N-acetylcysteine as powerful molecule to destroy bacterial biofilms. A systematic review

Biofilms are microbial communities consisting of bacteria, extremely capable to self-reproduce on biological surfaces, causing infections. Frequently, these biofilms are resistant to classical antibacterial treatments and host immune response. Thus, new adjuvant molecules are mandatory in clinical practice. N-acetylcysteine (NAC), a precursor to the antioxidant glutathione, has been investigated for its effectiveness both in inhibiting biofilm formation and in destroying developed biofilms. The aim of our study was to conduct a systematic literature review of clinical trials involving NAC as adjuvant treatment to eradicate pre-formed mature biofilms and to inhibit new biofilm production.

A careful analysis of the Medline was conducted and eight studies were selected according to the following criteria: site of infection, kind of bacteria, design of the research, dose of the treatment, administration, biological effects and results. We fixed an arbitrary scale of scores from 0 (lowest score) to 5 (highest score) for each criterion and a threshold value of 3.

The studies analyzed, with score over 3, suggested a potential role for NAC as adjuvant molecule in the treatment of bacterial biofilms, with an excellent safety and efficacy profile. NAC, in combination with different antibiotics, significantly promoted their permeability to the deepest layers of the biofilm, overcoming the problem of the resistance to the classic antibacterial therapeutic approach.

Overall, these results are encouraging to a more widespread clinical use of NAC, as adjuvant therapy for microbial infections followed by biofilm settle, which may occur in several body districts, such as the vaginal cavity.