The reculture technique: individualizing the treatment of Acanthamoeba keratitis.
OBJECTIVE
To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique.


METHODS
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 drug was defined as a medication that inhibited any growth of trophozoites using the reculture technique.


RESULTS
Chlorhexidine at concentrations of 0.1% and 0.02% was the only effective drug against all five strains of Acanthamoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts in the five strains examined.


CONCLUSIONS
We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was effective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in amoebic keratitis. Sensitivity testing, then, may be performed using the reculture technique and specification of therapy can be made accordingly.
Wysenbeek
Y S
YS
Goldschleger Eye Institute, Sheba Medical Center, Tel-Hashomer, Israel.
Blank-Porat
D
D
Harizman
N
N
Wygnanski-Jaffe
T
T
Keller
N
N
Avni
I
I
D000048:Acanthamoeba / Q000187:drug effects* / Q000254:growth & development; D015823:Acanthamoeba Keratitis / Q000188:drug therapy* / Q000469:parasitology; D000293:Adolescent; D000328:Adult; D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage; D001550:Benzamidines / Q000008:administration & dosage*; D001645:Biguanides / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D002710:Chlorhexidine / Q000008:administration & dosage*; D003315:Cornea / Q000469:parasitology*; D003470:Culture Media / Q000494:pharmacology; D004202:Disinfectants / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008297:Male; D009883:Ophthalmic Solutions; D021261:Parasitic Sensitivity Tests / Q000379:methods*
D000981:Antiprotozoal Agents; D001550:Benzamidines; D001645:Biguanides; D003470:Culture Media; D004202:Disinfectants; D009883:Ophthalmic Solutions; C031233:polihexanide; C046651:propamidine isethionate; D002710:Chlorhexidine