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[Amebicide activity of antiseptics and an antibiotic on 2 Acanthamoeba isolated from corneal ulcers]
C Debbasch1, C Chaumeil, S Quesnot
1Laboratoire de Biologie, C.H.N.O. des Quinze-Vingts, Paris.
Purpose:
To study the in vitro amoebicidal activity of antiseptics and antibiotics.
Methods:
Antiseptics (hexamidine, chlorhexidine, picloxydine, PHMB, polyvidone iodine) and an antibiotic (colimycine) were tested on two Acanthamoeba isolates from corneal ulcers under soft contact lenses. The appearence of trophozoïts and the increase of the number of cysts show their viability.
Results:
Four antiseptics and colimycin proved to be active in vitro on the two Acanthamoeba isolates: hexamidin 0.1% after 3 to 6 hours incubation, picloxydin 0.05% after 1 to 3 hours incubation (Wilcoxon test, p < 0.05), chlorhexidin 0.02% after 3 hours (Wilcoxon test, p < 0.01), PHBM 0.02% after 3 hours (Wilcoxon test, p < 0.01) and colimycin 125,000 Ul/ml after 1 to 3 hours incubation. Polyvidone iodine proved ineffective.
Conclusion:
Our results confirm that hexamidin, chlorhexidin and PHMB have an amoebicidal activity on the two stains, and show that colimycine, which has already been tested, has also an amoebicidal activity; picloxydine is effective after 1 to 3 hours; there is a considerable variability which exists between the isolates and the sensitivity of the isolates is time-dependent. Medical polytherapy is therefore necessary especially if the sensitivity of the Acanthamoeba has not been tested.
Insights
Certain antiseptics and colimycin show in vitro amoebicidal activity against Acanthamoeba. Hexamidine, chlorhexidine, and PHMB are effective, with varying times and isolate sensitivities, suggesting polytherapy may be needed.
Area of Science:
- Ophthalmology
- Microbiology
- Infectious Diseases
Background:
- Acanthamoeba keratitis is a severe corneal infection.
- Treatment options for Acanthamoeba infections are limited.
- Understanding the efficacy of various agents is crucial for effective management.
Purpose of the Study:
- To evaluate the in vitro amoebicidal activity of common antiseptics and an antibiotic.
- To compare the efficacy of different agents against Acanthamoeba isolates.
Main Methods:
- Tested antiseptics (hexamidine, chlorhexidine, picloxydine, PHMB, polyvidone iodine) and colimycin.
- Utilized two Acanthamoeba isolates from corneal ulcers.
- Assessed trophozoite appearance and cyst formation to determine viability.
Main Results:
- Hexamidine (0.1%), chlorhexidine (0.02%), picloxydine (0.05%), PHMB (0.02%), and colimycin (125,000 Ul/ml) demonstrated in vitro amoebicidal activity.
- Polyvidone iodine was ineffective against the tested isolates.
- Activity varied in onset, with picloxydine and colimycin effective within 1-3 hours.
Conclusions:
- Hexamidine, chlorhexidine, and PHMB possess significant amoebicidal properties.
- Colimycin also exhibits amoebicidal activity against Acanthamoeba.
- Isolate variability and time-dependent sensitivity highlight the need for tailored treatment, potentially involving polytherapy.