OBJECTIVES

Acanthamoeba spp. are free-living amoebae commonly found in aquatic environments, with pathogenic genotypes capable of causing severe diseases such as acanthamoeba keratitis and granulomatous amoebic encephalitis. Environmental factors, particularly pH, influence their survival and distribution. Tadlac Lake located at Los Baños, Laguna, Philippines is a Class C freshwater body used for aquaculture, recreation, and irrigation. To date, no study has specifically assessed Acanthamoeba colonization in Tadlac Lake.

In this study, detection of the presence of Acanthamoeba spp. and evaluation of pH as a potential factor influencing their persistence in Tadlac Lake was conducted. One-time sampling was conducted from nine sites of the lake. Surface water samples were collected at a depth of 10–20 cm, filtered through 1.2 μm glass microfiber filters, and cultured on non-nutrient agar plates lawned with live Escherichia coli. Plates were incubated at 30°C for 14 days and examined daily under light microscopy, while pH was measured in situ.

Cyst-like structures resembling amoebae were observed, but these did not exhibit definitive Acanthamoeba morphology under light microscopy. No Acanthamoeba spp. were confirmed and the recorded pH levels ranged from 8.72 to 10.51, exceeding the optimal growth range (7.0–9.0) reported for the organism.

Findings of this study suggest alkaline conditions may have inhibited the proliferation and persistence of Acanthamoeba spp. in the lake. These findings highlight pH as a potential limiting factor for Acanthamoeba survival in alkaline freshwater bodies and underscore the importance of integrating physicochemical monitoring into pathogen surveillance frameworks.

OBJECTIVE

Despite being a preventable and treatable condition, central microbial keratitis (CMK) and its complications remain to be a significant cause of vision loss in our country. This study presents the demographic profile, risk factors, etiologies, treatments, and outcomes of CMK in the Philippines.

The study was a two-center, prospective, non-randomized clinical study involving the patients of the External Disease and Cornea Clinics of two tertiary eye referral centers in the Philippines. It was conducted as the Philippine leg of the Asia Cornea Society Infectious Keratitis Study (ASCIKS).1 Patients with a clinical diagnosis of CMK rendered by a cornea specialist, and who signed the consent form, were recruited into the study. They underwent uniform sample collection and culture techniques as described in the ACSIKS. All patients were followed-up for 6 months. Data collected included demographics, risk factors, culture results, management, and treatment outcomes. Descriptive statistics and frequency were used to analyze the data.

A total of 348 patients diagnosed with CMK were included. Trauma (65.5%) among the middle-aged (42.9 ± 17.9 years) male population was the most significant risk factor for development of CMK, followed by contact lens wear (12.9%), prior ocular surgery (6.0%), and ocular surface diseases (3.4%). Bacterial keratitis (53.2%) was still the most common etiology of CMK, followed by fungal keratitis (27.0%), Acanthamoeba keratitis (5.7%), and viral keratitis (2.0%). Aspergillus species (18.3%) were the most common microbial isolates. Pseudomonas species (13.9%) were the most common bacterial isolates. The median time from onset of symptoms to consultation with the study centers was 2 weeks. Medical treatment was enough to treat the infection in 34.8% of cases. Surgical intervention was necessitated in 22.6% with evisceration/enucleation done in 1 out of 3 patients who had surgery.

Bacterial infection remains the most common cause of CMK in the Philippines, followed by fungal infection. Significant risk factors include trauma and contact lens wear. Aspergillus species and Pseudomonas species were the most common fungal and bacterial isolates, respectively. Despite medical treatment, almost a quarter of the cases still required surgical intervention.

Aspergillus fumigatus ; Cytokines ; Humans ; Interleukin-1beta ; Keratitis ; Receptors, IgE ; Tumor Necrosis Factor-alpha ; Tumor Necrosis Factors

Acanthamoeba Keratitis/epidemiology* ; Hospitals ; Humans ; Referral and Consultation ; Retrospective Studies ; Singapore/epidemiology*

