Polymerase chain reaction in pediatric post-traumatic fungal endophthalmitis among Egyptian children

Abstract

Purpose: The aim of this study was to evaluate the effectiveness of polymerase chain reaction (PCR) in accurate and rapid diagnosis of fungal endophthalmitis in comparison with conventional Gram stain and culture in pediatric fungal endophthalmitis.

Patients and methods: This study included 26 cases with endophthalmitis. Age was less than 16 years old, and all were males with history of ocular trauma and with clinical picture suggestive of fungal endophthalmitis. A prospective nonrandomized study was done. For all cases pars plana vitrectomy was done and sample of vitreous wash was collected from the vitrectomy cassette and was sent for laboratory diagnosis. At the end of surgery, intravitreal injection of 1.0 mg/0.1 mL vancomycin was given. PCR, culture sensitivity and ultrasound were done for all cases. Follow-up of cases by visual acuity, full ophthalmological examination, ultrasound, PCR, and other laboratory investigation. The schedule for follow-up was daily for 1 week, weekly for 1 month, and monthly for 1 year than all data collected and analysed.

Results: The ages ranged from 7 to 16 years old. All cases were males. Seventeen cases had central corneal ulcer, 5 of them with penetration full thickness, and 9 cases had peripheral corneal ulcer, 2 of them with penetration. Ophthalmological examination revealed a marked drop of vision ranging from HM to PL in the affected eye. Although Gram stain gave negative results in 20 cases (was positive in only 6 cases), KOH wet mount preparation revealed septate hyphae in only 4 cases, and culture on blood agar was negative in all samples, suggestive of Aspergillus niger and showing Candida albicans colonies in 8 samples. PCR assay was positive for the universal as well as for the Aspergillus-specific primers, but it was negative for Candida-specific primer in 4 samples. No recurrence of infection was noticed for the following 1 year The mean follow-up period was 10.3 months (range, 5-24 months), but with trivial improvement in visual acuity. The sensitivity of PCR assay was found to be highly significant, p < .0001, much superior to that of microscopy and culture in detecting fungal endophthalmitis.

Conclusion: PCR assay was found to be a highly sensitive and specific test that allows rapid and accurate diagnosis of pediatric fungal endophthalmitis. PCR was found to give a much more sensitive and more rapid result than Gram stain and culture technique with comparable high specificity. Thus, we recommend the use of conventional methods as culture and stained smears as they are useful if positive, inexpensive, and available in all laboratories. This is in addition to PCR assay, which must be added to the protocol of management of cases of pediatric fungal endophthalmitis.