Antimicrobial Action of Biguanides on the Viability ofAcanthamoebaCysts and Assessment of Cell Toxicity

Abstract

We demonstrated that the combined use of biguanides had greater cysticidal activity than individual drug application as well as a possible protective effect on endothelial cells. The biguanide compounds tested were able to induce corneal epithelial cell death in time and concentration-independent fashions. Findings support the hypothesis concerning the cysticidal effect and the differential patterns of toxicity expressed by polyhexamethylene biguanide and chlorhexidine digluconate on the endothelial and corneal cells.

Contact lens care solution killing efficacy against Acanthamoeba castellanii by in vitro testing and live-imaging

“…The second biocide differs among the solutions being polyaminopropyl biguanide, myristamidopropyl dimethylamine and alexidine dihydrochloride for polyquaternium/PHMB-based, OPTI-FREE 1 brands and polyquaternium/ alexidine-based respectively. Each of these agents has been shown to have activity against Acanthamoeba in vitro when tested independently (i.e., not as part of a care solution), although again the extent of the activity is variable depending upon the experimental conditions [39][40][41][42][43][44][45]. This, as well as possible interaction with other solution components, likely contributes to the varying degree of overall effectiveness of each care solution.…”

Optimized combinations of statins and azoles against Acanthamoeba trophozoites and cysts in vitro

“…There are many instances where this applies (e.g. HIV therapy) and this has also been found with Acanthamoeba, where polyhexamethylene biguanide combined effectively with chlorhexidine [4]. This has also been found with various other drug combinations [19].…”

“…In many cases, combinations of therapeutic drugs are found to be more efficient than the individually applied drugs. In the case of Acanthamoeba, this phenomenon has been demonstrated recently using combination of biguanides [4].…”

“…This means that there is an urgent to discover drugs and drug regimens that are active against both trophozoites and cysts of Acanthamoeba [1,2,[4][5][6].…”

Chloroquine Has a Cytotoxic Effect on Acanthamoeba Encystation through Modulation of Autophagy

“…The next day, cells were washed once with PBS and treated with PYG media containing 25, 50, and 100 M concentrations of chloroquine. The cells were incubated for 24 h at 25°C and observed for amoebicidal activity using trypan blue (0.2% final concentration) staining (28). To observe the effect of chloroquine during the encystation process, trophozoites were washed once with PBS and incubated in encystation media containing chloroquine (25,50,60,70,80,90, and 100 M) at 25°C.…”