymes are generally facile‐preparation and stable.…”

Bimetallic CuCo2S4 Nanozymes with Enhanced Peroxidase Activity at Neutral pH for Combating Burn Infections

“…To avoid the toxicity from high concentration of H 2 O 2 , we fixed the H 2 O 2 concentration at 2 mM for both Gram‐positive and ‐negative bacteria. After 1 h incubation with nanoparticles (100 μg/mL) and H 2 O 2 (2 mM) in pH 7.4 PBS, bacterial viability was then analyzed using the colony‐forming unit (CFU) method . As shown in Figure a, in the presence of H 2 O 2 , CuCo 2 S 4 NPs exhibited a 3.3‐log reduction in terms of the viability of Gram‐positive Staphylococcus aureus ( S. aureus ), with 1.3 and 2.8‐log higher inactivation efficiency compared with those of CuS and CoS NPs, respectively.…”

OxyR senses reactive sulfane sulfur and activates genes for its removal in Escherichia coli

“…In the presence of 400 μM H 2 S n , E coli significantly downregulated its energy metabolism-related genes, such as maltoporin (71.3 fold-change) and glycerol-3-phosphate transporter (33.7 fold-change). The most up regulated genes included phage holin (425.9 fold-change), phage recombination protein Bet (96 fold-change), and a putative single-stranded DNA binding protein, suggesting that H 2 S n is toxic to E. coli (Xu et al, 2018) . When we checked sulfane sulfur-removing enzymes, GrxA had the highest (2.1 fold) and TrxC and KatG had mild (1.6 fold and 1.5 fold) transcriptional increases in H 2 S n -stressed cells (Fig.…”

“…Fungi may use glutathione to reduce polysulfides to H 2 S as a detoxification mechanism (Samrat et al, 2013; Sato et al, 2011) . Organosulfur compounds can be used to treat antibiotic-resistant bacteria, and they are converted to hydrogen polysulfide inside the cells for the toxicity (Xu et al, 2018) . Both bacteria and fungi show reduced viability being exposed to sulfane sulfur stress (Sato et al, 2011; Xu et al, 2018) .…”

“…Organosulfur compounds can be used to treat antibiotic-resistant bacteria, and they are converted to hydrogen polysulfide inside the cells for the toxicity (Xu et al, 2018) . Both bacteria and fungi show reduced viability being exposed to sulfane sulfur stress (Sato et al, 2011; Xu et al, 2018) . Therefore, intracellular sulfane sulfur is likely maintained within a range for microorganisms under normal conditions.…”