Alteration of Cell Membrane Permeability by Cetyltrimethylammonium Chloride Induces Cell Death in Clinically Important Candida Species

Abstract

The increased incidence of healthcare-related Candida infection has necessitated the use of effective disinfectants/antiseptics in healthcare settings as a preventive measure to decontaminate the hospital environment and stop the persistent colonization of the offending pathogens. Quanternary ammonium surfactants (QASs), with their promising antimicrobial efficacy, are considered as intriguing and appealing candidates for disinfectants. From this perspective, the present study investigated the antifungal efficacy and action mechanism of the QAS cetyltrimethylammonium chloride (CTAC) against three clinically important Candida species: C. albicans, C. tropicalis, and C. glabrata. CTAC exhibited phenomenal antifungal activity against all tested Candida spp., with minimum inhibitory concentrations (MIC) and minimum fungicidal concentrations (MFC) between 2 and 8 µg/mL. The time–kill kinetics of CTAC (at 2XMIC) demonstrated that an exposure time of 2 h was required to kill 99.9% of the inoculums in all tested strains. An important observation was that CTAC treatment did not influence intracellular reactive oxygen species (ROS), signifying that its phenomenal anticandidal efficacy was not mediated via oxidative stress. In addition, sorbitol supplementation increased CTAC’s MIC values against all tested Candida strains by three times (8–32 μg/mL), indicating that CTAC’s possible antifungal activity involves fungus cell membrane destruction. Interestingly, the increased fluorescence intensity of CTAC-treated cells in both propidium iodide (PI) and DAPI staining assays indicated the impairment of cell plasma membrane and nuclear membrane integrity by CTAC, respectively. Additionally, CTAC at MIC and 2XMIC was sufficient (>80%) to disrupt the mature biofilms of all tested spp., and it inhibited the yeast-to-hyphae transition at sub-MIC in C. albicans. Finally, the non-hemolytic activity of CTAC (upto 32 µg/mL) in human blood cells and HBECs signified its non-toxic nature at the investigated concentrations. Furthermore, thymol and citral, two phytocompounds, together with CTAC, showed synergistic fungicidal effectiveness against C. albicans planktonic cells. Altogether, the data of the present study appreciably broaden our understanding of the antifungal action mechanism of CTAC and support its future translation as a potential disinfectant against Candida-associated healthcare infections.

Untargeted metabolomics uncovers prime pathways linked to antibacterial action of citral against bacterial vaginosis-causing Gardnerella vaginalis: An in vitro and in vivo study

“…Aforementioned twenty-one phytochemicals were used in the screening of potential antibacterial agents against G. vaginalis [ 24 , 25 ]. Briefly, 1 % of G. vaginalis cultures (at OD600 = 0.05) was inoculated into 24 well microtiter plates (MTPs) containing 1 mL of TSB medium supplemented with 1024 μg/mL of respective phytochemicals.…”

“…To determine MIC of citral against G. vaginalis , broth microdilution assay were performed [ 25 ]. In brief, G. vaginalis (1 × 10 7 cells/mL) was dispensed into 24 MTPs containing 1 mL of TSB medium supplemented with citral from 0 to 1024 μg/mL.…”

Multicationic Quaternary Ammonium Compounds: A Framework for Combating Bacterial Resistance

“…Thus, in many cases, the most effective compounds against Gram-positive and Gram-negative bacteria were those containing seven to nine carbon atoms in the alkyl tail. A further increase in the chain length leads to a decrease in activity, which can be explained by the cutoff effect (Figure ), which is characteristic of amphiphilic molecules. − …”

“…Kinetic aspects can also determine the activity of QAC. Steric effects, as well as self-assembly and micelle tendencies, can limit the rate of diffusion and permeation ability of compounds …”

“…Steric effects, as well as self-assembly and micelle tendencies, can limit the rate of diffusion and permeation ability of compounds. 50 Lipophilicity is a key physicochemical property influencing the effectiveness of surfactant biocides and is being investigated to predict the most effective QACs structures. 55,56 Therefore, the relationship between the antibacterial activity and lipophilicity of synthesized tris-QACs was assessed as a part of the SAR study (Figure 5).…”