PURPOSE: To analyze clinical aspects in a cohort of patients with Staphylococcus keratitis according to coagulase positivity (coagulase negative Staphylococcus [CNS], coagulase positive Staphylococcus [CPS]). METHODS: Epidemiology, predisposing factors, clinical characteristics, treatment outcomes, and antibiotic susceptibility were comparatively analyzed in 138 cases of culture-proven Staphylococcus keratitis (94 eyes with CNS and 44 eyes with CPS) over 20 years (1998–2017) at Yeungnam University Hospital. Poor clinical outcomes were defined as a final corrected visual acuity <0.1, a decreased visual acuity after treatment, complications, or surgical treatment. Risk factors for poor clinical outcomes were evaluated in the total cohort and analyzed using multivariate logistic regression. RESULTS: The most common predisposing factors were corneal trauma in the CNS group (47.9%) and previous ocular surface disease in the CPS group (31.8%). No significant differences were observed in mean age, sex, previous ocular surface disease, epithelial defect size, and hypopyon between the two groups. Methicillin susceptibility (39.4% vs. 72.7%, p < 0.001) was significantly lower in the CNS group, and poor clinical outcomes (28.0% vs. 43.9%, p = 0.076) were more common in the CPS group. The significant risk factors for poor clinical outcomes were initial best-corrected visual acuity <0.1, epithelial defect size ≥ 5 mm², symptom duration ≥10 days, and hypopyon. CONCLUSIONS: No significant differences were observed in epidemiological factors and initial clinical characteristics between the two study groups, but predisposing factors and methicillin susceptibility differed between the two groups. Treatment outcomes were relatively worse in the CPS group than in the CNS group, but the difference was not statistically significant. Poor clinical outcomes were more associated with long symptom duration and poor initial clinical characteristics than with coagulase positivity.
Causality ; Coagulase ; Cohort Studies ; Corneal Injuries ; Epidemiology ; Humans ; Keratitis ; Logistic Models ; Methicillin ; Risk Factors ; Staphylococcus ; Visual Acuity

No abstract available.
Keratitis

PURPOSE: We report a case of herpes simplex keratitis after Descemet membrane endothelial keratoplasty (DMEK). CASE SUMMARY: A 67-year-old male underwent DMEK in his left eye due to pseudophakic bullous keratopathy. One week after DMEK, re-bubbling was performed due to partial detachment of Descemet's membrane at the corneal periphery. After re-bubbling, the cornea remained clear and the patient's visual acuity gradually improved. Two months after DMEK, the patient presented with mild discomfort and decreased visual acuity. The cornea showed an irregular, narrow dendrite with an epithelial defect and surrounding opacity. After confirming that Descemet's membrane was attached, the patient was started on oral valacyclovir for suspected herpes keratitis. Herpes simplex virus type 1 was eventually identified by polymerase chain reaction. The corneal lesion resolved after three weeks of antiviral treatment. CONCLUSIONS: Similar to penetrating keratoplasty, DMEK can trigger outbreaks of herpes simplex keratitis. Herpes simplex keratitis should remain on the clinician's differential diagnosis for patients who present with a corneal epithelial irregularity and decreased visual acuity following DMEK.
Aged ; Cornea ; Corneal Transplantation ; Dendrites ; Descemet Membrane ; Diagnosis, Differential ; Disease Outbreaks ; Herpes Simplex ; Herpesvirus 1, Human ; Humans ; Keratitis ; Keratitis, Herpetic ; Keratoplasty, Penetrating ; Male ; Polymerase Chain Reaction ; Visual Acuity

PURPOSE: To report polymicrobial keratitis involving Pseudomonas aeruginosa, Acinetobacter baumannii, and Ochrobactrum anthropi. CASE SUMMARY: A 53-year-old female complained of pain and secretion in her right eye, which started 6 weeks before her visit. She applied steroid ointment, which was received from the dermatologist, to her eyelid 7 days prior to her visit but this treatment worsened her symptoms. At the initial visit, the visual acuity of the right eye was light perception, and purulent secretions were observed. Using a slit lamp, severe conjunctival hyperemia, hypopyon, and a ring-shaped central corneal ulcer were observed. The anterior chamber and fundus were not observed due to corneal lesions but ultrasonography showed no intraocular inflammation. Infectious keratitis was suspected and cultured by corneal scraping. During the incubation period, 0.5% moxifloxacin, 2% voriconazole, and 1% cyclopentolate were administered. A total of 400 mg of moxifloxacin and 100 mg of doxycycline were given orally. In the primary culture, Pseudomonas aeruginosa and Acinetobacter baumannii were identified so 5% ceftazidime, which was sensitive for the antibiotic susceptibility results was further instilled. Thereafter, the keratitis improved but the keratitis again worsened while maintaining the topical treatment. A secondary culture was positive for Ochrobactrum anthropi. Treatment with 1.4% gentamicin, which was sensitive for the antibiotic susceptibility test was added and the keratitis improved. A conjunctival flap was performed because of the increased risk of perforation. CONCLUSIONS: We report polymicrobial keratitis involving Pseudomonas aeruginosa, Acinetobacter baumannii, and Ochrobactrum anthropi for the first time in the Republic of Korea.
Acinetobacter baumannii ; Acinetobacter ; Anterior Chamber ; Ceftazidime ; Corneal Ulcer ; Cyclopentolate ; Doxycycline ; Eyelids ; Female ; Gentamicins ; Humans ; Hyperemia ; Inflammation ; Keratitis ; Middle Aged ; Ochrobactrum anthropi ; Ochrobactrum ; Pseudomonas aeruginosa ; Pseudomonas ; Republic of Korea ; Slit Lamp ; Ultrasonography ; Visual Acuity ; Voriconazole

