The reculture technique - Individualizing the treatment of Acanthamoeba keratitis

Purpose. To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique. Me thods. Cysts and trophozoites were immersed in five separate solutions. The solutions administered included 0.1% and 0.02% polyhexamethylene biguanide (PHMB), 0.1% and 0.02% chlorhexidine, and propamidine isethionate (Brolene ). Readings took place after 1, 5, and 24 hours. The cysts and trophozoites were then recultured for an additional period of 48 hours. An effective dr ug was defined as a medication that inhibited any growth of trophozoites us ing the reculture technique. Results. Chlorhexidine at concentrations of 0. 1% and 0.02% was the only effective drug against all five strains of Acanth amoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts i n the five strains examined. Conclusion. We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was e ffective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in am oebic keratitis. Sensitivity testing, then, may be performed using the recu lture technique and specification of therapy can be made accordingly.