The First Acanthamoeba keratitis Case of Non-Contact Lens Wearer with HIV Infection in Thailand

Acanthamoeba keratitis (AK) is a rare sight-threatening corneal infection, often reporting from contact lens wearers. An asymptomatic human immunodeficiency virus (HIV)-infected Thai male without history of contact lens use complained foreign body sensation at his left eye during motorbike riding. He had neither specific keratitis symptoms nor common drugs responding, which contributed to delayed diagnosis. By corneal re-scraping, Acanthamoeba-like cysts were detected by calcofluor white staining and agar culture. The etiological agent obtained from the culture was molecularly confirmed by Acanthamoeba spp.-specific PCR, followed by DNA sequencing. The results from BLAST and phylogenetic analysis based on the DNA sequences, revealed that the pathogen was Acanthamoeba T4, the major genotype most frequently reported from clinical isolates. The infection was successfully treated with polyhexamethylene biguanide resulting in corneal scar. This appears the first reported AK case from a non-contact lens wearer with HIV infection in Thailand. Although AK is sporadic in developing countries, a role of free-living Acanthamoeba as an opportunistic pathogen should not be neglected. The report would increase awareness of AK, especially in the case presenting unspecific keratitis symptoms without clinical response to empirical antimicrobial therapy.

Isolation of <i>Acanthamoeba</i> genotype T4 from a non-contact lens wearer from the Philippines

We report a case of a 76-year old Filipino male from the province of Porac, Pampanga who presented with pain, redness, and blurring of vision of the right eye (oculus dexter, OD) on 25 February 2009. One and a half weeks prior to consultation, patient complained of right eye discharge and lid swelling. The patient consulted an ophthalmologist and was given unrecalled topical eye medications. There was no improvement from the symptoms and patient complained of worsening pain and redness in the right eye. The patient was a non-contact lens wearer and he denied any trauma to the right eye. However, he admitted to washing both eyes with tap water. Visual acuity in the right eye was counting fingers at 3 feet. Slit lamp examination showed diffuse conjunctival injection. There was note of a ring-like infiltrate in the cornea almost extending to the limbus. There was also note of significant anterior chamber cells reaction and hypopyon. Primary working impression was Acanthamoeba keratitis (AK), OD. Corneal scraping was done and sent to the St. Luke's Research and Biotechnology for detection and identification of the infectious agent. Morphological detection was done 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 (a partial 18S ribosomal DNA gene) confirmed the morphological identification (band at 461-bp). Genotyping through sequence revealed that the organism belonged to T4, which is the genotype commonly present from the eye of keratitis patients.

Isolation of <i>Acanthamoeba</i> Genotype T4 from a Non-Contact Lens Wearer from the Philippines

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 <i>E. coli</i>. Trophozoites with acanthopodia and double-walled cysts characteristic of <i>Acanthamoeba</i> 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 <i>Acanthamoeba</i>-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.