Temperature‐dependent control of Staphylococcus aureus biofilms and virulence by thermoresponsive oligo(N‐vinylcaprolactam)

Abstract

Bacterial biofilms are associated with persistent infections because they are highly tolerant of antimicrobial agents, and in the case of Staphylococcus aureus, which is a leading cause of nosocomial infections because of its resistance to diverse antibiotics, biofilm formation is a known mechanism of drug resistance. In the present study, we investigated the ability of thermoresponsive oligo (N-vinylcaprolactam) (OVCL) to control biofilm formation by and the virulence of S. aureus. One synthetic and four commercial OVCLs (MW ≤ 240,000) at 50 µg/mL were found to increase S. aureus biofilm formation 7-fold at 25 °C, but to markedly inhibit S. aureus biofilm formation at 37 °C. Confocal and scanning electron microscopy confirmed the temperature-dependent effect of OVCL on S. aureus biofilms. It was found that the addition of OVCL to S. aureus culture caused cells to become dramatically more hydrophilic at 37 °C, which partially supports the biofilm reduction. Also, transcriptional analysis showed that OVCL temperature-dependently regulated biofilm-related genes (aur, agrA, and icaA) in S. aureus. In addition, it was found surface coatings containing OVCL effectively controlled S. aureus biofilm formation on solid glass surfaces. Furthermore, OVCL inhibited the hemolysis of human red blood cells by S. aureus at 37 °C and attenuated S. aureus virulence in the nematode Caenorhabditis elegans. These results suggest that OVCL has potential use for controlling bacterial biofilm formation and virulence.

Calcium-chelating alizarin and other anthraquinones inhibit biofilm formation and the hemolytic activity of Staphylococcus aureus

“…In particular, α-toxin (Hla) causes hemolysis 29 and contributes to biofilm formation 8 . In the present study, alizarin, purpurin, and quinalizarin showed antibiofilm and anti-hemolytic activities ( Figs 3 and 5 ), and previous studies have shown that several flavonoids 16 , nerolidol 22 , stilbenoids 40 , and thermoresponsive oligo ( N -vinylcaprolactam) 41 have antibiofilm activity and anti-hemolytic activity against S. aureus . Thus, it appears there is a positive relation between antibiofilm and anti-hemolytic activities.…”

Inhibition of Candida albicans biofilm and hyphae formation by biocompatible oligomers

“…) and to the controlling of cell‐surface hydrophilicity and haemolytic activity (Lee et al . ), respectively. Here, we report for the first time that OVCL MW 679 inhibits biofilm and hyphal formation and cell aggregation by C. albicans (Figs , and ).…”

“…) and Staphylococcus aureus (Lee et al . ), respectively. In the present study, OVCL/PLGA coatings on glass were found to have antibiofouling effects on C. albicans (Fig.…”

“…) and in S. aureus strains (Lee et al . ). Notably, the observed biofilm inhibition in the absence of any effect on planktonic cell growth suggests that, unlike conventional antifungal agents, OVCL MW 679 may be less prone to the development of drug resistance.…”

Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices

“…The basic principle involves causing irreversible damage in pathogenic cells by activating metal NPs or polymer-based systems using external energy sources, such as visible light [214], temperature [215], near-infrared (NIR) radiation [216], or high frequency alternating magnetic fields (AMF) [217]. Gold, iron oxide, and graphene NPs have been utilized as photothermal agents that absorb NIR light and convert this into heat energy.…”