Antifungal activity of low molecular weight chitosan against clinical isolates ofCandidaspp.

Abstract

Chitosan is a natural polymer derived from chitin, a structural component of fungi, insects and shrimp, which exerts antimicrobial effects against bacteria and fungi. The aim of this study was to investigate the in vitro antifungal activity of low molecular weight chitosan (LMWC), and the potential synergy between chitosan and a currently used antifungal drug, fluconazole. The in vitro minimal inhibitory concentrations (MICs) of chitosan and fluconazole against 105 clinical Candida isolates were measured by the broth microdilution method. LMWC exhibited a significant antifungal activity, inhibiting over 89.9% of the clinical isolates examined (68.6% of which was completely inhibited). The species included several fluconazole-resistant strains and less susceptible species such as C. glabrata, which was inhibited at a concentration of 4.8 mg/l LMWC. Although some strains were susceptible at pH 7.0, a greater antifungal activity of LMWC was observed at pH 4.0. There was no evidence of a synergistic effect of the combination of LMWC and fluconazole at pH 7.0. This is the first report in which the antifungal activity of LMWC was investigated with clinical Candida strains. The use of LMWC as an antifungal compound opens new therapeutic perspectives, as the low toxicity of LMWC in humans supports its use in new applications in an environment of pH 4.0-4.5, such as a topical agent for vulvovaginal candidiasis.

Activity of chitosan antifungal denture adhesive against common Candida species and Candida albicans adherence on denture base acrylic resin

“…In contrast, higher minimum inhibitory concentrations (MIC) have been reported at pH 7.0 for 70-kDa-MW chitosan than at pH 4.0. 30 This may be because of the poorer solubility of most chitosan at neutral pH. Thus, likely because of its water solubility, HMWC is effective at neutral pH and is suitable for oral applications where a neutral environment is more favorable for oral health.…”

“…16,25 Many chitosan derivatives exist, and their properties and antimicrobial activity vary with the molecular weight, degree of deacetylation, pH, and other factors. [26][27][28][29][30] Therefore, several chitosan derivatives with different chemical characteristics should be examined to determine those suitable for each application.…”

Antimicrobial and Anti-Inflammatory Activity of Chitosan–Alginate Nanoparticles: A Targeted Therapy for Cutaneous Pathogens

“…Work by other investigators has shown that chitosan has antimicrobial activities against various pathogens including bacteria, fungi and viruses, suggesting a broad antimicrobial spectrum (Alburquenque et al, 2010; El-Sharif and Hussain, 2011; Jayakumar et al, 2011; Potara et al, 2011; Tayel et al, 2010). Despite distinctive differences between gram-negative and gram-positive bacteria, an antibacterial agent’s first interaction with its target will be at the cell surface, compromising either the cell wall or outer membrane.…”

Biodegradable Chitosan Nanoparticles in Drug Delivery for Infectious Disease

“…Chitosan's antifungal activity has been reported in a variety of fungi [22,[36][37][38][39][40]. The literature does not reveal general trends in fungal inhibition with regard to chitosan's characteristics.…”