N-Acetylcysteine Protects Bladder Epithelial Cells from Bacterial Invasion and Displays Antibiofilm Activity against Urinary Tract Bacterial Pathogens

Abstract

Urinary tract infections (UTIs) affect more than 150 million individuals annually. A strong correlation exists between bladder epithelia invasion by uropathogenic bacteria and patients with recurrent UTIs. Intracellular bacteria often recolonise epithelial cells post-antibiotic treatment. We investigated whether N-acetylcysteine (NAC) could prevent uropathogenic E. coli and E. faecalis bladder cell invasion, in addition to its effect on uropathogens when used alone or in combination with ciprofloxacin. Methods: An invasion assay was performed in which bacteria were added to bladder epithelial cells (BECs) in presence of NAC and invasion was allowed to occur. Cells were washed with gentamicin, lysed, and plated for enumeration of the intracellular bacterial load. Cytotoxicity was evaluated by exposing BECs to various concentrations of NAC and quantifying the metabolic activity using resazurin at different exposure times. The effect of NAC on the preformed biofilms was also investigated by treating 48 h biofilms for 24 h and enumerating colony counts. Bacteria were stained with propidium iodide (PI) to measure membrane damage. Results: NAC completely inhibited BEC invasion by multiple E. coli and E. faecalis clinical strains in a dose-dependent manner (p < 0.01). This was also evident when bacterial invasion was visualised using GFP-tagged E. coli. NAC displayed no cytotoxicity against BECs despite its intrinsic acidity (pH ~2.6), with >90% cellular viability 48 h post-exposure. NAC also prevented biofilm formation by E. coli and E. faecalis and significantly reduced bacterial loads in 48 h biofilms when combined with ciprofloxacin. NAC visibly damaged E. coli and E. faecalis bacterial membranes, with a threefold increase in propidium iodide-stained cells following treatment (p < 0.05). Conclusions: NAC is a non-toxic, antibiofilm agent in vitro and can prevent cell invasion and IBC formation by uropathogens, thus providing a potentially novel and efficacious treatment for UTIs. When combined with an antibiotic, it may disrupt bacterial biofilms and eliminate residual bacteria.

Effects of Itxasol© Components on Gene Expression in Bacteria Related to Infections of the Urinary Tract and to the Inflammation Process

“…NAC can act against pathogens such as Escherichia coli and Enterococcus faecalis , preventing them from invading epithelial cells of the bladder [ 67 ]. This fact has been related to how the administration of NAC to cells can alter the synthesis of membrane proteins related to the recognition of bacteria in their first step, which is that of adhesion [ 68 ].…”

Successfully treating biofilms of extensively drug resistant Klebsiella pneumoniae isolates from hospital patients with N-Acetyl Cysteine

“…Due to its mucolytic activity, NAC has attracted microbiologists to explore its potential as an antibacterial and antibiofilm agent. A number of in vitro studies assessed the activity of NAC against different Gram positive and Gram-negative bacteria including Escherichia coli, Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Staphylococcus epidermidis amongst others (Quah et al,2012; Choi et al,2018; Feng et al,2018; Jun et al,2019; Ciacci et al, 2019; Li et al,2020; Guerini et al,2020; Kundukad et al, 2020; Manoharan et al, 2021). Given the broad-spectrum activity of NAC against bacteria, this study aims at repurposing N-acetyl cysteine (NAC) to treat biofilms of XDR K. pneumoniae , isolated from patients in hospitals.…”

Understanding the Role of the Antioxidant Drug Erdosteine and Its Active Metabolite on Staphylococcus aureus Methicillin Resistant Biofilm Formation

“…N-acetylcysteine is used as mucolytic drug and it is applied on a broad range of pathologies with the primary role of antioxidant agent [ 8 ]. N -acetylcysteine has been described as both decreasing or increasing the biofilm formation by different bacterial strains, depending on the experimental conditions [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ]. Further, 3-bromopyruvate and 5-fluorouracil are anti-cancer drugs that act by inducing oxidative stress via depletion of antioxidants and inactivation of antioxidant enzymes [ 16 , 17 ].…”

“…N-acetylcysteine has been described as both decreasing or increasing the biofilm formation by different bacterial strains, depending on the experimental conditions [9][10][11][12][13][14][15]. Further, 3-bromopyruvate and 5-fluorouracil are anti-cancer drugs that act by inducing oxidative stress via depletion of antioxidants and inactivation of antioxidant enzymes [16,17].…”