Abstract
Purpose :
The identification of infectious pathogens is necessary for proper treatment and management of microbial keratitis (MK). Pathogens are traditionally identified with corneal scraping and plating onto culture media. Recently, broad spectrum pathogen polymerase chain reaction (PCR) assays have been utilized to increase the sensitivity of testing. Our comparative analysis aims to evaluate the performance of traditional culture and PCR with an emphasis on how the rate of positive test is affected through use of PCR in cases of suspected bacterial or fungal MK.
Methods :
Patients who received both PCR and traditional culture upon visit were collected through patient health records from 2022 to 2023. PCR testing was performed using HealthTrackRx (Denton,TX) Ophthalmology assay panel. Traditional culture media included blood, chocolate, and Sabaroud agar, and thioglycollate broth. Detections were classified as positive, which included the identification of bacterial, fungal, and parasitic causative organisms, or negative, in which there were no identified infectious pathogens. The results from both methods were compared.
Results :
A total of 46 patients with suspected MK were examined. The average age was 52 (range 20-83), 55% were male, and 62% were white. There were 26 (57%) positive cultures and 25 positive PCR samples (54%). Together there were 34 patients with positive samples (74%). Of the 46 total comparisons, the findings revealed a 37% agreement rate (17/46) between testing types. In cases where results disagreed, there were 8 cases (17%) of a negative culture result and positive PCR test, and 10 (22%) cases involving both positive culture and PCR results with dissimilar pathogenic detections.
Conclusions :
PCR assay testing showed similar but not superior ability to detect pathogens compared to traditional culture media when testing for MK. When used alongside traditional culture media, PCR testing increases overall chance of positively identifying a causative organism and would aid in the targeted treatment of MK.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.