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Isolation of acanthamoeba genotype t4 from a non-contact lens wearer from the Philippines
Corazon C Buerano1, Abigail D Trinidad2, Lindsay Sydney N Fajardo3
1Department of Virology, Institute of Tropical Medicine, Nagasaki University , Nagasaki, Japan ; Institute of Biology, University of the Philippines , Diliman, Quezon City 1101, Philippines ; Research and Biotechnology, St. Luke's Medical Center , 279 E. Rodriguez Blvd. Quezon City 1112, Philippines.
Abstract:
We report the case of a 76-year old Filipino male who presented with pain, redness, and blurring of vision of the right eye. Corneal scraping was done and sent to the St. Luke's Research and Biotechnology Group for detection and identification of the infectious agent. Morphological detection was performed by allowing the organism from the scraping to grow in 1.5% non-nutrient agar plate with heat-killed E. coli. Trophozoites with acanthopodia and double-walled cysts characteristic of Acanthamoeba were observed within the first and second week of observations, respectively. Molecular identification of the amoebae at the genus level based on the presence of Acanthamoeba-specific amplimer S1, ASA.S1 confirmed the morphological identification. Genotyping through sequence revealed that the organism belonged to T4, which is the genotype commonly present in the eye of keratitis patients.
Insights
Acanthamoeba keratitis was diagnosed in a Filipino male using morphological and molecular methods. The identified T4 genotype is frequently associated with eye infections, highlighting the importance of prompt diagnosis.
Area of Science:
- Ophthalmology
- Infectious Diseases
- Microbiology
Background:
- Acanthamoeba keratitis is a severe eye infection that can lead to vision loss.
- Early and accurate diagnosis is crucial for effective treatment and visual recovery.
Purpose of the Study:
- To identify the causative agent of keratitis in a 76-year-old Filipino male.
- To confirm the diagnosis using both morphological and molecular techniques.
Main Methods:
- Corneal scraping was collected and cultured on non-nutrient agar with heat-killed Escherichia coli.
- Morphological identification of Acanthamoeba trophozoites and cysts.
- Molecular identification using Acanthamoeba-specific amplimer S1, ASA.S1.
- Genotyping of the identified Acanthamoeba isolate.
Main Results:
- Morphological analysis revealed characteristic Acanthamoeba trophozoites with acanthopodia and double-walled cysts.
- Molecular identification confirmed the presence of Acanthamoeba at the genus level.
- Genotyping identified the isolate as belonging to genotype T4, a common genotype in keratitis patients.
Conclusions:
- The study successfully identified Acanthamoeba T4 genotype as the cause of keratitis in the reported case.
- This case underscores the significance of integrating morphological and molecular methods for accurate diagnosis of Acanthamoeba keratitis.
- The prevalence of genotype T4 in ocular infections warrants further investigation into its pathogenic potential.
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