PURPOSE: The purpose of this study was to evaluate the clinical aspects of inpatients with bacterial keratitis according to culture positivity. METHODS: This was a retrospective review of 98 cases of inpatients with bacterial keratitis who were treated between January 2011 and December 2016 in Yeungnam University Hospital. Epidemiology, predisposing factors, clinical characteristics, and treatment outcomes were compared between culture positive (CP, 39 eyes) and culture negative (CN, 59 eyes) groups. Risk factors for poor clinical outcome were evaluated in the total cohort and analyzed using multivariate logistic regression. RESULTS: Pseudomonas spp. (31%) and Staphylococcus spp. (24%) were common in the CP group. There were no significant differences in previous ocular surface disease, contact lens wear, or hypopyon between the two groups. Epithelial defect size ≥5 mm² (51%:31%, p = 0.04) and initial visual acuity <0.1 (Snellen) (51%:31%, p = 0.04) were significantly higher in the CP group than in the CN group. Epithelial healing time ≥14 days (18%:5%, p = 0.08) and poor clinical outcome (28%:20%, p = 0.37) were more common in the CP group than in the CN group. Risk factors for poor clinical outcome were previous ocular surface disease (odds ratio [OR] = 11.29, 95% confidence interval [CI] = 2.01–63.41, p = 0.006) and previous ocular surgery (OR = 6.98, 95% CI = 1.51–32.20, p = 0.01). CONCLUSIONS: The CP group showed relatively worse initial clinical characteristics than the CN group. Treatment outcomes were slightly worse in the CP group than in the CN group; however, this difference was not statistically significant. Previous ocular surface disease and previous ocular surgery were associated with poor clinical outcome.
Bacterial Infections ; Causality ; Cohort Studies ; Corneal Ulcer ; Epidemiology ; Humans ; Inpatients ; Keratitis ; Logistic Models ; Pseudomonas ; Retrospective Studies ; Risk Factors ; Staphylococcus ; Visual Acuity

PURPOSE: To report a case of a Corynebacterium macginleyi-infected corneal ulcer of a patient who had been treated for conjunctivitis for more than 3 months. CASE SUMMARY: A 72-year-old female was transferred from a private ophthalmic clinic for evaluation of herpetic keratitis with progressive corneal edema and infiltration in the left eye. She had a history of conjunctival hyperemia and eyeball pain in her left eye 3 months prior to her visit. She was treated with levofloxacin eye drops and acyclovir ointment (Herpesid®, Samil, Co., Ltd. Seoul, Korea). On slit lamp examination, 5.4 × 4.0 mm corneal epithelial defects and stromal infiltrations were observed in the upper to central cornea, and endothelial keratic precipitates were found. Gram positive bacteria were detected on Gram staining and Corynebacterium macginleyi was identified on bacterial cultures from the conjunctiva and cornea. She was treated with topical vancomycin eye drops. After 3 months of treatment, the corneal ulcer was completely resolved, leaving mild superficial opacity on the cornea. CONCLUSIONS: While Corynebacterium macginleyi, normal flora of the conjunctiva, is considered a major causative agent for conjunctivitis and blepharitis, Corynebacterium macginleyi should also be considered a possible cause of slowly progressive keratitis in patients with chronic conjunctivitis.
Acyclovir ; Aged ; Blepharitis ; Conjunctiva ; Conjunctivitis ; Cornea ; Corneal Edema ; Corneal Ulcer ; Corynebacterium ; Female ; Gram-Positive Bacteria ; Humans ; Hyperemia ; Keratitis ; Keratitis, Herpetic ; Levofloxacin ; Ophthalmic Solutions ; Seoul ; Slit Lamp ; Vancomycin