Rapid Pathogen Detection in Severe Infectious Keratitis: Prospective Evaluation of Combined Multiplex PCR Panels Versus Standard Microbiology.

INTRODUCTION

Rapid pathogen identification in severe infectious keratitis is critical for targeted therapy to prevent vision loss, but conventional methods are slow and only moderately sensitive. Our objective was to evaluate the diagnostic accuracy and turnaround time of combined FilmArray® Meningitis-Encephalitis (ME)/Blood Culture Identification (BCID) multiplex polymerase chain reaction (PCR) panels versus standard microbiology (culture + pathogen-specific PCR) in severe infectious keratitis.

METHODS

This was a prospective pilot diagnostic study at a French tertiary center (July 2023-April 2025) including 23 adults with severe microbial keratitis. Corneal samples were analyzed using both conventional microbiological testing (culture and pathogen-specific PCR) and rapid multiplex PCR with the FilmArray® ME and BCID panels. Primary outcomes were diagnostic agreement between the FilmArray® multiplex PCR system and conventional microbiological methods, measured by Cohen's κ coefficient. Turnaround times were compared using the Wilcoxon signed-rank test.

RESULTS

Among 23 adult patients (mean age 61.0 [SD 21.2] years, range 24-99; 13 female patients [56.5%]), conventional microbiology identified pathogens in 16 cases (69.5%) versus 15 (65.2%) with multiplex PCR. Overall diagnostic agreement was moderate (κ = 0.50; 95% CI, 0.25-0.76), with perfect concordance (12/12, 100%) for monomicrobial infections detected by both methods. Multiplex PCR significantly reduced mean time to identification (2 h [no variation]) versus conventional methods (102 [SD 42.5] h; P < .001). Both methods were negative in six patients (26.1%) with comparable clinical severity.

CONCLUSION

Combined FilmArray® ME/BCID panels demonstrated complete concordance with standard microbiology for monomicrobial keratitis and reduced turnaround times by > 100 h. This strategy may accelerate targeted therapy, potentially improving visual outcomes.