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Keratitis
Published in Firza Alexander Gronthoud, Practical Clinical Microbiology and Infectious Diseases, 2020
Treatment of Acanthamoeba keratitis is mainly aimed at killing the amoebic cysts as opposed to the more sensitive trophozoites and consists of eye drops with two or three agents: Chlorhexidine 0.02%–0.06%Polyhexanide or polyhexamethylene biguanide (PHMB) 0,02% (most effective against the cysts)Propamidine isethionate (Brolene) of hexamidine
Corneal Ulcers and Contact Lens Keratitis
Published in Amy-lee Shirodkar, Gwyn Samuel Williams, Bushra Thajudeen, Practical Emergency Ophthalmology Handbook, 2019
Acanthamoeba keratitis: If there is some doubt about whether the causative organism is bacterial or protozoal it is much safer to treat as for acanthamoeba than the reverse. Intensive treatment depending on clinical suspicion and local protocols with either: Polyhexamethylene biguanide (PHMB) 0.02% with either hexamidine 0.1% or propamidine 0.1% (Brolene®)orChlorhexidine digluconate (0.02%) and hexamidine 0.1% or propamidine 0.1% (Brolene®)
Acanthamoeba castellanii
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
A diverse group of antimicrobials has been used in the clinical treatment of AK, skin infections, pulmonary cases, and patients with GAE. The drugs for AK are hourly topical application of 0.02% polyhexamethylene biguanide or 0.02% chlorhexidine digluconate, together with a diamidine (0.1% propamidine isethionate, also known as Brolene, or 0.1% hexamidine, also known as Desomedine), for 4–5 days. Subsequently, application is reduced to every 2 hours during the day for up to a month (3,5). This is followed by the application six times a day for the next several months to a year, and even then, the recurrence rate is more than 10%. Patients with AK are given broad-spectrum antibiotics as an adjuvant to prevent secondary bacterial infections. Atropine, a muscarinic receptor antagonist, has been used for extended periods in some cases alone and has been reported to treat a noncomplicated case of AK by mechanisms related to a possible antagonism of muscarinic receptor in Acanthamoeba, as seen in vitro by a similar agent procyclidine (3). Even with the above extensive therapy, the cases of AK usually complicate and result in blindness (Figure 49.2a).
Systemic Miltefosine as an Adjunct Treatment of Progressive Acanthamoeba Keratitis
Published in Ocular Immunology and Inflammation, 2021
Andrea Naranjo, Jaime D. Martinez, Darlene Miller, Rahul Tonk, Guillermo Amescua
A 16-year-old woman with a history of gas-permeable contact-lens wear was referred to our clinic with a 5-month history of presumed HSV keratitis of the left eye. Examination was notable for a punctate epithelial keratitis and mild corneal edema but no KED. Oral acyclovir was continued, and topical prednisolone acetate was started. After several more weeks of treatment, she developed a central epithelial defect and a pronounced ring infiltrate that were suspicious for AK. Corneal biopsy at this time demonstrated cysts on histopathologic analysis. The patient was started on PHMB and chlorhexidine; the latter was changed to propamidine isetionate after 1 month. After 3 months of treatment, her signs and symptoms persisted. Repeat culture was positive for Acanthamoeba. RB-PDAT was performed, and MLT 50 mg twice daily was started.
Acanthamoeba Keratitis: an update on amebicidal and cysticidal drug screening methodologies and potential treatment with azole drugs
Published in Expert Review of Anti-infective Therapy, 2021
Brian Shing, Mina Balen, James H. McKerrow, Anjan Debnath
Reports of propamidine’s minimum trophozoite amebicidal concentration range from values as low as 15.6 μg/mL (1.56 x 10−3%) to estimates as high as 1,000 μg/mL (1 x 10−1%) [35,78]. Its minimum cysticidal concentration has also been reported to be as low as 250 μg/mL (2.5 x 10−2%) and as high as 421 μg/mL (4.21 x 10−2%) [35,67]. Clinically, propamidine and neomycin as a combination therapy has been evaluated and reported to have high efficacy. Hargrave et al (1999) treated Acanthamoeba keratitis patients with 0.1% propamidine solution and neomycin and reported 50 of 60 eyes (83%) resolved successfully [76]. These clinical and in vitro reports suggest propamidine is broadly efficacious against both Acanthamoeba trophozoites and cysts and can be utilized to alleviate Acanthamoeba keratitis.
Acanthamoeba Keratitis: Perspectives for Patients
Published in Current Eye Research, 2021
Stefano Bonini, Antonio Di Zazzo, Giuseppe Varacalli, Marco Coassin
Patients with AK were selected based on a culture-proven Acanthamoeba infection, or histopathological confirmation of trophozoites or cysts, as well as on polymerase chain reaction amoebic-specific genome detection.12–15 Signs and symptoms were recorded and a standard treatment regimen with a combination of 0.1% propamidine isethionate and 0.02% polyhexamethylene biguanide was started once the diagnosis was confirmed.14,16,17 On the basis of their clinical records and corneal images obtained at their first visit, a staging of the AK severity was made according to previous reports.18,19 Briefly, stage I included patients with corneal epitheliopathy; stage II included patients with corneal epithelial defects and stromal or perineural infiltrates; stage III included patients with one or more features of stage II plus a corneal ring infiltrate (Figure 1).19